Question 1

Which of the following best describes the three stages of intercellular cell signaling?

Accepted Answer

Reception, transduction, and response

Question 2

A researcher is studying a receptor that, upon ligand binding, activates a G-protein by exchanging GDP for GTP. Which type of receptor is being studied?

Accepted Answer

G-protein Coupled Receptor (GPCR)

Question 3

Which enzyme catalyzes the conversion of ATP to cyclic AMP ($$cAMP) in $$the signal transduction pathway?

Accepted Answer

Adenylyl cyclase

Question 4

A patient is prescribed Herceptin for breast cancer. What is the mechanism of action for this drug?

Accepted Answer

It binds to and inhibits the HER2 receptor tyrosine kinase, blocking cell proliferation signals.

Question 5

During which phase of the eukaryotic cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 6

Which of the following best describes the structure of a duplicated chromosome during mitosis?

Accepted Answer

Two sister chromatids joined at a centromere, each with its own kinetochore

Question 7

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

Accepted Answer

They phosphorylate target proteins to regulate cell cycle progression.

Question 8

Which of the following is a key difference between mitosis and meiosis?

Accepted Answer

Meiosis results in four genetically unique haploid cells, while mitosis produces two identical diploid cells.

Question 9

A cell with $$2n = 46$$ chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$n = 23$$

Question 10

Which event during meiosis increases genetic diversity by exchanging genetic material between homologous chromosomes?

Accepted Answer

Crossing over (synapsis)

Question 11

A child is born with Down syndrome due to trisomy 21. Which meiotic error most likely caused this condition?

Accepted Answer

Non-disjunction during meiosis

Question 12

Which of the following best defines a dominant allele?

Accepted Answer

An allele that determines the phenotype in a heterozygote

Question 13

In a dihybrid cross between two heterozygotes ($$AaBb 	imes AaBb$$), what is the probability of obtaining an offspring with genotype $$aabb$$?

Accepted Answer

$$\frac{1}{16}$$

Question 14

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene mutation causing multiple symptoms in cystic fibrosis

Question 15

A woman who is a carrier for an X-linked recessive disorder and a man who is unaffected have a son. What is the probability that their son will have the disorder?

Accepted Answer

$$\frac{1}{2}$$

Question 16

Which statement best describes the difference between oncogenes and tumor suppressor genes?

Accepted Answer

Oncogenes result from gain-of-function mutations, while tumor suppressors result from loss-of-function mutations.

Question 17

Which of the following best describes dosage compensation in mammals?

Accepted Answer

Inactivation of one X chromosome in females, forming a Barr body

Question 18

Which second messenger is produced by the action of phospholipase C and is involved in the release of $$Ca^{2+}$$ from the endoplasmic reticulum?

Accepted Answer

$$IP_3 ($$inositol trisphosphate)

Question 19

A cell is exposed to a ligand that binds a ligand-gated ion channel. What is the immediate effect?

Accepted Answer

The channel opens, allowing specific ions to flow across the membrane.

Question 20

Which of the following best explains why cancer cells can form tumors in new locations (metastasis)?

Accepted Answer

They lose attachment to neighboring cells and invade other tissues via the bloodstream or lymphatic system.

Cell Communication, Cell Cycle, Meiosis, and Genetics: Study Guide for General Biology

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