Biology 2.5 Cell Divison - Binary Fission and Mitosis

Question 1

why do cells divide

Answer 1

to asexually reproduce (binary fission in prokaryotes), to grow and repair tissues (mitosis in eukaryotes) and to form gametes for sexual reproduction (meiosis in eukaryotes)

Question 2

how does binary fission occur

Answer 2

1. Single, circular chromosome replicates and fixes to the membrane.
2. The membrane expands and begins to separate.
3. A new membrane forms between the two rings of DNA.
4. Cells separate into two identical daughter cells, each with their own circular chromosome.

Question 3

What does mitosis do?

Answer 3

Mitosis is used for growth and repair. Mitosis produces two identical daughter cells that are diploid.

Question 4

what are the steps of mitosis

Answer 4

1. Interphase: Cell grows and chromosomes replicate.
2. Prophase: Duplicated chromosomes condense.
3. Metaphase: Chromosome pairs align in the centre of the cell (metaphase plate).
4. Anaphase: Spindle fibres pull chromosomes to opposite ends of the cell.
5. Telophase: Cell pinches in the middle (cleavage furrow).
6. Cytokinesis: Cells separate, forming two identical daughter cells.

Question 5

What are the difference between binary fission and mitosis.

Answer 5

Binary Fission:
- Prokaryotes
- No spindle formation
- Chromosome attaches to membrane
- Use for reproduction

Mitosis:
- Eukaryotes
- Spindle formation
- Chromosomes align at metaphase plate
- Used for growth and repair