Question 1

Which of the following best describes the process occurring in the first image (sperm surrounding an egg)?

Accepted Answer

Fertilization, where two haploid gametes fuse to form a diploid zygote.

Question 2

Refer to the second image (karyotype). What is the ploidy of the cell shown?

Accepted Answer

Diploid (2n)

Question 3

In the third image, chromosomes are shown in two colors. What do the red and blue colors represent?

Accepted Answer

Red: Maternal chromosomes, Blue: Paternal chromosomes

Question 4

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

Accepted Answer

$$n + n = 2n$$

Question 5

Which process is responsible for reducing the chromosome number from diploid to haploid in sexually reproducing organisms?

Accepted Answer

Meiosis

Question 6

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 7

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

Accepted Answer

Replication of DNA during S phase

Question 8

A cell with 2n = 6 undergoes meiosis. How many chromosomes will each gamete have after meiosis II?

Accepted Answer

3

Question 9

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

Accepted Answer

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

Question 10

In the life cycle of fungi such as Sordaria fimicola, which stage is diploid?

Accepted Answer

Zygote

Question 11

Which of the following events is unique to meiosis and does NOT occur in mitosis?

Accepted Answer

Pairing of homologous chromosomes and crossing over

Question 12

If a mutation occurs in a gene located at a specific locus, what is the most direct consequence?

Accepted Answer

The trait coded by that gene may be altered.

Question 13

Which equation correctly represents the chromosome number change during meiosis in a diploid organism?

Accepted Answer

$$2n \rightarrow n$$

Question 14

A human cell in metaphase I of meiosis contains how many chromatids?

Accepted Answer

92

Question 15

Which of the following best describes a gamete?

Accepted Answer

A cell with a single set of chromosomes (n)

Question 16

During which stage of meiosis do homologous chromosomes line up at the metaphase plate?

Accepted Answer

Metaphase I

Question 17

Which of the following is a direct result of independent assortment during meiosis?

Accepted Answer

Each gamete receives a random mix of maternal and paternal chromosomes.

Question 18

If nondisjunction occurs during meiosis II, what is the most likely outcome?

Accepted Answer

Some gametes will have an abnormal number of chromosomes.

Question 19

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

Accepted Answer

It maintains a constant chromosome number across generations by halving the chromosome number in gametes.

Question 20

Which of the following is NOT a difference between mitosis and meiosis?

Accepted Answer

Both processes result in cells with half the original chromosome number.

Meiosis and Sexual Reproduction: Study Notes for General Biology

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