Chapter 7.4 Meiosis Flashcards
What is a karyotype?
It is a diagram showing homologous chromosomes.
What are homologous chromosomes?
Chromosomes that carry the same genes, one coming from the female parent, one comong from the male parent.
How many chromosomes do humans have in regular body cells?
46
How many chromosomes do humans have in sex cells?
23
What is another name for a gamete or germ cell?
Sex cell
What is a somatic cell?
A body cell
What is a complete set of chromosomes called?
Diploid
What is half a set of chromosomes called?
Haploid
What is the notation for a diploid set of chromosomes?
2N
What is the notation for a haploid set of chromosomes?
N
What is meiosis?
The process by which the number of chromosomes is reduced by half as sex cells form.
Where does meiosis occur?
In the sex organs -
Testes in males
Ovaries in females
Where does mitosis occur.
In body cells (somatic cells)
In which stage of meiosis (I or II) do chromosomes double?
Meiosis I
What is crossover and homologous recombination?
During prophase 1 of meiosis, as homologous chromosomes pair up and form tetrads, they exchange portions of their chromatids
- tangled up = cross-over
- trade sections of DNA (from the same location on chromosome) = recombination
What happens to the pairs of homologous chromosomes during anaphase 1 of meiosis?
Tetrads separate
Homologous chromosomes move to opposite side of cell
Sister chromatids remain attached
How many and what type of cells are formed at the end of meiosis I?
2 diploid cells with the same number of chromosomes as the parent cell
What happens to chromosomes during prophase II of meiosos?
Chromosomes thicken but DO NOT double
What happens during to the chromasomes during anaphase II?
Sister chromatids of each chromosome move to opposite ends toward the centrioles
How many and what type of cells are formed at the end of meiosis II?
4 unique (different) and haploid cells with half the chromosomes of the starting cell
