Question 1

Which of the following best explains why muscle cells in athletes have a higher proportion of mitochondria compared to liver cells?

Accepted Answer

Muscle cells require more energy for contraction, so they need more mitochondria for ATP production.

Question 2

A protein destined for the nucleus must have which of the following features to be imported?

Accepted Answer

A nuclear localization signal (NLS) that acts as a 'zip code' for import.

Question 3

During exocytosis, which of the following occurs?

Accepted Answer

Vesicles fuse with the plasma membrane, releasing their contents outside the cell and increasing cell size.

Question 4

Which statement about ribosomes is correct?

Accepted Answer

Free and bound ribosomes are structurally and functionally identical; their location depends on the protein being synthesized.

Question 5

A mutation prevents the formation of desmosomes in epithelial cells. Which outcome is most likely?

Accepted Answer

Cells will lose strong adhesion, leading to increased blister formation.

Question 6

Which of the following is a function of the cytoskeleton?

Accepted Answer

Providing structural support, maintaining cell shape, and organizing internal contents.

Question 7

What is the main difference between the extracellular matrix (ECM) of animal cells and the cell wall of plant cells?

Accepted Answer

Animal ECM contains more protein and is more bendable, while plant cell walls contain more carbohydrates and are stiffer.

Question 8

Which process decreases cell size and is often exploited by viruses to gain entry into cells?

Accepted Answer

Endocytosis

Question 9

Which of the following best describes the role of tight junctions in epithelial tissue?

Accepted Answer

They form a watertight seal preventing the flow of solutions between cells.

Question 10

A scientist adds a nuclear localization signal (NLS) to a cytoplasmic protein. What is the expected outcome?

Accepted Answer

The protein will be imported into the nucleus through nuclear pore complexes.

Question 11

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

Accepted Answer

They allow signals and molecules to pass directly between adjacent cells.

Question 12

Which of the following best describes the relationship between cytoskeleton and vesicle transport?

Accepted Answer

Motor proteins use ATP to 'walk' vesicles along microtubules.

Question 13

Which of the following is a correct statement about nuclear transport?

Accepted Answer

Nucleotides freely diffuse down their concentration gradient, while larger molecules require nuclear pore complexes.

Question 14

Which localization signal is used to target proteins to lysosomes?

Accepted Answer

Mannose-6-phosphate

Question 15

Which of the following equations best represents the energy usage by motor proteins during vesicle transport?

Accepted Answer

$$ \mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy} $$

Question 16

Which of the following statements about cell surface components is correct?

Accepted Answer

Most cells have extracellular components outside the plasma membrane, which are secreted by the cells.

Question 17

Which of the following is a function of cadherin proteins in animal cells?

Accepted Answer

They mediate specific cell-cell adhesion in desmosomes.

Question 18

Which of the following best explains why the extracellular matrix (ECM) and cytoskeleton are linked in animal cells?

Accepted Answer

The linkage helps anchor cells in place and is monitored by signals; improper anchoring can lead to cell death.

Question 19

Which of the following statements about fiber composites in eukaryotic cells is correct?

Accepted Answer

Plant cell walls contain cellulose fibers that resist tension, while the ground substance (pectin) resists compression.

Cell Structure, Function, and Interactions: Organelle Proportions, Endomembrane System, Cytoskeleton, and Cell Connections

Guida di studio - Domande di pratica