Question 1

Which of the following best explains why offspring produced by sexual reproduction are genetically different from their parents?

Accepted Answer

Because meiosis and fertilization shuffle alleles through independent assortment, crossing over, and random fertilization.

Question 2

If a human cell has 46 chromosomes, how many chromosomes will be present in each gamete after meiosis?

Accepted Answer

$$23$$

Question 3

Which event during meiosis is primarily responsible for the independent assortment of genes?

Accepted Answer

Random alignment of homologous chromosomes at the metaphase I plate

Question 4

A diploid organism has a haploid number $$n = 4. $$How many possible combinations of chromosomes can be produced in its gametes by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 5

Which of the following statements about crossing over is correct?

Accepted Answer

It results in the exchange of genetic material between homologous chromosomes, increasing genetic variation.

Question 6

Which process restores the diploid number of chromosomes in sexually reproducing organisms?

Accepted Answer

Fertilization

Question 7

In humans, what is the total number of possible chromosome combinations in a zygote, considering only independent assortment and random fertilization (not crossing over)?

Accepted Answer

$$(2^{23})^2$ = 70,368,744,177,664$

Question 8

Which of the following is a key difference between mitosis and meiosis?

Accepted Answer

Mitosis conserves chromosome number, while meiosis reduces it by half.

Question 9

A mutation occurs in a gene located on a chromosome. Which of the following best describes the potential impact of this mutation on future generations?

Accepted Answer

It can be passed to offspring only if it occurs in a gamete.

Question 10

During which phase of meiosis do homologous chromosomes separate?

Accepted Answer

Anaphase I

Question 11

Which of the following best describes a clone?

Accepted Answer

A group of genetically identical individuals produced by asexual reproduction.

Question 12

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

Accepted Answer

Replication of DNA during mitosis

Question 13

A plant species has a diploid number of $$2n = 8. $$After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

$$4$$

Question 14

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 15

If a sperm cell containing an abnormal number of chromosomes fertilizes a normal egg, what is the likely result?

Accepted Answer

The zygote will have an abnormal number of chromosomes, potentially leading to genetic disorders.

Question 16

Which of the following best defines a gene locus?

Accepted Answer

The physical location of a gene on a chromosome.

Question 17

In which type of organism does the multicellular haploid stage dominate the life cycle?

Accepted Answer

Most fungi and some protists

Question 18

Which of the following equations correctly represents the relationship between diploid and haploid chromosome numbers?

Accepted Answer

$$2n = $$ diploid number; $$n = $$ haploid number

Question 19

Which of the following is the best example of heredity?

Accepted Answer

A child inherits eye color from their parents.

Question 20

Which of the following statements about genetic variation is correct?

Accepted Answer

Genetic variation is produced by mutations, crossing over, independent assortment, and random fertilization.

Meiosis and Sexual Life Cycles: Study Notes for General Biology

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