Question 1

Which of the following best describes the main purpose of meiosis in sexually reproducing organisms?

Accepted Answer

To reduce the chromosome number by half, creating haploid gametes from diploid cells

Question 2

A human cell with 46 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$23$$

Question 3

Which process is responsible for restoring the diploid chromosome number in sexually reproducing organisms?

Accepted Answer

Fertilization

Question 4

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

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes

Question 5

If an animal has 26 chromosomes in its somatic cells, how many chromosomes will be present in each of its egg cells?

Accepted Answer

$$13$$

Question 6

Which of the following contains identical DNA?

Accepted Answer

Sister chromatids

Question 7

What is the result of independent assortment during meiosis?

Accepted Answer

Each gamete receives a random mix of maternal and paternal chromosomes

Question 8

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Independent assortment and crossing over during meiosis create genetic variation

Question 9

What is the chromosomal composition of a zygote immediately after fertilization in humans?

Accepted Answer

Diploid ($$2n)$$

Question 10

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

Accepted Answer

Replication of DNA during S phase of mitosis

Question 11

A karyotype is useful for which of the following purposes?

Accepted Answer

Arranging chromosomes by length to detect chromosomal abnormalities

Question 12

Which syndrome is associated with an individual having only one X chromosome (XO)?

Accepted Answer

Turner's syndrome

Question 13

What is the main difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes have the same genes but may have different versions; sister chromatids are identical copies

Question 14

Which of the following best describes the outcome of meiosis II?

Accepted Answer

Sister chromatids are separated, resulting in four genetically distinct haploid cells

Question 15

If nondisjunction occurs during meiosis, what is a possible outcome?

Accepted Answer

Some gametes may have an abnormal number of chromosomes, leading to conditions like Down syndrome

Question 16

Which of the following is true about the X and Y chromosomes in humans?

Accepted Answer

The X chromosome is essential and larger, while the Y chromosome is much smaller

Question 17

Which process ensures that each gamete receives only one chromosome from each homologous pair?

Accepted Answer

Meiosis I

Question 18

Why is genetic variation important for a population?

Accepted Answer

It allows natural selection to act on differences, increasing the population's adaptability

Question 19

Which of the following is NOT a source of genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of chromosomes during mitosis

Question 20

What is the ploidy of cells produced at the end of meiosis I and meiosis II, respectively?

Accepted Answer

Haploid after both meiosis I and meiosis II

ch 8Meiosis and Inheritance: Mechanisms of Genetic Variation

Study Guide - Practice Questions