SB2a - Mitosis

Question 1

Compare and contrast The characteristics of Sexual and Asexual reproduction.

Answer 1

Characteristic Asexual Sexual reproduction

Number of parents 1 2

Fertilisation No Yes

Gametes No Yes (sperm cell, egg cell)

Genetic variation No Yes

Offspring is copy of
parent (clone) Yes No

Question 2

Why do we need mitosis?

Answer 2

1) Growth and repair

2) Asexual reproduction (genetically identical offspring/cells produced – so they
will survive only if there is not change in the environment)

Question 2

Name two examples of Animals that use Asexual reproduction.

Answer 2

aphids and Komodo dragons

Question 2

Name two examples of plants that use Asexual reproduction.

Answer 2

strawberry plants (using runners),
potatoes (which use tubers)

Question 3

What are the 5 stages of mitosis?

Answer 3

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis

Question 4

When does interface occur and what happens during the interphase?

Answer 4

• Interphase happens BEFORE MITOSIS starts (before prophase

1. DNA replicates / doubles
2. All organelles double so that when the cell divides in two, half of the
   organelles go into one cell and half into the other cell
3. The cell grows bigger so that when the cell divides it forms two cells with
   equal size to the parent / original cell

Question 5

Explain all the stages of mitosis in order.

Answer 5

1. Prophase - nuclear membrane breaks down, chromosomes condense and spindle fibers appear
2. Metaphase - chromosomes line up in the middle of the cell (equator) and spindle is attached to them
3. Anaphase - the spindle fibers pull chromosomoes to opposite poles and spindle is attached to them
4. Telophase - the nuclear membrane starts to reform and the cell start to split
5. Cytokinesis - the cell contents are divided into two daughter cells, two nuclei from two cells

Question 6

Compare and Contrast features of Mitosis and Meiosis.

Answer 6

Mitosis under goes 1 cell division and produces 2 daughter cells which are both diploid meaning they have 46 chromosomes. The daughter cells are body cells and are genetically different than their mother cell. Mitosis produces these daughter through asexual reproduction and the reason they reproduce is to grow and repair

On the other hand, Meiosis goes under 2 cell division which means 4 daughter cells are produced which have 23 chromosomes (Haploid) and are classified as sex cells and are completely identical to their original cell. Copies.They are produces through sexual reproduction.