Question 1

Which process during meiosis is primarily responsible for generating new combinations of maternal and paternal alleles in gametes?

Accepted Answer

Crossing over during prophase I

Question 2

If a dog has a haploid chromosome number $$n = 39$$, how many possible combinations of maternal and paternal chromosomes can be produced by independent assortment alone?

Accepted Answer

$$2^{39}$$

Question 3

Which of the following is NOT a source of genetic diversity in sexually reproducing species?

Accepted Answer

Binary fission

Question 4

A human zygote is formed from the fusion of two gametes. Without crossing over, what is the approximate number of possible diploid chromosome combinations at fertilization?

Accepted Answer

More than 70 trillion

Question 5

During which phase of meiosis does independent assortment of homologous chromosomes occur?

Accepted Answer

Anaphase I

Question 6

What is the result of nondisjunction during meiosis?

Accepted Answer

Gametes with abnormal numbers of chromosomes

Question 7

Which term describes an organism with an extra set of all chromosomes?

Accepted Answer

Polyploid

Question 8

A child is born with Down syndrome. Which chromosomal abnormality is most likely responsible?

Accepted Answer

Trisomy 21 (an extra chromosome 21)

Question 9

Which of the following best explains why sexual reproduction leads to genetically unique offspring?

Accepted Answer

It combines genetic material from two individuals and involves recombination and independent assortment.

Question 10

If nondisjunction occurs during meiosis II, what is the expected outcome for the resulting gametes?

Accepted Answer

One gamete with an extra chromosome, one with a missing chromosome, and two normal gametes

Question 11

Which of the following is true about aneuploidy in humans?

Accepted Answer

It is usually lethal to the embryo, except for certain cases like trisomy 21 and sex chromosome aneuploidy.

Question 12

Which event during meiosis ensures that sister chromatids are a mix of maternal and paternal DNA?

Accepted Answer

Crossing over during prophase I

Question 13

What is the definition of a euploid cell?

Accepted Answer

A cell with the normal number of chromosomes

Question 14

Which of the following scenarios would most likely result in polyploidy?

Accepted Answer

Failure of spindle formation during mitosis in germ cells

Question 15

Why does fertilization further increase genetic diversity beyond meiosis?

Accepted Answer

It combines two unique gametes, each with different genetic combinations.

Question 16

Which formula correctly represents the number of possible combinations of maternal and paternal chromosomes due to independent assortment, where $$n is $$the haploid chromosome number?

Accepted Answer

$$2^n$$

Question 17

A mutation occurs in a germ cell during meiosis. What is the most likely consequence for the offspring?

Accepted Answer

The offspring may inherit a new genetic variant not present in either parent.

Question 18

Which of the following best describes the process of crossing over?

Accepted Answer

Exchange of genetic material between homologous chromosomes during prophase I

Question 19

If a human gamete is missing a chromosome due to nondisjunction, what is the term for the resulting zygote after fertilization?

Accepted Answer

Monosomic

Question 20

Which of the following statements about genetic variation in meiosis is correct?

Accepted Answer

Segregation of recombinant chromatids in meiosis II increases genetic diversity among gametes.

Meiosis and Genetic Variation: Mechanisms and Consequences

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