Question 1

Which of the following best describes quorum sensing in bacteria?

Accepted Answer

A mechanism by which bacteria coordinate behavior by releasing and detecting signaling molecules, often to regulate gene expression collectively.

Question 2

In yeast cell mating, what is the role of the mating factor?

Accepted Answer

It binds to receptors on the opposite mating type, triggering fusion of the two cells.

Question 3

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

Accepted Answer

They are involved in embryonic development, sensory perception, and are targets for many medications.

Question 4

What is the correct sequence of events in the activation of a G-protein?

Accepted Answer

1. Ligand binds to receptor 2. G-protein exchanges GDP for GTP 3. G-protein activates enzyme

Question 5

Which equation correctly represents the phosphorylation reaction catalyzed by a protein kinase?

Accepted Answer

$$\mathrm{Protein} + \mathrm{ATP} \rightarrow \mathrm{Protein{-}P} + \mathrm{ADP}$$

Question 6

A mutation causes a cell to lose the ability to deactivate cAMP. What is a likely consequence?

Accepted Answer

The cell may experience prolonged activation of protein kinase A, potentially leading to excessive signaling and disease.

Question 7

Which of the following best explains why calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$are effective second messengers?

Accepted Answer

Their concentration can be rapidly changed by release from organelles like the ER and mitochondria, allowing for quick cellular responses.

Question 8

During mitosis, what is the function of kinetochores?

Accepted Answer

They attach chromosomes to spindle microtubules, allowing movement during cell division.

Question 9

Which phase of the cell cycle is primarily responsible for DNA replication?

Accepted Answer

S phase

Question 10

What is the main difference between binary fission and mitosis?

Accepted Answer

Binary fission is a simpler process without spindle formation, while mitosis involves complex spindle assembly and chromosome segregation.

Question 11

Which of the following is a function of scaffolding proteins in signal transduction?

Accepted Answer

They organize and hold together multiple proteins in a signaling pathway to increase efficiency.

Question 12

A cell is exposed to a toxin that inhibits phosphodiesterase. What is the expected effect on cAMP levels?

Accepted Answer

cAMP levels will remain elevated because phosphodiesterase normally breaks down cAMP.

Question 13

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the spindle before proceeding?

Accepted Answer

M checkpoint

Question 14

What is the role of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

They phosphorylate target proteins to regulate progression through the cell cycle.

Question 15

Which of the following best describes apoptosis?

Accepted Answer

A programmed cell death mechanism that removes malfunctioning or unnecessary cells.

Question 16

Which of the following is a real-world example of a disease caused by a malfunction in signal transduction pathways?

Accepted Answer

Eczema, which can result from abnormal signal relay proteins.

Question 17

During cytokinesis in animal cells, what structure is responsible for physically dividing the cell?

Accepted Answer

Cleavage furrow formed by a contractile ring of actin and myosin

Question 18

Which of the following statements about chromatid separation during mitosis is correct?

Accepted Answer

Sister chromatids separate during anaphase, moving to opposite poles of the cell.

Question 19

Which of the following is a key difference between local and long-distance signaling in multicellular organisms?

Accepted Answer

Local signaling involves direct contact or short-range molecules, while long-distance signaling uses hormones that travel through the circulatory system.

Cell Communication and the Cell Cycle: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards