Question

What is the main purpose of chromosome pairing in meiosis I?

Group of answer choices

For crossing over to occur

For proper chromosome segregation to occur

For mitosis to occur

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Question 291 pts

Male bees are haploid. How do they produce gametes?

Group of answer choices

By mitosis

By meiosis

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Question 301 pts

Which of the following determines the correct segregation of X and Y chromosomes during meiosis I in humans (males):

Group of answer choices

Lack of homology between X and Y

Presence of “pseudoautosomal” (PAR) regions shared by X and Y

The presence of the SRY gene

Answer 1

Answer: For crossing over to occur and For proper chromosome segregation to occur

Rationale: In meiosis duplicated homologous chromosomes paired up at the equator of the spindle. This structural arrangement of chromosome is important for cross over events which results in chromosome with altered genetic makeup. Homologous pairing is also important for proper segregation of each chromosome of homologous pair.

291: answer: mitosis

Rationale: Haploid male bees produce the gamete by mitotic spermatogenesis. Meiotic reduction division does not occur in haploid male bees.

302: answer: Presence of “pseudoautosomal” (PAR) regions shared by X and Y

Rationale: X and Y chromosomes contain pseudoautosomal regions known as PAR1, PAR2. pseudoautosomal regions contains a homologous sequence corresponding to X and Y chromosomes. Pseudoautosomal regions enabled X and y chromosome to align and cross over events.