Mitosis & Meiosis

Question 1

Mitosis overall purpose

Answer 1

• Passes along identical genetic information to daughter cells
• Cell division

Question 2

Meiosis overall purpose

Answer 2

• Passes along information to gamete cells in sexually reproducing organisms
• To make haploid cells

Question 3

How many stages of mitosis?

Answer 3

• One stage. (divides only once)
• 4 phases

Question 4

How many stages of meiosis?

Answer 4

Occurs in two stages.
1. Reduction = cells become haploid
2. Division = cells further multiply

Question 5

Types of cells involved in mitosis

Answer 5

• Occurs in somatic cells (body cells) of multi-cellular organisms
• May occur asexually reproducing unicellular

Question 6

Types of cells involved in meiosis

Answer 6

Both female and male gametes
Ex. sperm & ova in animals
Ex. pollen & ova in flowering plants

Question 7

Final outcome of mitosis

Answer 7

• Produces diploid cells with the full amount of genetic information (2n)
• Daughter cell identical to mother

Question 8

Final outcome of meiosis

Answer 8

• Produces haploid cells (n) with half of the diploid number, so that 2 haploid parent cells can come together to make a diploid offspring.
• Cells are not identical to parent cells

Question 9

How many chromosomes in somatic cells after mitosis?

Answer 9

46

Question 10

How many chromosomes do human gametes have after meiosis?

Answer 10

23

Question 11

Importance of meiosis

Answer 11

Allows for sexual reproduction (2 parents) which increases genetic variation in the offspring

Question 12

What are the types of sex chromosomes?

Answer 12

Male: XY
Female: XX

Question 13

Interphase

Answer 13

Not part of mitosis. Takes place prior to division and immediately following cytokinesis. Consists of the G1, S and G2 phases of the cell cycle.

Question 14

Cytokinesis - Last part of M phase (follows mitosis)

Answer 14

• Division of cell contents (cytoplasm and organelles)
• The cell membrane pinches inwards forming a cleavage furrow (halving) in animal cells

Question 15

Meiosis: Late prophase I

Answer 15

• Chromosome pairs called “Homologous Chromosomes” overlap and carry out “crossover

Question 16

What is crossover?

Answer 16

Special event in Meiosis which creates genetic variation between the gametes of each parent.
Occurs during prophase I where genes are shuffled between homologous chromosomes.

Question 17

Homologous pairs

Answer 17

Tetrad and bivalent

Question 18

Spermatogenesis

Answer 18

Cytoplasm is equally divided during each cell division and results in 4 equal sized sperm cells

Question 19

Oogenesis

Answer 19

Cytoplasm of the female gametes does not divide equally during each of the two cell divisions of meiosis. One of the daughter cells receives most of the cytoplasm. Other cells die and the final product of oogenesis is a single egg cell.