Week 6

Question 1

Q1: What is the purpose of meiosis?

Answer 1

A1: To produce gametes (sperm or egg cells) with half the number of chromosomes for sexual reproduction.

Question 1

Q2: What type of cells does meiosis produce?

Answer 1

A2: Haploid cells (1 set of chromosomes, n), like sperm and eggs.

Question 2

Q3: What does “haploid” mean?

Answer 2

A3: A cell with one set of chromosomes (n).

Question 3

Q4: What does “diploid” mean?

Answer 3

A4: A cell with two sets of chromosomes (2n), one from each parent.

Question 4

Q5: How is meiosis similar to mitosis?

Answer 4

A5: Both involve DNA replication, chromosome alignment, and cell division stages (PMAT).

Question 5

Q6: How is meiosis different from mitosis?

Answer 5

Meiosis: Two divisions, produces 4 haploid cells, includes crossing over, increases genetic variation.

Mitosis: One division, produces 2 diploid identical cells, no genetic variation.

Question 6

Q7: What happens in Prophase I?

Answer 6

A7: Chromosomes condense, homologous chromosomes pair up, and crossing over occurs (exchange of DNA between homologs).

Question 7

Q8: What is “crossing over”?

Answer 7

A8: Exchange of DNA between homologous chromosomes, which increases genetic variation.

Question 8

Q9: What happens in Metaphase I?

Answer 8

A9: Homologous chromosome pairs line up in the middle of the cell.

Question 9

Q10: What happens in Metaphase II?

Answer 9

A10: Single chromosomes (not pairs) line up in the center in each haploid cell.

Question 10

Q11: At what stage does the cell go from diploid to haploid?

Answer 10

A11: After Meiosis I—specifically after Telophase I and cytokinesis, cells are haploid.

Question 11

Q12: What is “independent assortment”?

Answer 11

A12: Random arrangement of homologous chromosomes during Metaphase I, leading to unique combinations in gametes.

Question 12

Q13: How do crossing over and independent assortment contribute to genetic diversity?

Answer 12

A13:
Crossing over mixes genes between homologs.

Independent assortment randomly distributes chromosomes, creating unique gametes.

Question 13

Q1: What is the difference between sexual and asexual reproduction?

Answer 13

A1:
Sexual reproduction involves two parents and the fusion of gametes (egg + sperm); offspring are genetically unique.

Asexual reproduction involves one parent; offspring are genetically identical clones.

Question 14

Q2: What are some examples of asexual reproduction?

Question 15

Q3: What are the advantages of asexual reproduction?

Answer 15

A3:

Fast, requires no mate, good in stable environments.

Question 16

Q4: What are the advantages of sexual reproduction?

Answer 16

Creates genetic diversity, helps populations adapt to changing environments.

Question 17

Q5: What is the basic sexual life cycle in animals?

Answer 17

Diploid (2n): Most cells in the body (somatic cells).

Haploid (n): Gametes (sperm and egg).

Meiosis makes haploid gametes from diploid cells.

Fertilization fuses haploid gametes to make a diploid zygote.

Question 18

Q6: How do meiosis and fertilization relate to haploid and diploid stages?

Answer 18

Meiosis reduces chromosome number (diploid → haploid).

Fertilization restores chromosome number (haploid → diploid).

Question 19

Q7: Do plants, animals, and fungi all use sexual reproduction the same way?

Answer 19

A7: No—while they all use meiosis and fertilization, they have different patterns of when cells are haploid or diploid in their life cycles.