Question 1

Which of the following best explains why bacterial cell walls containing peptidoglycan are important for survival in extreme environments?

Accepted Answer

They provide a rigid structure that protects against osmotic pressure and environmental stress.

Question 2

A scientist discovers a microorganism with a cell wall that lacks peptidoglycan but contains pseudopeptidoglycan. Which domain does this organism most likely belong to?

Accepted Answer

Archaea

Question 3

Which structure is primarily responsible for the selective permeability of the eukaryotic cell membrane?

Accepted Answer

Phospholipid bilayer

Question 4

A mutation causes a cell to produce only saturated fatty acids in its membrane lipids. What is the most likely effect on membrane fluidity at low temperatures?

Accepted Answer

Membrane fluidity will decrease.

Question 5

Which of the following equations correctly represents Gibbs Free Energy?

Accepted Answer

$\Delta G = \Delta H - T\Delta S$

Question 6

During insulin synthesis, which sequence of cellular compartments does the polypeptide travel through before secretion?

Accepted Answer

Rough ER $\rightarrow$ Golgi apparatus $\rightarrow$ Secretory vesicle $\rightarrow$ Plasma membrane

Question 7

Which of the following statements about the endosymbiotic theory is supported by evidence from mitochondria and chloroplasts?

Accepted Answer

They have their own circular DNA and ribosomes similar to bacteria.

Question 8

Which process is most directly responsible for the breakdown of large macromolecule-containing particles in animal cells?

Accepted Answer

Lysosomal digestion

Question 9

A cell is observed to have a high rate of actin polymerization at its leading edge. What cellular process is most likely occurring?

Accepted Answer

Cell movement (motility)

Question 10

Which of the following best describes the role of competitive inhibition in enzyme regulation?

Accepted Answer

An inhibitor binds to the active site, preventing substrate binding.

Question 11

Which of the following is a major function of the cytoskeleton in eukaryotic cells?

Accepted Answer

Structural support, shape, and movement

Question 12

A cell is exposed to a toxin that inhibits kinesin motor proteins. Which cellular process will be most directly affected?

Accepted Answer

Organelle positioning and intracellular transport along microtubules

Question 13

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Membrane fluidity increases with increased unsaturated fatty acids.

Question 14

Which of the following is NOT a function of the plasma membrane?

Accepted Answer

Synthesize proteins

Question 15

Which of the following best describes the difference between exergonic and endergonic reactions in cells?

Accepted Answer

Endergonic reactions have $\Delta G > 0$ and require energy input.

Question 16

Which of the following is a real-world example of feedback inhibition in metabolic pathways?

Accepted Answer

A product of a pathway inhibits an enzyme that functions early in the pathway.

Question 17

Which of the following statements about simple diffusion across the cell membrane is correct?

Accepted Answer

It moves molecules from high to low concentration without energy input.

Question 18

A cell is placed in a solution with a higher concentration of solutes than inside the cell. What will most likely happen to the cell?

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 19

Which of the following is a correct statement about the first law of thermodynamics as it applies to biological systems?

Accepted Answer

Energy is conserved and can only be transformed from one form to another.

Question 20

Which of the following mechanisms do enzymes use to lower activation energy ($E_a$) in biological reactions?

Accepted Answer

Bringing reactants together in the correct orientation

Cell Structure, Function, and Membranes: Prokaryotic and Eukaryotic Cells, Energy, and Enzymes

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