Mitosis Flashcards
1
Q
Importance of mitosis
A
- Mitosis ensures that both daughter cells produced when a parent cell divides are genetically identical.
- Needed for growth of multicellular organisms and for repairing damaged tissues.
- Some animals, plants and fungi also use it to reproduce asexually.
- PMAT+C (Prophase, Metaphase, Anaphase, Telophase + Cytokinesis)
2
Q
Chromosomes
A
- Before replication, 1 chromosome has 1 chromatid (strand).
- After replication, chromosome has 2 chromatids.
- Centromere is the middle region where 2 chromatids are joined together.
- 2 strands on the same chromosome are called sister chromatids.
3
Q
Prophase
A
- Chromosomes condense, getting shorter and fatter.
- Centrioles start moving to opposite ends of the cell, forming a network of protein fibres across it called the spindle.
- Nuclear envelope breaks down and chromosomes lie free in cytoplasm.
4
Q
Metaphase
A
- Chromosomes line up on the spindle equator and become attached to spindle by their centromere.
5
Q
Anaphase
A
- Centromeres divide, separating each pair of sister chromatids.
- Spindles contract, pulling chromatids to opposite ends of the cell, centromere first.
6
Q
Telophase
A
- Chromatids reach opposite poles on spindle.
- They uncoil and become long and thin again.
- They’re now called chromosomes again.
- A nuclear envelope reforms around the 2 groups of chromosomes.
- So there are 2 nuclei.
7
Q
Cytokinesis
A
- The cytoplasm divides.
- In animal cells a cleavage furrow forms around the middle of the cell.
- There are now 2 daughter cells that are genetically identical to the original cell and to each other.
8
Q
Investigating mitosis
A
- Stain the chromosomes so you can see them under a microscope. This allows you to see what happens during mitosis.
- Make a squash microscope slide. Squashes can be made by treating the root tips with hydrochloric acid.
- Add stain and then physically squish cells beneath cover slip.
