Question 1

Which of the following best explains why offspring produced by sexual reproduction are genetically unique?

Accepted Answer

Because independent assortment, crossing over, and random fertilization create new combinations of alleles.

Question 2

If a human somatic cell contains 46 chromosomes, how many chromosomes will be found in a human gamete?

Accepted Answer

$$n = 23$$

Question 3

During which phase of meiosis does crossing over occur, and what is its genetic significance?

Accepted Answer

Crossing over occurs during Prophase I and creates recombinant chromosomes, increasing genetic variation.

Question 4

What is the formula for calculating the number of possible chromosome combinations due to independent assortment in a species with a haploid number $$n$$?

Accepted Answer

$$2^n$$

Question 5

Which statement correctly distinguishes autosomes from sex chromosomes in humans?

Accepted Answer

Autosomes are the 22 pairs of chromosomes that do not determine sex, while sex chromosomes (X and Y) determine the individual's sex.

Question 6

A diploid cell ($$2n) $$undergoes meiosis. How many genetically distinct haploid cells are produced, and how do they differ from the parent cell?

Accepted Answer

Four haploid cells, each genetically distinct from the parent cell and each other.

Question 7

Which process is responsible for the physical exchange of genetic material between homologous chromosomes?

Accepted Answer

Crossing over

Question 8

Why do monoclonal crops face greater risk from environmental changes compared to genetically diverse populations?

Accepted Answer

Genetic variation in diverse populations allows for adaptive advantages, while monoclonal crops lack variation to overcome changes.

Question 9

During Anaphase I of meiosis, what separates and moves toward opposite poles?

Accepted Answer

Homologous chromosomes

Question 10

Which of the following is a direct result of random fertilization in humans?

Accepted Answer

Any sperm can fuse with any ovum, increasing genetic variation among offspring.

Question 11

A human male has one X and one Y chromosome. Which type of gamete can he produce with respect to sex chromosomes?

Accepted Answer

Both X and Y chromosome gametes

Question 12

Which event occurs during Metaphase I of meiosis and contributes to genetic diversity?

Accepted Answer

Homologous pairs line up randomly at the metaphase plate.

Question 13

What is the genetic consequence of synapsis and crossing over during Prophase I?

Accepted Answer

Formation of recombinant chromosomes with new allele combinations.

Question 14

Which of the following best describes a clone produced by asexual reproduction?

Accepted Answer

An organism genetically identical to its parent.

Question 15

If a species has a haploid number $$n = 4$$, how many possible combinations of chromosomes can result from independent assortment?

Accepted Answer

$$2^4 = 16$

Question 16

Which of the following is true about the products of meiosis II?

Accepted Answer

Each cell contains a haploid set of unreplicated chromosomes.

Question 17

What is the role of the locus on a chromosome?

Accepted Answer

It is the specific position of a gene along a chromosome.

Question 18

Which phase of meiosis is responsible for reducing the chromosome number from diploid to haploid?

Accepted Answer

Meiosis I

Question 19

Why are the two sister chromatids of each chromosome no longer genetically identical by Metaphase II?

Accepted Answer

Because crossing over in meiosis I exchanges genetic material between homologs.

Question 20

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of chromosomes during S phase

Meiosis and Genetic Variation: Mechanisms and Significance

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