Question 1

Which of the following best explains why muscle cells contain a high concentration of mitochondria?

Accepted Answer

Muscle cells require large amounts of ATP for contraction, and mitochondria are the primary site of ATP production.

Question 2

Which structural feature of mitochondria is most directly responsible for increasing the efficiency of ATP production?

Accepted Answer

The folding of the inner membrane into cristae, which increases surface area for metabolic reactions.

Question 3

Which of the following statements about mitochondrial DNA is correct?

Accepted Answer

Mitochondrial DNA is independent of nuclear DNA and encodes some, but not all, mitochondrial proteins.

Question 4

Which of the following best describes the evolutionary origin of mitochondria and chloroplasts?

Accepted Answer

They originated from free-living prokaryotes that were engulfed by ancestral eukaryotic cells, forming a mutually beneficial relationship.

Question 5

Which of the following is a unique feature of chloroplasts compared to mitochondria?

Accepted Answer

Chloroplasts contain thylakoids arranged in stacks called grana, which are involved in photosynthesis.

Question 6

Which of the following reactions occurs in peroxisomes and why is compartmentalization important for this process?

Accepted Answer

Ethanol oxidation, because the byproduct hydrogen peroxide is toxic and must be detoxified within the peroxisome.

Question 7

Which cytoskeletal element is responsible for the separation of chromosomes during cell division and what is its main subunit?

Accepted Answer

Microtubules, composed of alpha and beta tubulin dimers.

Question 8

A mutation disrupts the function of kinesin in a cell. Which process would be most directly affected?

Accepted Answer

The movement of vesicles along microtubules toward the positive end.

Question 9

Which of the following best explains why intermediate filaments are important for the structural integrity of animal cells?

Accepted Answer

They provide mechanical strength and help maintain the shape of the nucleus and other organelles.

Question 10

Which of the following is a function of the extracellular matrix (ECM) in animal cells?

Accepted Answer

Providing structural support and mediating cell attachment through proteins like collagen and fibronectin.

Question 11

Which cell junction would be most abundant in tissues that experience high mechanical stress, such as heart muscle or skin?

Accepted Answer

Desmosomes, because they provide strong adhesion between adjacent cells.

Question 12

Which of the following best describes the role of gap junctions in animal cells?

Accepted Answer

They form channels that allow ions and small molecules to pass directly between adjacent cells, facilitating rapid communication.

Question 13

Which of the following is true about plasmodesmata in plant cells?

Accepted Answer

They are channels that traverse cell walls, allowing cytoplasmic continuity between adjacent cells.

Question 14

A patient has a genetic defect that results in the loss of fibronectin production. Which cellular process would be most directly affected?

Accepted Answer

Attachment of cells to the extracellular matrix.

Question 15

Which cytoskeletal element is most directly involved in cytoplasmic streaming in plant cells, and what motor protein is required?

Accepted Answer

Actin filaments (microfilaments) and myosin.

Question 16

Which of the following best explains why tight junctions in the intestine are less restrictive than those in the bladder?

Accepted Answer

The intestine requires some permeability for nutrient absorption, while the bladder must prevent leakage of waste.

Question 17

Which of the following statements about the polarity of cytoskeletal elements is correct?

Accepted Answer

Both microtubules and microfilaments have polarity, with faster polymerization at the plus end.

Question 18

Which of the following best describes the function of integrins in animal cells?

Accepted Answer

They are cell surface receptors that connect the extracellular matrix to the cytoskeleton.

Question 19

A scientist observes that a certain cell type is unable to maintain the shape of its nucleus. Which cytoskeletal component is most likely defective?

Accepted Answer

Intermediate filaments, which form the nuclear lamina.

Bio 100 LEC Chapter 6 Part 2

Study Guide - Practice Questions