Question 1

Which of the following best describes why only certain cells respond to a specific hormone in the bloodstream?

Accepted Answer

Only cells with the appropriate receptor for the hormone can respond to it.

Question 2

Which of the following is the correct sequence of events for a G protein-coupled receptor (GPCR) signaling pathway?

Accepted Answer

Ligand binds receptor → G protein activated → G protein activates enzyme → Second messenger produced

Question 3

A kinase is an enzyme that:

Accepted Answer

Adds a phosphate group to a substrate using ATP.

Question 4

How is the second messenger cAMP produced in a cell?

Accepted Answer

By the conversion of ATP to cAMP by adenylyl cyclase.

Question 5

During cell signaling, which second messengers are directly involved in the release of $$\mathrm{Ca$$^{2+}$$}$$ from the endoplasmic reticulum?

Accepted Answer

Inositol triphosphate ($$\mathrm{IP_3$}) $$and diacylglycerol ($$\mathrm{DAG})$$

Question 6

Which of the following best describes apoptosis in the nematode worm C. elegans?

Accepted Answer

A genetically programmed cell death process essential for normal development.

Question 7

If a human cell is in G2 phase, how many chromatids are present?

Accepted Answer

$$92$$

Question 8

Which cytoskeletal component is primarily responsible for separating chromosomes during mitosis?

Accepted Answer

Microtubules

Question 9

What is the first visible sign of cytokinesis in an animal cell?

Accepted Answer

Formation of a cleavage furrow

Question 10

Which cell cycle checkpoint is primarily responsible for ensuring that DNA is undamaged before replication?

Accepted Answer

G1 checkpoint

Question 11

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Question 12

Which event is unique to meiosis I and does NOT occur in mitosis?

Accepted Answer

Pairing and crossing over of homologous chromosomes

Question 13

During which phase of meiosis does independent assortment of chromosomes occur?

Accepted Answer

Metaphase I

Question 14

A plant with genotype $$YyRr is $$crossed with another plant with genotype $$yyrr. $$What is the probability that an offspring will have yellow, wrinkled seeds ($$Y	ext{-}y$$, $$rr$$)?

Accepted Answer

$$1/4$$

Question 15

In Mendel’s monohybrid cross between true-breeding purple-flowered and white-flowered pea plants, what was the phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1 ($$purple:white)

Question 16

A testcross is performed between a plant with an unknown genotype and a homozygous recessive plant. If the offspring show a 1:1 phenotypic ratio, what is the genotype of the unknown parent?

Accepted Answer

Heterozygous

Question 17

Which law explains why alleles for different traits are inherited independently of each other?

Accepted Answer

Law of Independent Assortment

Question 18

If a cell has a diploid number $$2n = 16$$, how many chromosomes are present in a gamete produced by meiosis?

Accepted Answer

$$8$$

Question 19

Which of the following best describes the role of cell cycle checkpoints in preventing cancer?

Accepted Answer

They ensure damaged or unprepared cells do not proceed to the next phase, reducing mutation accumulation.

Question 20

A heterozygous individual ($$Aa) $$self-crosses. What is the probability that an offspring will be homozygous recessive ($$aa$$)?

Accepted Answer

$$1/4$$

Cell Communication, Cell Cycle, Meiosis, and Mendelian Genetics: Study Guide for Chapters 11-14

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