10.3 Flashcards
Meiosis
Cell division to create gametes
Homologous Chromosomes
A pair of chromosomes with the same genes in the same order, but possibly different versions of each gene
Sister chromatids
The chromatids that form a chromosome
Fertilization
Restores chromosome #
Asexual reproduction
Mitosis
Sexual reproduction
Meiosis
Gamete
A cell that comes from meiosis
Somatic cell
A cell that comes from mitosis
Haploid
n (n = number of each chromosome)
Diploid
2n
Tetrad
A pair of homologous chromosomes
Synpasis
The pairing of homologous chromosomes
Crossing over
When genes in one chromosome of a tetrad cross over to the other chromosome
Independent Assortment
The rule that sister cells resulting from meiosis can have different genes or gene arrangements.
Order and events of Meiosis
Prophase 1: Crossing over occurs
Metaphase 1: Chromsomes line up in pairs
Anaphase 1: Homologous chromosomes seperate
Telophase 1: Chromosome number reduced by half
Prophase 2 - Telophase 2: Mitosis, but daughter cells are not the same as original parent cell.
When is the chromosome number reduced by half?
After meiosis 1
Sources of genetic variation
- Independent assortment
- Crossing over
- Random fertilization
Differences between meiosis and mitosis
Meiosis: Diploid > haploid, not reliant on mutation for genetic variation, produces 4 gametes
Mitosis: Diploid > diploid, reliant on mutation for genetic variation, produces 2 somatic cells.
