Do you remember what mitosis and meiosis are? Let me remind you!
- In mitosis a cell splits to create 2 identical copies, for growth and repair.
- The daughter cells are diploid (2 sets of chromosomes).
- The chromosomes line up, get pulled apart and the cytoplasm closes around them.
- The chromosomes have to replace themselves first.
Mitosis produces new cells for:
- Repairing damaged body parts
- Asexual reproduction
- No fertilisation
- When bacteria split in two
- Produces genetically identical offspring
Meiosis and Fertilisation
The features of meiosis:
- Meiosis is the splitting of a cell to form 4 non-identical cells.
- The daughter cells are haploid (half the normal number of cells).
- It occurs to produce gametes (sex cells).
- Each cell is unique.
- The DNA replicates, splits and then these split again into 4.
Fertilisation and formation of a foetus:
- Sperm (haploid, 23 chromosomes) + egg (haploid, 23) ➡️ zygote (diploid, 46)
- Nuclei of the two fused together
- Zygote embryo (ball of cells) ➡️ this process uses mitosis
- The embryonic stem cells specialize to cells needed in the foetus’ body
And we're done with this topic! Well Done!
Drafted by Alyssa (Biology)
- "Mitosis", https://ib.bioninja.com.au/_Media/mitosis-3_med.jpeg
- "Meiosis". Photo from the internet.
- "Human embryonic development", https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/HumanEmbryogenesis.svg/1200px-HumanEmbryogenesis.svg.png