What is the Purpose of Meiosis?

Life cycle of plants

Haploid multicellular organism, mitosis, fertilization, zygote, mitosis, diploid multicellular organism, meiosis, and mitosis

Karyotype

Lets us view our chromosomes

What is the significance of meiosis and fertilization in sexual life cycles?

Meiosis is when the gametes become haploid. Each daughter cell receives one chromosome from each homologous pair

Homologous chromosomes

2 chromosomes that have genes for the same traits; one member of the pair comes from the mother and one from the father

What is the overall process by which meiosis reduces the diploid chromosome number to haploid?

A parent diploid starts out with 2 chromosomes and undergoes meiosis I where the homologous chromosomes separate. Each daughter cell receives one replicated chromosome which still consists of a pair of chromatids. Then, each cell divides again in meiosis II. The chromatids separate and each daughter cell now has one chromosome, the haploid number for the organism. Meiosis consists of 2 cell divisions resulting in 4 daughter cells

How is a human karyotype prepared?

Blood is collected from a person, added to a growth medium and mitotic stimulator which the cells grow in for 2-3 days at body temperature. Colchicine is added to arrest cell division at metaphase, the arrested cells are centrifuged. Then a hypotonic salt solution is added and causes the cells to swell up and move apart. Those cells are then placed on a microscope slide; the cell is photographed and the part of the photo that shows the chromosomes is cut out; this is done for every chromosome and individual chromosomes are laid out horizontally.

Diploid

Both sets of chromosomes together

Haploid

Each set of chromosomes

Life cycle of animals

Gametes, fertilization, mitosis, diploid multicellular organism, and meiosis

Life cycle of multicellular fungi

Produces haploid gametes that fuse to form a diploid zygote, but the zygote does not develop into a diploid organism; it immediately undergoes meiosis to form haploid cells that develop into the multicellular stage of the life cycle

Asexual Reproduction

Reproduction that is not sexual; binary fission in prokaryotes and budding in eukaryotes

Sexual Reproduction

The union of 2 gamete cells to form a new cell containing chromosomes from both parents; sperm fuses with an egg and the fertilized egg develops into a new organism with characteristics of both parents; mammals