TOPIC 3: CELL DIVISION AND SEX DETERMINATION

Question 1

The 3 main stages of the cell cycle

Answer 1

1) Interphase
2) Mitosis
3) Cytokinesis

Question 2

Interphase

Answer 2

G1 – organelle duplication
S – DNA synthesis
G2 – protein synthesis

Question 3

Mitosis

Answer 3

the division of cell which results in 2 daughter cells that are genetically identical (diploid cells – number of chromosomes stay the same)

Question 4

4 Stages of Mitosis

Answer 4

1) Prophase
2) Metaphase
3) Anaphase
4) Telophase

Question 5

Functions of Mitosis

Answer 5

G.A.T.E
G: growth
A: aesexual reproduction
T: tissue repair
E: embryonic development

Question 6

Relationship between cancer & cell division

Answer 6

mutations in genes can cause cancer by accelerating cell division rates (they divide uncontrollably)

Question 7

Meiosis

Answer 7

cell division that results in the production of 4 daughter cells (4 haploid cells – number of chromosomes is halved), that are all genetically different

Question 8

Stages of Meiosis

Answer 8

1) Prophase I
2) Metaphase I
3) Anaphase I
4) Telophase I
5) Prophase II
6) Metaphase II
7) Anaphase II
8) Telophase II

Question 9

Mitosis vs Meiosis

Answer 9

Mitosis:
- 46 chromosomes (pairs of chromosomes)
- diploid cells
- genetically identical
- body cells produced

Meiosis
- 23 chromosomes (single chromosomes)
- Haploid cells
- Gamete cells (sex cells) produced
- Genetically different
- 4 haploid cells

Question 10

Fertilisation

Answer 10

• a zygote has the combined number of haploid chromosome number (ex: 46 chromosomes in humans)
• the diploid number has to be even for the animal to be fertile (so they can reproduce)

Question 11

Characteristics of Asexual Reproduction

Answer 11

• only via mitosis.
• It only requires one parent cell,
• genetically identical
• the daughter cells formed are clones because they are genetically identical copies of the original, or parent, cell

Question 12

Characteristics of Sexual Reproduction

Answer 12

• via meiosis
• requires two parent cells (male + female)
• genetically different

Question 13

Sex Determination

Answer 13

Female: XX
Male: XY