Biology H Unit 7 Meiosis Blockout Review

Gamete

A haploid cell (e.g., sperm or egg) involved in sexual reproduction that combines with another gamete during fertilization.

Somatic Cell

Any body cell that is not a gamete; these cells are diploid and undergo mitosis.

Autosome

A non-sex chromosome; humans have 22 pairs of autosomes.

Sex Chromosome

A chromosome involved in determining the sex of an organism (e.g., X and Y chromosomes in humans).

Haploid

A cell with half the normal number of chromosomes (n); found in gametes.

Diploid

A cell containing two sets of chromosomes (2n); one set inherited from each parent.

Tetrad

A structure formed during Prophase I of meiosis when homologous chromosomes pair up, consisting of four chromatids.

Centromere

The region of a chromosome where sister chromatids are attached and where spindle fibers attach during cell division.

Sister Chromatids

Two identical copies of a single chromosome connected by a centromere; they separate during Anaphase II of meiosis.

Homologous Chromosomes

Pairs of chromosomes (one from each parent) with the same genes but possibly different alleles.

Gametogenesis

The process by which gametes (sperm or egg cells) are produced through meiosis.

Polar Bodies

Small, non-functional cells produced during female meiosis; they eventually degenerate.

Centriole

A structure in animal cells that helps organize spindle fibers during cell division.

Germ Cell

A specialized cell that undergoes meiosis to produce gametes.

Fertilization

The process in which a sperm and egg cell combine to form a diploid zygote.

Zygote

A fertilized egg cell that results from the union of a sperm and egg; it is diploid.

Random Assortment

The random distribution of homologous chromosome pairs during Metaphase I, contributing to genetic diversity.

Prophase I

The first stage of meiosis where chromosomes condense, homologous chromosomes pair up, and crossing over occurs.

Crossing Over (Stage)

The exchange of genetic material between homologous chromosomes during Prophase I, increasing genetic diversity.

Metaphase I

The stage of meiosis where homologous chromosomes align at the metaphase plate.

Anaphase I

The stage of meiosis where homologous chromosomes are pulled apart to opposite poles of the cell.

Telophase I

The stage of meiosis where the cell divides into two haploid cells after homologous chromosomes separate.

Prophase II

The first phase of meiosis II where spindle fibers form, and chromosomes begin to move toward the center of the cell.

Metaphase II

The stage of meiosis II where individual chromosomes align at the metaphase plate.

Anaphase II

The stage of meiosis II where sister chromatids are separated and pulled to opposite poles of the cell.

Telophase II

The final stage of meiosis II where the cell divides, resulting in four haploid daughter cells.

Result of Meiosis

Four genetically diverse haploid cells (gametes).

Result of Mitosis

Two genetically identical diploid cells.

Chromosome Number in Humans

46 (diploid; 23 pairs of chromosomes).

n

Represents the haploid number of chromosomes in a cell.

2n

Represents the diploid number of chromosomes in a cell.