Question 1

Which of the following best explains why SDS is used in SDS-PAGE for protein separation?

Accepted Answer

It coats proteins with a uniform negative charge and denatures them, allowing separation based on size.

Question 2

A researcher is using gel filtration chromatography to separate a mixture of proteins. Which property is primarily responsible for the separation in this technique?

Accepted Answer

Molecular size

Question 3

A mutation in a liver cell causes a dramatic decrease in smooth endoplasmic reticulum (SER). Which process would be most directly affected?

Accepted Answer

Detoxification of lipid-soluble drugs

Question 4

Which of the following statements about enzyme catalysis is correct?

Accepted Answer

Enzymes lower the activation energy, but do not change the overall Gibbs free energy ($$\Delta G) of $$the reaction.

Question 5

A scientist is using a DNA microarray to analyze gene expression in cancer cells. What information can be obtained from this technique?

Accepted Answer

Which genes are actively transcribed (expressed) versus inactive in the sample

Question 6

Which of the following best describes the function of the primary antibody in a Western blot?

Accepted Answer

It recognizes and binds specifically to the target protein (antigen).

Question 7

A protein mixture containing proteins of 10,000 Da, 25,000 Da, and 60,000 Da is run on an SDS-PAGE gel. Which protein will migrate the farthest (closest to the bottom of the gel)?

Accepted Answer

The 10,000 Da protein

Question 8

Which of the following best explains the effect of a catalyst on a chemical reaction?

Accepted Answer

It decreases the activation energy ($$E_a$$), increasing the reaction rate.

Question 9

Which of the following is NOT a function of the cytoskeleton?

Accepted Answer

Carrying out photosynthesis

Question 10

A patient is diagnosed with a lysosomal storage disease. Which organelle is most likely defective?

Accepted Answer

Lysosome

Question 11

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind to a different site on the enzyme.

Question 12

Which of the following is a direct result of feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of the pathway inhibits an earlier enzyme, reducing pathway activity.

Question 13

Which of the following best describes the endosymbiotic theory?

Accepted Answer

Mitochondria and chloroplasts originated from free-living prokaryotes engulfed by ancestral eukaryotic cells.

Question 14

Which of the following statements about mitochondrial DNA is correct?

Accepted Answer

It is inherited almost exclusively from the mother.

Question 15

Which of the following best describes the role of a signal peptide in protein targeting?

Accepted Answer

It is a short amino acid sequence that directs the protein to a specific cellular compartment.

Question 16

Which of the following is NOT a characteristic of the Southern blot technique?

Accepted Answer

It uses antigen-antibody reactions for detection.

Question 17

A scientist wants to separate two proteins that have the same molecular mass but different charges. Which technique should they use?

Accepted Answer

Ion exchange chromatography

Question 18

Which of the following best describes the relationship between photosynthesis and cellular respiration?

Accepted Answer

The products of photosynthesis serve as the reactants for cellular respiration.

Question 19

Which of the following is a correct statement about the effect of temperature on enzyme-catalyzed reactions?

Accepted Answer

Increasing temperature increases the rate up to an optimum, after which the enzyme denatures and activity decreases.

Question 20

Which of the following best describes the function of a ribozyme?

Accepted Answer

An RNA molecule that acts as a catalyst in biochemical reactions.

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