Cells: Basic Features

For a deeper dive into this material, complete this tutorial: Topics 2.1 – 2.2, Part 1. Introduction to Cells

1. Watch this Video

2. Study this Summary

Key Points

  • Cells are the basic unit of life and the foundation of structure and function in all organisms.
  • Prokaryotic and eukaryotic cells differ in size, complexity, and structure, but both share essential features such as membranes and genetic material.
  • Eukaryotic cells are defined by their nucleus and membrane-bound organelles, while prokaryotic cells are simpler and lack these structures.

Basic Structure and Fundamental Parts of Cells

  • All cells share three fundamental components:
    • Cell Membrane: Separates the living cytoplasm from the external environment.
    • Genetic Material: DNA, organized as a double helix, carries the cell’s instructions.
    • Systems for Maintenance and Replication: Maintain cellular function and replicate the cell and its DNA.
  • Gene Expression: DNA is transcribed into messenger RNA (mRNA), which ribosomes translate into proteins.
  • Proteins:
    • Serve as the cell’s “workhorses,” including enzymes that control metabolism.
    • Some proteins are embedded in the membrane or exported outside the cell.

Prokaryotic vs. Eukaryotic Cells

  • Prokaryotic Cells:
    • Small and simple in structure.
    • No nucleus; their genetic material is organized as a circular chromosome (looped DNA).
    • Contain additional small DNA molecules called plasmids.
    • Found in two of the three domains of life: Archaea and Bacteria.
  • Eukaryotic Cells:
    • Larger and more complex than prokaryotic cells.
    • Found in the domain Eukarya.
    • Have a nucleus containing multiple linear chromosomes.
      • DNA is associated with proteins for packaging and organization.
    • Defined by the presence of mitochondria.
    • Contain many membrane-bound organelles, each surrounded by a membrane.

3. Master these Flashcards

[qdeck style=”width: 600px !important; min-height: 450px !important;” bold_text=”false” random=”true”]

[h] Key facts about cells,

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c110″ question_number=”101″] What are the three fundamental components shared by all cells?

[a]
1. <strong>Cell Membrane:</strong> Separates the cytoplasm from the external environment.
2. <strong>Genetic Material:</strong> DNA, the double helix that carries instructions.
3. <strong>Systems for Maintenance and Replication:</strong> Maintain cellular functions and replicate DNA.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c111″ question_number=”102″] Describe the process of gene expression in cells.

[a]
1. DNA is transcribed into messenger RNA (mRNA).
2. Ribosomes read the mRNA and translate it into proteins.
3. Proteins act as the cell’s workhorses, carrying out a variety of functions relating to growth, repair, and reproduction.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c112″ question_number=”103″] What are prokaryotic cells, and what are their key features?

[a]
1. Prokaryotic cells are small and simple.
2. They lack a nucleus and have circular DNA (looped chromosomes).
3. May contain plasmids (small extra-chromosomal DNA).
4. Found in two domains: Bacteria and Archaea.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c113″ question_number=”104″] What are eukaryotic cells, and what are their defining features?

[a]
1. Eukaryotic cells are larger and more complex than prokaryotic cells.
2. They have a nucleus with multiple linear chromosomes.
3. Their DNA is associated with proteins for organization and packaging
4. Contain mitochondria and other membrane-bound organelles.
5. Found in the domain Eukarya.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c114″ question_number=”105″] How do prokaryotic and eukaryotic cells differ in terms of DNA organization?

[a]
1. Prokaryotes: Circular DNA without protein association.
2. Eukaryotes: Linear chromosomes with DNA associated with proteins.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c115″ question_number=”106″] In which domains of life are prokaryotic and eukaryotic cells found?

[a]
1. <strong>Prokaryotic cells:</strong> Domains Bacteria and Archaea.
2. <strong>Eukaryotic cells:</strong> Domain Eukarya.

[q json=”true” yy=”4″ unit=”2.Cell_Structure” topic=”2.1.Cells” dataset_id=”AP_Bio_Flashcards_2022|1c2b3fb4c116″ question_number=”107″] What is the significance of mitochondria in eukaryotic cells?

[a] Mitochondria (along with the presence of a nucleus) can be thought of as the defining feature of eukaryotic cells. They are membrane-bound organelles responsible for generating energy (ATP) through cellular respiration.

[x][restart]

[/qdeck]

4. Tackle this quiz

[qwiz random = “true”]

[h]Basic Cell Parts and Concepts Quiz

[i]This quiz will test your mastery of all the ideas in this tutorial. Here’s how the quiz works:

  • Each question is multiple choice or matching, but the entire quiz is like a series of flashcards.
  • If you get the question right, it comes off the deck.
  • If you get the question wrong, it goes to the bottom of the deck, so you can try it again.

[q] A student is observing cells under a microscope. The cells are extremely small. Doing further research, the student learns that the cells have DNA, but the DNA is not in a nucleus. There are no complex organelles. This cell would best be described as a

[c]YW5pbWFsIGNlbGw=[Qq]

[c]cHJva2FyeW90 aWMgY2VsbA==[Qq]

[c]cGxhbnQgY2VsbA==[Qq]

[f]wqBOby7CoEFuaW1hbCBjZWxscyBoYXZlIG9yZ2FuZWxsZXMgYW5kIGEgbnVjbGV1cy4=[Qq]

[f]IE5pY2Ugam9iOiBwcm9rYXJ5b3RpYyBjZWxscyBhcmUgc21hbGwgYW5kIG11Y2ggc2ltcGxlciB0aGFuIGV1a2FyeW90aWMgY2VsbHMuIFRoZXkgaGF2ZSBETkEsIGJ1dCBpdCYjODIxNztzIG5vdCBlbmNsb3NlZCBpbiBhIG51Y2xldXMuIFRoZXJlIGFyZSBubyBjb21wbGV4IG9yZ2FuZWxsZXMu[Qq]

[f]wqBOby4gUGxhbnQgY2VsbHMgaGF2ZSBvcmdhbmVsbGVzIGFuZCBhIG51Y2xldXMu

Cg==

[Qq]

[q]Which of the following statements about prokaryotic cells is TRUE?

[c]UHJva2FyeW90aWMgY2VsbHMgaGF2ZSBjaGxvcm9wbGFzdHM=[Qq]

[c]UHJva2FyeW90aWMgY2VsbHMgYXJlIHNtYWxs ZXIgdGhhbiBldWthcnlvdGljIGNlbGxzLg==[Qq]

[c]UHJva2FyeW90aWMgY2VsbHMgaGF2ZSBhIG51Y2xldXM=[Qq]

[f]Tm8uwqBQcm9rYXJ5b3RpYyBjZWxscyBkb24mIzgyMTc7dCBoYXZlIGNvbXBsZXggb3JnYW5lbGxlcyBsaWtlIGNobG9yb3BsYXN0cy4=[Qq]
[f]IFllcy7CoFByb2thcnlvdGljIGNlbGxzIGFyZSBzbWFsbGVyIHRoYW4gZXVrYXJ5b3RpYyBjZWxscy4=[Qq]
[f]wqBOby7CoFByb2thcnlvdGljIGNlbGxzIGRvbiYjODIxNzt0IGhhdmUgYSBudWNsZXVz

Cg==

Cg==[Qq]

[q]Which of the following kinds of organisms have prokaryotic cells?

[c]QW5pbWFscw==[Qq]

[c]UGxhbnRzLg==[Qq]

[c]RnVuZ2k=[Qq]

[c]QmFjdG VyaWE=[Qq]

[f]Tm8uwqBBbmltYWxzIGhhdmUgZXVrYXJ5b3RpYyBjZWxscw==[Qq]

[f]Tm8uIFBsYW50cyBoYXZlIGV1a2FyeW90aWMgY2VsbHM=[Qq]

[f]wqBOby7CoEZ1bmdpIGhhdmUgZXVrYXJ5b3RpYyBjZWxscw==[Qq]

[f]WWVzLiBCYWN0ZXJpYSBoYXZlIHByb2thcnlvdGljIGNlbGxzLg==

Cg==

[Qq]

[q]What’s the name for the barrier that surrounds the cytoplasm. It’s present in all cells.

[c]Y2VsbCB3YWxs[Qq]

[c]bnVjbGV1cw==[Qq]

[c]Y2VsbCBtZW 1icmFuZQ==[Qq]

[c]Y3l0b3BsYXNt[Qq]

[c]c3RhcmNoIHBsYXN0aWQ=[Qq]

[f]Tm8uwqBDZWxsIHdhbGxzIGFyZSBmb3VuZCBvdXRzaWRlIHRoZSBjZWxsIG1lbWJyYW5lLg==[Qq]

[f]Tm8uIFRoZSBudWNsZXVzIGlzIHdoYXQgaG9sZHMgYW5kIHByb3RlY3RzIHRoZSBETkEgKGdlbmVzKSBpbiBhIGV1a2FyeW90aWMgY2VsbA==[Qq]

[f]WWVzLiBJbiBhbGwgY2VsbHMsIHRoZSBiYXJyaWVyIHRoYXQgc3Vycm91bmRzIHRoZSBjeXRvcGxhc20gaXMgdGhlIGNlbGwgbWVtYnJhbmUu[Qq]

[f]Tm8uIFRoZSBjeXRvcGxhc20gaXMgdGhlIGZsdWlkIGluc2lkZSB0aGUgbWVtYnJhbmUuIEl0JiM4MjE3O3Mgd2hlcmUgdGhlIGNlbGwmIzgyMTc7cyBjaGVtaWNhbCByZWFjdGlvbnMgb2NjdXIu[Qq]

[f]Tm8uIENobG9yb3BsYXN0cyBhcmUgc21hbGwsIGdyZWVuIGVsbGlwdGljYWwgYm9kaWVzIGZvdW5kIGluc2lkZSB0aGUgY3l0b3BsYXNtIG9mIHBsYW50IGNlbGxzLiBUaGVpciBmdW5jdGlvbiBpcyB0byBwcm9kdWNlIGZvb2QgdGhyb3VnaCBwaG90b3N5bnRoZXNpcy4=

Cg==

[Qq]

[q]What’s the name for the organelle inside the cytoplasm which holds the genes/DNA?

[c]Y2VsbCB3YWxs[Qq]

[c]bnVjbG V1cw==[Qq]

[c]Y2VsbCBtZW1icmFuZQ==[Qq]

[c]Y3l0b3BsYXNt[Qq]

[c]Y2hsb3JvcGxhc3Q=[Qq]

[f]Tm8uIFRoZSBjZWxsIHdhbGwgaXMgdGhlIG91dGVyIGJvdW5kYXJ5IG9mIGEgcGxhbnQgY2VsbC4gT25lIG9mIGl0cyBmdW5jdGlvbnMgaXMgdG8gcHJvdmlkZSBzdHJlbmd0aCBhbmQgcmlnaWRpdHkgdG8gdGhlIGNlbGwu[Qq]

[f]WWVzLiBUaGUgbnVjbGV1cyBpcyB3aGF0IGhvbGRzIGFuZCBwcm90ZWN0cyB0aGUgRE5BIChnZW5lcykgaW4gYSBldWthcnlvdGljIGNlbGw=[Qq]

[f]Tm8uIFRoZSBjZWxsIG1lbWJyYW5lIGlzwqB0aGUgYmFycmllciB0aGF0IHN1cnJvdW5kcyB0aGUgY3l0b3BsYXNtLiBJdCBjb250cm9scyB3aGF0IGVudGVycyBhbmQgbGVhdmVzIHRoZSBjZWxsLg==[Qq]

[f]Tm8uIFRoZSBjeXRvcGxhc20gaXMgdGhlIGZsdWlkIGluc2lkZSB0aGUgbWVtYnJhbmUuIEl0JiM4MjE3O3Mgd2hlcmUgdGhlIGNlbGwmIzgyMTc7cyBjaGVtaWNhbCByZWFjdGlvbnMgb2NjdXIu[Qq]

[f]Tm8uIENobG9yb3BsYXN0cyBhcmUgc21hbGwsIGdyZWVuIGVsbGlwc2VzIG9yIHNwaGVyZXMgZm91bmQgaW5zaWRlIHRoZSBjeXRvcGxhc20gb2YgcGxhbnQgY2VsbHMuIFRoZWlyIGZ1bmN0aW9uIGlzIHRvIHByb2R1Y2UgZm9vZCB0aHJvdWdoIHBob3Rvc3ludGhlc2lzLg==

Cg==

[Qq]

[q]What’s the name for the fluid inside the cell where chemical reactions occur?

[c]Y2VsbCB3YWxs[Qq]

[c]bnVjbGV1cw==[Qq]

[c]Y2VsbCBtZW1icmFuZQ==[Qq]

[c]Y3l0b3 BsYXNt[Qq]

[c]Y2hsb3JvcGxhc3Q=[Qq]

[f]Tm8uIFRoZSBjZWxsIHdhbGwgaXMgdGhlIG91dGVyIGJvdW5kYXJ5IG9mIGEgcGxhbnQgY2VsbC4gT25lIG9mIGl0cyBmdW5jdGlvbnMgaXMgdG8gcHJvdmlkZSBzdHJlbmd0aCBhbmQgcmlnaWRpdHkgdG8gdGhlIGNlbGwu[Qq]

[f]Tm8uIFRoZSBudWNsZXVzIGlzIHdoYXQgaG9sZHMgYW5kIHByb3RlY3RzIHRoZSBETkEgKGdlbmVzKSBpbiBhIGV1a2FyeW90aWMgY2VsbA==[Qq]

[f]Tm8uIFRoZSBjZWxsIG1lbWJyYW5lIGlzwqB0aGUgYmFycmllciB0aGF0IHN1cnJvdW5kcyB0aGUgY3l0b3BsYXNtLiBJdCBjb250cm9scyB3aGF0IGVudGVycyBhbmQgbGVhdmVzIHRoZSBjZWxsLg==[Qq]

[f]WWVzLiBUaGUgY3l0b3BsYXNtIGlzIHRoZSBmbHVpZCBpbnNpZGUgdGhlIG1lbWJyYW5lLiBJdCYjODIxNztzIHdoZXJlIHRoZSBjZWxsJiM4MjE3O3MgY2hlbWljYWwgcmVhY3Rpb25zIG9jY3VyLg==[Qq]

[f]Tm8uIENobG9yb3BsYXN0cyBhcmUgc21hbGwsIGdyZWVuIGVsbGlwdGljYWwgc3BoZXJlcyBmb3VuZCBpbnNpZGUgdGhlIGN5dG9wbGFzbSBvZiBwbGFudCBjZWxscy4gVGhlaXIgZnVuY3Rpb24gaXMgdG8gcHJvZHVjZSBmb29kIHRocm91Z2ggcGhvdG9zeW50aGVzaXMu[Qq]

[q]Which type of cells contain plasmids, small extra-chromosomal DNA molecules?
[c]RXVrYXJ5b3RpYyBjZWxscw==[Qq]
[c]UHJva2FyeW90 aWMgY2VsbHM=[Qq]
[c]QW5pbWFsIGNlbGxz[Qq]
[c]UGxhbnQgY2VsbHM=[Qq]
[f]Tm8uIEV1a2FyeW90aWMgY2VsbHMgdHlwaWNhbGx5IGRvIG5vdCBjb250YWluIHBsYXNtaWRzLiBUcnkgYWdhaW4h[Qq]
[f]Q29ycmVjdCEgUHJva2FyeW90aWMgY2VsbHMgbWF5IGNvbnRhaW4gcGxhc21pZHMsIHdoaWNoIGFyZSBzbWFsbCwgY2lyY3VsYXIgRE5BIG1vbGVjdWxlcyBzZXBhcmF0ZSBmcm9tIHRoZWlyIGNocm9tb3NvbWFsIEROQS4=[Qq]
[f]Tm8uIEFuaW1hbCBjZWxscyBhcmUgYSB0eXBlIG9mIGV1a2FyeW90aWMgY2VsbCBhbmQgZG8gbm90IGhhdmUgcGxhc21pZHMu[Qq]
[f]Tm8uIFBsYW50IGNlbGxzIGFyZSBldWthcnlvdGljIGFuZCBkbyBub3QgaGF2ZSBwbGFzbWlkcy4=

Cg==[Qq]

[q]What feature defines eukaryotic cells and is absent in prokaryotic cells?
[c]QSBudW NsZXVz[Qq]
[c]Q2lyY3VsYXIgRE5B[Qq]
[c]QSBjZWxsIG1lbWJyYW5l[Qq]
[c]Umlib3NvbWVz[Qq]
[f]Q29ycmVjdCEgRXVrYXJ5b3RpYyBjZWxscyBoYXZlIGEgbnVjbGV1cywgd2hpY2ggaG91c2VzIHRoZWlyIEROQSwgdW5saWtlIHByb2thcnlvdGljIGNlbGxzLg==[Qq]
[f]Tm8uIENpcmN1bGFyIEROQSBpcyBmb3VuZCBpbiBwcm9rYXJ5b3RpYyBjZWxscywgbm90IGV1a2FyeW90aWMgY2VsbHMu[Qq]
[f]Tm8uIEJvdGggcHJva2FyeW90aWMgYW5kIGV1a2FyeW90aWMgY2VsbHMgaGF2ZSBhIGNlbGwgbWVtYnJhbmUu[Qq]
[f]Tm8uIEJvdGggcHJva2FyeW90aWMgYW5kIGV1a2FyeW90aWMgY2VsbHMgaGF2ZSByaWJvc29tZXMgZm9yIHByb3RlaW4gc3ludGhlc2lzLg==

Cg==[Qq]

[q]Which domain of life contains organisms with mitochondria?
[c]RXVrYX J5YQ==[Qq]
[c]QmFjdGVyaWE=[Qq]
[c]QXJjaGFlYQ==[Qq]
[f]Q29ycmVjdCEgTWl0b2Nob25kcmlhIGFyZSBhIGhhbGxtYXJrIG9mIGV1a2FyeW90aWMgY2VsbHMsIHdoaWNoIGFyZSBmb3VuZCBpbiB0aGUgZG9tYWluIEV1a2FyeWEu[Qq]
[f]Tm8uIEJhY3RlcmlhIGFyZSBwcm9rYXJ5b3RpYyBhbmQgZG8gbm90IGhhdmUgbWl0b2Nob25kcmlhLg==[Qq]
[f]Tm8uIEFyY2hhZWEgYXJlIHByb2thcnlvdGljIGFuZCBkbyBub3QgaGF2ZSBtaXRvY2hvbmRyaWEu

Cg==[Qq]

[q]What is the function of ribosomes in cells?
[c]VG8gcHJvZHVjZSBlbmVyZ3kgdGhyb3VnaCBjZWxsdWxhciByZXNwaXJhdGlvbg==[Qq]
[c]VG8gcGFja2FnZSBhbmQgdHJhbnNwb3J0IHByb3RlaW5z[Qq]
[c]VG8gc3ludGhlc2l6ZSBwcm90ZWlu cyBieSB0cmFuc2xhdGluZyBtUk5B[Qq]
[c]VG8gc3RvcmUgZ2VuZXRpYyBtYXRlcmlhbA==[Qq]
[f]Tm8uIEVuZXJneSBwcm9kdWN0aW9uIG9jY3VycyBpbiBtaXRvY2hvbmRyaWEu[Qq]
[f]Tm8uIFBhY2thZ2luZyBhbmQgdHJhbnNwb3J0IG9mIHByb3RlaW5zIG9jY3VyIGluIHRoZSBHb2xnaSBhcHBhcmF0dXMu[Qq]
[f]Q29ycmVjdCEgUmlib3NvbWVzIHRyYW5zbGF0ZSBtUk5BIGludG8gcHJvdGVpbnMsIHdoaWNoIGFyZSBlc3NlbnRpYWwgZm9yIGNlbGx1bGFyIGZ1bmN0aW9ucy4=[Qq]
[f]Tm8uIEdlbmV0aWMgbWF0ZXJpYWwgaXMgc3RvcmVkIGluIHRoZSBudWNsZXVzIG9mIGV1a2FyeW90aWMgY2VsbHMgb3IgdGhlIGN5dG9wbGFzbSBvZiBwcm9rYXJ5b3RpYyBjZWxscy4=

Cg==[Qq]

[q]How is DNA organized in prokaryotic cells compared to eukaryotic cells?
[c]UHJva2FyeW90aWMgRE5BIGlzIGxpbmVhciwgd2hpbGUgZXVrYXJ5b3RpYyBETkEgaXMgY2lyY3VsYXIu[Qq]
[c]UHJva2FyeW90aWMgRE5BIGlzIGNpcmN1bGFyLCB3 aGlsZSBldWthcnlvdGljIEROQSBpcyBsaW5lYXIu[Qq]
[c]Qm90aCBwcm9rYXJ5b3RpYyBhbmQgZXVrYXJ5b3RpYyBETkEgYXJlIGxpbmVhci4=[Qq]
[c]Qm90aCBwcm9rYXJ5b3RpYyBhbmQgZXVrYXJ5b3RpYyBETkEgYXJlIGNpcmN1bGFyLg==[Qq]
[f]Tm8uIFByb2thcnlvdGljIEROQSBpcyBjaXJjdWxhciwgbm90IGxpbmVhci4=[Qq]
[f]Q29ycmVjdCEgUHJva2FyeW90aWMgY2VsbHMgaGF2ZSBjaXJjdWxhciBETkEsIHdoaWxlIGV1a2FyeW90aWMgY2VsbHMgaGF2ZSBsaW5lYXIgY2hyb21vc29tZXMu[Qq]
[f]Tm8uIE9ubHkgZXVrYXJ5b3RpYyBjZWxscyBoYXZlIGxpbmVhciBjaHJvbW9zb21lcy4=[Qq]
[f]Tm8uIEV1a2FyeW90aWMgRE5BIGlzIGxpbmVhciwgbm90IGNpcmN1bGFyLg==

Cg==[Qq]

[q]What distinguishes mitochondria from other organelles?
[c]VGhleSBhcmUgZm91bmQgaW4gYm90aCBwcm9rYXJ5b3RpYyBhbmQgZXVrYXJ5b3RpYyBjZWxscy4=[Qq]
[c]VGhleSBwcm9kdWNlIHJpYm9zb21lcyBmb3IgcHJvdGVpbiBzeW50aGVzaXMu[Qq]
[c]VGhleSBnZW5lcmF0ZSBBVFAgdGhyb3Vn aCBjZWxsdWxhciByZXNwaXJhdGlvbi4=[Qq]
[c]VGhleSBjb250YWluIHBsYXNtaWRzIGZvciBnZW5ldGljIGV4Y2hhbmdlLg==[Qq]
[f]Tm8uIE1pdG9jaG9uZHJpYSBhcmUgb25seSBmb3VuZCBpbiBldWthcnlvdGljIGNlbGxzLg==[Qq]
[f]Tm8uIFJpYm9zb21lcyBhcmUgcHJvZHVjZWQgaW4gdGhlIG51Y2xlb2x1cywgbm90IG1pdG9jaG9uZHJpYS4=[Qq]
[f]Q29ycmVjdCEgTWl0b2Nob25kcmlhIGFyZSByZXNwb25zaWJsZSBmb3IgcHJvZHVjaW5nIEFUUCwgdGhlIGNlbGzigJlzIGVuZXJneSBjdXJyZW5jeSwgdGhyb3VnaCBjZWxsdWxhciByZXNwaXJhdGlvbi4=[Qq]
[f]Tm8uIE1pdG9jaG9uZHJpYSBkbyBub3QgY29udGFpbiBwbGFzbWlkczsgdGhlc2UgYXJlIGZvdW5kIGluIHNvbWUgcHJva2FyeW90aWMgY2VsbHMu

Cg==[Qq]

[x]If you want to take this quiz again, please click the button below.

[restart]
[/qwiz]

What’s next?

Please proceed to this next tutorial: Cell Size and Surface Area:Volume