Question 1

Which of the following is NOT a function of the plasma membrane?

Accepted Answer

Synthesizes ATP for cellular energy

Question 2

A hydrophilic signaling molecule is most likely to interact with its receptor at which location?

Accepted Answer

The outer surface of the plasma membrane

Question 3

Which type of cell junction allows direct passage of substances between the cytosol of adjacent animal cells?

Accepted Answer

Gap junctions

Question 4

In the context of cell signaling, what is the role of a ligand?

Accepted Answer

It is a signaling molecule that binds to a receptor

Question 5

Which of the following best describes paracrine signaling?

Accepted Answer

A signaling cell releases molecules that affect nearby target cells

Question 6

Which type of membrane protein is a receptor protein?

Accepted Answer

Integral membrane protein

Question 7

What is the main function of gap junctions in animal cells?

Accepted Answer

To allow direct passage of ions and small molecules between cells

Question 8

Which process is responsible for amplifying a signal during a signal transduction pathway?

Accepted Answer

Phosphorylation cascade

Question 9

Which enzyme removes phosphate groups from proteins, turning off signal transduction pathways?

Accepted Answer

Phosphatase

Question 10

Which of the following is a common second messenger in signal transduction pathways?

Accepted Answer

Cyclic AMP ($$\mathrm{cAMP})$$

Question 11

Steroid hormones typically bind to receptors located in which part of the cell?

Accepted Answer

In the cytoplasm or nucleus

Question 12

Which of the following best describes the sequence of events in a signal transduction pathway?

Accepted Answer

Reception → Transduction → Response

Question 13

A researcher discovers a new molecule that is hydrophobic and acts as a signaling molecule. Where is its receptor most likely located?

Accepted Answer

In the cytoplasm or nucleus

Question 14

Which of the following is TRUE about G protein-coupled receptors (GPCRs)?

Accepted Answer

They interact with G proteins that bind to GTP

Question 15

What is the effect of phosphorylation on a protein in a signal transduction pathway?

Accepted Answer

It often changes the protein's shape and activity

Question 16

Which of the following is an example of long-distance signaling in animals?

Accepted Answer

Endocrine signaling via hormones

Question 17

Which of the following best explains why signal transduction pathways often involve multiple steps?

Accepted Answer

To amplify the signal and allow for greater regulation

Question 18

Which molecule acts as the 'first messenger' in a signal transduction pathway?

Accepted Answer

The extracellular ligand

Question 19

A mutation prevents the removal of phosphate groups from proteins in a cell. What is the most likely consequence?

Accepted Answer

Signal transduction pathways remain active longer than normal

Question 20

Which of the following is a direct result of ligand binding to a receptor protein on the plasma membrane?

Accepted Answer

The receptor undergoes a shape change and initiates a signal transduction pathway

Cell Signaling and the Plasma Membrane: Structure, Function, and Communication

Study Guide - Practice Questions