Ch. 13 Biology Meiosis and Sexual Life Cycles

Gene

Small segments of DNA encoding proteins that could lead to expression of a trait.

Alleles

Alternative versions of the same specific gene (e.g. gene for blue eyes vs. gene for brown eyes).

Haploid cell

Cells that contain one set of chromosomes (n), typically seen in gametes (sperm and eggs).

Diploid cell

Cells that contain two sets of chromosomes (2n), one inherited from each parent, found in somatic cells.

Karyotype

An ordered display of all chromosomes in a cell.

Homologous chromosomes

Pairs that are similar in size/shape and carry the same genes but can have different alleles.

Meiosis

Form of eukaryotic cell division that produces haploid (n) gametes (sperm or egg cells).

Fertilization

Process of merging gametes (sperm and egg fusion) to create a zygote.

Zygote

The very first diploid (2n) cell of a new developing organism where mitosis starts.

Cell Ploidy

The number of sets of specific genes found in a cell. (Haploid or Diploid)

Germ Cells

Diploid cells that are the precursor for making gametes (sperm or egg).

Meiosis 1

Reductional division that reduces ploidy by separating homologous chromosomes; a diploid (2n) germ cell divides into two haploid (n) daughter cells.

Meiosis 2

Equational division that maintains equal ploidy by separating sister chromatids.