Question 1

Which organelle is primarily responsible for ATP synthesis in eukaryotic cells, and what structural feature increases its efficiency?

Accepted Answer

Mitochondrion; cristae formed by the inner membrane increase surface area for ATP production.

Question 2

A patient with cystic fibrosis has thick mucus in the lungs due to a defect in which cellular structure, and what is the underlying molecular cause?

Accepted Answer

Motile cilia; defective chloride channel proteins prevent proper saline layer formation.

Question 3

Which of the following best describes the function of the Golgi apparatus in the endomembrane system?

Accepted Answer

It modifies, sorts, and packages proteins and lipids received from the ER for transport.

Question 4

Which cytoskeletal filament is primarily composed of actin and is involved in cellular movement such as phagocytosis?

Accepted Answer

Microfilaments

Question 5

A cell is observed to have an extensive network of smooth endoplasmic reticulum (SER). Which function is this cell most likely specialized for?

Accepted Answer

Synthesis of lipids and detoxification of harmful substances

Question 6

Which organelle contains acid hydrolases and is responsible for digesting worn-out cell components?

Accepted Answer

Lysosome

Question 7

The endomembrane system is essential for the transport of proteins and lipids within the cell. Which sequence correctly describes the pathway of a protein destined for secretion?

Accepted Answer

Rough ER → transport vesicle → Golgi apparatus → transport vesicle → plasma membrane

Question 8

Which cellular extension increases the absorptive surface area of cells, especially in the intestinal epithelium?

Accepted Answer

Microvilli

Question 9

Which cytoskeletal component forms the mitotic spindle during cell division and serves as 'tracks' for organelle movement?

Accepted Answer

Microtubules

Question 10

A mutation in the gene encoding tubulin would most directly affect which cellular structure and function?

Accepted Answer

Microtubules; impairing cell division and intracellular transport

Question 11

Which organelle is thought to have originated from an ancestral prokaryotic cell via endosymbiosis, and what evidence supports this theory?

Accepted Answer

Mitochondrion; it contains its own circular DNA similar to prokaryotes

Question 12

Which of the following is TRUE regarding the structure and function of ribosomes?

Accepted Answer

They consist of large and small protein subunits and are specialized for protein synthesis.

Question 13

A sperm cell uses a whip-like cellular extension for motility. What is this structure called, and what is its microtubule arrangement?

Accepted Answer

Flagellum; 9+2 arrangement of microtubules

Question 14

Which organelle is responsible for breaking down fatty acids and detoxifying alcohol, and what is the main enzyme involved?

Accepted Answer

Peroxisome; contains catalase to convert hydrogen peroxide

Question 15

Which cytoskeletal filament provides mechanical strength to cells and is composed of proteins such as keratin in hair and nails?

Accepted Answer

Intermediate filaments

Question 16

During mitosis, which structure organizes the microtubules to form the mitotic spindle?

Accepted Answer

Centrosome containing centrioles

Question 17

Which of the following best explains the role of the cytoskeleton in cellular motion?

Accepted Answer

It interacts with motor proteins to move organelles and allows for whole cell movement, such as during phagocytosis and mitosis.

Question 18

A cell is unable to transport newly synthesized proteins to the plasma membrane for secretion. Which part of the endomembrane system is most likely malfunctioning?

Accepted Answer

Golgi apparatus

Question 19

Which equation best represents the process of osmosis that allows water to follow chloride ions across the membrane in motile cilia?

Accepted Answer

$$ \Delta \Psi = \Psi_s + \Psi_p $$

Question 20

A researcher stains a cell for actin and observes a dense network just beneath the plasma membrane. Which structure is being visualized, and what is its primary function?

Accepted Answer

Terminal web; provides structural support and anchors microvilli

Cytoskeleton and Organelles: Structure and Function (Chapter 3: 3.4–3.5)

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