Question 1

A certain animal species has a diploid number of 4 ($$2n=4). At $$the end of Meiosis I, how many chromosomes does each daughter cell have, and how many chromosomes does each have at the end of Meiosis II?

Accepted Answer

2 chromosomes at the end of Meiosis I, 2 chromosomes at the end of Meiosis II

Question 2

How many different combinations of gametes can a species with $$2n=4$$ produce just from independent assortment?

Accepted Answer

$$2^2 = 4$ combinations

Question 3

Which of the following best describes paracrine signaling?

Accepted Answer

A cell releases local regulators that affect nearby target cells.

Question 4

Which type of cell signaling is responsible for the rapid reflex action when you touch a hot stove?

Accepted Answer

Synaptic (nervous) signaling

Question 5

What is the correct sequence of the three main steps in cell signaling?

Accepted Answer

Reception, Transduction, Response

Question 6

Which of the following is NOT a type of cell surface receptor?

Accepted Answer

Steroid hormone receptor

Question 7

What is the main function of phosphorylation cascades in signal transduction?

Accepted Answer

To amplify the signal from the receptor to the target molecules

Question 8

Which of the following molecules can act as a second messenger in signal transduction pathways?

Accepted Answer

cAMP

Question 9

A small, hydrophobic hormone enters a cell and binds to a receptor in the cytoplasm. What is the most likely result?

Accepted Answer

The hormone-receptor complex acts as a transcription factor in the nucleus.

Question 10

Which of the following best explains why a single signaling molecule can cause different responses in different cell types?

Accepted Answer

Different cells have different receptors and signal transduction pathways.

Question 11

Which step in cell signaling is most directly responsible for activating transcription factors?

Accepted Answer

Response

Question 12

What is the role of protein kinases in a phosphorylation cascade?

Accepted Answer

They transfer phosphate groups from ATP to proteins.

Question 13

Which of the following scenarios is an example of endocrine signaling?

Accepted Answer

The adrenal gland releases adrenaline into the bloodstream affecting multiple organs.

Question 14

If a mutation prevents a G-protein from binding GTP, what is the most likely consequence for cell signaling?

Accepted Answer

The G-protein will not activate, and the signal will not be relayed.

Question 15

Which of the following best describes the function of ligand-gated ion channels?

Accepted Answer

They open or close in response to binding of a signaling molecule, allowing ions to flow across the membrane.

Question 16

A researcher adds a drug that blocks all protein kinases in a cell. Which process will be most directly affected?

Accepted Answer

Phosphorylation cascades during signal transduction

Question 17

Which of the following is a real-life example of a second messenger amplifying a signal inside a cell?

Accepted Answer

cAMP activating protein kinase A after adrenaline binds to its receptor

Question 18

Which of the following statements about receptor tyrosine kinases is correct?

Accepted Answer

They are activated by forming a dimer and autophosphorylating tyrosine residues.

Question 19

Which of the following best explains why small, hydrophobic signaling molecules do not require a cell surface receptor?

Accepted Answer

They can diffuse directly through the lipid bilayer and bind to intracellular receptors.

Cell Communication and Cell Signaling in Biology

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