Biology Test Biology Cellular and Molecular 3

Question 1

What is the role of ATP synthase in cellular respiration?

Accepted Answer

Uses the proton gradient to synthesize ATP

Answer

Splits water molecules in the matrix

Answer

Transfers electrons to oxygen

Answer

Converts pyruvate to acetyl-CoA

Question 2

Which process describes the movement of water across a selectively permeable membrane from low to high solute concentration?

Accepted Answer

Osmosis

Answer

Active transport

Answer

Facilitated diffusion

Answer

Endocytosis

Question 3

In the lac operon of E. coli, what happens when lactose is absent from the environment?

Accepted Answer

The repressor protein binds to the operator and blocks transcription

Answer

RNA polymerase binds and transcribes the operon

Answer

The CAP-cAMP complex activates transcription

Answer

The structural genes are constitutively expressed

Question 4

Which cytoskeletal element is primarily responsible for maintaining cell shape in animal cells?

Accepted Answer

Microfilaments (actin)

Answer

Microtubules

Answer

Intermediate filaments

Answer

Centrioles

Question 5

What is a nucleosome?

Accepted Answer

DNA wrapped around a histone octamer

Answer

A single-stranded RNA molecule in the nucleus

Answer

The site of ribosome assembly

Answer

A small membrane-bound organelle containing enzymes

Question 6

Which stage of cellular respiration produces the most ATP per glucose molecule?

Accepted Answer

Oxidative phosphorylation

Answer

Glycolysis

Answer

Pyruvate oxidation

Answer

Krebs cycle

Question 7

What is the function of telomeres?

Accepted Answer

Protect chromosome ends from degradation and fusion

Answer

Initiate DNA replication at origins

Answer

Encode for essential structural proteins

Answer

Regulate gene expression through methylation