B1 - Chromosones and Mitosis

What form is genetic information in the nucleus stored in?

In chromosomes.

What are chromosomes made of?

Coiled up lengths of DNA molecules.

What do genes control?

The development of different characteristics, e.g. hair colour.

Why do body cells usually have two copies of each chromosome?

One is from the ‘mother’ and the other from its ‘father’.

What is the stage of the cell cycle where the cell divides called?

Mitosis

What is the cell cycle?

The series of stages which a cell goes through to divide to create new cells.

What happens during the growth and DNA replication stage of the cell cycle?

• The DNA is spread out into long strings.

• The cell grows and increases the amount of subcellular structures such as mitochondria and ribosomes.

• The cell replicated its DNA which forms X-shaped chromosomes where each arm is an exact duplicate of the other.

What are the two main stages of the cell cycle?

Growth & DNA replication and mitosis.

What happen during the mitosis stage of the cell cycle?

• The chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms or each chromosome go to opposite sides of the cell.

• Membranes form around each of the sets of chromosomes, becoming nuclei - the nucleus has divided.

• The cytoplasm and cell membrane divide.