1. Unit 4 Learning Objectives

Topics 4.1.-4.4: Cell Signaling, Cell Communication, and Signal Transduction

Describe three ways that cells communicate with one another, and provide examples of each one.
- Cell-to-cell contact (examples: immune signaling, plasmodesmata)
- Short distance signaling using local regulators (examples: neurotransmitters, quorum sensing, morphogens during embryonic development)
- Long-distance signaling (examples: endocrine signaling)
Describe the function of signal transduction
- linking signal reception with a cellular response
List the three components of signal transduction systems
- reception, transduction, response
Describe the key features of reception
- specific receptors — usually membrane proteins — bind with ligands.
Describe the key features of signal transduction
- ligand binding leading to changes in the intracellular domain of a membrane protein;
- propagation of the signal to and through second messengers such as cyclic AMP;
- amplification of the signal through phosphorylation cascades.
List examples of cellular responses that result from signal transduction
- Examples: cell division, secretion of molecules, gene expression, apoptosis.
Explain how changes in the components of a signaling system (ligand, receptor, transduction components) can alter cellular responses.
- Mutations in receptors (changes in shape or number) can affect downstream signal transduction.
- Chemicals interfering with any part of a signaling system component can change transduction.

Topic 4.5: Feedback and Homeostasis

Describe the function of feedback mechanisms
- Maintaining internal environments and responding to internal and external environmental changes.
Define the physiological concept of a set point.
- The value around which a physiological process fluctuates. For example, the temperature set point in humans is 37 degrees C.
Explain how negative feedback helps to maintain homeostasis
- Returning a perturbed system to its target set point.
Explain how positive feedback works
- Amplifying responses and processes in a way that increases the initial stimulus, which further activates the response.

Topic 4.6: Cell Division and the Cell Cycle

Compare and contrast cell division in prokaryotes and eukaryotes
- binary fission v. mitosis
Describe the functions of cell division in eukaryotes
- Asexual reproduction, growth, and repair.
List the phases of the cell cycle, and explain what happens during each phase
- List: interphase, G₁, S, G₂, M
Explain the importance of the G₀ phase.
Describe, on a big-picture level, what happens in mitosis
- Cloning of a parent cell’s entire genome into two genetically identical daughter cells
List and describe the phases of mitosis.

Topic 4.7: Cell Cycle Regulation

Describe how the cell cycle is regulated
- answers should include a general description of internal checkpoints, and how these checkpoints work to control progression through the cycle
Explain how interactions between cyclins and cyclin-dependent kinases control the cell cycle.
Describe how disruptions to the cell cycle can lead to cancer.
- Cancer can result from any process that increases cell division, removes inhibition of cell division, or both.
- Processes that increase cell division are connected to mutations in oncogenes. Processes that remove cell division inhibitors are connected to mutations in tumor suppressor genes.
Define apoptosis
- A regulated process resulting in cell death.

2. Unit 4 Cumulative Flashcards

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[h] Unit 4 Flashcards

[i]

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142764643a3ff9″ question_number=”1″ topic=”4.1.Cell_Communication”] On the most fundamental level, what are the two ways that cells communicate with one another?

[a] Cells can communicate with one another by 1) direct contact, or by 2) sending chemical signals to one another. These chemical signals might travel very short distances between cells that might be close to one another. Or they might travel between distant parts of the body (endocrine signaling), or even between different organisms (pheromone signaling).

*Note: Terms like “paracrine” (or “juxtacrine”) are not important to know. On the other hand, every biology student should know what the endocrine system is. It’s the system of glands that release hormones into the blood.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14274ac7b773f9″ question_number=”2″ topic=”4.1.Cell_Communication”] Describe how cell communication via cell-to-cell contact occurs in plants.

[a] Plant cells can directly communicate via plasmodesmata. These are gaps in the cell walls of adjacent cells. These gaps allow the cell membranes of adjacent cells to form an open channel through which cytoplasm can flow, allowing for the passage of molecules and ions from cell to cell, including ions and molecules that serve as cell signals.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1427153aa5f7f9″ question_number=”3″ topic=”4.1.Cell_Communication”] In terms of cell communication, what’s a “local regulator?” How is this type of signaling different from endocrine signaling?

[a] Local regulators are signaling molecules that work over short distances (but without the cells touching). Endocrine glands, by contrast, release their signals (hormones) into the blood and can have an effect on the most distant parts of the body.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426f94a1747f9″ question_number=”4″] How do neurons (nerve cells) communicate with one another (or with their targets)?

[a] Neurons signal one another (or their targets) by releasing molecules called neurotransmitters (a) across tiny gaps called a synapse (2). The neurotransmitters bind with receptors (d and e) in the second cell.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426e201a05ff9″ question_number=”5″] Local signaling is a key part of embryonic development. Describe how this works.

[a] During embryonic development ligands called morphogens (1) are synthesized and released in one group of cells (A), and then diffuse to nearby cells (B), activating genes or inducing apoptosis (programmed cell death).

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426c61111aff9″ question_number=”6″ topic=”4.1.Cell_Communication”] What’s a biofilm? Explain how bacteria use quorum sensing during biofilm formation.

Illustrative Example, Cell Communication

[a] A biofilm is a slimy matrix of extracellular polymers that improve the ability of bacteria to stick to a substrate (such as your teeth, where they contribute to the formation of dental plaque). As the bacteria form a biofilm, they use quorum sensing to determine when to secrete molecules that provide them with increased virulence and antibiotic resistance, and when to form spores that would enable them to create additional bacterial colonies.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426aec89ac7f9″ question_number=”7″ topic=”4.1.Cell_Communication”] What is quorum sensing?

Illustrative Example, Cell Communication

[a] Quorum sensing is a process by which organisms restrict the expression of certain genes (represented by “4” on the right) until cell density reaches a certain level. That’s because only at that level will the phenotype that results from the expression of these genes be beneficial. The use of quorum sensing has been documented in bacteria, plants, and social insects (but might be more widely used).

[!]4.2 – 4.4. Signal Transduction[/!]

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426952c17fbf9″ question_number=”8″ topic=”4.2-4.Signal_Transduction”] Cell signaling involves 3 key phases. List them.

[a] The three phases of cell signaling are I) reception; II) signal transduction (often with signal amplification), and III) cellular response.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.2-4.Signal_Transduction” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426793b894bf9″ question_number=”9″] On a big-picture level, describe what happens during the reception phase of cell to cell signaling.

[a] During reception a receptor molecule embedded in the cell membrane (2) binds with a signal molecule (1: also called a ligand). This binding is based on complementary shape.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.2-4.Signal_Transduction” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14265d4afa9bf9″ question_number=”10″] Briefly describe what happens during the transduction phase of cell to cell signaling.

[a] During transduction, binding of the ligand with the receptor induces a conformational change in the receptor on its cytoplasmic side, which activates a second messenger, often cyclic AMP (6). This second messenger then interacts with molecules in the cytoplasm (8) in a way that results in cellular response (9)

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.2-4.Signal_Transduction” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1426415a6bebf9″ question_number=”11″] Briefly describe what happens during the response phase of cell signaling.

[a] During the response phase, the amplified signal that arose during transduction (represented by 4 and 5 on the right) finally reaches the target (6). Changes in the target molecule, which often involve the activation of an inactive enzyme, bring about the cellular response.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14260e216653f9″ question_number=”12″ topic=”4.2-4.Signal_Transduction”] Describe how binding of epinephrine with receptors on the surface of liver cells leads to the release of cyclic AMP.

Illustrative Example: Cell communication

[a] Epinephrine (8) binds with a G-protein coupled receptor. Binding causes a change in shape on the cytoplasmic side of the receptor, enabling the receptor to bind with a G protein (2). Binding causes the G protein to release GDP (3) and bind with GTP (9). This activates the G protein, allowing it to move until it hits the membrane-embedded enzyme adenylyl cyclase (4), which converts a molecule of ATP into cyclic AMP (cAMP).

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1425f484e387f9″ question_number=”13″ topic=”4.2-4.Signal_Transduction”] When epinephrine binds with a G-protein coupled receptor in cells in the liver, changes in the membrane result in the release of a second messenger, cyclic AMP. Describe how, as part of the fight or flight response, the release of this second messenger can result in the conversion of glycogen to glucose.

Illustrative Example: Cell communication

[a] Cyclic AMP (5) binds with proteins called kinases (b-k) which activate other kinases in what’s called a phosphorylation cascade. Through signal amplification, millions of target molecules (in this case, glycogen phosphorylase) are activated. As a result, glycogen is hydrolyzed to glucose, which diffuses from the liver into the bloodstream, where it can assist the skeletal muscles as they carry out the fight-or-flight response.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1425d89454d7f9″ question_number=”14″ topic=”4.2-4.Signal_Transduction”] Describe how steroid hormones (such as testosterone or estrogen) work.

Illustrative Example: Cell communication

[a] Steroid hormones (F) are nonpolar, and therefore able to diffuse through the membrane’s phospholipid bilayer and into the cytoplasm. Once there, they bind with mobile cytoplasmic receptors (G). This creates a hormone-receptor complex (H), which can diffuse through nuclear pores and enter the nucleus. There, the hormone-receptor complex can interact with DNA and activate genes. This often causes long-term cellular changes, such as changes associated with puberty, which are caused by steroid hormones such as testosterone and estrogen.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1425bca3c627f9″ question_number=”15″ topic=”4.2-4.Signal_Transduction”] List some of the cellular responses that can be elicited by signal transduction pathways, and provide specific examples.

Illustrative Example: Cell communication

Note: on the AP exam you won’t need to list these by memory, but there could be questions about any of the examples in the answer on the reverse side of this card.

[a] Signal transduction pathways can result in

enzyme activation (epinephrine acting upon liver cells),
cell division (cytokines inducing cell division, which is an important part of mobilizing an immune response).
changes in gene expression (various morphogens activating genes in other cells during development), and
apoptosis (programmed cell suicide, which occurs in a variety of circumstances, including during development).

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.2-4.Signal_Transduction” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14258716b4abf9″ question_number=”16″]Explain how changes in any of the components of a signaling system (ligand, receptor, transduction components) can alter cellular responses.

[a]

Mutations in receptors (changes in shape or number) can affect downstream signal transduction. One such mutation in HER2 receptors is strongly associated with abnormal signaling during cell division, resulting in breast cancer.
Chemicals interfering with any part of a signaling system component can change transduction. This can change cell behavior and growth patterns in tissues and organs.

[!]4.5.Feedback[/!]

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142553ddaf13f9″ question_number=”17″] What are the functions of feedback mechanisms?

[a] Feedback mechanisms allow organisms to maintain homeostasis as they respond to changes within their bodies or in their external environment.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14253a412c47f9″ question_number=”18″] Define the physiological concept of a setpoint.

[a] A setpoint is the value around which a physiological process fluctuates. For example, the setpoint for human body temperature is 37 degrees C. The setpoint for blood glucose is about 90 mg/dL (milligrams/deciliter)

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142520a4a97bf9″ question_number=”19″ topic=”4.5.Feedback”] Explain the difference between positive and negative feedback.

[a] In positive feedback, the output of a system feeds back into the system, increasing the system’s activity and output. Positive feedback drives a biological process (such as childbirth) to a conclusion, after which the system shuts down.

In negative feedback, the output of a system feeds back to the system in a way that decreases the system’s output. Negative feedback is essential in homeostasis, returning a system to its set point.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142504b41acbf9″ question_number=”20″ topic=”4.5.Feedback”] Describe how feedback functions during childbirth.

Illustrative Example: Cell communication

[a] Childbirth is an example of positive feedback. During childbirth, the baby’s head pushes against its mother’s cervix (the tip of the uterus at the end of a female mammal’s vagina), stretching the tissue. Nerve impulses from the cervix to the brain cause secretion of the hormone oxytocin from the pituitary gland into the blood. In the uterus, oxytocin causes the uterine muscles to contract. This pushes the baby’s head against the cervix even more, which feeds back to the pituitary, which secretes more oxytocin, increasing uterine contractions. The process ends when the baby is born.

[q json=”true” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1424ed6ba3e3f9″ question_number=”21″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.5.Feedback”] Describe how feedback functions during fruit ripening.

Illustrative Example: Cell communication

[a] Fruit ripening is an example of positive feedback. As a fruit ripens, a variety of cellular changes occur, one of which is the production of the hormone ethylene, a gas that is released into the surrounding air. Ethylene receptors in nearby fruit bind with the ethylene, inducing them to ripen and produce their own ethylene. Increased concentration of ethylene accelerates the ripening process in all the affected fruit, causing the release of more ethylene, which in turn enhances the ripening process.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1424d17b1533f9″ question_number=”22″ topic=”4.5.Feedback”] Explain how insulin works to maintain blood glucose homeostasis.

Illustrative Example: Homeostasis

[a] When blood glucose levels increase above their optimal set point (about 90mg/dL), Beta cells in the pancreas secrete insulin into the blood. When insulin binds with insulin receptors in tissues in the liver and skeletal muscles, these cells open up glucose channels. Glucose diffuses from the blood into these cells, where it’s converted into glycogen, a polysaccharide. In fat cells, the absorbed glucose is converted into fat. This absorption of blood glucose lowers blood glucose levels back to the set point, and this feeds back to the pancreas, shutting down insulin secretion.

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1424b0e26ebbf9″ question_number=”23″ topic=”4.5.Feedback”] Explain how glucagon works to maintain blood glucose homeostasis.

Illustrative Example: Homeostasis

[a] When blood glucose levels fall, alpha cells in the pancreas secrete glucagon. Glucagon diffuses into the bloodstream. When glucagon binds with receptors in its target cells in the liver and skeletal muscles, it causes these cells to break down glycogen into glucose. The glucose diffuses into the bloodstream, raising blood glucose levels back to the set point. This is detected by cells in the pancreas, which shut down glucagon secretion.

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142476ad4577f9″ question_number=”24″] Sketch a diagram showing how glucagon and insulin maintain blood glucose homeostasis.

Illustrative Example: Homeostasis

Importance for the AP exam: High

[a] Key to unlabeled parts:

A. Glucose set point; D. Insulin; G. Blood glucose falls; J. Glucagon; L. Blood glucose rises.

[!]4.6.Cell Cycle[/!]

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14245abcb6c7f9″ question_number=”25″ topic=”4.6.Cell_Cycle”] List the two major phases of the cell cycle. Then list the sub-phases of each phase. (note: this is not asking you to describe the stages of mitosis, but the entire cycle).

[a] The cell cycle consists of two major phases: Interphase (I) and M Phase. Interphase has 3 sub-phases: G₁, S, and G₂. M Phase has 2 sub-phases: mitosis and cytokinesis.

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14243ecc2817f9″ question_number=”26″ topic=”4.6.Cell_Cycle”] Describe what occurs in each of the three sub-phases of interphase.

[a] Interphase involves three sub-phases.

G₁ is a growth phase in which the cell increases in size. At the end of G₁ is a checkpoint in which the cell checks that everything is ready for DNA replication.
If a cell passes the G₁ checkpoint, it enters the S (synthesis) phase. During this phase, DNA is replicated.
Following S the cell enters into G₂. G₂ involves the continued growth and production of molecules and structures required for the M phase. G₂ ends with another checkpoint.

If the G₂ checkpoint is passed, the cell enters into the M phase (mitosis and cytokinesis)

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1424252fa54bf9″ question_number=”27″ topic=”4.6.Cell_Cycle”] On the big picture level, what does mitosis do? List three of its key functions in living things. Note that in this context, “mitosis” is synonymous with “eukaryotic cell division.”

Importance for the AP exam: High

[a] Mitosis duplicates the chromosomes of a eukaryotic cell, transmitting that cell’s entire genome to its daughter cells. In multicellular organisms, mitosis is how the organism grows and repairs itself. In unicellular eukaryotes, mitosis is how reproduction occurs.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1423e1aa4c77f9″ question_number=”28″ topic=”4.6.Cell_Cycle”] Describe the three phases of mitosis that follow metaphase.

Importance for the AP exam: Medium

[a] During anaphase, the sister chromatids are pulled apart (3), and dragged to opposite ends of the cell. Non-kinetochore microtubules cause the cell to elongate. During telophase, a new nuclear membrane (2) forms around each set of chromosomes. The chromosomes spread out, and a nucleolus appears in each nucleus. During cytokinesis, the cell splits apart into two daughter cells.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.6.Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1423a2cd0b6bf9″ question_number=”29″] Briefly describe the first three stages of mitosis.

[a] During interphase, the cell grows and replicates its DNA. (2). During prophase, the chromosomes (3) condense, the nuclear membrane (2) disintegrates, and a spindle apparatus (1) begins to form. During metaphase, the spindle fibers, pull each chromosome to the cell equator. Each chromosome is doubled, consisting of two sister chromatids.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.6.Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142386dc7cbbf9″ question_number=”30″] Explain the importance of the G₀ phase of the cell cycle.

Importance for the AP exam: Medium

[a] Not all cells go through the entire cycle. Any specialized cell — muscle cells and nerve cells, for example — leaves the cell cycle and enters into what’s called G₀. Cells in G₀ no longer divide. Certain stimuli, however, can induce a cell in G₀ to reenter the cell cycle.

[!]4.7.Regulation of the Cell Cycle[/!]

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14236d3ff9eff9″ question_number=”31″ topic=”4.7.Regulation_of_the_Cell_Cycle”] What are cyclins and cyclin-dependent kinases?

[a] Cyclins are molecules whose concentration rises and falls throughout the cell cycle. Kinases are a class of molecules that activate other molecules, often by phosphorylating them. Cyclin-dependent kinases, or CDKs, are kinases that respond to rising and falling cyclin levels.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1423514f6b3ff9″ question_number=”32″ topic=”4.7.Regulation_of_the_Cell_Cycle”] What can happen when the cell cycle is disrupted?

[a] Disruptions to the cell cycle can cause cells to divide when they’re not supposed to. Abnormally accelerated cell division can lead to cancer. Alternatively, if cells don’t divide correctly during embryonic development, then the pattern of development might be disrupted, leading to developmental abnormalities.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|14230225d6f7f9″ question_number=”33″ topic=”4.7.Regulation_of_the_Cell_Cycle”] What is apoptosis?

[a] Apoptosis is programmed cell death. Unlike cell death which results from traumatic injury, apoptosis is highly regulated. Cells are broken down into cytoplasmic fragments called blebs (at “b” and “c”) that can be consumed by cells of the immune system, preventing cellular debris and enzymes from damaging nearby cells.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1422e889542bf9″ question_number=”34″] Describe the role that checkpoints play in regulating the cell cycle.

Importance for the AP exam: High

[a] Cell cycle checkpoints are moments when the cell “checks” its internal conditions and “decides” whether to progress to the next phase of the cell cycle. If certain molecules are in the right concentration, the cell continues through the cell cycle. If not, the cell moves into G₀ or, in certain cases, initiates apoptosis (programmed cell death). The primary checkpoints occur during G₁, G₂, and M. (“1,” “2,” and “3”).

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1422cc98c57bf9″ question_number=”35″] Explain how interactions between cyclins and cyclin-dependent kinases (CDKs) control the cell cycle.

Importance for the AP exam: High

[a] CDKs are present at a constant level throughout the cell cycle. By contrast, the level of cyclins (of which there are several) rises and falls. When cyclin levels are high, cyclin binds with CDK to form a complex called MPF (maturation promoting factor). MPF allows the cell to pass through the G₂ checkpoint and divide. During M phase, cyclin is broken down, allowing the process to repeat in each daughter cell.

[q json=”true” yy=”4″ unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1422b2fc42aff9″ question_number=”36″] What are the two types of genetic mutations that are connected to cancer?

Importance for the AP exam: High

[a] Disruptions to the cell cycle that increase cell division are often connected to mutations in proto-oncogenes, which mutate to become cancer-causing oncogenes. Disruptions to the cell cycle that remove cell division inhibitors are connected to mutations in tumor suppressor genes.

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|1422970bb3fff9″ question_number=”37″] Using the diagram below, describe how a mutation in the RAS proto-oncogene can induce a noncancerous cell to become cancerous.

[a]

RAS (C) is a G protein. As a proto-oncogene (Image I), RAS only becomes active when an outside growth-factor ligand (A) binds with RAS’s coupled receptor (B). This causes RAS to bind with GTP (D), enabling it to initiate a signaling cascade (E) that results in a transcription factor that results in a protein (I) that promotes cell division (J)

When RAS mutates into an oncogene (Image II), it becomes constitutively active. In this condition (K), RAS can bind with GTP even in the absence of a growth signal (notice the unbound receptor at “J”). Because RAS is always active, the molecule that results in cell division (L) is overproduced, resulting in too much cell division.

[q json=”true” unit=”4.Cell_Communication,_Cell_Cycle,_Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Flashcards Dataset, v2.0|142271caf5bff9″ question_number=”38″] Using the image below, explain how mutations in a tumor suppressor gene such as the p53 gene can contribute to the development of cancer.

[a]

p53 is a tumor suppressor gene. When it’s working, it functions as shown in Image 1. When cells experience DNA damage (A), a signaling cascade (B) activates p53. If the DNA can be repaired, p53 will halt the cell cycle (1) while DNA repair enzymes fix the damage (2). If the damage is too great, p53 will signal the cell to initiate apoptosis.

If mutations lead p53 to become non-functional (C in Image 2) then the cell will continue to divide, even with damaged DNA (A). That will increase the chance of the cell acquiring further mutations that can lead it to become cancerous.

[/qdeck]

3. Unit 4 Cumulative Multiple Choice Quiz 1

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[h] Unit 4 Cumulative Multiple Choice Quiz 1

[i]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234fc2aa9e3339″ question_number=”1″] Plasmodesmata (shown below) are channels through which plants can send chemical signals between one cell and the next.

Researchers are testing the effects of a drug that inhibits the formation of plasmodesmata on plant growth. They tested two concentrations of this drug on the average growth of the plant in five trials.

Which of the following is the best explanation for the effect of this drug?

[c]IFRoZSBkcnVnIG1ha2VzIGl0IG1vcmUgZGlmZmljdWx0IGZvciBtb2xlY3VsZXMgdGhhdCBzdGltdWxhdGUgY2 VsbCBkaXZpc2lvbiB0byBtb3ZlIGZyb20gY2VsbCB0byBjZWxsLCBpbmhpYml0aW5nIHBsYW50IGdyb3d0aC4=[Qq]

[f]IFllcy4gV2l0aG91dCBwbGFzbW9kZXNtYXRhLCBzaWduYWxpbmcgbW9sZWN1bGVzIHdpbGwgYmUgcHJldmVudGVkIGZyb20gbW92aW5nIGZyb20gb25lIGNlbGwgdG8gdGhlIG5leHQuIElmIHRoZXNlIG1vbGVjdWxlcyBzdGltdWxhdGVkIGNlbGwgZGl2aXNpb24sIHRoZW4gcGxhbnQgZ3Jvd3RoIHdvdWxkIGJlIGluaGliaXRlZC4=[Qq]

[c]IFRoZSBkcnVnIG1ha2VzIGl0IGVhc2llciBmb3IgbW9sZWN1bGVzIHRoYXQgc3RpbXVsYXRlIGNlbGwgZGl2aXNpb24gdG8gbW92ZSBmcm9tIGNlbGwgdG8gY2VsbCwgc3RpbXVsYXRpbmcgcGxhbnQgZ3Jvd3RoLg==[Qq]

[f]IE5vLiBQbGFzbW9kZXNtYXRhIGFyZSBjaGFubmVscyBiZXR3ZWVuIGFkamFjZW50IGNlbGxzLiBXaXRob3V0IHBsYXNtb2Rlc21hdGEsIGNlcnRhaW4gc2lnbmFsaW5nIG1vbGVjdWxlcyB3aWxsIGJlIA==cHJldmVudGVkIGZyb20gbW92aW5nIGZyb20gb25lIGNlbGwgdG8gdGhlIG5leHQu[Qq]

[c]IFRoZSBkcnVnIG1ha2VzIGl0IGVhc2llciBmb3IgbW9sZWN1bGVzIHRoYXQgaW5oaWJpdCB0aGUgY2VsbCBjeWNsZSB0byBtb3ZlIGZyb20gY2VsbCB0byBjZWxsLCBpbmhpYml0aW5nIHBsYW50IGdyb3d0aC4=[Qq]

[f]IE5vLiBXaXRob3V0IHBsYXNtb2Rlc21hdGEsIGl0IHdvdWxkIGJlIG1vcmUgZGlmZmljdWx0IGZvciBtb2xlY3VsZXMgdG8gbW92ZSBmcm9tIG9uZSBjZWxsIHRvIHRoZSBuZXh0Lg==[Qq]

[c]IFRoZSBkcnVnIG1ha2VzIGl0IG1vcmUgZGlmZmljdWx0IGZvciBtb2xlY3VsZXMgdGhhdCBpbmhpYml0IHRoZSBjZWxsIGN5Y2xlIHRvIG1vdmUgZnJvbSBjZWxsIHRvIGNlbGwsIGluaGliaXRpbmcgcGxhbnQgZ3Jvd3RoLg==[Qq]

[f]IE5vLiBJZiBpdCB3ZXJlIG1vcmUgZGlmZmljdWx0IGZvciBhIHN1YnN0YW5jZSB0aGF0IGluaGliaXRlZCBjZWxsIGdyb3d0aCB0byBtb3ZlIGZyb20gY2VsbCB0byBjZWxsLCB0aGVuIHRoZSBvdmVyYWxsIGVmZmVjdCBzaG91bGQgYmUgdG8gc3RpbXVsYXRlIHBsYW50IGdyb3d0aCAoYmVjYXVzZSB3ZSYjODIxNztyZSByZW1vdmluZyBhIGdyb3d0aCBpbmhpYml0b3IpLg==

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234fab62274b39″ question_number=”2″] Which of the following mechanisms of cell communication are not found in animal cells?

[c]IGxvbmctZGlzdGFuY2Ugc2lnbmFsaW5nIHRocm91Z2ggaG9ybW9uZXMgdGhhdCBiaW5kIHRvIHJlY2VwdG9ycyBpbiB0YXJnZXQgY2VsbHM=[Qq]

[f]IE5vLiBMb25nLWRpc3RhbmNlIHNpZ25hbGluZyAoaWxsdXN0cmF0ZWQgaW4gJiM4MjIwOzEmIzgyMjE7IGJlbG93KSBpcyBhbiBpbXBvcnRhbnQgcGFydCBvZiBjZWxsIGNvbW11bmljYXRpb24gaW4gYW5pbWFscy4gSXQmIzgyMTc7cyBob3cgaG9ybW9uZXMgd29yay4=

Cg==

[Qq]

[c]IGRpcmVjdCBjZWxsLXRvLWNlbGwgY29udGFjdA==[Qq]

[f]IE5vLiBEaXJlY3QgY2VsbC10by1jZWxsIGNvbnRhY3QgKGlsbHVzdHJhdGVkIGluICYjODIyMDs0JiM4MjIxOyBiZWxvdykgaXMgYW4gaW1wb3J0YW50IHBhcnQgb2YgY2VsbCBjb21tdW5pY2F0aW9uIGluIGFuaW1hbHMu

Cg==

[Qq]

[c]IHRyYW5zZmVyIG9mIHNpZ25hbGluZyBtb2 xlY3VsZXMgdmlhIHBsYXNtb2Rlc21hdGE=[Qq]

[f]IEV4Y2VsbGVudC4gUGxhc21vZGVzbWF0YSAoc2hvd24gYmVsb3cpIGFyZSBmb3VuZCBpbiBwbGFudCBjZWxscywgbm90IGFuaW1hbCBjZWxscw==

Cg==

[Qq]

[c]IHNob3J0LWRpc3RhbmNlIHNpZ25hbGluZyB0aHJvdWdoIHRoZSByZWxlYXNlIG9mIGxpZ2FuZHMgdGhhdCBiaW5kIHRvIG5lYXJieSByZWNlcHRvcnMu[Qq]

[f]IE5vLiBTaG9ydC1kaXN0YW5jZSBzaWduYWxpbmcgdGhyb3VnaCB0aGUgcmVsZWFzZSBvZiBsaWdhbmRzIHRoYXQgYmluZCB0byBuZWFyYnkgcmVjZXB0b3JzLsKgIChpbGx1c3RyYXRlZCBpbiAmIzgyMjA7MiYjODIyMTsgYmVsb3cpIGlzIGFuIGltcG9ydGFudCBwYXJ0IG9mIGNlbGwgY29tbXVuaWNhdGlvbiBpbiBhbmltYWxzLiBUaGlzIHR5cGUgb2Ygc2lnbmFsaW5nIHBsYXlzIGEga2V5IHJvbGUgaW4gdGhlIG5lcnZvdXMgYW5kIGltbXVuZSBzeXN0ZW1zLg==

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.2-3.Signal_Transduction” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f966dbc4739″ question_number=”3″] During many cell signaling processes, the enzyme adenylyl cyclase converts the molecule below into an important second messenger.

As part of this conversion, which bond is broken?

[c]IEEg[Qq][c]IE Ig[Qq][c]IEMg[Qq][c]IEQg[Qq][c]IEU=

Cg==[Qq]

[f]IE5vLiBCcmVha2luZyBib25kICYjODIyMDtBJiM4MjIxOyB3b3VsZCByZXN1bHQgaW4gQURQIChhZGVub3NpbmUgZGlwaG9zcGhhdGUpLiBIZXJlJiM4MjE3O3MgYSBoaW50OiB0aGUgc2Vjb25kIG1lc3NlbmdlciYjODIxNztzIG5hbWUgaXMgY3ljbGljIGFkZW5vc2luZSBtb25vcGhvc3BoYXRlIChjQU1QKS4gSGVyZSYjODIxNztzIHdoYXQgaXQgbG9va3MgbGlrZS4=

Cg==

[Qq]

[f]IEV4Y2VsbGVudC4gQnJlYWtpbmcgYm9uZCAmIzgyMjA7QiYjODIyMTsgaXMgcGFydCBvZiB0aGUgcHJvY2VzcyBieSB3aGljaCBhZGVueWx5bCBjeWNsYXNlIGNvbnZlcnRzIEFUUCBpbnRvIGN5Y2xpYyBhZGVub3NpbmUgbW9ub3Bob3NwaGF0ZSAoY0FNUCksIHNob3duIGJlbG93Lg==

Cg==

[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50IGZvciB0aGUgbmV4dCB0aW1lIHlvdSBzZWUgdGhpcyBxdWVzdGlvbi4gVGhlIHNlY29uZCBtZXNzZW5nZXImIzgyMTc7cyBuYW1lIGlzIA==Y3ljbGljIGFkZW5vc2luZSBtb25vcGhvc3BoYXRlIChjQU1QKS4gSGVyZSYjODIxNztzIHdoYXQgaXQgbG9va3MgbGlrZS4=

Cg==

[Qq]

Cg==

[Qq]

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.2-3.Signal_Transduction” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f8179514339″ question_number=”4″] Epinephrine, also known as adrenaline, is produced by the adrenal glands. The structural formula for epinephrine is shown below.

Diagrams “S” and “T” below are general models for signal reception and transduction.

Which of the following correctly identifies and explains the model that corresponds to how epinephrine works?

[c]IE1vZGVsICYjODIyMDtTLCYjODIyMTsgYmVjYXVzZSBpdCBzaG93cyBlcGluZXBocmluZSBkaWZmdXNpbmcgdGhyb3VnaCB0aGUgY2VsbCBtZW1icmFuZSBhbmQgYWN0aXZhdGluZyBnZW5lcy4=[Qq]

[f]IE5vLiBFcGluZXBocmluZSBpcyBwb2xhciwgd2hpY2ggeW91IGNhbiB0ZWxsIGJ5IHRoZSDigJRPSCBncm91cHMgKGh5ZHJveHlsIGdyb3VwcykgdGhhdCBhcmUgYSBwYXJ0IG9mIGl0cyBzdHJ1Y3R1cmUuIEFzIGEgcmVzdWx0LCBpdCB3b3VsZG4mIzgyMTc7dCBiZSBhYmxlIHRvIGRpZmZ1c2UgdGhyb3VnaCB0aGUgbWVtYnJhbmUu[Qq]

[c]IE1vZGVsICYjODIyMDtTLCYjODIyMTsgYmVjYXVzZSBpdCBzaG93cyBlcGluZXBocmluZSBiaW5kaW5nIHdpdGggYSBjeXRvcGxhc21pYyByZWNlcHRvci4=[Qq]

[c]IE1vZGVsICYjODIyMDtULCYjODIyMTsgYmVjYXVzZSBpdCBzaG93cyBlcGluZXBocmluZSBwaG9zcGhvcnlsYXRpbmcgYSByZWxheSBtb2xlY3VsZS4=[Qq]

[f]IE5vLiBCZWNhdXNlIGVwaW5lcGhyaW5lIGlzIHBvbGFyLCBpdCBhY3RzIGJ5IGJpbmRpbmcgdG8gYSBtZW1icmFuZSByZWNlcHRvci4gQWZ0ZXIgYmluZGluZywgdGhlIHRyYW5zbWVtYnJhbmUgcmVjZXB0b3IgYWN0aXZhdGVzIGEgc2Vjb25kIG1lc3NlbmdlciB0aGF0IGlzIHJlc3BvbnNpYmxlIGZvciBpbml0aWF0aW5nIGEgc2lnbmFsIHRyYW5zZHVjdGlvbiBjYXNjYWRlIHRoYXQgZW5kcyBpbiBhIGNlbGx1bGFyIHJlc3BvbnNlLg==[Qq]

[c]IE1vZGVsICYjODIyMDtULCYjODIyMTsgYmVjYXVzZSBpdCBzaG93cyBlcG luZXBocmluZSBiaW5kaW5nIHdpdGggYSBtZW1icmFuZSByZWNlcHRvci4=[Qq]

[f]IFdheSB0byBnby4gQmVjYXVzZSBlcGluZXBocmluZSBpcyBwb2xhciwgaXRzIG1lY2hhbmlzbSBpcyB0byBiaW5kIHdpdGggYSBtZW1icmFuZSByZWNlcHRvci4gQWZ0ZXIgZXBpbmVwaHJpbmUgYmluZHMgd2l0aCB0aGUgbWVtYnJhbmUgcmVjZXB0b3IsIGEgc2Vjb25kIG1lc3NlbmdlciBpcyByZXNwb25zaWJsZSBmb3IgaW5pdGlhdGluZyBhIHNpZ25hbCB0cmFuc2R1Y3Rpb24gY2FzY2FkZSB0aGF0IHBob3NwaG9yeWxhdGVzIHJlbGF5IG1vbGVjdWxlcywgYWN0aXZhdGluZyBhIGNlbGx1bGFyIHJlc3BvbnNlLg==

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f6c84e63f39″ question_number=”5″ topic=”4.2-3.Signal_Transduction”] The image below represents a signal transduction pathway. Which letter could represent a hormone?

[c]IE Eg[Qq][c]IEIg[Qq][c]IEMg[Qq][c]IEQ=

Cg==[Qq]

[f]IEV4YWN0bHkuICYjODIyMDtBJiM4MjIxOyB3b3VsZCByZXByZXNlbnQgYSBob3Jtb25lLg==[Qq]

[f]IE5vLiAmIzgyMjA7QiYjODIyMTsgaXMgdGhlIHJlY2VwdG9yLiBUaGUgaG9ybW9uZSBpcyB0aGUgbW9sZWN1bGUgdGhhdCBiaW5kcyB3aXRoIHRoZSByZWNlcHRvci4=[Qq]

[f]IE5vLiBJZiB0aGlzIGRpYWdyYW0gd2VyZSBhIHJlcHJlc2VudGF0aW9uIG9mIGEgRy1jb3VwbGVkIHJlY2VwdG9yLCB0aGUgbGV0dGVyICYjODIyMDtDJiM4MjIxOyB3b3VsZCByZXByZXNlbnQgYSBHIHByb3RlaW4uIFRoZSBHIHByb3RlaW4mIzgyMTc7cyBmdW5jdGlvbiBpcyB0byBhY3RpdmF0ZSBhIHNlY29uZCBtZXNzZW5nZXIgdGhhdCB3b3VsZCBzZW5kIGEgbWVzc2FnZSB0aHJvdWdoIHZhcmlvdXMgcmVsYXkgbW9sZWN1bGVzIGluIHRoZSBjeXRvcGxhc20gdG8gYWN0aXZhdGUgYSBjZWxsdWxhciByZXNwb25zZS4gVGhlIGhvcm1vbmUgaXMgdGhlIG1vbGVjdWxlIHRoYXQgYmluZHMgd2l0aCB0aGUgcmVjZXB0b3Iu[Qq]

[f]IE5vLiBJZiB0aGlzIGRpYWdyYW0gd2VyZSBhIHJlcHJlc2VudGF0aW9uIG9mIGEgRy1jb3VwbGVkIHJlY2VwdG9yLCB0aGUgbGV0dGVyICYjODIyMDtEJiM4MjIxOyB3b3VsZCByZXByZXNlbnQgYSBzZWNvbmQgbWVzc2VuZ2VyIG9yIGFuIGVudGlyZSBwaG9zcGhvcnlsYXRpb24gY2FzY2FkZS4gVGhlIGhvcm1vbmUgaXMgdGhlIG1vbGVjdWxlIHRoYXQgYmluZHMgd2l0aCB0aGUgcmVjZXB0b3Iu

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f57907b3b39″ question_number=”6″ topic=”4.2-3.Signal_Transduction”] In the image below, which letter represents a receptor?

[c]IEEg[Qq][c]IE Ig[Qq][c]IEMg[Qq][c]IEQ=

Cg==[Qq]

[f]IE5vLiBBIGlzIHRoZSBsaWdhbmQuIFlvdSYjODIxNztyZSBsb29raW5nIGZvciB0aGUgcmVjZXB0b3IsIHdoaWNoIGlzIHRoZSBtZW1icmFuZSBwcm90ZWluIHRoYXQgYmluZHMgd2l0aCB0aGUgbGlnYW5kLg==[Qq]

[f]IENvcnJlY3QhICYjODIyMDtCJiM4MjIxOyBpcyB0aGUgcmVjZXB0b3Iu[Qq]

[f]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[Qq]

[f]IE5vLiBJZiB0aGlzIGRpYWdyYW0gd2VyZSBhIHJlcHJlc2VudGF0aW9uIG9mIGEgRy1jb3VwbGVkIHJlY2VwdG9yLCB0aGUgbGV0dGVyICYjODIyMDtEJiM4MjIxOyB3b3VsZCByZXByZXNlbnQgdGhlIGFjdGl2aXR5IG9mIGEgc2Vjb25kIG1lc3Nlbmdlciwgb3IgYW4gZW50aXJlIHBob3NwaG9yeWxhdGlvbiBjYXNjYWRlLiBZb3UmIzgyMTc7cmUgbG9va2luZyBmb3IgdGhlIHJlY2VwdG9yLCB3aGljaCBpcyB0aGUgbWVtYnJhbmUgcHJvdGVpbiB0aGF0IGJpbmRzIHdpdGggdGhlIGxpZ2FuZC4=

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f4048045339″ question_number=”7″ topic=”4.2-3.Signal_Transduction”] In the diagram below, which stage represents reception?

[c]IE kg[Qq][c]IElJIA==[Qq][c]IElJSSA=[Qq][c]IElWIA==[Qq][c]IFY=

Cg==[Qq]

[f]IE5pY2UhIFN0YWdlIEkgaXMgcmVjZXB0aW9uLg==[Qq]

[f]IE5vLiBTdGFnZSBJSSBpcyB0cmFuc2R1Y3Rpb24uIFJlY2VwdGlvbiBpcyB3aGVuIHRoZSBsaWdhbmQgKHVzdWFsbHkgYSBob3Jtb25lKSBiaW5kcyB3aXRoIGEgcmVjZXB0b3IgKHVzdWFsbHkgb24gdGhlIG1lbWJyYW5lKS4=[Qq]

[f]IE5vLiBTdGFnZSBJSUkgaXMgcmVzcG9uc2UuIFJlY2VwdGlvbiBpcyB3aGVuIHRoZSBsaWdhbmQgKHVzdWFsbHkgYSBob3Jtb25lKSBiaW5kcyB3aXRoIGEgcmVjZXB0b3IgKHVzdWFsbHkgb24gdGhlIG1lbWJyYW5lKS4=[Qq]

[f]IE5vLiBJbiBzdGFnZSBJViwgc29tZXRoaW5nIHRoYXQgbGVmdCB0aGUgbnVjbGV1cyAoNSkgaXMgaGVhZGVkIHRvd2FyZCB0aGUgR29sZ2kgYXBwYXJhdHVzLiBSZWNlcHRpb24gaXMgd2hlbiB0aGUgbGlnYW5kICh1c3VhbGx5IGEgaG9ybW9uZSkgYmluZHMgd2l0aCBhIHJlY2VwdG9yICh1c3VhbGx5IG9uIHRoZSBtZW1icmFuZSku[Qq]

[f]IE5vLiBJbiBzdGFnZSBWLCBzb21ldGhpbmcgaXMgYmVpbmcgZXhwb3J0ZWQgZnJvbSB0aGUgY2VsbCAod2hpY2ggaXMgcGFydCBvZiB0aGUgY2VsbHVsYXIgcmVzcG9uc2UpLiBSZWNlcHRpb24gaXMgd2hlbiB0aGUgbGlnYW5kICh1c3VhbGx5IGEgaG9ybW9uZSkgYmluZHMgd2l0aCBhIHJlY2VwdG9yICh1c3VhbGx5IG9uIHRoZSBtZW1icmFuZSku

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f2b53994f39″ question_number=”8″] Tumor suppressor genes inhibit cell division. Proto-oncogenes promote cell division. When proto-oncogenes mutate, they can become oncogenes that cause uncontrolled cell division, leading to cancer.

Which of the following statements is true of the two models shown below?

[c]IE1vZGVsIDEgaXMgYSBmdW5jdGlvbmluZyB0dW1vciBzdXBwcmVzc29yIGdlbmUuIE1vZGVsIDIgaXMgYSBwcm90by1vbmNvZ2VuZS4=[Qq]

[f]IE5vLiBZb3UmIzgyMTc7cmUgcmlnaHQgYWJvdXQgTW9kZWwgMS4gQnV0IG5vdGljZSBob3cgTW9kZWwgMiBzaG93cyBjYW5jZXIgc2lnbmFsaW5nIGluIHRoZSBhYnNlbmNlIG9mIGEgbGlnYW5kIGJpbmRpbmcgdG8gYSByZWNlcHRvci4gVGhhdCBtZWFucyB0aGF0IGEgbm9ybWFsIHNpZ25hbGluZyBwYXRod2F5IHRoYXQgd291bGQgcmVzdWx0IGluIGNlbGwgZGl2aXNpb24gaXMgbm93IA==YWx3YXlzIHNpZ25hbGluZyBmb3IgdGhlIGNlbGwgdG8gZGl2aWRlLg==[Qq]

[c]IE1vZGVsIDEgaXMgYSBtdXRhdGVkIChub24tZnVuY3Rpb25hbCkgdHVtb3Igc3VwcHJlc3NvciBnZW5lLiBNb2RlbCAyIGlzIGEgcHJvdG8tb25jb2dlbmUu[Qq]

[f]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[Qq]

[c]IE1vZGVsIDEgaXMgYSBmdW5jdGlvbmluZyB0dW1vciBzdXBw cmVzc29yIGdlbmUuIE1vZGVsIDIgaXMgYW4gb25jb2dlbmUu[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234f140b226739″ question_number=”9″] The image below is a model of a cell-signaling malfunction associated with cancer. The difference between the model below and a model of a non-cancerous cell involves

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234efcc2ab7f39″ question_number=”10″] Insulin is a hormone produced by the pancreas in response to high blood glucose levels. The diagram below shows a model of insulin activity in normal cells. IRS-1, PI 3 Kinase, PDK, and AKT are signaling molecules. GLUT-4 is a membrane protein involved in glucose transport.

In type 2 diabetes, insulin is produced by the pancreas, but liver, muscle, and fat cells fail to absorb glucose from the bloodstream and convert it into glycogen or fat.

To understand the cellular basis of type 2 diabetes, a team of researchers compared cellular activity in normal mice and a strain of diabetic mice. Some of their findings are shown below.

Based on the model above and the researchers’ findings, what is the most likely cause of type 2 diabetes?

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234ee57a349739″ question_number=”11″] To maintain blood osmolarity at an optimal level, humans and other animals can mobilize membrane channels called aquaporins to the cells making up the collecting ducts of nephrons, the tubules that make up the kidneys (the organs that create urine). When the collecting duct cells have many aquaporins, water leaves the collecting ducts and gets reabsorbed into the blood. As a result, only a small volume of urine leaves the body, and that urine is highly concentrated with solutes such as urea.

Which environmental conditions would cause a mammal’s kidneys to mobilize the most aquaporins to the collecting ducts of their nephrons?

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Cg==

[Qq]

If a wolf is unable to get food for many hours, the system would lead the

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[f]IE5vLiBJZiB0aGUgd29sZiBnb2VzIGhvdXJzIHdpdGhvdXQgZWF0aW5nLCBpdHMgZ2x1Y29zZSB3aWxsIGZhbGwgYmVsb3cgdGhlIHNldCBwb2ludC4gSW4gdGhhdCBjYXNlLCB3aGF0IGhvcm1vbmUgaXMgcmVsZWFzZWQ/

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234ea8f0ff6f39″ question_number=”13″ unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback”] Like humans, elephants maintain a relatively constant body temperature.

Which of the following actions would have the greatest effect on decreasing the body temperature of an elephant in extremely hot conditions?

[c]IEZsYXBwaW5nIH RoZWlyIGVhcnM=[Qq]

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[c]IEh1ZGRsaW5nIHdpdGggb3RoZXIgZWxlcGhhbnRz[Qq]

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[c]IERlY3JlYXNpbmcgYmxvb2QgZmxvdyB0byB0aGUgZWFycw==[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6.Cell_Cycle” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234e91a8888739″ question_number=”14″] Colchicine is a drug that binds to tubulin, the protein subunits that make up microtubules. By binding to tubulin, colchicine prevents microtubules from forming. As a result, dividing cells that are exposed to colchicine are unable to form spindle fibers.

When a culture of dividing cells that are exposed to colchicine is examined under a microscope, the last possible phase of mitosis that can be observed would be

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Cg==

[Qq]

[c]IHByb3 BoYXNl[Qq]

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[c]IG1ldGFwaGFzZQ==[Qq]

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Cg==

[Qq]

[c]IGFuYXBoYXNl[Qq]

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Cg==

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Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234e7363edf339″ question_number=”15″ topic=”4.6.Cell_Cycle”] The image below shows stages of cell division, but not necessarily in the correct order. Which of the following lists the correct sequence?

[c]IDEtMi0zLTQ=[Qq]

[f]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[Qq]

[c]IDItMS00LTM=[Qq]

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[c]IDQtMi0zLTE=[Qq]

[f]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[Qq]

[c]IDMtMi 00LTE=[Qq]

[f]IEV4Y2VsbGVudCEgTmljZSBqb2IgaWRlbnRpZnlpbmcgdGhlIGNvcnJlY3Qgc2VxdWVuY2Ugb2YgZXZlbnRzOiBudWNsZWFyIG1lbWJyYW5lIGRpc2ludGVncmF0aW9uLCBjaHJvbW9zb21lIGNvbmRlbnNhdGlvbiwgYWxpZ25tZW50IGluIHRoZSBtaWRkbGUsIHRoZW4gc2VwYXJhdGlvbiAob3IsIGlmIHlvdSYjODIxNzt2ZSBsZWFybmVkIHRoZSBuYW1lIG9mIHRoZSBwaGFzZXM6IGVhcmx5IHByb3BoYXNlLCBsYXRlIHByb3BoYXNlLCBtZXRhcGhhc2UsIGFuYXBoYXNlKS4=

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234e5c1b770b39″ question_number=”16″] The diagram below shows some of the cellular events associated with apoptosis (programmed cell death) in nematode worms. Cell 1 is not undergoing apoptosis, but Cell 2 is.

A characteristic of cancer cells is their lack of apoptosis. Because of homologies between the signaling pathways in nematode works and pathways found in human cells, a researcher is proposing that the lack of apoptosis in cancer cells is most likely a result of

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[c]IEluY3JlYXNlZCBzaWduYWxpbmcgYmV0d2VlbiBDZWQtNCwgQ2VkLTMgYW5kIHRoZSBhcG9wdG9zaXMgcGF0aHdheS4=[Qq]

[f]IE5vLiBJbmNyZWFzZWQgc2lnbmFsaW5nIGJldHdlZW4gQ2VkLTQsIENlZC0zLCBhbmQgdGhlIGFwb3B0b3NpcyBwYXRod2F5IHdvdWxkIGluY3JlYXNlIGFwb3B0b3Npcy4gRmluZCBzb21ldGhpbmcgdGhhdCB3b3VsZCA=ZGVjcmVhc2U=IGFwb3B0b3Npcy4=[Qq]

[c]IEluY3JlYXNlZCBwcm9kdWN0aW9uIG9mIGJsZWJzIChjeXRvcGxhc21pYyBmcmFnbWVudHMpLg==[Qq]

[f]IE5vLiBCbGViYmluZyBpcyBwYXJ0IG9mIHRoZSBwcm9jZXNzIG9mIGFwb3B0b3Npcy4gSW5jcmVhc2VkIGJsZWJiaW5nIHdvdWxkIGJlIGFzc29jaWF0ZWQgd2l0aCBpbmNyZWFzZWQgYXBvcHRvc2lzLiBGaW5kIHNvbWV0aGluZyB0aGF0IHdvdWxkIA==ZGVjcmVhc2U=IGFwb3B0b3Npcy4=

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234e44d3002339″ question_number=”17″] Which of the following correctly pairs a cell cycle checkpoint with its function?

[c]IEc=_MQ==IGNoZWNrcG9pbnQgJiM4MjExOyBlbnN1cmVzIHRoYXQgc3BpbmRsZSBmaWJlcnMgYXJlIHByb3Blcmx5IGF0dGFjaGVkIGJlZm9yZSBhbmFwaGFzZQ==[Qq]

[f]IE5vLiBUaGUgRw==_MQ==IGNoZWNrcG9pbnQgb2NjdXJzIGJlZm9yZSBETkEgcmVwbGljYXRpb24gKFMgcGhhc2UpIGFuZCBzcGluZGxlIGZvcm1hdGlvbiAoTSBwaGFzZSkuIFRoZSBH_MQ==IGNoZWNrcG9pbnQgY2hlY2tzIGZvciBjZWxsIHNpemUsIG51dHJpZW50IGF2YWlsYWJpbGl0eSwgRE5BIGRhbWFnZSwgYW5kIG90aGVyIGZhY3RvcnMgdGhhdCBtYXkgaW5mbHVlbmNlIHdoZXRoZXIgdGhlIGNlbGwgc2hvdWxkIGNvbnRpbnVlIGludG8gdGhlIFMgcGhhc2Ugb2YgdGhlIGNlbGwgY3ljbGUu

[Qq]

[c]IE c=_Mg==IGNoZWNrcG9pbnQgJiM4MjExOyBlbnN1cmVzIHRoYXQgRE5BIHJlcGxpY2F0aW9uIGhhcyBiZWVuIGNvbXBsZXRlZCBiZWZvcmUgdGhlIGNlbGwgZGl2aWRlcy4=[Qq]

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[f]IE5vLiBUaGUgTSBjaGVja3BvaW50IGVuc3VyZXMgdGhhdCBhbGwgY2hyb21vc29tZXMgYXJlIHByb3Blcmx5IGF0dGFjaGVkIHRvIHNwaW5kbGUgZmliZXJzIGJlZm9yZSB0aGUgY2VsbCBwcm9ncmVzc2VzIHRvIGFuYXBoYXNlLiBUaGVyZSBpcyBubyBtb25pdG9yaW5nIG9mIG1pdG9jaG9uZHJpYWwgZGlzdHJpYnV0aW9uIGJlZm9yZSBtaXRvc2lzLg==

Cg==

[Qq]

[c]IFMgY2hlY2twb2ludCAmIzgyMTE7IGNoZWNrcyBmb3IgRE5BIGRhbWFnZSBiZWZvcmUgdGhlIGNlbGwgcmVwbGljYXRlcyBpdHMgRE5BLg==[Qq]

[f]IE5vLiBUaGUgRw==_MQ==IGNoZWNrcG9pbnQgaXMgd2hlcmUgdGhlIGNlbGwgY2hlY2tzIGZvciBETkEgZGFtYWdlLiBUaGUgUyBjaGVja3BvaW50IGVuc3VyZXMgdGhhdCBETkEgcmVwbGljYXRpb24gaGFzIGJlZW4gY29tcGxldGVkIGJlZm9yZSB0aGUgY2VsbCBlbnRlcnMgdGhlIG5leHQgcGhhc2UgKEc=_Mg==KQ==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234e28e2717339″ question_number=”18″] Note: This question is part of a series. If you’ve already seen this text and diagram, feel free to skip down to the question that’s below the diagram. Cyclins control the cell cycle and trigger specific cyclin-dependent kinases at the peak of their concentration. They are subsequently degraded by a regulatory protein called ubiquitin.

Which cyclin is likely to be involved in signaling proper attachment of spindle fibers to chromosomes?

[c]IEN5Y2xpbiBB[Qq]

[f]IE5vLiBDeWNsaW4gQSBwZWFrcyBkdXJpbmcgRw==_Mg==LiBIZXJlJiM4MjE3O3MgYSBoaW50LiBXaGVuIGluIHRoZSBjZWxsIGN5Y2xlIGRvIHNwaW5kbGUgZmliZXJzIGF0dGFjaCB0byBjaHJvbW9zb21lcz8=

Cg==

[Qq]

[c]IEN5Y2 xpbiBC[Qq]

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Cg==

[Qq]

[c]IEN5Y2xpbiBF[Qq]

[f]IE5vLiBDeWNsaW4gRSBwZWFrcyBhdCB0aGUgYmVnaW5uaW5nIG9mIFMgcGhhc2UuIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFdoZW4gaW4gdGhlIGNlbGwgY3ljbGUgZG8gc3BpbmRsZSBmaWJlcnMgYXR0YWNoIHRvIGNocm9tb3NvbWVzPw==

Cg==

[Qq]

[c]IEN5Y2xpbiBE[Qq]

[f]IE5vLiBDeWNsaW4gRCBwZWFrcyBkdXJpbmcgUyBwaGFzZS4gSGVyZSYjODIxNztzIGEgaGludC4gV2hlbiBpbiB0aGUgY2VsbCBjeWNsZSBkbyBzcGluZGxlIGZpYmVycyBhdHRhY2ggdG8gY2hyb21vc29tZXM/

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234de0b500d739″ question_number=”19″] Note: This question is part of a series. If you’ve already seen this text and diagram, feel free to skip down to the question that’s below the diagram. Cyclins control the cell cycle and trigger specific cyclin-dependent kinases at the peak of their concentration. They are subsequently degraded by a regulatory protein called ubiquitin.

Which cyclin is likely to be involved in signaling that the cell has sufficient levels of nucleotide triphosphates to replicate its genome?

[c]IEN5Y2xpbiBB[Qq]

[f]IE5vLiBDeWNsaW4gQSBwZWFrcyBkdXJpbmcgRw==_Mg==LiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgbnVjbGVvdGlkZSB0cmlwaG9zcGhhdGVzIHdvdWxkIGJlIHJlcXVpcmVkIGZvciBETkEgcmVwbGljYXRpb24uIFdoZW4gaXMgdGhlIGNlbGwgY3ljbGUgZG9lcyBETkEgcmVwbGljYXRpb24gb2NjdXI/

Cg==

[Qq]

[c]IEN5Y2xpbiBC[Qq]

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[c]IEN5Y2 xpbiBF[Qq]

[f]IEZhYnVsb3VzLiBDeWNsaW4gRSBwZWFrcyBhdCB0aGUgYmVnaW5uaW5nIG9mIFMgcGhhc2UsIHdoaWNoIGlzIHdoZW4gdGhlIG51Y2xlb3RpZGUgdHJpcGhvc3BoYXRlcyB3b3VsZCBiZSB1c2VkIGZvciBETkEgcmVwbGljYXRpb24u

Cg==

[Qq]

[c]IEN5Y2xpbiBE[Qq]

[f]IE5vLiBDeWNsaW4gRCBwZWFrcyBpbiB0aGUgbWlkZGxlIG9mIFMgcGhhc2UuIEF0IHRoYXQgcG9pbnQsIEROQSByZXBsaWNhdGlvbiB3b3VsZCBiZSB3ZWxsIHVuZGVyd2F5LiBGaW5kIGEgY3ljbGluIHRoYXQgcGVha3MgcmlnaHQgYXQgdGhlIGJlZ2lubmluZyBvZiBTIHBoYXNlLg==

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative Multiple Choice Dataset, v2.0|234d2d6d6d4339″ question_number=”20″] The diagram below shows events that help control milk production in humans. Which of the following is a correct interpretation of how the system works?

[c]IFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBwb3NpdGl2ZSBmZWVkYmFjayBiZWNhdXNlIG1vcmUgc3Vja2luZyBsZWFkcyB0aG UgcGl0dWl0YXJ5IHRvIHJlbGVhc2UgcHJvbGFjdGluLCB3aGljaCBsZWFkcyB0byBtb3JlIG1pbGsgcHJvZHVjdGlvbi4=[Qq]

[f]IE5pY2UuIFN1Y2tpbmcgaW5oaWJpdHMgdGhlIGh5cG90aGFsYW11cyBmcm9tIHJlbGVhc2luZyBQSUguIFdpdGhvdXQgUElILCB0aGUgcGl0dWl0YXJ5IHJlbGVhc2VzIHByb2xhY3Rpbiwgd2hpY2ggbGVhZHMgdG8gbW9yZSBtaWxrIHByb2R1Y3Rpb24uIE1vcmUgbWlsayBpbmdlc3Rpb24gbGVhZHMgdG8gYSBsYXJnZXIgYmFieSBhbmQgYSBncmVhdGVyIG5lZWQgZm9yIG1pbGsgcHJvZHVjdGlvbi4gVGhpcyBhbXBsaWZpY2F0aW9uIGlzIHBvc2l0aXZlIGZlZWRiYWNrLg==[Qq]

[c]IFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBwb3NpdGl2ZSBmZWVkYmFjayBiZWNhdXNlIHN1Y2tpbmcgaW5jcmVhc2VzIHRoZSBoeXBvdGhhbGFtaWMgc2VjcmV0aW9uIG9mIFBJSCwgd2hpY2ggaW5jcmVhc2VzIHByb2xhY3Rpbiwgd2hpY2ggaW5jcmVhc2VzIG1pbGsgcHJvZHVjdGlvbi4=[Qq]

[f]IE5vLiBTdWNraW5nIGluaGliaXRzIHRoZSBoeXBvdGhhbGFtaWMgcmVsZWFzZSBvZiBQSUgu[Qq]

[c]IFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBuZWdhdGl2ZSBmZWVkYmFjayBiZWNhdXNlIHN1Y2tpbmcgc3RpbXVsYXRlcyB0YWN0aWxlIHJlY2VwdG9ycyBpbiB0aGUgbmlwcGxlLCB3aGljaCBoYXZlIGEgbmVnYXRpdmUgZWZmZWN0IG9uIHRoZSBoeXBvdGhhbGFtaWMgcmVsZWFzZSBvZiBQSUgu[Qq]

[f]IE5vLiBUaGUgaW5oaWJpdGlvbiBvZiBQSUggYWxsb3dzIHRoZSBwaXR1aXRhcnkgZ2xhbmQgdG8gcmVsZWFzZSBwcm9sYWN0aW4sIHdoaWNoIHN0aW11bGF0ZXMgbWlsayBwcm9kdWN0aW9uLCB3aGljaCB0aGVuIGdvZXMgdG8gdGhlIGJhYnksIHdoaWNoIHdpbGwgaW5nZXN0IG1vcmUgbWlsayBhbmQgZ3JvdyBiaWdnZXIsIHJlcXVpcmluZyBtb3JlIG1pbGsuIFdoYXQga2luZCBvZiBmZWVkYmFjayBsb29wIGlzIHRoYXQ/[Qq]

[c]IFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBuZWdhdGl2ZSBmZWVkYmFjayBiZWNhdXNlIHRocmVlIGluaGliaXRvcnkgcGF0aHdheXMgYXJlIGludm9sdmVkOiB0YWN0aWxlIHJlY2VwdG9ycyB0byB0aGUgaHlwb3RoYWxhbXVzLCBQSUggdG8gcHJvbGFjdGluLCBhbmQgRklMIHRvIG1pbGsgcHJvZHVjdGlvbi4=[Qq]

[f]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[Qq]

[/qwiz]

4. Unit 4 Cumulative Multiple Choice Quiz 2

[qwiz style=”width: 550px !important; min-height: 400px !important;” dataset=”Unit 4 Cumulative MC Dataset 2″ qrecord_id=”sciencemusicvideosMeister1961-Unit 4 Summative MC Quiz 2″]

[h] Unit 4 Cumulative Multiple Choice Quiz 2

[i]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d0b0a6d9d4cf” question_number=”1″] Plasmodesmata (shown below) are channels through which plants can send chemical signals between one cell and the next.

Which of the following is the best interpretation of the results of this experiment?

[c]IDEwIHVMIG9mIHRoZSBkcnVnIGhhcyBhIHNpZ25pZmljYW50IGVmZmVjdCBvbiBwbGFudCBncm93dGggYXQgNcKgIGRheXMsIDEwIGRheXMsIGFuZCAyMCBkYXlzLg==[Qq]

[f]IE5vLiBBdCA1IGRheXMgd2l0aCAxMHVMLCB0aGUgYW1vdW50IG9mIGdyb3d0aCBvdmVybGFwcyB3aXRoIHRoZSBhbW91bnQgb2YgZ3Jvd3RoIGluIHRoZSBjb250cm9sIGdyb3VwLg==[Qq]

[c]IEF0IDEwIGFuZCAyMCBkYXlzLCAxMCB1TCBhbmQgMjB1TCBjYXVzZW QgYSBzaWduaWZpY2FudCBkZWNsaW5lIGluIHBsYW50IGdyb3d0aC4=[Qq]

[f]IE5pY2UuIEF0IDEwIGFuZCAyMCBkYXlzLCB0aGUgMTAgdUwgYW5kIHRoZSAyMHVMIGdyb3VwcyBzaG93ZWQgYSBzdGF0aXN0aWNhbGx5IHNpZ25pZmljYW50IGRlY2xpbmUgaW4gZ3Jvd3RoLg==[Qq]

[c]IE5vIGFtb3VudCBvZiB0aGUgZHJ1ZyBoYXMgYSBzdGF0aXN0aWNhbGx5IHNpZ25pZmljYW50IGVmZmVjdCBvbiBwbGFudCBncm93dGgu[Qq]

[f]IE5vLiBBZnRlciAxMCBkYXlzLCBib3RoIDEwdUwgYW5kIDIwdUwgb2YgdGhlIGRydWcgY2F1c2VkIGEgc2lnbmlmaWNhbnQgZGVjbGluZSBpbiBncm93dGgu

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1.Cell_Communication” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d09bb26ed0cf” question_number=”2″] Bacteria that form biofilms are associated with tooth decay. Biofilms are formed when initially free-floating (planktonic) bacteria stick to one another and to surfaces by excreting a slimy substance.

A model of biofilm formation is shown below.

Which of the following statements most accurately describes how biofilm formation works?

[c]IEJpb2ZpbG1zIGZvcm0gd2hlbiBzaWduYWxpbmcgbW9sZWN1bGVzIGFjdGl2YXRlIHJpYm9zb21lcy4gVGhlIHJpYm9zb21lcyB0cmFuc2xhdGUgbVJOQSBpbnRvIHRoZSBwcm90ZWlucyB0aGF0IG1ha2UgdXAgdGhlIGJpb2ZpbG0u[Qq]

[f]IE5vLiBTaWduYWxpbmcgbW9sZWN1bGVzIGJpbmQgd2l0aCByZWNlcHRvcnMgKHN1Y2ggYXMgdGhlIG9uZSBzaG93biBhdCAmIzgyMjA7MiYjODIyMTspLCBub3Qgcmlib3NvbWVzLg==[Qq]

[c]IEJpb2ZpbG1zIGZvcm0gd2hlbiBlbm91Z2ggc2lnbmFsaW5nIG1vbGVjdWxlcyBiaW5kIHdpdGggaW50cm FjZWxsdWxhciByZWNlcHRvcnMsIGFjdGl2YXRpbmcgZ2VuZXMgZm9yIGJpb2ZpbG0gZm9ybWF0aW9uLg==[Qq]

[f]IEV4YWN0bHkuIFRoYXQmIzgyMTc7cyB3aGF0IHlvdSBzZWUgb24gdGhlIHJpZ2h0IHNpZGUgb2YgdGhlIGRpYWdyYW0u[Qq]

[c]IEJpb2ZpbG1zIGZvcm0gd2hlbiBsaWdhbmQgZGVuc2l0eSBpcyBhdCBhIGxvdyBsZXZlbCwgbGVhZGluZyB0byB0aGUgdHJhbnNjcmlwdGlvbiBhbmQgdHJhbnNsYXRpb24gb2YgZW56eW1lcyB0aGF0IGNhdGFseXplIHRoZSByZWFjdGlvbnMgaW52b2x2ZWQgaW4gYmlvZmlsbSBmb3JtYXRpb24u[Qq]

[f]IE5vLiBXaGF0IHRoZSBiYWN0ZXJpYSBhcmUgZG9pbmcgaXMgcXVvcnVtIHNlbnNpbmc=IGJ5IHNlY3JldGluZyBzaWduYWxpbmcgbW9sZWN1bGVzLiBOb3RpY2UgdGhhdCBiaW9maWxtIGZvcm1hdGlvbiBvbmx5IG9jY3VycyB3aGVuIHRoZSBjb25jZW50cmF0aW9uIG9mIHRoZSBzaWduYWxpbmcgbW9sZWN1bGUgcmlzZXMgdG8gYSBoaWdoIGVub3VnaCBsZXZlbCB0byBhY3RpdmF0ZSB0aGUgZ2VuZXMgZm9yIGJpb2ZpbG0gZm9ybWF0aW9uLg==[Qq]

[c]IEJpb2ZpbG1zIGZvcm0gd2hlbiBjZWxsLXRvLWNlbGwgY29udGFjdCBiZXR3ZWVuIGJhY3RlcmlhbCBjZWxscyBsZWFkcyB0byByZXZlcnNlIHRyYW5zY3JpcHRpb24gb2YgYmlvZmlsbSBSTkEgaW50byBiaW9maWxtIEROQSwgd2hpY2ggaW5jb3Jwb3JhdGVzIGl0c2VsZiBpbnRvIHRoZSBjZWxsJiM4MjE3O3MgY2hyb21vc29tZS4gU3Vic2VxdWVudCBleHByZXNzaW9uIG9mIGJpb2ZpbG0gRE5BIGxlYWRzIHRvIHRoZSB0cmFuc2NyaXB0aW9uIGFuZCB0cmFuc2xhdGlvbiBvZiBlbnp5bWVzIHRoYXQgY2F0YWx5emUgdGhlIHJlYWN0aW9ucyBpbnZvbHZlZCBpbiBiaW9maWxtIGZvcm1hdGlvbi4=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBJbiB0aGUgZGlhZ3JhbSBhYm92ZSwgJiM4MjIwOzEmIzgyMjE7IGlzIGEgbGlnYW5kLCBhbmQgJiM4MjIwOzImIzgyMjE7IGlzIGFuIGludHJhY2VsbHVsYXIgcmVjZXB0b3Iu

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.2-3.Signal_Transduction” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d089120fb0cf” question_number=”3″] During several phases of development, steroid hormones such as estrogen or testosterone are secreted from endocrine glands such as the ovaries or testes. These hormones are released into the blood and circulate throughout the body.

Which of the following best explains why only some tissues respond to estrogen or testosterone?

[c]IERpZmZlcmVudCBjZWxscyBoYXZlIGRpZmZlcmVudCBETkEgc2VxdWVuY2VzLiBFc3Ryb2dlbiBvciB0ZXN0b3N0ZXJvbmUgd2lsbCBvbmx5IGFmZmVjdCBjZWxscyBpbiB3aGljaCBzcGVjaWZpYyBETkEgc2VxdWVuY2VzIGFyZSBwcmVzZW50Lg==[Qq]

[f]IE5vLiBBIGtleSBwcmluY2lwbGUgb2YgZGV2ZWxvcG1lbnQgaXMgdGhhdCBhbGwgY2VsbHMgaGF2ZSB0aGUgc2FtZSBETkEuIFdoYXQgZGlmZmVycyBmcm9tIHRpc3N1ZSB0byB0aXNzdWUgaXMgdGhlIHBhdHRlcm4gb2YgZ2VuZSBleHByZXNzaW9uLg==[Qq]

[c]IFN0ZXJvaWQgaG9ybW9uZXMgY2FuIG9ubHkgYWZmZWN0IGNlbGxzIHdpdGggbWVtYnJhbmUgcmVjZXB0b3JzIHRoYXQgYXJlIGNvbXBsZW1lbnRhcnkgdG8gdGhlIHNoYXBlIG9mIHRoZSBob3Jtb25lcy4=[Qq]

[f]IE5vLiBCZWNhdXNlIHN0ZXJvaWQgaG9ybW9uZXMgYXJlIG5vbnBvbGFyIGxpcGlkcywgdGhleSYjODIxNztyZSBjYXBhYmxlIG9mIGRpZmZ1c2luZyB0aHJvdWdoIHRoZSBwaG9zcGhvbGlwaWQgYmlsYXllci4gVGhleSBiaW5kIHdpdGggY3l0b3BsYXNtaWMgcmVjZXB0b3JzLCBub3QgbWVtYnJhbmUgcmVjZXB0b3JzLg==[Qq]

[c]IE9ubHkgc29tZSBjZWxscyBwcm9kdWNlIGN5dG9wbGFzbWljIHJlY2VwdG 9ycyB0aGF0IGNhbiB0aGVzZSBob3Jtb25lcyBjYW4gYmluZCB3aXRoLg==[Qq]

[f]IEZhYnVsb3VzLiBCYXNlZCBvbiB0aGVpciBwYXR0ZXJuIG9mIGRldmVsb3BtZW50LCBvbmx5IHNvbWUgY2VsbHMgdGhyb3VnaG91dCB0aGUgYm9keSB3aWxsIHRyYW5zY3JpYmUgYW5kIHRyYW5zbGF0ZSB0aGUgY3l0b3BsYXNtaWMgcmVjZXB0b3JzIHRoYXQgc3BlY2lmaWMgc3Rlcm9pZCBob3Jtb25lcyBzdWNoIGFzIGVzdHJvZ2VuIG9yIHRlc3Rvc3Rlcm9uZSBjYW4gYmluZCB3aXRoLg==[Qq]

[c]IE1hbnkgY2VsbHMgdXNlIFJOQSBpbnRlcmZlcmVuY2UgdG8gYnJlYWsgZG93biBtUk5BIGJlZm9yZSBpdCBjYW4gYmUgdHJhbnNsYXRlZCBieSBhIHJpYm9zb21lLCBzdWNoIGFzIHRoZSBvbmUgc2hvd24gYXQgJiM4MjIwO0wuJiM4MjIxOw==[Qq]

[f]IE5vLiBTdHVkeSB0aGUgZGlhZ3JhbSBhYm92ZS4gVGhlIGRpZmZlcmVuY2UgaW4gc2Vuc2l0aXZpdHkgaGFzIHRvIGRvIHdpdGggaG93IHN0ZXJvaWQgaG9ybW9uZXMgZW50ZXIgY2VsbHMgYW5kIGFjdGl2YXRlIGdlbmVzLg==

Cg==

[Qq]

Which of the following statements about these models is correct?

[c]IE1vZGVsICYjODIyMDtTJiM4MjIxOyBicmluZ3MgYWJvdXQgZmFzdGVyIHJlc3BvbnNlcyBiZWNhdXNlIHRoZSBsaWdhbmQgY2FuIGRpZmZ1c2UgZGlyZWN0bHkgaW50byB0aGUgY3l0b3BsYXNtLCB3aXRob3V0IGhhdmluZyB0byBhY3RpdmF0ZSBhIHNlY29uZCBtZXNzZW5nZXIu[Qq]

[f]IE5vLiBXaGlsZSBpdCYjODIxNztzIHRydWUgdGhhdCBNb2RlbCAmIzgyMjA7UyYjODIyMTsgc2hvd3MgdGhlIGxpZ2FuZCBkaWZmdXNpbmcgZGlyZWN0bHkgaW50byB0aGUgY3l0b3BsYXNtLCB0aGUgc3Vic2VxdWVudCBzdGVwcyAod2hpY2ggaW52b2x2ZSB0cmFuc2NyaXB0aW9uIG9mIGdlbmVzIGFuZCB0cmFuc2xhdGlvbiBvZiBwcm90ZWlucykgYXJlIG11Y2ggc2xvd2VyIHRoYW4gd2hhdCBoYXBwZW5zIGluIE1vZGVsICYjODIyMDtULCYjODIyMTsgd2hpY2ggaW52b2x2ZXMgYWN0aXZhdGlvbiBvZiBkb3JtYW50IGVuenltZXMu[Qq]

[c]IE1vZGVsICYjODIyMDtUJiM4MjIxOyBicmluZ3MgYWJvdXQgYSBsb25nZXItbGFzdGluZyByZXNwb25zZSBiZWNhdXNlIG9mIHRoZSB3YXkgdGhhdCBpdCBhbHRlcnMgdGhlIHNpZ25hbGluZyBiZWhhdmlvciBvZiBtZW1icmFuZSByZWNlcHRvcnMu[Qq]

[f]IE5vLiBXaGlsZSBpdCYjODIxNztzIHRydWUgdGhhdCAmIzgyMjA7VCYjODIyMTsgYWx0ZXJzIHRoZSBzaWduYWxpbmcgYmVoYXZpb3Igb3IgbWVtYnJhbmUgcmVjZXB0b3JzLCB0aGUgY2hhbmdlIGlzIHRlbXBvcmFyeS4gV2hlbiB0aGUgc2lnbmFsaW5nIG1vbGVjdWxlIHN0b3BzIGJlaW5nIHNlY3JldGVkLCB0aGUgbWVtYnJhbmUgd2lsbCByZXZlcnQgdG8gaXRzIGZvcm1lciBjb25kaXRpb24gYW5kIHN0b3Agc2lnbmFsaW5nLCBhcyBzaG93biBpbiBzdGVwcyBJSUkgYW5kIElWIGJlbG93Lg==

Cg==

[Qq]

[c]IE1vZGVsICYjODIyMDtUJiM4MjIxOyBicmluZ3MgYWJvdXQgYSBsb25nZXItbGFzdGluZyByZXNwb25zZSBiZWNhdXNlIG9mIHNpZ25hbCBhbXBsaWZpY2F0aW9uIHRoYXQgcmVzdWx0cyBmcm9tIHRoZSBpbml0aWF0aW9uIG9mIGEgcGhvc3Bob3J5bGF0aW9uIGNhc2NhZGUu[Qq]

[f]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

Cg==

[Qq]

[c]IE1vZGVsICYjODIyMDtTJiM4MjIxOyBicmluZ3MgYWJvdXQgYSBsb25nZXItbGFzdGluZyByZXNwb25zZSBi ZWNhdXNlIGl0IG1vYmlsaXplcyB0cmFuc2NyaXB0aW9uIGZhY3RvcnMgdGhhdCBhY3RpdmF0ZSBnZW5lcy4=[Qq]

[f]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

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d05cd52dc4cf” question_number=”5″ topic=”4.2-3.Signal_Transduction”] The image below represents a signal transduction pathway. Which roman numeral represents reception?

[c]IE kg[Qq][c]IElJIA==[Qq][c]IElJSQ==

Cg==[Qq]

[f]IFllcy4gJiM4MjIwO0kmIzgyMjE7IHJlcHJlc2VudHMgcmVjZXB0aW9uLg==[Qq]

[f]IE5vLiAmIzgyMjA7SUkmIzgyMjE7IHJlcHJlc2VudHMgc2lnbmFsIHRyYW5zZHVjdGlvbiAoY29udmVyc2lvbiBvZiB0aGUgaW5pdGlhbCBzaWduYWwsIHRoZSBob3Jtb25lLCBpbnRvIG9uZSB0aGF0IGNhbiBiZSBjYXJyaWVkIGludG8gdGhlIGN5dG9wbGFzbSB0byBicmluZyBhYm91dCBhIGNlbGx1bGFyIHJlc3BvbnNlKS4=[Qq]

[f]IE5vLiAmIzgyMjA7SUlJJiM4MjIxOyByZXByZXNlbnRzIHRoZSBjZWxsdWxhciByZXNwb25zZS4=

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d047e0c2c0cf” question_number=”6″ topic=”4.2-3.Signal_Transduction”] The image below represents a signal transduction pathway. Which letter represents a ligand?

[c]IE Eg[Qq][c]IEIg[Qq][c]IEMg[Qq][c]IEQ=

Cg==[Qq]

[f]IEV4YWN0bHkuIEEgaXMgdGhlIGxpZ2FuZC4=[Qq]

[f]IE5vLiAmIzgyMjA7QiYjODIyMTsgaXMgdGhlIHJlY2VwdG9yLiBUaGUgbGlnYW5kIGlzIHRoZSBtb2xlY3VsZSB0aGF0IGJpbmRzIHdpdGggdGhlIHJlY2VwdG9yLg==[Qq]

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Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d030984bd8cf” question_number=”7″ topic=”4.2-3.Signal_Transduction”] In the diagram below, which part represents a ligand?

[c]ID Eg[Qq][c]IDIg[Qq][c]IDMg[Qq][c]IDQg[Qq][c]IDU=

Cg==[Qq]

[f]IE5pY2UhIDEgaXMgdGhlIGxpZ2FuZC4=[Qq]

[f]IE5vLiAyIGlzIGEgcmVjZXB0b3IuIFRoZSBsaWdhbmQgaXMgd2hhdCBiaW5kcyB3aXRoIGEgcmVjZXB0b3Iu[Qq]

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[f]IE5vLiA1IGlzIHNvbWV0aGluZyB0aGF0JiM4MjE3O3MgaGVhZGluZyB0b3dhcmQgdGhlIEdvbGdpIGFwcGFyYXR1cywgbWFraW5nIDUgYSBuZXdseSBzeW50aGVzaXplZCBwcm90ZWluLiBUaGUgbGlnYW5kIGlzIHdoYXQgYmluZHMgd2l0aCBhIHJlY2VwdG9yLg==

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways” dataset_id=”Unit 4 Cumulative MC Dataset 2|13d0194fd4f0cf” question_number=”8″] The image below is a model of a cell-signaling malfunction associated with cancer. The mutation responsible for the cancer is most likely in the gene for

[c]IHRoZSByZWNlcHRvcg==[Qq]

[f]IE5vLCBidXQgeW91JiM4MjE3O3JlIGNsb3NlLiBUaGUgcmVjZXB0b3IgaXMgJiM4MjIwO3dhaXRpbmcmIzgyMjE7IGZvciBhIGxpZ2FuZCB0byBiaW5kLiBCdXQgbm90aWNlIHRoYXQgYSBzaWduYWwgaXMgYmVpbmcgdHJhbnNtaXR0ZWQgaW5zaWRlIHRoZSBjZWxsLCBldmVuIHRob3VnaCBubyBsaWdhbmQgaGFzIGJvdW5kIHdpdGggdGhlIHJlY2VwdG9yLiBVc2UgdGhhdCBhcyBhIGhpbnQgZm9yIHRoZSBuZXh0IHRpbWUgeW91IHNlZSB0aGlzIHF1ZXN0aW9u[Qq]

[c]IHRoZSBHLX Byb3RlaW4=[Qq]

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[c]IG9uZSBvciBtb3JlIG9mIHRoZSBraW5hc2VzIGluIHRoZSBwaG9zcGhvcnlsYXRpb24gY2FzY2FkZQ==[Qq]

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[c]IHRoZSB0cmFuc2NyaXB0aW9uIGZhY3Rvcg==[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cfffb35224cf” question_number=”9″] The Epidermal Growth Factor Receptor (EGFR) gene is a proto-oncogene located on chromosome 7. As a proto-oncogene, it codes for a growth factor cell surface receptor, which responds to the EGF ligand. A model of the EGFR signaling system is shown below.

Which of the following mutations in this system would not lead to increased cell proliferation?

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[c]IEEgbXV0YXRpb24gdGhhdCBpbmNyZWFzZWQgdGhlIG51bWJlciBvZiBFR0ZSIHJlY2VwdG9ycy4=[Qq]

[f]IE5vLiBJZiB0aGVyZSB3ZXJlIG1vcmUgcmVjZXB0b3JzLCB0aGVuIHRoZSBjZWxsIHdvdWxkIGJlIG1vcmUgc2Vuc2l0aXZlIHRvIHRoZSBsaWdhbmQuIFRoYXQgd291bGQgbGVhZCB0byBpbmNyZWFzZWQgYWN0aXZhdGlvbiBvZiB0aGUgcGF0aHdheSwgYW5kIGluY3JlYXNlZCBjZWxsIGRpdmlzaW9uLiBGaW5kIGEgY2hhbmdlIHRoYXQgd291bGQgbWFrZSB0aGlzIHBhdGh3YXkgbGVzcyBhY3RpdmUsIGFuZCBkZWNyZWFzZSBjZWxsIHByb2xpZmVyYXRpb24u[Qq]

[c]IEEgbXV0YXRpb24gdGhhdCBhbHRlcmVkIEVHRlLigJlzIGludHJhY2VsbHVsYXIgZG9tYWluIHNvIHRoYXQgaXQgc2lnbmFsZWQgUkFTIGluIHRoZSBhYnNlbmNlIG9mIGEgbGlnYW5kLg==[Qq]

[f]IE5vLiBUaGlzIHR5cGUgb2YgbXV0YXRpb24gd291bGQgYWN0aXZhdGUgUkFTIGV2ZW4gaW4gdGhlIGFic2VuY2Ugb2YgYSBsaWdhbmQuIFRoaXMgd291bGQgbWFrZSB0aGUgcGF0aHdheSBhY3RpdmUgYWxsIG9mIHRoZSB0aW1lLCB3aGljaCB3b3VsZCA=aW5jcmVhc2U=IGNlbGwgcHJvbGlmZXJhdGlvbi4gRmluZCBhIGNoYW5nZSB0aGF0IHdvdWxkIG1ha2UgdGhpcyBwYXRod2F5IGxlc3MgYWN0aXZlLCBhbmQgZGVjcmVhc2UgY2VsbCBwcm9saWZlcmF0aW9uLg==[Qq]

[c]IEEgbXV0YXRpb24gdGhhdCBpcnJldmVyc2libHkgYm91bmQgR1RQIHRvIFJBUy4=[Qq]

[f]IE5vLiBUaGlzIHR5cGUgb2YgbXV0YXRpb24gd291bGQgbWFrZSBSQVMgYWN0aXZlIGFsbCBvZiB0aGUgdGltZSwgd2hpY2ggd291bGQgaW5jcmVhc2UgY2VsbCBwcm9saWZlcmF0aW9uLiBGaW5kIGEgY2hhbmdlIHRoYXQgd291bGQgbWFrZSB0aGlzIHBhdGh3YXkgbGVzcyBhY3RpdmUsIGFuZCBkZWNyZWFzZSBjZWxsIHByb2xpZmVyYXRpb24u

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cfe616cf58cf” question_number=”10″ unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.4.Changes_in_Signal_Transduction_Pathways”] In damaged and aging cells, regulated cell death involves caspases, a type of activated enzyme. Caspase activation causes the breakdown of the cytoskeleton, the nuclear membrane, and the mitochondrial membrane. During activation, caspases are cut at a specific amino acid sequence. The model below illustrates one pathway for caspase activation that is triggered by the presence of cytotoxic T cells (a key cell in the immune response), represented as “T_C.”

Which of the following statements is supported by the model?

[c]IEROQSBkYW1hZ2UgdHJpZ2dlcnMgcmVndWxhdGVkIGNlbGwgZGVhdGggdG8gYmVnaW4u[Qq]

[f]IE5vLiBUaGF0IG1pZ2h0IGJlIHRydWUsIGJ1dCBpdCYjODIxNztzIG5vdCBzdXBwb3J0ZWQgYnkgdGhlIG1vZGVsIGFib3ZlLiBTdHVkeSB0aGUgZGlhZ3JhbSwgYW5kIHNlZSBpZiB5b3UgY2FuIGNvbm5lY3QgaXQgdG8gb25lIG9mIHRoZXNlIGNob2ljZXMu[Qq]

[c]IE1pdG9jaG9uZHJpYWwgbWVtYnJhbmUgZGVjb21wb3NpdGlvbiBsZWFkcyB0byBjYXNwYXNlIGFjdGl2YXRpb24u[Qq]

[f]IE5vLiBUaGUgaW5mb3JtYXRpb24gaW4gdGhlIHF1ZXN0aW9uIHN0YXRlcyB0aGUgcmV2ZXJzZTogY2FzcGFzZSBhY3RpdmF0aW9uIGxlYWRzIHRvIG1pdG9jaG9uZHJpYWwgbWVtYnJhbmUgZGVjb21wb3NpdGlvbi4gU3R1ZHkgdGhlIGRpYWdyYW0sIGFuZCBzZWUgaWYgeW91IGNhbiBjb25uZWN0IGl0IHRvIG9uZSBvZiB0aGVzZSBjaG9pY2VzLg==[Qq]

[c]IENhc3Bhc2VzIGFuZCBhZGFwdG9yIHByb3RlaW5zIGNvbXBldGUgZm9yIGJpbmRpbmcgc2l0ZXMgb24gdGhlIEZhcyByZWNlcHRvci4=[Qq]

[f]IE5vLiBUaGF0JiM4MjE3O3MgdW5saWtlbHksIGJlY2F1c2UgdGhlIGFkYXB0b3IgcHJvdGVpbnMgYXJlIGluc2lkZSB0aGUgY2VsbCwgd2hpbGUgdGhlIEZhcyByZWNlcHRvciBpcyBvdXRzaWRlIHRoZSBjZWxsLiBTdHVkeSB0aGUgZGlhZ3JhbSwgYW5kIHNlZSBpZiB5b3UgY2FuIGNvbm5lY3QgaXQgdG8gb25lIG9mIHRoZXNlIGNob2ljZXMu[Qq]

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[f]IFllcy4gQ2FzcGFzZXMgYXJlIGFjdGl2YXRlZCBhZnRlciB0aGUgRmFzIHByb3RlaW4gb24gYSBU_Qw==IGNlbGwgYmluZHMgd2l0aCB0aGUgRmFzIHJlY2VwdG9yLg==

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cfd1226454cf” question_number=”11″] The chart below depicts glucose homeostasis in mammals.

After a carbohydrate-rich meal, how would the system respond?

[c]IFRoZSBsaXZlciB3b3VsZCBzZWNyZXRlIGdsdWNhZ29uIHNvIHRoYXQgZ2x1Y29zZSBjYW4gYmUgY29udmVydGVkIGludG8gZ2x5Y29nZW4gYW5kIGZhdC4=[Qq]

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[c]IFRoZSBwYW5jcmVhcyB3b3VsZCBzZWNyZXRlIGdsdWNhZ29uIHNvIHRoYXQgZ2x5Y29nZW4gY2FuIGJlIGh5ZHJvbHl6ZWQgaW50byBnbHVjb3NlLg==[Qq]

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[c]IFRoZSBsaXZlciB3b3VsZCBzZWNyZXRlIGluc3VsaW4gc28gdGhhdCBnbHVjb3NlIGNhbiBiZSBjb252ZXJ0ZWQgdG8gZ2x5Y29nZW4gYW5kIGZhdC4=[Qq]

[f]IE5vLiBTdHVkeSB0aGUgY2hhcnQuIFdoYXQgc2VjcmV0ZXMgdGhlIGluc3VsaW4/[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cfb9d9ed6ccf” question_number=”12″] The process of oxytocin release during childbirth involves positive feedback because

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Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cfa4e58268cf” question_number=”13″] The diagram below shows events that help control milk production in humans. When a baby is present, which of the following statements is most correct?

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[f]IE5vLiBOb3RlIHRoYXQgc3Vja2luZyBpbmhpYml0cyB0aGUgaHlwb3RoYWxhbXVzLCB3aGljaCBvbmx5IHNlY3JldGVzIFBJSCBvbmx5IGluIHRoZSBhYnNlbmNlIG9mIHN1Y2tpbmcsIG5vdCBpbiBpdHMgcHJlc2VuY2Uu[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6.Cell_Cycle” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cf8b48ff9ccf” question_number=”14″] A team of scientists is experimenting with a drug that could slow or stop cancer by preventing cells from completing mitosis.

One of the scientists examines a culture of dividing cells that have been exposed to the drug and creates the following sketch which represents how the cells appear.

Which of the following mechanisms is most likely at work?

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Cg==

[Qq]

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Cg==

[Qq]

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Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6.Cell_Cycle” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cf71ac7cd0cf” question_number=”15″] Which of the following correctly pairs a stage in the cell cycle with events that occur in that stage?

[c]IFMgJiM4MjExOyB0aGUgdG90YWwgYW1vdW50IG9mIEROQSBpbiBhIGNlbGwgaW5jcmVhc2VzLg==[Qq]

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[f]IFlvdSYjODIxNztyZSBoYWxmd2F5IHRoZXJlLiBEdXJpbmcgRw==_Mg==IHRoZSBETkEgaXMgY2hlY2tlZCBmb3IgZXJyb3JzLiBXaGF0IG90aGVyIHN0YXRlbWVudCBpcyB0cnVlPw==[Qq]

[c]IE0gJiM4MjExOyBETkEgaXMgZHVwbGljYXRlZC4=[Qq]

[f]IE5vLiBNIGlzIGZvciAmIzgyMjA7bWl0b3Npcy4mIzgyMjE7IFRoZSBjZWxsIGRpdmlkZXMgaW50byB0d28gZGF1Z2h0ZXIgY2VsbHMuIEROQSByZXBsaWNhdGlvbiBoYXMgYWxyZWFkeSBvY2N1cnJlZC4=[Qq]

[c]IEJvdGggYSBhbmQgYi BhcmUgY29ycmVjdC4=[Qq]

[f]IFllcy4gJiM4MjIwO1MmIzgyMjE7IGlzIHRoZSBzeW50aGVzaXMgcGhhc2Ugb2YgdGhlIGNlbGwgY3ljbGUgYW5kIGludm9sdmVzIEROQSByZXBsaWNhdGlvbi4gRHVyaW5nIEc=_Mg==LCB0aGVyZSYjODIxNztzIGEgY2hlY2twb2ludCBhdCB3aGljaCBETkEgaXMgY2hlY2tlZCBmb3IgZXJyb3JzIGJlZm9yZSB0aGUgbW90aGVyIGNlbGwgZGl2aWRlcyBpbnRvIHRoZSB0d28gZGF1Z2h0ZXIgY2VsbHMu

Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cf580ffa04cf” question_number=”16″] The diagram below shows the “multi-step model of cancer” and illustrates some of the changes that cells undergo as they progress to become malignant cancers.

When compared to cancer cells, normal cells will have

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[c]IGEgc2hvcnRlciBjZWxsIGN5Y2xl[Qq]

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[c]IGZhc3RlciByYXRlcyBvZiBETkEgcmVwbGljYXRpb24=[Qq]

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Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cf3e737738cf” question_number=”17″ unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle”] What is the role of the G₂ checkpoint in the cell cycle?

[c]IFRvIGVuc3VyZSB0aGF0IGFsbCBvZiB0aGUgY2hyb21vc29tZXMgaGF2ZSBiZWVuIHJlcGxpY2F0ZWQgYW5kIHRoYX QgdGhlIHJlcGxpY2F0ZWQgRE5BIGlzIG5vdCBkYW1hZ2VkIGJlZm9yZSB0aGUgY2VsbCBlbnRlcnMgbWl0b3Npcy4=[Qq]

[f]IE5pY2UuIFRoYXQmIzgyMTc7cyB0aGUgZnVuY3Rpb24gb2YgdGhlIEc=_Mg==IGNoZWNrcG9pbnQu

Cg==

[Qq]

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[f]IE5vLiBUaGF0JiM4MjE3O3MgdGhlIGZ1bmN0aW9uIG9mIHRoZSBH_MQ==IGNoZWNrcG9pbnQu

Cg==

[Qq]

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Cg==

[Qq]

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[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBMb29rIGF0IHdoZXJlIHRoZSBH_Mg==IGNoZWNrcG9pbnQgaXMgcmVsYXRpdmUgdG8gdGhlIHJlc3Qgb2YgdGhlIGNlbGwgY3ljbGUu

Cg==

[Qq]

[q json=”true” xyz=”2″ multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cf202edca4cf” question_number=”18″] Note: This question is part of a series. If you’ve already seen this text and diagram, feel free to skip down to the question that’s below the diagram. Cyclins control the cell cycle and trigger specific cyclin-dependent kinases at the peak of their concentration. They are subsequently degraded by a regulatory protein called ubiquitin.

Which cyclin is likely to be involved in signaling that the cell has sufficient histones and scaffolding proteins to condense chromosomes?

[c]IEN5Y2 xpbiBB[Qq]

[f]IE5pY2Ugam9iISBDaHJvbW9zb21lcyBjb25kZW5zZSBpbiB0aGUgdmVyeSBmaXJzdCBzdGVwIG9mIG1pdG9zaXMuIFRoZXJlZm9yZSwgdGhlIHNpZ25hbCB0aGF0IHN1ZmZpY2llbnQgaGlzdG9uZXMgYXJlIHByZXNlbnQgbXVzdCBjb21lIHByaW9yIHRvIHRoZSBiZWdpbm5pbmcgb2YgbWl0b3Npcy4=

Cg==

[Qq]

[c]IEN5Y2xpbiBC[Qq]

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Cg==

[Qq]

[c]IEN5Y2xpbiBF[Qq]

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Cg==

[Qq]

[c]IEN5Y2xpbiBE[Qq]

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Cg==

[Qq]

[q json=”true” multiple_choice=”true” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.7.Regulation_of_the_Cell_Cycle” dataset_id=”Unit 4 Cumulative MC Dataset 2|13cee84dbf44cf” question_number=”19″] The diagram below shows some of the molecular interactions that regulate the cell cycle.

A drug that prevented cyclin from binding with CdK would most likely have which of the following effects?

[c]IHByZXZlbnRpbmcgRE5BIHBvbHltZXJhc2UgZnJvbSBzeW50aGVzaXppbmcgbmV3IEROQS4=[Qq]

[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBOb3RlIGhvdyBDREsgYW5kIEN5Y2xpbiBiaW5kIGp1c3QgYXMgdGhlIGNlbGwgcmVhY2hlcyB0aGUgRw==_Mg==IGNoZWNrcG9pbnQuIEF0IHRoYXQgcG9pbnQsIHRoZSBTIHBoYXNlIGhhcyBhbHJlYWR5IGJlZW4gY2xlYXJlZCwgYW5kIEROQSBoYXMgYmVlbiByZXBsaWNhdGVkLiBJZiBjeWNsaW4gZG9lc24mIzgyMTc7dCBiaW5kIHdpdGggQ2RLLCBhIGNlbGwgY291bGRuJiM4MjE3O3QgZm9ybSBNUEYgYW5kIHBhc3MgdGhlIEc=_Mg==IGNoZWNrcG9pbnQuIFdoYXQgaGFwcGVucyBhZnRlciBH_[Qq]2?

[c]IHByZXZlbnRpbmcgY2hyb21vc29t ZXMgZnJvbSBjb25kZW5zaW5nLg==[Qq]

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[c]IGFjY2VsZXJhdGluZyBjZWxsIGRpdmlzaW9uLg==[Qq]

[f]IE5vLiBUaGUgZWZmZWN0IHdvdWxkIGJlIHRoZSBvcHBvc2l0ZSwgc2xvd2luZyBkb3duIG9yIGNvbXBsZXRlbHkgaGFsdGluZyBjZWxsIGRpdmlzaW9uLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBOb3RlIGhvdyBDREsgYW5kIEN5Y2xpbiBiaW5kIGp1c3QgYXMgdGhlIGNlbGwgcmVhY2hlcyB0aGUgRw==_Mg==IGNoZWNrcG9pbnQuIEF0IHRoYXQgcG9pbnQsIHRoZSBTIHBoYXNlIGhhcyBhbHJlYWR5IGJlZW4gY2xlYXJlZCwgYW5kIEROQSBoYXMgYmVlbiByZXBsaWNhdGVkLiBJZiBjeWNsaW4gZG9lc24mIzgyMTc7dCBiaW5kIHdpdGggQ2RLLCBhIGNlbGwgY291bGRuJiM4MjE3O3QgZm9ybSBNUEYgYW5kIHBhc3MgdGhlIEc=_Mg==IGNoZWNrcG9pbnQuIFdoYXQgaGFwcGVucyBhZnRlciBH_[Qq]2?

[c]IGluY3JlYXNpbmcgY2VsbCBncm93dGggZHVyaW5nIEc=_MQ==Lg==[Qq]

[f]IE5vLiBUaGUgYmluZGluZyBvZiBjeWNsaW4gYW5kIENkSyBoYXBwZW5zIGxvbmcgYWZ0ZXIgdGhlIGV2ZW50cyBvZiBH_MQ==LiBIZXJlJiM4MjE3O3MgYSBoaW50LiBOb3RlIGhvdyBDREsgYW5kIEN5Y2xpbiBiaW5kIGp1c3QgYXMgdGhlIGNlbGwgcmVhY2hlcyB0aGUgRw==_Mg==IGNoZWNrcG9pbnQuIEF0IHRoYXQgcG9pbnQsIHRoZSBTIHBoYXNlIGhhcyBhbHJlYWR5IGJlZW4gY2xlYXJlZCwgYW5kIEROQSBoYXMgYmVlbiByZXBsaWNhdGVkLiBJZiBjeWNsaW4gZG9lc24mIzgyMTc7dCBiaW5kIHdpdGggQ2RLLCBhIGNlbGwgY291bGRuJiM4MjE3O3QgZm9ybSBNUEYgYW5kIHBhc3MgdGhlIEc=_[Qq]2 checkpoint. What happens after G₂?

[q json=”true” xyz=”2″ multiple_choice=”true” dataset_id=”Unit 4 Cumulative MC Dataset 2|13ce42fe7308cf” question_number=”20″ unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.5.Feedback”] The figure below represents how carbon dioxide concentration is regulated in the arterial blood of a human.

As the carbon dioxide concentration returns to normal levels, which of the following events is most likely to occur?

[c]IENvbnRyYWN0aW9uIG9mIHRoZSByZXNwaXJhdG9yeSBtdXNjbGVzIHN0b3BzLg==[Qq]

[f]IE5vLiBIYXZpbmcgdGhlIHJlc3BpcmF0b3J5IG11c2NsZXMgc3RvcCB3b3VsZCBiZSBkaXNhc3Ryb3VzIChiZWNhdXNlIGl0IHdvdWxkIGNhdXNlIGJyZWF0aGluZyB0byBjZWFzZSkuIFdoYXQgbWlnaHQgYmUgYSBsZXNzIGRyYXN0aWMgcmVzcG9uc2U/[Qq]

[c]IEEgcGVyc29uJiM4MjE3O3MgYnJlYXRoaW5n IHJhdGUgYW5kIGRlcHRoIGRlY3JlYXNlLg==[Qq]

[f]IFllcy4gSW5jcmVhc2VkIGJyZWF0aGluZyByYXRlcyB3aWxsIGRlY3JlYXNlIGJsb29kIGNhcmJvbiBkaW94aWRlIGNvbmNlbnRyYXRpb24uIEluIHJlc3BvbnNlLCBicmVhdGhpbmcgcmF0ZSBhbmQgZGVwdGggd2lsbCBkZWNyZWFzZSBhcyBob21lb3N0YXNpcyBpcyByZXN0b3JlZC4=[Qq]

[c]IFRoZSBudW1iZXIgb2YgbmVydmUgaW1wdWxzZXMgdG8gdGhlIHJlc3BpcmF0b3J5IG11c2NsZXMgaW5jcmVhc2VzLg==[Qq]

[f]IE5vLiBBcyBjYXJib24gZGlveGlkZSBsZXZlbHMgZGVjcmVhc2UsIHRoZSBudW1iZXIgb2YgbmVydmUgaW1wdWxzZXMgdG8gdGhlIG11c2NsZXMgc2hvdWxkIGFsc28gZGVjcmVhc2Uu[Qq]

[c]IEluIHRoZSBicmFpbiwgdGhlIHJlc3BpcmF0b3J5IGNlbnRlciBmYWlscyB0byB0cmFuc21pdCBtb3RvciBuZXJ2ZSBpbXB1bHNlcy4=[Qq]

[f]IE5vLiBUaGF0IHdvdWxkIGJlIGRpc2FzdHJvdXMgYmVjYXVzZSBpdCB3b3VsZCBsZWFkIGJyZWF0aGluZyB0byBjZWFzZS4gU2VlIGlmIHlvdSBjYW4gdGhpbmsgb2YgYSBsZXNzIGRyYXN0aWMgcmVzcG9uc2Uu[Qq]

[/qwiz]

5. Unit 4 Cumulative FRQs

[qwiz style=”width: 600px !important; min-height: 450px !important;” dataset=”Unit 4 Cumulative FRQs” qrecord_id=”sciencemusicvideosMeister1961-Unit 4 Summative FRQs”]

[h]Unit 4 Cumulative FRQs

[i]

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1-4.4.Cell_Communication” dataset_id=”Unit 4 Cumulative FRQs|14412d2551161e” question_number=”1″] Scientists wish to investigate the mechanisms of biofilm formation by the bacterial species L. monocytogenes. Biofilms are formed when microorganisms stick to one another and to surfaces by excreting a slimy substance. When L. monocytogenes contains a mutated receptor protein, it is unable to form biofilms (as shown in the diagram on the right).

PART 1: Propose a function of the receptor protein, using evidence from the scientists’ observations.

PART 2: Explain how the presence of a membrane receptor protein enables L. monocytogenes to form biofilms.

PART 3: Identify another part of the cell or cellular environment that scientists could inhibit to block biofilm formation without killing the bacteria.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

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Cg==

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[Qq]

PART 3: Any of the following responses are acceptable:

Scientists could mutate the ligand so that it no longer fits with the receptor.
Scientists could create a competitive inhibitor that prevents the ligand from binding with the receptor.
Scientists could mutate/block a secondary messenger/relay protein involved in the signaling pathway that produces the molecules required for biofilm formation.

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.1-4.4.Cell_Communication” dataset_id=”Unit 4 Cumulative FRQs|14411830e6121e” question_number=”2″] Researchers are testing the effects of a drug that inhibits the formation of plasmodesmata, channels through which plants can send chemical signals. They tested two concentrations of this drug on the average growth of the plant in five trials.

PART 1: Describe the relationship between the inhibition of plasmodesmata formation and the height of the plant.

PART 2: Propose both the type of cellular communication taking place and the type of substance that could be transmitted via plasmodesmata in this experiment.

PART 3: Contrast this type of cellular communication with a type of communication found in human cells.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

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Cg==

UEFSVCAyOiBUaGlzIGlzIA==[Qq]direct cell-to-cell communication, as the plasmodesmata form a physical channel between cells. One substance that could be transmitted is a growth hormone or growth regulator, as, without plasmodesmata, growth is inhibited.

PART 3: Human cells do not have plasmodesmata, but can signal between cells via long-distance (endocrine) signaling (1 below), local signaling (2 below), or direct cell-to-cell (contact) signaling (4 below). Any of the preceding options are acceptable: the diagram below is for explanatory purposes.

[q json=”true” xx=”1″ multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative FRQs|1441033c7b0e1e” question_number=”3″ topic=”4.1-4.4.Cell_Communication”] The diagram below represents signal transduction.

PART 1: Explain how the initiation of signal transduction ensures that a cell’s response to a signal will be controlled and specific.

PART 2: List the type of molecules that generally act as intermediate or relay molecules.

PART 3: In a multicellular organism, signals can come in various forms. Explain how you know that in the system shown above, the ligand is NOT a steroid hormone.

PART 4: Describe a specific example of a cellular response that could occur in the kind of system depicted above.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

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Cg==

UEFSVCAyOiBBIGNvbW1vbiBzZWNvbmQgbWVzc2VuZ2VyIGlzIGNBTVAgKGN5Y2xpYyBBTVApOyBvdGhlcnMgaW5jbHVkZSBJUDMgKGlub3NpdG9sIHRyaXNwaG9zcGhhdGUpLCBhbmQgY2FsY2l1bSBpb25zLg==

Cg==

[Qq]PART 3: In this system, the ligand is binding at the membrane, making it most likely a polar ligand. Steroid hormones are nonpolar and would diffuse through the membrane and bind with a cytoplasmic receptor. A hormone-receptor complex would then diffuse into the nucleus.

PART 4: One example of possible cellular response is the activation of enzymes, such as when liver cells respond to epinephrine by activating enzymes that break down glycogen into glucose as part of the fight or flight response. (note: MANY other examples are possible)

[q json=”true” xx=”1″ multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative FRQs|1440e4f7e07a1e” question_number=”4″ topic=”4.1-4.4.Cell_Communication”] During the fight or flight response, a molecule of epinephrine, released from the adrenal glands, can induce liver cells to convert glycogen to glucose, providing essential fuel for survival. Because epinephrine (also known as adrenaline) is not lipid-soluble, it cannot diffuse through the cell membrane.

PART 1: Describe the events that occur after epinephrine reaches its target cells that result in changes in target cell activities.

PART 2: Epinephrine relies on a second messenger system that involves multiple steps. Explain how having a number of steps in a signaling pathway can promote survival for an organism as a whole.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]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

Cg==

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

Cg==

[Qq]

[q json=”true” xx=”1″ multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative FRQs|1440d00375761e” question_number=”5″ topic=”4.5.Feedback”] Anti-diuretic hormone (ADH) is synthesized in the hypothalamus and released into the blood when body fluids become too hypertonic. When ADH reaches the kidney, it increases the amount of water reabsorbed from the kidney’s tubules back into the blood, decreasing urine output.

Different drugs can affect the production of ADH. MDMA (methylenedioxymethamphetamine) can increase the amount of ADH produced. Alcohol, by contrast, decreases ADH production.

The graph below shows data from a clinical trial for a new medicine. Three groups of patients (A, B, and C) had their total urine output measured over a four-day period. The data have been adjusted to account for differences in body size and fluid intake in the patients’ diets. Patient Group B had normal results.

Identify which group of patients was likely to include people consuming alcohol, and which group of patients was likely to include people taking the drug MDMA. Explain your response in relation to each substance’s effect on ADH.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]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[Qq]

[q json=”true” xx=”1″ multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative FRQs|1440aac2b7361e” question_number=”6″ topic=”4.5.Feedback”] Type 2 diabetes and certain heart conditions can lead to fatigue, which can be described as extreme tiredness, due to a lack of energy. Fatigue is also associated with chronic fatigue syndrome, which has been linked to viral infections, immune system problems, and hormonal imbalances; and emphysema, in which impaired lung function creates difficulty breathing.

PART 1: In Type 2 diabetes, the target cells do not respond correctly to the insulin produced when there is an increase in blood glucose concentration. Explain why fatigue may occur in a person with Type 2 diabetes who is not taking medication.

PART 2: Certain heart conditions result in a weak and irregular heartbeat. Explain how a weak and irregular heartbeat could result in fatigue.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]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

Cg==

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[Qq]

[q json=”true” xx=”1″ multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” dataset_id=”Unit 4 Cumulative FRQs|144095ce4c321e” question_number=”7″ topic=”4.5.Feedback”] The table below summarizes the results of a study of two mammal species living in their natural habitat. The study’s focus was on the ways in which the mammals gained and lost water.

Water gain or loss from various processes in two mammal species

One of these species lives in an environment in which water is freely available. The other lives in an environment in which water is scarce.

PART 1: Identify the type of environment in which each of these species normally lives.

PART 2: Support your answer with evidence from the table.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]IFBBUlQgMTogU3BlY2llcyBJIGxpdmVzIGluIGEgaG90IGRyeSBlbnZpcm9ubWVudCwgcHJvYmFibHkgYSBkZXNlcnQuIFNwZWNpZXMgMiBsaXZlcyBpbiBhbiBlbnZpcm9ubWVudCB3aGVyZSB3YXRlciBpcyBmcmVlbHkgYXZhaWxhYmxlLg==

Cg==

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Cg==

[Qq]Species 1 does not drink, presumably because water is not available and it generates most of its water from its metabolism.
The majority of water loss is by evaporation which provides a cooling mechanism and thus suggests a hot environment.
The small percentage of water lost in urine and feces suggests that the conservation of water is important for this mammal.

We know that species II lives in a warm, humid environment because

Species II takes in much more water per day than species I with the majority obtained from drinking. This suggests that water is freely available.
The large percentage loss in urine is further confirmation of the availability of water.
Species II loses only 36% of its water by evaporation, suggesting that its environment is cooler or more humid than that of I.

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6-4.7.Cell_Cycle” dataset_id=”Unit 4 Cumulative FRQs|14407e85d54a1e” question_number=”8″] Hydroxyurea is a medication that treats cancer by inhibiting the S-phase of the cell cycle. To further investigate the effects of Hydroxyurea (HU) as a potential cancer treatment, researchers exposed yeast to different concentrations of the drug for 24 hours, with the initial introduction of HU at hour 0. They collected data on the optical density of liquid yeast cultures, a measurement that is often used as a proxy for growth rate, as the higher the optical density, the more yeast cells are present in the sample.

PART 1: Calculate the percent change in optical density at 24 hours in yeast exposed to 50mM HU compared to the control.

PART 2: Describe the relationship between the concentration of Hydroxyurea (HU) and the growth rate of yeast.

PART 3: Make a claim about which process in the cell cycle Hydroxyurea must disrupt and propose an explanation for why Hydroxyurea is used to treat cancer.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

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Cg==

Q2FsY3VsYXRpb246IFsoMC40ICYjODIxMTsgMS4yKSAvIDEuMiBdICogMTAwID0gLTAuOC8xLjMgPSAtNjYl

[Qq]

PART 2: As the concentration of Hydroxyurea increases, the growth rate for yeast decreases.

PART 3:

Claim: Hydroxyurea must affect DNA replication. Information is provided that Hydroxyurea affects S-phase, and DNA replication is the major event in S-phase. Without the proper replication of DNA, the cell cannot divide.
Explanation: Cancer is caused by uncontrolled cell division. Hydroxyurea inhibits a step in the cell cycle, thereby inhibiting the cell’s progression through the rest of the cycle.

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6-4.7.Cell_Cycle” dataset_id=”Unit 4 Cumulative FRQs|1440673d5e621e” question_number=”9″] To investigate the function of a particular gene, Gene X, scientists randomly disrupted a line of human cells with radiation and then observed the proportion of cells undergoing mitosis thereafter. In the figure below, the shaded boxes represent cells with no alleles of the gene disrupted, the un-shaded squares represent cells with both alleles disrupted and the half-shaded boxes represent genes with one allele disrupted.

PART 1: Identify the independent and dependent variables in this experiment.

PART 2: Describe the relationship between the functioning of Gene X and the percent of cells undergoing Mitosis (mitotic index).

PART 3: Propose a function for gene X in the cell. Justify your response.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

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Cg==

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[Qq]

PART 3: Gene X in the cell is a tumor suppressor gene. According to the graph, there is a higher percentage of cells undergoing mitosis when both alleles of gene X are disrupted. Therefore, when gene X is active, it seems to prevent mitosis. Tumor suppressor proteins prevent mitosis, so tumor suppression is the probable function of the gene.

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6-4.7.Cell_Cycle” dataset_id=”Unit 4 Cumulative FRQs|144048f8c3ce1e” question_number=”10″] The diagram below shows an important step in cell division involving spindle fibers. Researchers studying fruit flies wanted to look into how different genes affect the formation of spindle fibers in Drosophila melanogaster fruit flies. In their study, they examined the role of a gene called DGT3, which plays a key role in spindle fiber formation in Drosophila cells undergoing cell division.

PART 1: With reference to the cell cycle diagram below, identify the stage in the cell cycle in which the process above occurs.

PART 2: Explain the function of spindle fibers and relate this function to the transmission of genetic information between cells.

PART 3: If DGTC were completely inhibited, predict the effect on mitosis. Justify your answer.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

UEFSVCAxOiBUaGUgZGlhZ3JhbSBzaG93cyBhIGNlbGwgaW4gTS1waGFzZS4=

Cg==

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[Qq]

PART 3: Complete inhibition of DGT3 would prevent spindle fibers from forming properly. Because spindle fibers are responsible for moving and separating chromosomes during mitosis, mitosis would end during prophase (after the chromosomes condense).

[q json=”true” multiple_choice=”false” unit=”4.Cell Communication, Cell Cycle, Feedback” topic=”4.6-4.7.Cell_Cycle” dataset_id=”Unit 4 Cumulative FRQs|143f9f015fca1e” question_number=”11″] The figure below shows the relationship between the number of stem cell divisions in the lifetime of a given tissue and the lifetime risk of cancer in that tissue.

PART 1: Describe the relationship between total stem cell divisions and lifetime risk of cancer, based on the graph.

PART 2: Identify the differences between total stem cell divisions and the lifetime risk of lung cancer in both smokers and non-smokers. Propose an explanation for the differences identified.

PART 3: FAP Colorectal cancer is a rare inherited condition that is caused by the misfunctioning of a protein. Propose a probable role for the protein that misfunctions in this condition.

[c]IFNob3cgdGhl IGFuc3dlcg==[Qq]

[f]

Cg==

UEFSVCAxOiBUaGUgbW9yZSB0b3RhbCBzdGVtIGNlbGwgZGl2aXNpb25zLCB0aGUgaGlnaGVyIHRoZSByaXNrIG9mIGNhbmNlciBpbiB0aGF0IHRpc3N1ZS4=

Cg==

UEFSVCAyOg==

[Qq]

Identify: The total stem cell divisions in lung cancer tissue from smokers and nonsmokers are equal, but the lifetime risk of cancer is greater in those who smoke.
Propose: Smoking is an environmental toxin that can cause DNA damage and mutation, both of which can disrupt the cell cycle.

PART 3: The protein involved in FAP colorectal cancer could be (any of the following are acceptable, and other answers might be possible):

Tumor-suppressor protein (such as p53)
An overexpressed receptor for a cell division signal (like HER2)
A protein that’s part of a signaling cascade that becomes constitutively active (like RAS)
A cell cycle checkpoint protein

[/qwiz]

6. Unit 4 Click-On Challenge 1: Cell Division

[qwiz use_dataset=”mitosis-and-cell-cycle-click-on-challenge” random = “true” style=”width: 600px !important;” quiz_timer=”true” dataset_intro=”true” spaced_repetition=”false” qrecord_id=”sciencemusicvideosMeister1961-Unit 4 Cell Division Click-on Challenge (v2.0)”]

[h]Unit 4 Cell Division Click-On Challenge

[i] Note the timer in the top right. Your goal is accuracy and speed. A good strategy: once through slowly, then additional trials for improvement.

[/qwiz]

7. Unit 4 Click-On Challenge 2: Cell Communication

[qwiz use_dataset=”cell-signaling-click-on-challenge” random = “true” style=”width: 600px !important;” quiz_timer=”true” dataset_intro=”true” spaced_repetition=”false” qrecord_id=”sciencemusicvideosMeister1961-Unit 4 Cell Communication Click-on Challenge (v2.0)”]

[h]Unit 4 Cell Signaling Click-On Challenge

[i] Note the timer in the top right. Your goal is accuracy and speed. A good strategy: once through slowly, then additional trials for improvement.

[/qwiz]

1. Unit 4 Learning Objectives

Topics 4.1.-4.4: Cell Signaling, Cell Communication, and Signal Transduction

Topic 4.5: Feedback and Homeostasis

Topic 4.6: Cell Division and the Cell Cycle

Topic 4.7: Cell Cycle Regulation

2. Unit 4 Cumulative Flashcards

[!]4.2 – 4.4. Signal Transduction[/!]

[!]4.5.Feedback[/!]

[!]4.6.Cell Cycle[/!]

[!]4.7.Regulation of the Cell Cycle[/!]

3. Unit 4 Cumulative Multiple Choice Quiz 1

[Qq]

4. Unit 4 Cumulative Multiple Choice Quiz 2

5. Unit 4 Cumulative FRQs

6. Unit 4 Click-On Challenge 1: Cell Division

7. Unit 4 Click-On Challenge 2: Cell Communication

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