Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways break down complex molecules into simpler ones, releasing energy, while anabolic pathways build complex molecules from simpler ones, requiring energy input.

Question 2

A chemical reaction has a change in free energy $\Delta G = -7.3\ \mathrm{kcal/mol}$. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is exergonic and releases energy.

Question 3

Which of the following is an example of local cell communication in animals?

Accepted Answer

Neurotransmitters released at a synapse between two nerve cells.

Question 4

In the context of cell signaling, what is the primary function of a ligand-gated ion channel receptor?

Accepted Answer

To allow specific ions to flow across the membrane in response to ligand binding.

Question 5

Which of the following best explains why epinephrine does not directly activate glycogen phosphorylase in a test tube, but does so in living cells?

Accepted Answer

Epinephrine requires a signal transduction pathway involving receptors and intracellular signaling molecules to activate glycogen phosphorylase.

Question 6

Which of the following is a key feature of G protein-linked receptors?

Accepted Answer

They activate G proteins by facilitating the exchange of GDP for GTP upon ligand binding.

Question 7

A mutation prevents the dimerization of a tyrosine kinase receptor. What is the most likely consequence for cell signaling?

Accepted Answer

The receptor will fail to autophosphorylate, preventing activation of downstream signaling pathways.

Question 8

Which of the following signaling molecules is most likely to bind to an internal (intracellular) receptor?

Accepted Answer

A steroid hormone such as testosterone.

Question 9

In plants, which process is an example of cell communication leading to a physiological response?

Accepted Answer

Root movement towards a water source (hydrotropism).

Question 10

Which of the following best describes quorum sensing in bacteria?

Accepted Answer

A mechanism where bacteria release chemical signals to monitor population density and coordinate group behavior.

Question 11

Which of the following equations correctly represents the change in free energy for a chemical reaction?

Accepted Answer

$\Delta G = G_{\mathrm{Products}} - G_{\mathrm{Reactants}}$

Question 12

A patient is given a drug that blocks the dissociation of GDP from the G protein. What is the most likely effect on G protein-coupled receptor signaling?

Accepted Answer

The G protein will remain inactive, and downstream signaling will be inhibited.

Question 13

Which of the following is a real-life example of endocrine (long-distance) signaling?

Accepted Answer

A hormone such as insulin released into the bloodstream to regulate blood sugar.

Question 14

Which of the following best explains why only certain cells respond to a particular signaling molecule?

Accepted Answer

Only cells with the specific receptor for the signaling molecule can respond.

Question 15

Which of the following is a correct sequence of the three stages of cell signaling?

Accepted Answer

Reception, Transduction, Response

Question 16

A researcher observes that a signaling molecule can diffuse through the plasma membrane and bind to a receptor in the cytoplasm, leading to changes in gene expression. Which type of signaling molecule is most likely involved?

Accepted Answer

A hydrophobic steroid hormone

Question 17

Which of the following best describes the process of reaction coupling in cellular metabolism?

Accepted Answer

An endergonic reaction is driven by the energy released from an exergonic reaction, such as ATP hydrolysis.

Question 18

Which of the following is NOT a characteristic of ligand-gated ion channel receptors?

Accepted Answer

They directly activate G proteins upon ligand binding.

Question 19

A plant cell is exposed to ethylene gas, which diffuses through the plasma membrane and binds to an internal receptor. What is the most likely cellular response?

Accepted Answer

Altered gene expression leading to changes in growth or development.

Question 20

Which of the following scenarios best illustrates the importance of cell-cell recognition in the immune system?

Accepted Answer

A T cell recognizing and binding to an infected cell via specific surface proteins.

Cell Communication and Signaling: Study Notes for Bio 202

Study Guide - Practice Questions

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