Page 129 - Knowledge Organiser Yr9 24-25

Knowledge Base: Science B1: Cell Biology Year 9
10. Cell Differentiation
10.1 What is cell differentiation?
The process of a cell becoming specialised.
10.2
What happens to a cell as it differentiates?
It acquires different sub-cellular structures to enable it to carry out certain functions.
10.3
Which type of cells only differentiate at early stages?
Animal cells.
10.4
Which type of cells retain the ability to differentiate throughout life?
Plant cells.
10.5
In mature animals what is the purpose of cell division?
Repair and replacement.
11. Chromosomes
11.1 What is found in the nucleus of a cell?
11.2 What is a gene?
Chromosomes made of DNA molecules.
A section of DNA found on a chromosome.
11.3
How are chromosomes arranged in the nuclei of body cells?
They are normally found in pairs.
12. Mitosis and the Cell Cycle
12.1
What is the cell cycle?
A series of stages in which a cell divides to make new cells.
12.2
What is mitosis?
The stage in the cell cycle in which the nucleus divides.
12.3 What is the purpose of the cell cycle?
For growth and repair.
12.4
What must happen to a cell before it can divide?
• The number of sub-cellular structures doubles (e.g. ribosomes and mitochondria).
• The DNA replicates to form two copies of each chromosome.
12.5
What happens to the chromosomes and the nucleus during mitosis?
One set of chromosomes is pulled to each end of the cell and the nucleus divides.
12.6
What happens in the last stage of the cell cycle (following mitosis)?
The cytoplasm and cell membrane divide to form two identical cells.
129