1. Watch this video
2.a. Read this: A key point not covered (well) in the video
- Unlike today’s atmosphere, which is 21% oxygen (O2), the early Earth’s atmosphere had no O2. That’s because free oxygen (O2) only appeared as a result of millions of years of photosynthesis by cyanobacteria (photosynthetic bacteria), which split water molecules to obtain hydrogen and electrons, releasing O2 as a waste product.
- That’s important because oxygen is an oxidizer, stealing electrons from reduced molecules (like sugars or amino acids). The presence of oxygen would have made some of the early steps in the emergence of life – such as the abiotic emergence of monomers – difficult if not impossible.
2.b. Study this summary
Key Concepts
- Life began approximately 3.8 billion years ago (bya).
- The emergence of life followed the formation of Earth, 4.5 billion years ago, which was followed by a period of massive collisions during which the emergence of life would have been impossible.
- Life’s emergence coincides with the end of the bombardment period, about 3.8 bya.
- Understanding the origin of life focuses on how life emerged naturally on Earth, transitioning from chemistry to biology.
- The challenge in understanding the origin of life is explaining how populations of cells (and all of their molecular components) emerged abiotically (from non-living processes).
Steps in the Origin of Life
For life to emerge on the early Earth 3.8 bya, a series of milestones in chemical complexity had to have been reached. These milestones are described below, along with some of the challenges in explaining their emergence.
- Earth Becomes Hospitable for Living Things
- Early Earth (4.5 to ~ 3.8 billion years ago) was inhospitable to life due to asteroid impacts and other extreme conditions.
- By about 3.8 billion years ago, the Earth had become stable enough to allow for life to emerge.
- Note that the most stable environments at that time were undersea hydrothermal events (not required info for the AP Bio exam).
- Abiotic Synthesis of Monomers:
- The molecules that make up living things (proteins, carbohydrates, nucleic acids, and lipids) are all composed of simpler components. These include monomers like amino acids, nucleotides, monosaccharides, and fatty acids.
- In today’s environment, all of these monomers are synthesized by living things. For example carbohydrates are created from inorganic substances during photosynthesis. These carbohydrates are then used to synthesize all of the other monomers.
- To explain the origin of life, we need to be able to explain how these monomers could form abiotically (without living systems to create them). A key experiment explaining how this could occur was performed by Stanley Miller and Harold Urey in 1953 (explained below).
- Formation of Polymers
- To create proteins, nucleic acids, etc. monomers have to combine into polymers. In today’s world, that’s driven by living systems using enzymes.
- Origin of life scenarios have to account for the formation of polymers abiotically, because these polymers serve as the foundation for biological complexity.
- Formation of Vesicles
- All life is composed of cells.
- Origin of life scenarios have to account for the formation of vesicles, lipid-bound structures, which abiotically formed to create compartments.
- These compartments concentrated emerging biological monomers, acting as precursors to cells.
- Emergence of Proto-Cells
- Proto-cells (cell-like structures that were unable to reproduce themselves like living cells) are an elaboration on the vesicles described above.
- They contained polymers and may have had many life-like properties.
- At some point, these proto-cells encapsulation genetic information (probably RNA: see below) that stored information about how to replicate the cell and its key components.
- Emergence of Self-Replicating Systems
- RNA is thought to be the first hereditary molecule due to its ability to both store genetic information and catalyze reactions (e.g., in ribosomes and regulatory microRNAs).
- DNA, by contrast, is less versatile. Because of its double-helical form, it can only store information.
- The RNA World Hypothesis:
- Self-replicating RNA molecules preceded DNA and proteins.
- RNA systems evolved under natural selection, growing in complexity.
- The Last Universal Common Ancestor (LUCA)
- LUCA represents the population of organisms giving rise to all subsequent life.
- Key features of LUCA:
- Lipid bilayer membranes.
- DNA as genetic material.
- RNA for information transfer and catalysis.
- Ribosomes for protein synthesis.
- Use of ATP to drive endergonic reactions.
- Enzymes for synthesis (creating polymers from monomers) and hydrolysis (breaking down polymers to monomers, and metabolizing monomers for processes like cellular respiration).
- ATP synthase for energy production.
- These features of LUCA can be thought of as the shared derived features of the clade that includes all living things.
Miller-Urey Experiment:
The Miller-Urey experiment (despite its many shortcomings) stands are the archetypal origin of life experiment. It established the possibility of the emergence of biological monomers in an abiotic environment.
The entire apparatus was a closed, sterile system, with various valves that could be used to vacuum out all air from the system (3), and sample what the system was producing without contaminating it (9). The system contained a water-filled chamber that simulated the ancient ocean (2). A heat source (1) heated the “ocean,” creating water vapor that would rise into a chamber that represented the primitive atmosphere (6) with methane (CH4), ammonia (NH3), molecular hydrogen (H2), and water vapor (H2O)
The apparatus also contained electrodes (4) which could produce sparks (5), simulating lightning. A condenser (7) cooled the circulating gas. The cooled gas condensed as a liquid in a trap (8), which allowed Miller to see what his apparatus was brewing up.
After five days, Miller sampled the liquid in the trap, and through paper chromatography, he identified several amino acids in the mixture.
Miller’s work has been criticized for using an atmospheric mix that was too reduced, and thus too conducive to the formation of organic compounds. The Earth’s ancient atmosphere probably didn’t have significant amounts of molecular hydrogen or methane. But Miller’s work inspired many other experiments, which have used different mixes of atmospheric gases, energy sources, and minerals (such as iron), and have resulted in the production of the nitrogenous bases found in RNA and DNA (though not complete nucleotides) and a wide array of other amino acids.
3. Master these flashcards
[qdeck qrecord_id=”sciencemusicvideosMeister1961-Origin of LIfe Flashcards (APBVP)” bold_text=”false” style=”width: 600px !important; min-height: 450px !important;”]
[h] Origin of Life Flashcards
[i]
[start]
[q] Describe 5 key steps in the origin of life.
[a]
- Formation of a habitable Earth (stabilization after asteroid impacts).
- Abiotic synthesis of monomers (e.g., amino acids, nucleotides).
- Abiotic synthesis of polymers (e.g., proteins, nucleic acids).
- Formation of vesicles (lipid-bound compartments).
- Emergence of proto-cells and self-replicating systems.
[q] What role do vesicles play in the origin of life?
[a] Vesicles are lipid-bound compartments that mimic cell membranes. They provide an isolated environment where chemical reactions can occur and are precursors to modern cells. Proto-cells formed when polymers and self-replicating systems were encapsulated within vesicles.
[q] Why is the concept of LUCA important in understanding the origin of life?
[a] LUCA, or the Last Universal Common Ancestor, represents the population of organisms that gave rise to all modern life. It had essential features such as:
- A lipid bilayer.
- DNA for genetic information.
- ATP for driving endergonic reactions
- RNA for information transfer and catalysis.
- Ribosomes for protein synthesis.
- Enzymes for polymerization and hydrolysis.
- ATP synthase for energy production.
[q] How does the RNA world hypothesis connect to the origin of life?
[a] The RNA world hypothesis suggests that RNA was the first hereditary molecule because it can store genetic information and catalyze chemical reactions. This dual functionality allowed RNA to drive early life processes before the emergence of DNA and proteins.
[q] What is the importance of abiotic polymer formation in the origin of life?
[a] Abiotic polymer formation is the process by which monomers (e.g., amino acids, nucleotides) link to form complex molecules like proteins and nucleic acids without enzymes. These polymers are essential for the structure and function of living systems.
[q] What distinguishes protocells from modern cells?
[a] Proto-cells are primitive structures that lack the full complexity of modern cells. They:
- Have a lipid membrane but may not be phospholipid-based.
- Contain polymers and RNA but lack fully developed metabolic pathways.
- Represent an intermediate step between non-living chemical systems and living organisms.
[q] How did the absence of oxygen in the early Earth’s atmosphere aid the origin of life?
[a] The lack of oxygen prevented the oxidation of monomers, which are reduced molecules essential for the formation of life’s building blocks. A reducing or non-oxidizing atmosphere was necessary for abiotic synthesis.
[q json=”true” yy=”4″ dataset_id=”AP_Bio_Flashcards_2022|13e1d8efe6910″ question_number=”346″ unit=”7.Evolution_and_Natural_Selection” topic=”7.13.Origin_of_Life”] In any origin of life scenario, what’s the first step? Explain.
[a] In any origin of life scenario, the first step is the formation of monomers: the amino acids, nucleotides, monosaccharides, and fatty acids that serve as the building blocks of life. Only if these molecules are present can more complex molecules (polymers like proteins and nucleic acids) come into being.
Monomer formation is difficult to explain because these monomers don’t spontaneously form. Rather, these energy-rich molecules are generated biologically by plants, cyanobacteria, and algae during photosynthesis. So the challenge in explaining the origin of life is to explain how to generate monomers abiotically (in the absence of life).
[q json=”true” yy=”4″ unit=”7.Evolution_and_Natural_Selection” topic=”7.13.Origin_of_Life” dataset_id=”AP_Bio_Flashcards_2022|d112b223e40ea” question_number=”348″] Describe the Miller-Urey experiment and its results.
[a] The Miller-Urey experiment validated the idea of the abiotic formation of monomers. The experiment combined methane, ammonia, and hydrogen (thought at that time to be a plausible mix for the early Earth’s atmosphere) in a reaction chamber (5). The chamber was connected to a flask containing heated water (2) which represented the early Earth’s oceans. Sparks (5) simulated lightning. After several days, the circulating mixture in the apparatus was sampled, and analysis showed the presence of several amino acids (the monomers of proteins).
[q json=”true” yy=”4″ unit=”7.Evolution_and_Natural_Selection” dataset_id=”AP_Bio_Flashcards_2022|13c404178d510″ question_number=”349″ topic=”7.13.Origin_of_Life”] Why is the Miller-Urey experiment widely regarded as a keystone in origin of life research?
[a] The overall achievement of the Miller-Urey experiment was validation of the idea that monomers can be formed abiotically. In subsequent years, this has been confirmed in a variety of experimental settings, with many different starting compounds and energy sources. This idea has also been validated by the discovery of monomers on meteorites (meaning that certain monomers can form out in space).
[q json=”true” yy=”4″ unit=”7.Evolution_and_Natural_Selection” dataset_id=”AP_Bio_Flashcards_2022|13abb6db71910″ question_number=”352″ topic=”7.13.Origin_of_Life”] The early Earth’s atmosphere was quite different from the atmosphere today. Why is that important for the origin of life?
[a] Unlike today’s atmosphere, which consists of about 21% oxygen, the early Earth’s atmosphere had no free oxygen (O2). The reason why this is important to the origin of life is that for life to arise, its molecular components, biological monomers, need to arise. These monomers are reduced molecules, and in the presence of oxygen, their spontaneous tendency is to become oxidized. A world with abundant oxygen is not a world where new life could arise, and the presence of a reducing (or at least non-oxidizing) atmosphere and ocean was probably a precondition for the emergence of the monomers (amino acids, nucleotides, fatty acids, and monosaccharides) that were combined to create the polymers in the first living cells.
[q json=”true” yy=”4″ dataset_id=”AP_Bio_Flashcards_2022|139bff8b2e910″ question_number=”353″ unit=”7.Evolution_and_Natural_Selection” topic=”7.13.Origin_of_Life”] What is the RNA world hypothesis?
[a] The RNA world hypothesis is the idea that life emerged as a population of self-replicating molecules of RNA. Because RNA can be both information (as in messenger RNA) and act as a catalyst (as in ribosomal RNA), it’s thought that early in Earth’s history, a population of RNAs that could catalyze their own reproduction could arise. Once this happened, then mutation during replication would lead to variation. Subsequent natural selection would lead to greater complexity, leading to protocells, setting the stage for the emergence of DNA-based life.
[q json=”true” yy=”4″ unit=”7.Evolution_and_Natural_Selection” dataset_id=”AP_Bio_Flashcards_2022|13918555ac910″ question_number=”354″ topic=”7.13.Origin_of_Life”] What are two attributes of RNA that make it a better candidate than DNA for playing the role of the first genetic molecule?
[a] RNA is thought to be a better candidate for the first genetic molecule than DNA because RNA can serve as both genetic information (as it does in RNA viruses and mRNA) and as a catalyst for chemical reactions (as it does in ribozymes — shown on the left — and as the catalytic part of ribosomes). DNA, by contrast, is purely informational.
[x] [restart]
[/qdeck]
4. Tackle these quizzes
4.1. Steps in the Origin of Life: LUCA
[qwiz random = “false” style=”width: 700px !important; min-height: 450px !important;” qrecord_id=”sciencemusicvideosMeister1961-Steps in the Origin of Life: LUCA, APBVP”]
[h]Steps in the Origin of Life: LUCA
[i]
[q]In the diagram below, which number represents the first polymers?
[textentry single_char=”true”]
[c]ID M=
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[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFBvbHltZXJzIGFyZSBvZnRlbiBsb25nIGNoYWlucyBvZiBtb2xlY3VsZXM=[Qq]
[q]In the diagram below, which number represents a protocell?
[textentry single_char=”true”]
[c]ID Q=
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[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEZpbmQgYSBsaXBpZCBiaWxheWVyIHdpdGggc29tZSBnZW5ldGljIG1hdGVyaWFsIGluc2lkZSBvZiBpdC4=[Qq]
[q]In the diagram below, which number represents the first monomers?
[textentry single_char=”true”]
[c]ID I=
[f]IEF3ZXNvbWUuIE51bWJlciAyIHJlcHJlc2VudHMgdGhlIGZpcnN0IG1vbm9tZXJzLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIE1vbm9tZXJzIGFyZSByZWxhdGl2ZWx5IHNtYWxsIG1vbGVjdWxlcyBjb21wb3NlZCBvZiBhIGRvemVuIG9yIGEgZmV3IGRvemVuIGF0b21zLg==[Qq]
[q]In the diagram below, the split that led to Archaea and Bacteria is represented by…
[textentry single_char=”true”]
[c]ID Y=
[f]IEdvb2Qgd29yay4gTnVtYmVyIDYgcmVwcmVzZW50cyB0aGUgc3BsaXQgYmV0d2VlbiBiYWN0ZXJpYSBhbmQgYXJjaGFlYS4=[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEZpbmQgTFVDQSwgYW5kIHRoZW4gZmluZCB3aGVyZSBpdCBzcGxpdHMgaW50byB0d28gYnJhbmNoZXMu[Qq]
[q labels= “top”]The table below shows some key steps involved in the origin of life. Use what you learned above (and trial and error) to figure it out.
| FIRST | Abiotic creation of _____________ (the molecular building blocks of life) | |||
| NEXT | Abiotically link monomers to form ___________ | Origin of ______________. Create a self-perpetuating system for processing matter and _________ and for removing wastes. | Origin of _____________. Provide the system with a way to pass on ______________ for maintenance, growth, and reproduction | Encapsulate the system with a _____________ to keep it from dissolving away, creating the first primitive _______. |
[l]cells
[f*] Correct!
[fx] No, that’s not correct. Please try again.
[l]energy
[f*] Correct!
[fx] No, that’s not correct. Please try again.
[l]heredity
[f*] Excellent!
[fx] No. Please try again.
[l]instructions
[f*] Great!
[fx] No. Please try again.
[l]metabolism
[f*] Excellent!
[fx] No. Please try again.
[l]membrane
[f*] Great!
[fx] No. Please try again.
[l]monomers
[f*] Great!
[fx] No, that’s not correct. Please try again.
[l]polymers
[f*] Good!
[fx] No, that’s not correct. Please try again.
[q labels= “top”]This table shows some of the key steps involved in the origin of life. Fill in the blanks.
| FIRST | __________ creation of monomers (the molecular__________ blocks of life. | |||
| NEXT | Abiotically link _____________ to form polymers | Origin of metabolism. Create a self-_______________ system for processing ________ and energy and for removing ________ | Origin of heredity. Provide the system with a way to ___________ instructions about maintenance, growth, and _______________. | ___________ the system with a membrane to keep it from dissolving away, creating the first primitive cells. |
[l]Abiotic
[f*] Good!
[fx] No, that’s not correct. Please try again.
[l]building
[f*] Correct!
[fx] No, that’s not correct. Please try again.
[l]Encapsulate
[f*] Correct!
[fx] No, that’s not correct. Please try again.
[l]matter
[f*] Correct!
[fx] No, that’s not correct. Please try again.
[l]monomers
[f*] Great!
[fx] No. Please try again.
[l]pass on
[f*] Great!
[fx] No, that’s not correct. Please try again.
[l]perpetuating
[f*] Great!
[fx] No. Please try again.
[l]reproduction
[f*] Great!
[fx] No. Please try again.
[l]wastes
[f*] Correct!
[fx] No. Please try again.
[q multiple_choice=”true”] Based on what you know about biology, the first self-replicating informational molecule would probably be a(n) __________ acid.
[c]IGFtaW5v[Qq]
[f]IE5vLiBBbWlubyBhY2lkcyBhcmUgdGhlIG1vbm9tZXJzIG9mIHByb3RlaW5zLiBUaGV5JiM4MjE3O3JlIG5vdCBpbmZvcm1hdGlvbmFsLg==[Qq]
[c]IG51Y2 xlaWM=[Qq]
[f]IEV4Y2VsbGVudC4gSW4gbGlmZSB0b2RheSwgaW5mb3JtYXRpb25hbCBtb2xlY3VsZXMgYXJlIG51Y2xlaWMgYWNpZHM6IGVpdGhlciBETkEgb3IgUk5BLg==[Qq]
[c]IGZhdHR5[Qq]
[f]IE5vLiBGYXR0eSBhY2lkcyBhcmUgY29tcG9uZW50cyBvZiBsaXBpZHMuIFRoZXkmIzgyMTc7cmUgbm90IHVzZWQgZm9yIGluZm9ybWF0aW9uLCBhbmQgaXQmIzgyMTc7cyBoYXJkIHRvIHNlZSBob3cgdGhleSBjb3VsZCBiZS4=[Qq]
[q multiple_choice=”true”] From the choices below, the type of molecule that would make up an encapsulating membrane would probably be primarily composed of _________ acids.
[c]IGFtaW5v[Qq]
[f]IE5vLiBBbWlubyBhY2lkcyBhcmUgdGhlIG1vbm9tZXJzIG9mIHByb3RlaW5zLiBUaGV5IGFyZSBjcnVjaWFsbHkgaW1wb3J0YW50IHBhcnRzIG9mIG1lbWJyYW5lcywgYnV0IHRoZXkmIzgyMTc7cmUgbm90IHRoZSBtYWluIHN0cnVjdHVyYWwgY29tcG9uZW50IG9mIG1lbWJyYW5lcy4=[Qq]
[c]IG51Y2xlaWM=[Qq]
[f]IE5vLiBJbiBsaWZlIHRvZGF5LCBpbmZvcm1hdGlvbmFsIG1vbGVjdWxlcyBhcmUgbnVjbGVpYyBhY2lkcy4gWW91JiM4MjE3O3JlIGxvb2tpbmcgZm9yIGEgbW9sZWN1bGUgdGhhdCB3b3VsZCBtYWtlIHVwIG9uZSBvZiB0aGUgY29tcG9uZW50cyBvZiBtZW1icmFuZXMu[Qq]
[c]IGZh dHR5[Qq]
[f]IEV4Y2VsbGVudC4gRmF0dHkgYWNpZHMgYXJlIGEga2V5IGNvbXBvbmVudCBvZiB0aGUgbW9sZWN1bGVzIHRoYXQgbWFrZSB1cCBtZW1icmFuZXMgKHBob3NwaG9saXBpZHMgaW4gYmFjdGVyaWEgYW5kIGV1a2FyeWEsIGEgcmVsYXRlZCBsaXBpZCBtb2xlY3VsZSBpbiBhcmNoYWVhKS4=[Qq]
[q]In the diagram below, which number represents chemiosmosis
[textentry single_char=”true”]
[c]ID c=
[f]IEV4Y2VsbGVudC4gTnVtYmVyIDcgcmVwcmVzZW50cyB0aGUgY2hlbWlvc21vdGljIHByb2R1Y3Rpb24gb2YgQVRQIHZpYSB0aGUgQVRQIHN5bnRoYXNlIGNoYW5uZWwu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIENoZW1pb3Ntb3NpcyBpbnZvbHZlcyB0aGUgZmFjaWxpdGF0ZWQgZGlmZnVzaW9uIG9mIGh5ZHJvZ2VuIGlvbnMgdG8gcG93ZXIgQVRQIHN5bnRoZXNpcy4=[Qq]
[q]In the diagram below, which number represents translation?
[textentry single_char=”true”]
[c]ID Q=
[f]IEV4Y2VsbGVudC4gTnVtYmVyIDQgc2hvd3MgYSByaWJvc29tZSB0cmFuc2xhdGluZyBtUk5BIGludG8gcHJvdGVpbi4=[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFRyYW5zbGF0aW9uIGlzIHByb3RlaW4gc3ludGhlc2lzLCBhbmQgaXQmIzgyMTc7cyBjYXJyaWVkIG91dCBieSByaWJvc29tZXMu[Qq]
[q]The diagram below shows the array of features that are thought to have been present in [hangman].
[c]TFVDQQ==[Qq]
[x]
[restart]
[/qwiz]
4.2. The Miller-Urey Experiment, the Origin of Monomers, and the RNA World
[qwiz random = “true” qrecord_id=”sciencemusicvideosMeister1961-The Miller-Urey Experiment and the Origin of Monomers, APBVP”]
[h]The Miller-Urey Experiment, the Origin of Monomers, and the RNA World
[i]
[q] In the Miller-Urey experiment, which number represents the part that simulated the ancient oceans?
[textentry single_char=”true”]
[c]ID I=
[f]IEV4Y2VsbGVudC4gTnVtYmVyIDIgcmVwcmVzZW50cyB0aGUgd2F0ZXIgaW4gdGhlIGFuY2llbnQgb2NlYW5zLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFdoaWNoIHBhcnQgbG9va3MgbGlrZSBpdCB3b3VsZCBjb250YWluIHdhdGVyPw==[Qq]
[q] In the Miller-Urey experiment, which number represents simulated lightning in the ancient atmosphere?
[textentry single_char=”true”]
[c]ID U=
[f]IE5pY2Ugam9iLiBOdW1iZXIgNSByZXByZXNlbnRzIGxpZ2h0bmluZyBpbiB0aGUgYW5jaWVudCBhdG1vc3BoZXJlLg==[Qq]
[c]ID Q=[Qq]
[f]IE9rLiBUaGF0IHdhc24mIzgyMTc7dCBleGFjdGx5IHdoYXQgdGhlIHF1ZXN0aW9uIHdhcyBhc2tpbmcsIGJ1dCBpdCYjODIxNztzIGNsb3NlIGVub3VnaDogJiM4MjIwOzQmIzgyMjE7IHJlcHJlc2VudHMgZWxlY3Ryb2RlcyB0aGF0IGNyZWF0ZWQgdGhlIHNwYXJrcyB0aGF0IHNpbXVsYXRlZCBsaWdodG5pbmcgaW4gdGhlIGFuY2llbnQgYXRtb3NwaGVyZS4=[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFdoaWNoIHBhcnQgbG9va3MgbGlrZSBpdCB3b3VsZCByZXByZXNlbnQgYW4gZWxlY3RyaWNhbCBzcGFyaz8=[Qq]
[q] In the Miller-Urey experiment, which number represents a part that simulated heat from volcanoes?
[textentry single_char=”true”]
[c]ID E=
[f]IEdvb2Qgd29yay4gTnVtYmVyIDEgcmVwcmVzZW50cyBoZWF0IGZyb20gYW5jaWVudCB2b2xjYW5vZXMu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFdoaWNoIHBhcnQgbG9va3MgbGlrZSBpdCB3b3VsZCBwcm9kdWNlIGhlYXQ/[Qq]
[q] In the diagram below of the Miller-Urey experiment, the electrodes that produce the lighting are represented by which number?
[textentry single_char=”true”]
[c]ID Q=
[f]V2F5IHRvIGdvLiBOdW1iZXIgNCByZXByZXNlbnRzIHRoZSBzcGFyay1wcm9kdWNpbmcgZWxlY3Ryb2Rlcy4=[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEVsZWN0cmljaXR5IGhhcyBwb3NpdGl2ZSBhbmQgbmVnYXRpdmUgY2hhcmdlcy4gV2hlcmUgZG8geW91IHNlZSBzeW1ib2xzIHRoYXQgd291bGQgcmVwcmVzZW50IHBsdXMgYW5kIG1pbnVzIGNoYXJnZXM/[Qq]
[q] In the diagram below of the Miller-Urey experiment, the chamber that contains the gases in the ancient atmosphere would be found at which number?
[textentry single_char=”true”]
[c]Ng ==
[f]Q29ycmVjdC4gTnVtYmVyIDYgcmVwcmVzZW50cyB0aGUgYW5jaWVudCBhdG1vc3BoZXJlLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFRoZSBsaWdodGluZyBvY2N1cnMgd2l0aGluIHRoZSBhdG1vc3BoZXJlLg==[Qq]
[q] In the diagram below of the Miller-Urey experiment, the condenser that cooled the gases in the atmosphere, causing whatever was in the atmosphere to precipitate into the trap, is found at which number?
[textentry single_char=”true”]
[c]Nw ==
[f]TmljZS4gTnVtYmVyIDcgcmVwcmVzZW50cyB0aGUgY29uZGVuc2VyLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIENvbmRlbnNlcnMgY2lyY3VsYXRlIHdhdGVyIHRoYXQgY2F1c2VzIHZhcG9ycyB0byBjb25kZW5zZS4gRmluZCB3aGVyZSB3YXRlciBpcyBjaXJjdWxhdGluZyBpbiBhbmQgb3V0Lg==[Qq]
[q] In the diagram below of the Miller-Urey experiment, where would amino acids and other organic compounds have been collected?
[textentry single_char=”true”]
[c]OA ==
[f]TmljZS4gTnVtYmVyIDggcmVwcmVzZW50cyB0aGUgdHJhcCwgYW5kIHRoYXQmIzgyMTc7cyB3aGVyZSBvcmdhbmljIGNvbXBvdW5kcyBsaWtlIGFtaW5vIGFjaWRzIHdvdWxkIHByZWNpcGl0YXRlIGZvciBjb2xsZWN0aW9uLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFRoZSB0cmFwIGlzIGJlbmVhdGggdGhlIGNvbmRlbnNlci4=[Qq]
[q]In the Miller-Urey experiment, the mixture of gases used in the experiment differed from the gases in the current atmosphere in many ways. For one thing, [hangman] (a gas produced by photosynthesis) was lacking.
[c]b3h5Z2Vu[Qq]
[q]The Miller-Urey experiment was designed to prove that [hangman] synthesis of monomers might have been possible on the early Earth
[c]YWJpb3RpYw==[Qq]
[q] DNA can only serve as an organism’s [hangman]. RNA, by contrast, can play DNA’s role, and also serve as [hangman]. Additional hint: think of two rhyming terms associated with genetics.
[c]IGdlbm90eXBl[Qq]
[f]IEdyZWF0IQ==[Qq]
[c]IHBoZW5vdHlwZQ==[Qq]
[f]IEdyZWF0IQ==[Qq]
[q] For RNAs in the RNA world to be able to evolve, reproduction would have to be accompanied by the changes in nucleic acid sequences that are called [hangman], creating the variation that makes natural [hangman]possible.
[c]IG11dGF0aW9u[Qq]
[f]IENvcnJlY3Qh[Qq]
[c]IHNlbGVjdGlvbg==[Qq]
[f]IENvcnJlY3Qh[Qq]
[q] In the RNA world representation below, which letter represents RNA nucleotides?
[textentry single_char=”true”]
[c]IG I=[Qq]
[f]IE5pY2UuIFRoZSBsZXR0ZXIgJiM4MjIwO2ImIzgyMjE7IHJlcHJlc2VudHMgUk5BIG51Y2xlb3RpZGVzLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBMb29rIGZvciB0aGUgbW9ub21lcnMgdGhhdCwgb25jZSBjb21iaW5lZCwgZm9ybSB0aGUgUk5BIHNob3duIGFudCAmIzgyMjA7YyYjODIyMTsgYW5kICYjODIyMDtkLiYjODIyMTs=[Qq]
[q] In the RNA world representation below, which letter represents template-driven RNA replication of new RNA molecules.
[textentry single_char=”true”]
[c]IG U=[Qq]
[f]IEF3ZXNvbWUuIFRoZSBsZXR0ZXIgJiM4MjIwO2UmIzgyMjE7IHJlcHJlc2VudHMgUk5BIHBvbHltZXJzIHNlcnZpbmcgYXMgYSB0ZW1wbGF0ZSBmb3IgdGhlIHJlcHJvZHVjdGlvbiBvZiBuZXcgcG9seW1lcnMu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBMb29rIGZvciBhIGRpYWdyYW0gdGhhdCBzaG93cyBSTkEgYmVpbmcgY29waWVkIGZyb20gb3RoZXIgUk5BLg==[Qq]
[q] In the RNA world representation below, which letter represents a protocell with RNA for its genetic material, and RNA-based enzymes?
[textentry single_char=”true”]
[c]IG Y=[Qq]
[f]IFRlcnJpZmljLiBUaGUgbGV0dGVyICYjODIyMDtmJiM4MjIxOyByZXByZXNlbnRzIGFuIFJOQS1iYXNlZCBwcm90b2NlbGwu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBMb29rIGZvciBhIGRpYWdyYW0gdGhhdCBzaG93cyBzb21ldGhpbmcgdGhhdCBsb29rcyBsaWtlIGEgY2VsbC4=[Qq]
[x]
[restart]
[/qwiz]
What’s Next?
This topic ends Unit 7 of the AP Bio Video Pathway
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