Question 1

Which of the following best defines a ligand in the context of cell signaling?

Accepted Answer

A signaling molecule that binds to a receptor protein, initiating a signal cascade.

Question 2

Which of the following is an example of a receptor protein?

Accepted Answer

G-protein coupled receptor

Question 3

Which statement correctly describes paracrine signaling?

Accepted Answer

It uses secreted messenger molecules that travel only short distances to affect nearby target cells.

Question 4

Gap junctions in animal cells and plasmodesmata in plant cells are similar because:

Accepted Answer

Both provide cytoplasmic channels that allow signaling molecules to pass directly between adjacent cells.

Question 5

A researcher observes that a signaling molecule is secreted by one cell and stimulates growth in a neighboring cell, but not in distant cells. This is an example of:

Accepted Answer

Paracrine signaling

Question 6

Which of the following best describes the specificity of receptor proteins?

Accepted Answer

They are specific to each ligand and change shape slightly upon ligand binding.

Question 7

Which of the following is NOT a characteristic of direct signaling between animal cells?

Accepted Answer

It requires secreted messenger molecules to travel through the bloodstream.

Question 8

Which structure in plant cells allows for the passage of water, small solutes, and sometimes proteins and RNA between cells?

Accepted Answer

Plasmodesmata

Question 9

A hormone acts as a ligand by binding to a receptor protein. What is the immediate result of this binding?

Accepted Answer

The receptor protein changes shape, initiating a signal cascade.

Question 10

Which of the following scenarios best illustrates local signaling?

Accepted Answer

A neuron releases neurotransmitters that bind to receptors on an adjacent neuron.

Question 11

Which of the following is a key difference between gap junctions and paracrine signaling?

Accepted Answer

Gap junctions allow direct cytoplasmic exchange, while paracrine signaling relies on diffusion of molecules through extracellular fluid.

Question 12

Which of the following best describes the role of a first messenger in cell signaling?

Accepted Answer

It is a signaling molecule (ligand) that initiates the signal cascade by binding to a receptor.

Question 13

Which of the following is most likely to occur if a mutation prevents the formation of gap junctions in animal cells?

Accepted Answer

Direct cytoplasmic exchange of signaling molecules between adjacent cells would be impaired.

Question 14

Which of the following is an example of direct signaling via cell-surface molecules?

Accepted Answer

Immune cells recognizing and binding to antigens on the surface of other cells.

Question 15

Which of the following statements about plasmodesmata is correct?

Accepted Answer

They are channels in plant cells that connect the cytoplasm of adjacent cells.

Chapter 11: Cell Communication – Study Guide Notes

Study Guide - Practice Questions

Study Guide - Flashcards