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

Which organelle(s) play a role in maintaining cell shape and structure?
d. Cell wall, i. Cytoskeleton
Which organelle is responsible for storing nutrients, waste products, and maintaining turgor pressure in plant cells?
a. Vacuole
Which organelles are directly involved in energy conversion?
c. Chloroplast, m. Mitochondria
Which organelle contains most of the genetic material of a eukaryotic cell?
e. Nucleus
Which organelle breaks down fatty acids and detoxifies harmful substances?
g. Peroxisome
Which organelle is involved in protein synthesis and modification?
f. Endoplasmic reticulum, h. Golgi apparatus

Membrane and Organelles

Which organelle is the site of lipid synthesis?
c. Endoplasmic reticulum
Which of the following are components of the endomembrane system?
e. All of the above
Where does the citric acid cycle take place?
a. Matrix
Which organelle is responsible for photosynthesis?
b. Photosynthesis
What is the correct order of organelles involved in the secretion of proteins?
a. Endoplasmic reticulum → Golgi apparatus → secretory vesicle
True or False: Ribosomes are only found attached to the rough ER.
False (ribosomes are also free in the cytoplasm)
What is the function of peroxisomes?
b. They form hydrogen peroxide
Which organelles have a double membrane?
c. Chloroplast, e. Nucleus, m. Mitochondria
Which structures do NOT contain a phospholipid bilayer?
b. Ribosomes, d. Cell wall, i. Cytoskeleton, l. Extracellular matrix
Which structures provide support and shape to the cell?
d. Cell wall, i. Cytoskeleton, l. Extracellular matrix
Which organelles contain nucleic acids?
b. Ribosomes, c. Chloroplast, e. Nucleus, m. Mitochondria

Which of the following is NOT a characteristic of viruses?
d. They do not contain their own genetic material
Which cellular component sediments first during centrifugation?
a. Nuclei
Where does translation occur in eukaryotic cells?
e. Protein synthesis

Membranes and Fluidity

In the fluid-mosaic model, the term “mosaic” refers to:
b. "Mosaic"
Which membrane component plays a role in cell recognition?
b. Glycolipids
True or False: Cholesterol is found in animal cell membranes and helps regulate membrane fluidity.
True
Which membrane is LESS fluid?
a. The one with long, saturated fatty acids
A membrane with more unsaturated fatty acids will be:
a. More fluid
A transmembrane protein is also called:
a. Integral membrane protein
Which molecules can pass through the plasma membrane via simple diffusion?
a. Small nonpolar molecules, b. Small polar molecules

Transport Mechanisms

Which type of transport requires a transport protein but no energy?
b. Facilitated transport
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
What charge would you expect the inside of a Na+ channel to have?
b. Negative charge (to attract Na+, a positive ion)
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

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)
If a DNA sequence is 3’ TAA 5’, what is the corresponding mRNA codon?
c. 3’ AUU 5’
Which amino acid does the codon AAU code for?
a. Asparagine
Where does translation occur in a eukaryotic cell?
b. Cytosol, c. Mitochondria, d. Chloroplast, e. Rough ER
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
Which parts of an mRNA sequence are needed for translation?
b. Start codon, c. Coding sequence

Translation Stages

Which step in translation involves releasing the polypeptide?
c. Termination
During which stage are amino acids added to the growing polypeptide chain?
b. Elongation
Which stage of translation begins when the ribosome assembles?
a. Initiation
During which stage does tRNA bring in new amino acids?
b. Elongation
Which stage ends when a stop codon is reached?
c. Termination

Post-Translation Processing

What effect does a nonsense mutation have?
c. It causes premature termination of translation
What is the term for changes to proteins after translation?
a. Post-translational modification
Which method allows scientists to study protein location in living cells?
a. Location of proteins can be observed in vivo

Endomembrane System and Sorting

Which process is associated with proteins made in the ER?
b. Secretory protein synthesis
What is the forward movement of proteins through the Golgi called?
a. Anterograde
Where do secretory proteins enter the endomembrane system?
b. ER
Which organelle is the final processing station for proteins?
c. Golgi
Which type of import occurs after translation?
b. Posttranslational import

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

Correct order of cytoskeletal thickness, smallest to largest:
a. Microtubules, microfilaments, intermediate filaments
b. Microfilaments, intermediate filaments, microtubules
c. Intermediate filaments, microfilaments, microtubules
Which is NOT a function of the cytoskeleton?
a. Cell movement
b. Cell division
c. Organelle movement
d. Establishing cell shape
e. Passive transport
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
Which protein class is associated with microtubule depolymerization during mitosis?
a. MAPs
b. +-TIPs
c. Catastrophins
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
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
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

Involved in muscle contraction
B. Microfilament
Involved in movement via lamellipodia and filopodia
B. Microfilament
Important for chromosome movements during cell division
A. Microtubule
Subunits bind and can hydrolyze phosphonucleotides
A. Microtubule
B. Microfilament
Repeating subunit is a dimer
A. Microtubule
Subunits vary depending on cell type
C. Intermediate filament
Polymerization co-opted by Listeria for infection
**B.