Question 1

Which of the following statements best summarizes the modern cell theory?

Accepted Answer

All living organisms are composed of one or more cells, and all cells arise from pre-existing cells.

Question 2

A patient has a genetic disorder affecting the structure of their mitochondria. Which cellular process is most likely to be directly impaired?

Accepted Answer

ATP production via aerobic respiration

Question 3

Which of the following best describes the function of the Golgi apparatus?

Accepted Answer

Modifying, sorting, and packaging proteins for secretion or delivery to other organelles

Question 4

A cell is observed to have abundant rough endoplasmic reticulum. What is the most likely function of this cell?

Accepted Answer

Producing large amounts of proteins for export

Question 5

Which of the following best explains why ions such as Na$$^+$$ and K$$^+$$ cannot freely cross the plasma membrane?

Accepted Answer

They are charged and cannot pass through the hydrophobic core of the lipid bilayer.

Question 6

A researcher is studying a protein that spans the plasma membrane and allows glucose to enter the cell only when Na$$^+ is $$present. Which type of transport is this an example of?

Accepted Answer

Secondary active transport (co-transport)

Question 7

Which equation correctly represents Fick's First Law of Diffusion for the net flux $$F of $$particles?

Accepted Answer

$$F = -D \frac{\Delta C}{\Delta x}$$

Question 8

A cell is placed in a solution and begins to swell. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic to the cell.

Question 9

Which of the following best describes the role of the Na$$^+/K$^+$$ ATPase in maintaining the resting membrane potential?

Accepted Answer

It actively transports 3 Na$$^+$$ out and 2 K$$^+$$ into the cell, creating both chemical and electrical gradients.

Question 10

A mutation causes a cell to lack functional lysosomes. Which of the following is a likely consequence?

Accepted Answer

Accumulation of undigested cellular debris

Question 11

Which of the following best describes the function of gap junctions in cardiac muscle?

Accepted Answer

They allow direct passage of ions and small molecules between adjacent cells, enabling coordinated contraction.

Question 12

Which of the following is a correct sequence of events for receptor-mediated endocytosis?

Accepted Answer

Ligand binds receptor → vesicle forms → vesicle uncoats → ligand is released inside the cell

Question 13

A cell is observed to have a single, non-motile primary cilium. Which of the following is a likely function of this structure?

Accepted Answer

Sensing extracellular signals and regulating cell growth

Question 14

Which of the following best explains why the plasma membrane is described as a 'fluid mosaic'?

Accepted Answer

It consists of a dynamic arrangement of lipids and proteins that can move laterally within the bilayer.

Question 15

Which of the following best describes the process of phagocytosis?

Accepted Answer

The cell engulfs large particles by extending pseudopods and enclosing them in a membrane-bound vesicle.

Question 16

Which of the following is a function of peripheral membrane proteins?

Accepted Answer

They associate with the membrane surface and can act as enzymes or signaling molecules.

Question 17

A cell is exposed to a toxin that blocks the function of SNARE proteins. Which process will be most directly affected?

Accepted Answer

Exocytosis of vesicles

Question 18

Which of the following best explains why the resting membrane potential of most cells is negative?

Accepted Answer

The plasma membrane is more permeable to K$$^+$$ than Na$$^+$$, allowing K$$^+ to $$leave the cell and leaving behind negatively charged proteins.

Question 19

Which of the following is a correct description of the role of microtubules in the cell?

Accepted Answer

They provide structural support and serve as tracks for intracellular transport.

Cytology: The Study of Cells – Structure, Function, and Diversity

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