2.Cells and control

Question 1

What is Mitosis?

Answer 1

Mitosis is a nuclear division that gives rise to two genetically identical diploid daughter cells.

All body cells ( not gametes) are produced by mitosis of the zygote

Question 2

What is mitosis required for?

Answer 2

Mitosis is required for:
Growth: mitosis produces new cells
Repair: to replace damaged or dead cells
Asexual reproduction: mitosis produces offspring that are genetically identical to the parent

Question 3

What are the three parts of the cell cycle?

Answer 3

Interphase - Just before mitosis, the DNA in the nucleus copies itself exactly (forms x-shaped chromosomes)
Mitosis - Chromosomes line up along the centre of the cell where cell fibres pull them apart
Cytokinesis - The cell cytoplasm and membrane divides to produce two daughter cells; each new cell has a copy of each of the chromosomes

Question 4

what are the stages of mitosis?

Answer 4

Prophase-The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.

Metaphase-Chromosomes and their copies line up in the middle of the cell.

Anaphase-Chromosomes and their copies are pulled to different ends of the cell.

Telophase-New membranes form around the chromosomes at each end of the cell.

Question 5

What is cancer the result of?

Answer 5

When a cell becomes
cancerous, it begins to grow and divide uncontrollably. A group of cancerous cells produces a growth called a
tumor.
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