Mitosis and Meiosis Flashcards
What is a Telomere?
Repeated sequence at the ends of every chromosome.
TTAGGG
What are the 3 different centromere locations?
Middle-metacentric
2/3-submetacentric
Near top-acrocentric
What happens in Prophase of Mitosis?
Chromosomes condense
Nuclear envelope break down
What happens in Prometaphase of Mitosis?
Spindle fibres (formed by centrioles) bind to chromosomes.
What happens in Metaphase of Mitosis?
Chromosomes line up along the metaphase plate (randomly)
What happens in Anaphase of Mitosis?
Spindle fibres pull sister chromatids apart, to opposite poles of the cell.
What happens in Telophase of Mitosis?
Nuclear envelope reforms
Cleavage forms
Then cytokinesis
What happens in Prophase I of Meiosis?
Nuclear envelope breaks down
Paternal and maternal chromosomes find each other.
What happens in Metaphase I of Meiosis?
Homologous chromosomes line up in pairs (in Tetrads)
Crossing over- formation of Chiasmata (recombination)
Random assortment
What happens in Anaphase I of Meiosis?
Separation of homologous pairs
Daughter cells are haploid.
What happens in Meiosis II?
An almost identical process to Mitosis
Describe spermatogenesis…
Diploid spermatogonium
Haploid primary spermatocyte
4 spermatids
Mature to sperm
Describe Oogenesis…
Oogonium
Haploid primary oocyte
3 polar bodies and big egg
Matures to ovum
Meiosis I stops at birth
