Question 1

During which phase of the cell cycle does DNA replication occur, and what is the result of this process?

Accepted Answer

DNA replication occurs during the S phase, resulting in each chromosome consisting of two sister chromatids.

Question 2

A researcher observes a cell with condensed chromosomes aligned at the center of the cell, with spindle fibers attached to the centromeres. Which stage of mitosis is being observed?

Accepted Answer

Metaphase

Question 3

Which of the following best describes the difference between cytokinesis in animal cells and plant cells?

Accepted Answer

Animal cells form a cleavage furrow, while plant cells form a cell plate.

Question 4

A cell is observed to have 46 chromosomes at the start of mitosis. How many chromosomes will each daughter cell have after mitosis is complete?

Accepted Answer

46

Question 5

Which checkpoint in the cell cycle is primarily responsible for determining whether a cell will proceed to DNA replication or enter a non-dividing state?

Accepted Answer

G1 checkpoint

Question 6

In a species of plant, the diploid number of chromosomes is 24. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

12

Question 7

Which process during meiosis increases genetic variation by exchanging genetic material between homologous chromosomes?

Accepted Answer

Crossing over

Question 8

A human karyotype shows 47 chromosomes, including three copies of chromosome 21. What is this condition called?

Accepted Answer

Trisomy 21

Question 9

Which of the following best explains the Law of Independent Assortment?

Accepted Answer

Each pair of alleles segregates independently of other pairs during gamete formation.

Question 10

A cross between two heterozygous pea plants (Yy) for yellow seed color results in a 3:1 ratio of yellow to green seeds in the F2 generation. Which principle does this illustrate?

Accepted Answer

Law of Segregation

Question 11

A woman with blood type A (genotype $$I^A i) $$and a man with blood type B (genotype $$I^B i) $$have a child. Which blood type is NOT possible for their child?

Accepted Answer

Type C

Question 12

In Labrador retrievers, coat color is determined by two genes: one for pigment color (B = black, b = brown) and one for pigment deposition (E = color, e = no color, resulting in yellow). What is the expected phenotype ratio in the offspring of two dihybrid black Labs ($$BbEe 	imes BbEe$$)?

Accepted Answer

$$9:3:4$$

Question 13

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 14

Which of the following best describes pleiotropy?

Accepted Answer

One gene affects multiple phenotypic traits.

Question 15

A fruit fly with a gray body and normal wings is crossed with a fly with a black body and vestigial wings. Most offspring have parental phenotypes, but some have recombinant phenotypes. What does this suggest about the genes for body color and wing type?

Accepted Answer

They are linked but crossing over has occurred.

Question 16

If a nondisjunction event occurs during meiosis II in a human female, what is the expected outcome for the resulting gametes?

Accepted Answer

Half the gametes will be normal, one will have an extra chromosome, and one will be missing a chromosome.

Question 17

Which of the following is an example of polygenic inheritance?

Accepted Answer

Height in humans

Question 18

A geneticist is mapping two genes and finds a recombination frequency of 12%. How many map units apart are these genes?

Accepted Answer

$$12$$ map units

Question 19

Which of the following chromosomal alterations results in a chromosome segment being reversed end to end?

Accepted Answer

Inversion

Question 20

A plant with genotype $$AaBb is $$testcrossed with $$aabb. $$What is the expected phenotypic ratio if the genes are unlinked?

Accepted Answer

$$1:1:1:1$$

Cell Division, Meiosis, Mendelian Genetics, and Chromosomal Inheritance: Study Guide (Chapters 9-12)

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