8b. Mitosis and Cancer Flashcards
How many chromosomes do humans have
23 Homologous pairs
What is the diploid number
The total number of chromosomes is a normal body cell
e.g 46
What happens prior to cell devision
DNA in the chromosomes replicate all the way along its length and each chromosome becomes two threads called chromatids
Held together at the centromeres
What is a chromosome
Long, linear structures consisting of DNA and histone proteins
What is a homologous chromosome
A pair of chromosomes containing the same genes in the same positions, each derived origionally to form a different parents gamete at fertilisation
What is a chromotid
One of the two threads of a chromosomes, formed after DNA replication. Each chromatid in a chromosome is an exact replica of the other
What happens in mitosis
A parent cell divides to produce two daughter cells
-It increases thr number of cells during growth
-It replaces tissue during repair
-Allows asexual reproducton which produces fertile offspring which ar egenetically identical to parent
What is the only way that variation can arise when a cell divides by mitosis
Mutation
