Cell Division and Mitosis

What is the function of DNA?

DNA carries genetic information and instructions for making proteins

Where are chromosomes found?

In the nucleus of eukaryotic cells

What is a gene?

A section of DNA that codes for a particular protein.

How many chromosomes are in a human body cell?

46 chromosomes, arranged in 23 pairs.

What happens during DNA replication?

DNA is copied, producing two identical copies of genetic information.

What is mitosis?

Division of the nucleus, where chromosomes are separated into two identical sets.

What are the stages of the cell cycle?

Cell grows → DNA replicates → nucleus divides → cytoplasm divides

What is produced by mitosis and cell division?

Two genetically identical daughter cells with the same chromosome number as the parent cell.

What are the three main purposes of mitosis in multicellular organisms?

Growth, repair and replacement of damaged or worn-out cells.

How can mitosis be used in asexual reproduction?

It produces genetically identical offspring from one parent.

What is meiosis?

Cell division that produces four genetically different haploid cells.

Give two differences between mitosis and meiosis.

Mitosis produces 2 identical cells; meiosis produces 4 genetically different cells. Mitosis maintains chromosome number; meiosis halves it.

Explain why DNA replicates before mitosis

DNA replicates to produce two copies of genetic information. Chromosomes are separated equally during mitosis. Each daughter cell receives a complete, identical set of DNA.

Explain how mitosis allows an organism to grow.

Mitosis produces two genetically identical daughter cells. This increases the number of cells, allowing the organism to grow

Describe the stages of the cell cycle.

The cell grows and increases its subcellular structures. DNA replicates. The nucleus divides during mitosis. Finally, the cytoplasm and cell membrane divide, producing two genetically identical daughter cells.

Explain why gametes have half the normal chromosome number.

• During fertilisation, the sperm and egg combine. Having half the normal chromosome number ensures the normal diploid number is restored.