Mitosis and Meiosis

Flashcards covering key vocabulary from lecture notes on cell division (mitosis and meiosis).

Mitosis

Nuclear division resulting in two new nuclei (daughter cells) each having the same number of chromosomes as the original nucleus (parent cells). Needed for growth and repair of tissues (multicellular) and asexual reproduction (unicellular).

Chromosome

Rod-shaped body in the nucleus that is seen during mitosis and meiosis and that contains DNA and, therefore the hereditary units, or genes

Spindle

Microtubule structure that brings about chromosome movement during cell division

Centromere

A constriction where duplicates (sister chromatids) of a chromosome are held together

Cytokinesis

Each daughter cell receives a share of organelles that duplicated during interphase. Begins in anaphase, continues in telophase, and reaches completion by the start of next interphase.

Meiosis

Is a form of nuclear division in which chromosome number is reduced by half during the production of gametes. Parent cell is diploid (2n), daughter nuclei are haploid (1n).

Gametogenesis

Leads to the production of gametes (sperms in males, eggs or oocyte in females in animals) from germ cells (sex cells).

Homologous Chromosomes (Homologues)

Diploid nucleus contains these. They look alike and carry the genes for the same traits. Before meiosis begins, the chromosomes are already double stranded, that is, they contain sister chromatids.

Synapsis

Homologues line up next to one another during Prophase I of Meiosis .

Crossing-over

Exchange of genetic material between nonsister chromatids of a homologue pair during Prophase I of Meiosis.

Karyotype

The chromosomes of an organism are arranged so that the pairs of chromosomes can be seen, which makes it possible to observe any possible anomalies in chromosomes number and structure.

Deletion (Chromosome)

Chromosome is shorter than usual because some portion is missing.

Duplication (Chromosome)

Chromosome is longer than usual because some portion is present twice over.

Translocation (Chromosome)

Two chromosomes have switched portions and each switched portion is on the wrong chromosome.

Fertilization

The fusion of the sperm’s nucleus with the egg’s nucleus.