Describe the role of mitosis in maintaining genetic stability.

1. Produces two nuclei/cells with same number of chromosomes as parent cell
2. thus daughter cells are genetically identical to parents
3. DNA replicated via semi-conservative replication during interphase to give exact copies
4. Each strand of parental DNA acts as template for the exact replication to form the new daughter strand
5. through complementary base pairing
6. In prophase, chromatin condenses to form chromosome which exists as 2 identical chromatids joined by single centromere
7. During metaphase, sister chromatids are attached to microtubulues from either pole
8. During anaphase, centromere divides and microtubules shorten
9. which ensures sister chromatids are separated to opposite pole during anaphase
10. ensuring equal distribution of chromosomes to daughter nuclei
11. In asexual reproduction, mitosis produces genetically identical daughter cells
12. which are clones

During anaphase, centromere divides, it doesn't split
DNA is replicated, not duplicated

What causes genetic variation in meiosis?

• Chiasma formation and crossing over- portions of non-sister chromatids of homologous chromosomes may break and rejoin. Exchange of alleles between homologous chromosomes ⇒ new combination of alleles 
• In metaphase I – (independent assortment) orientation of homologous chrm pairs at equator is random and how one homologous pair orientates does not affect how other homologous pair orientates. Metaphase II- orientation of non-identical sister chromatids of one chromosome at equator is random. Each daughter cell will receive a random mix of maternal and paternal chromosomes. 
• Random fusion of two gametes will result in 223x223 different possible types of offspring in humans. Can also be non-disjunction of homologous chromosomes in mei I or non-disjunction of sister chromatids during mei II resulting in polyploidy.