Question 1

Which of the following best explains Mendel's Law of Segregation as it relates to meiosis?

Accepted Answer

During anaphase I, the two alleles for a gene separate as homologous chromosomes are pulled to opposite poles.

Question 2

In a dihybrid cross between two pea plants heterozygous for seed shape (Rr) and seed color (Yy), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 3

Which process during meiosis is responsible for the independent assortment of genes located on different chromosomes?

Accepted Answer

Random orientation of homologous chromosome pairs at metaphase I

Question 4

A plant with genotype RrYy produces gametes. Which combination of alleles is NOT possible in a single gamete due to the law of segregation?

Accepted Answer

RR

Question 5

Why do genes located close together on the same chromosome often violate Mendel's law of independent assortment?

Accepted Answer

They are linked and tend to be inherited together unless separated by crossing over.

Question 6

During meiosis, what is the result of the random orientation of homologous chromosomes at metaphase I?

Accepted Answer

It increases genetic variation by producing gametes with different combinations of parental chromosomes.

Question 7

In humans, how many autosomes are present in a typical somatic cell?

Accepted Answer

$$44$$

Question 8

Which of the following best describes the chromosomal basis of sex determination in humans?

Accepted Answer

Females have two X chromosomes; males have one X and one Y chromosome.

Question 9

If a male human's sperm contains an X chromosome, what sex chromosomes will be present in the resulting offspring if the egg contains an X chromosome?

Accepted Answer

XX (female)

Question 10

Which of the following scenarios is an example of Mendel's law of independent assortment?

Accepted Answer

A plant with genotype RrYy produces gametes with RY, Ry, rY, and ry combinations.

Question 11

Which event during meiosis ensures that each gamete contains only one allele for each gene?

Accepted Answer

Separation of homologous chromosomes during anaphase I

Question 12

A geneticist observes that two genes are inherited together more often than expected by chance. What is the most likely explanation?

Accepted Answer

The genes are linked and located close together on the same chromosome.

Question 13

Which of the following best describes the outcome of crossing over during meiosis?

Accepted Answer

It increases genetic variation by exchanging segments between homologous chromosomes.

Question 14

If a pea plant with genotype RrYy is self-fertilized, what fraction of the offspring will have wrinkled green seeds (rryy)?

Accepted Answer

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

Question 15

Which of the following is true regarding the inheritance of sex-linked genes in humans?

Accepted Answer

Females inherit X-linked genes from both parents.

Question 16

A woman with genotype XX and a man with genotype XY have a child. What is the probability that the child will be male?

Accepted Answer

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

Question 17

Which of the following best explains why crossing over can break genetic linkage between two genes?

Accepted Answer

Crossing over exchanges DNA between homologous chromosomes, separating linked genes.

Question 18

During meiosis, how many different types of gametes can an individual with genotype AaBb produce, assuming independent assortment?

Accepted Answer

$$4$$

Question 19

Which of the following is a direct consequence of the law of segregation?

Accepted Answer

Each gamete receives only one allele for each gene.

Question 20

A male with genotype XYY mates with a female with genotype XX. What is the expected sex chromosome composition of their offspring?

Accepted Answer

50% XX, 50% XYY

Chromosomal Basis of Inheritance: Mendel’s Laws, Meiosis, and Sex Determination

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