m2

• Which of the following events did NOT occur early in the evolution of cells?
  c. Endosymbiosis of a bacterium into another cell (this happened later in evolution)

• Which of the following is a key difference between eukaryotic and prokaryotic cells?
  d. Have membrane-bound nuclei and organelles (only eukaryotes have these)

• Which of the following is a reason why cells are so small?
  a. Structural molecules that maintain cell shape and integrity cannot support larger cell volumes or surface areas

4. Which organelle(s) play a role in maintaining cell shape and structure?
   d. Cell wall, i. Cytoskeleton

5. Which organelle is responsible for storing nutrients, waste products, and maintaining turgor pressure in plant cells?
   a. Vacuole

6. Which organelles are directly involved in energy conversion?
   c. Chloroplast, m. Mitochondria

7. Which organelle contains most of the genetic material of a eukaryotic cell?
   e. Nucleus

8. Which organelle breaks down fatty acids and detoxifies harmful substances?
   g. Peroxisome

9. Which organelle is involved in protein synthesis and modification?
   f. Endoplasmic reticulum, h. Golgi apparatus

Membrane and Organelles

10. Which organelle is the site of lipid synthesis?
    c. Endoplasmic reticulum

11. Which of the following are components of the endomembrane system?
    e. All of the above

12. Where does the citric acid cycle take place?
    a. Matrix

13. Which organelle is responsible for photosynthesis?
    b. Photosynthesis

14. What is the correct order of organelles involved in the secretion of proteins?
    a. Endoplasmic reticulum → Golgi apparatus → secretory vesicle

15. True or False: Ribosomes are only found attached to the rough ER.
    False (ribosomes are also free in the cytoplasm)

16. What is the function of peroxisomes?
    b. They form hydrogen peroxide

17. Which organelles have a double membrane?
    c. Chloroplast, e. Nucleus, m. Mitochondria

18. Which structures do NOT contain a phospholipid bilayer?
    b. Ribosomes, d. Cell wall, i. Cytoskeleton, l. Extracellular matrix

19. Which structures provide support and shape to the cell?
    d. Cell wall, i. Cytoskeleton, l. Extracellular matrix

20. Which organelles contain nucleic acids?
    b. Ribosomes, c. Chloroplast, e. Nucleus, m. Mitochondria

21. Which of the following is NOT a characteristic of viruses?
    d. They do not contain their own genetic material

22. Which cellular component sediments first during centrifugation?
    a. Nuclei

23. Where does translation occur in eukaryotic cells?
    e. Protein synthesis

Membranes and Fluidity

24. In the fluid-mosaic model, the term “mosaic” refers to:
    b. "Mosaic"

25. Which membrane component plays a role in cell recognition?
    b. Glycolipids

26. True or False: Cholesterol is found in animal cell membranes and helps regulate membrane fluidity.
    True

27. Which membrane is LESS fluid?
    a. The one with long, saturated fatty acids

28. A membrane with more unsaturated fatty acids will be:
    a. More fluid

29. A transmembrane protein is also called:
    a. Integral membrane protein

30. Which molecules can pass through the plasma membrane via simple diffusion?
    a. Small nonpolar molecules, b. Small polar molecules

Transport Mechanisms

31. Which type of transport requires a transport protein but no energy?
    b. Facilitated transport

32. What happens to oxygen in a red blood cell in a high-oxygen environment?
    a. Oxygen will diffuse out of the red blood cell through the membrane

33. What charge would you expect the inside of a Na+ channel to have?
    b. Negative charge (to attract Na+, a positive ion)

34. Which of the following is TRUE about the Na+/K+ pump?
    a. It must expend ATP, c. It moves Na+ and K+ against their gradients

Genetic Code and Translation

1. Which statement about the genetic code is FALSE?
   b. Each codon is usually associated with more than one amino acid (not true, codons are specific)

2. If a DNA sequence is 3’ TAA 5’, what is the corresponding mRNA codon?
   c. 3’ AUU 5’

3. Which amino acid does the codon AAU code for?
   a. Asparagine

4. Where does translation occur in a eukaryotic cell?
   b. Cytosol, c. Mitochondria, d. Chloroplast, e. Rough ER

5. What happens if all valine codons in a gene are replaced with glycine codons?
   a. There will be glycines at all valine positions and valines at all glycine positions

6. Which parts of an mRNA sequence are needed for translation?
   b. Start codon, c. Coding sequence

Translation Stages

7. Which step in translation involves releasing the polypeptide?
   c. Termination

8. During which stage are amino acids added to the growing polypeptide chain?
   b. Elongation

9. Which stage of translation begins when the ribosome assembles?
   a. Initiation

10. During which stage does tRNA bring in new amino acids?
    b. Elongation

11. Which stage ends when a stop codon is reached?
    c. Termination

Post-Translation Processing

12. What effect does a nonsense mutation have?
    c. It causes premature termination of translation

13. What is the term for changes to proteins after translation?
    a. Post-translational modification

14. Which method allows scientists to study protein location in living cells?
    a. Location of proteins can be observed in vivo

Endomembrane System and Sorting

15. Which process is associated with proteins made in the ER?
    b. Secretory protein synthesis

16. What is the forward movement of proteins through the Golgi called?
    a. Anterograde

17. Where do secretory proteins enter the endomembrane system?
    b. ER

18. Which organelle is the final processing station for proteins?
    c. Golgi

19. Which type of import occurs after translation?
    b. Posttranslational import

1. After fusion with the plasma membrane, is GFP going to be on the cytosolic or extracellular side of the plasma membrane?
   a. Cytosolic
   b. Extracellular

2. Order the events of receptor-mediated endocytosis:
   g. Ligand binds to receptor on cell membrane
   a. Ligand-receptor diffuses laterally to coated pit
   d. Vesicle coat proteins aggregate to pit and facilitate invagination
   b. Invagination leads to coated vesicle formation inside cell
   f. Vesicle fuses with early endosome
   c. Coat proteins removed from vesicle and recycled to coated pits
   e. Endosome develops into lysosome, vesicle contents exported, or receptors recycled

3. Which of the following is NOT a function of coat proteins on coated vesicles?
   a. Protect vesicle from fusing with other vesicles or organelles
   b. Act as signal molecule to traffic vesicle to correct cellular location
   c. Maintain vesicle in spherical form instead of flat disc
   d. Regulate transport of molecules across vesicle membrane

4. If a cell had a defective form of COPII, what might be full of extra proteins?
   a. Golgi apparatus
   b. ER
   c. Lysosomes
   d. Nuclear membrane

5. Cells use distinctive coats on vesicles because:
   a. Proteins such as clathrin, COPI, COPII, and caveolin are in limited supply
   b. Clathrin does not always form the proper shape
   c. Vesicles with distinctive coats maintain compartmentalization of organelle functions
   d. Only COPI and COPII interact with cytoskeleton proteins for directional transport

6. Single-celled organisms typically use which mechanism to uptake whole cells?
   a. Receptor-mediated endocytosis
   b. Phagocytosis
   c. Autophagy
   d. Lysosomal maturation

7. If a late endosome lacks functional ATPase proton pumps, what characteristic is missing for lysosome development?
   a. Hydrolytic enzymes
   b. Molecules to digest
   c. Low pH

8. A disease with high levels of reactive oxygen species from damaged mitochondria suggests disruption of:
   a. Receptor-mediated endocytosis
   b. Phagocytosis
   c. Autophagy
   d. Anti-inflammatory response

9. True or False: Crohn’s disease is caused by mutations in genes that control phagocytosis, leading to inflammation from excessive bacterial uptake.
   False

Cytoskeleton & Cellular Structure

10. Correct order of cytoskeletal thickness, smallest to largest:
    a. Microtubules, microfilaments, intermediate filaments
    b. Microfilaments, intermediate filaments, microtubules
    c. Intermediate filaments, microfilaments, microtubules

11. Which is NOT a function of the cytoskeleton?
    a. Cell movement
    b. Cell division
    c. Organelle movement
    d. Establishing cell shape
    e. Passive transport

12. Tubulin may assemble onto one end while disassembling from the other in a process called:
    a. Dynamic instability
    b. Treadmilling
    c. Nucleation
    d. Oligomerization
    e. Catastrophe-rescue

13. Which protein class is associated with microtubule depolymerization during mitosis?
    a. MAPs
    b. +-TIPs
    c. Catastrophins

14. Which is TRUE about the microtubule wall structure?
    a. α-β-tubulin heterodimers are arranged with mixed orientation in each protofilament, and protofilaments have mixed polarity
    b. α-β-tubulin heterodimers are arranged with the same orientation in each protofilament, and protofilaments have mixed polarity
    c. α-β-tubulin heterodimers are arranged with mixed orientation in each protofilament, and protofilaments have the same polarity
    d. α-β-tubulin heterodimers are arranged with the same orientation in each protofilament, and protofilaments have the same polarity
    e. Orientation is random and depends on assembly conditions

15. Which drug would prevent microfilament depolymerization?
    a. Drug A, which binds to the plus and minus ends of actin chains, blocking noncovalent bonding
    b. Drug B, which binds to actin monomers, blocking noncovalent bonding
    c. Drug C, which binds to the plus and minus ends of 𝛼β-tubulin chains, blocking noncovalent bonding
    d. Drug D, which binds to keratin protofilaments, blocking disulfide bonding

16. To design a flexible cell membrane for shape changes, you would include more:
    a. Stress fibers
    b. Centrosomes
    c. Cortical actin networks
    d. Lamellipodia
    e. +-TIPs

Cytoskeletal Matching

17. Involved in muscle contraction
    B. Microfilament

18. Involved in movement via lamellipodia and filopodia
    B. Microfilament

19. Important for chromosome movements during cell division
    A. Microtubule

20. Subunits bind and can hydrolyze phosphonucleotides
    A. Microtubule
    B. Microfilament

21. Repeating subunit is a dimer
    A. Microtubule

22. Subunits vary depending on cell type
    C. Intermediate filament

23. Polymerization co-opted by Listeria for infection
    **B.