In I/GCSE Biology, it is important to remember the topic regarding mitosis and meiosis. Let's get started!!!! 😁

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).

1. The chromosomes line up, get pulled apart and the cytoplasm closes around them.
2. The chromosomes have to replace themselves first.

Mitosis produces new cells for:

• growth
• Repairing damaged body parts
• Asexual reproduction

Asexual reproduction:

• No fertilisation
• When bacteria split in two
• Produces genetically identical offspring

Then, let's look at the meiosis and fertilisation in I/GCSE Biology!

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!

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Drafted by Alyssa (Biology)

References:

1. "Mitosis", https://ib.bioninja.com.au/_Media/mitosis-3_med.jpeg
2. "Meiosis". Photo from the internet.
3. "Human embryonic development", https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/HumanEmbryogenesis.svg/1200px-HumanEmbryogenesis.svg.png