Question 1

Which of the following best describes the difference between a gene and a chromosome?

Accepted Answer

A gene is a segment of DNA that codes for a specific trait, while a chromosome is a structure that contains many genes.

Question 2

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

Accepted Answer

Crossing over occurs during prophase I and increases genetic variation by exchanging DNA between homologous chromosomes.

Question 3

A human somatic cell contains 46 chromosomes. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

Each gamete will contain 23 chromosomes, which is the haploid number ($$n = 23).$$

Question 4

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

Accepted Answer

Synapsis and crossing over between homologous chromosomes during prophase I.

Question 5

If a plant exhibits alternation of generations, which of the following statements is true?

Accepted Answer

The plant alternates between a multicellular haploid gametophyte and a multicellular diploid sporophyte.

Question 6

Which mechanism is responsible for the independent assortment of chromosomes during meiosis?

Accepted Answer

Random alignment of homologous chromosome pairs at the metaphase plate during metaphase I.

Question 7

A mutation occurs in a gene that codes for eye color. What is the most likely outcome?

Accepted Answer

The mutation may create a new allele, resulting in a different eye color phenotype.

Question 8

During anaphase I of meiosis, what is separated?

Accepted Answer

Homologous chromosomes are separated and move to opposite poles.

Question 9

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

Accepted Answer

Genetic variation arises from independent assortment, crossing over, and random fertilization.

Question 10

If a sperm cell contains an X chromosome, what is the possible sex chromosome composition of the resulting zygote after fertilization with an egg?

Accepted Answer

XX, resulting in a female offspring.

Question 11

Which of the following equations correctly represents the chromosome number after meiosis in humans?

Accepted Answer

After meiosis, each gamete contains $$n = 23$$ chromosomes.

Question 12

Which process results in the formation of recombinant chromosomes?

Accepted Answer

Crossing over during prophase I of meiosis.

Question 13

A karyotype is used in medical genetics to:

Accepted Answer

Visualize and analyze the number and structure of chromosomes in a cell.

Question 14

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

Accepted Answer

Four genetically distinct haploid cells are produced.

Question 15

Which of the following best describes the role of the synaptonemal complex?

Accepted Answer

It holds homologous chromosomes together tightly during prophase I, facilitating crossing over.

Question 16

Which equation represents the number of possible combinations of chromosomes due to independent assortment in humans?

Accepted Answer

The number of possible combinations is $$2^{23}.$$

Question 17

Which of the following is a direct consequence of random fertilization?

Accepted Answer

Any sperm can fuse with any ovum, increasing genetic diversity in offspring.

Question 18

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They are similar in length and shape and carry genes controlling the same characters.

Question 19

Which of the following best explains why meiosis is essential for sexual reproduction?

Accepted Answer

Meiosis reduces the chromosome number from diploid to haploid, ensuring that fertilization restores the diploid state.

Meiosis and Sexual Life Cycles: Genetics, Chromosomes, and Genetic Variation

Study Guide - Practice Questions