Science - Genetics
Mitosis
- Mitosis is the process by which one parent cell splits into two identical daughter cells.
- Mitosis is the most common method of reproduction for single-celled organisms.
- There are 5 main stages of mitosis:
- Prophase: number of chromosomes in the cell double up
- Metaphase: chromosomes wind up and align along the equator of the cells
- Anaphase: Chromatids (Not Chromosomes, this is explained later) are drawn towards the ends of the cell by spindle fibers
- Telophase: Cell nuclei forms, chromosomes form and unwind
- Cytokinesis: Cell splits into two, completing the process of mitosis
- In the human body, all cells other than sex cells (sperm and ova) are generated through mitosis.
Punnett Squares
- Chromosomes contain genes, which dictate traits
- An Allele is any of the possible forms of a gene, e.g. Tall/short
- Alleles tend to be either Dominant or Recessive. Dominant alleles are represented by a capital letter, while recessive alleles are represented by the same letter, but lower case.
- Every chromosome pairs up with another chromosome. The alleles in each pair of chromosomes dictates the properties of the organism. One chromosome is inherited from the organism’s male parent, while the other is inherited from the female parent.
- When an organism has a pair of Homozygous Alleles, both chromosomes for that trait have the same allele (Both Dominant or both recessive)
- When an organism has Heterozygous Alleles, one chromosome has the Dominant allele, while the other has the recessive allele. An organism with Heterozygous Alleles will display the characteristics of the Dominant Allele.
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