Meiosis - AP Biology

Through crossing over and independent assortment. These mechanisms create unique genetic combinations in offspring.

Germ cells. Located in reproductive organs like ovaries and testes.

Meiosis creates diverse gametes; fertilization combines them randomly. Each process independently shuffles genetic material.

Two phases: Meiosis I and Meiosis II. Each phase consists of multiple sub-stages like prophase, metaphase, etc.

23 chromosomes. Half the diploid number, enabling chromosome restoration at fertilization.

The exchange of genetic material between homologous chromosomes during Prophase I. Creates new combinations of alleles, increasing genetic variation.

A type of cell division that reduces chromosome number by half, producing gametes. Essential for sexual reproduction and genetic diversity.

Four genetically distinct haploid cells. Final products are gametes ready for fertilization.

To discard extra chromosomes and cytoplasm during oogenesis. Ensures maximum resources go to the viable ovum.

Tetrads align at the metaphase plate. Tetrads are paired homologous chromosomes ready for separation.

Chromosomes line up individually along the metaphase plate. Unlike metaphase I, individual chromosomes align rather than homologous pairs.

To produce haploid gametes and ensure genetic diversity. Crucial for maintaining species chromosome number across generations.

The pairing of homologous chromosomes during Prophase I of meiosis. Enables crossing over and genetic recombination between chromosomes.

The random orientation of homologous chromosome pairs during Metaphase I. Creates $2^n$ possible chromosome combinations where n = chromosome pairs.

Meiosis II separates sister chromatids, not homologous chromosomes. Similar to mitosis but operates on haploid cells.

The process by which sperm cells are produced by meiosis. Occurs continuously after puberty in males.

A group of four chromatids formed by synapsis of homologous chromosomes. Forms when homologous chromosomes undergo synapsis during prophase I.

Homologous chromosomes pair and exchange segments (crossing over). This creates genetic diversity through recombination of parental chromosomes.

The point where two homologous chromosomes exchange genetic material during crossing over. Visible evidence of crossing over between homologous chromosomes.

The process of forming gametes through meiosis. Occurs in reproductive organs to produce sex cells.

Sister chromatids are pulled apart to opposite poles of the cell. Produces individual chromatids that become separate chromosomes.

One viable ovum and polar bodies. Unequal cytoplasm division creates one large functional gamete.

Four viable sperm cells. All products are functional and capable of fertilization.

Homologous chromosomes are pulled to opposite poles of the cell. Reduces chromosome number from diploid to haploid in daughter cells.

Chromosomes condense, and spindle fibers form in each new cell. No DNA replication occurs between meiosis I and II.

Two haploid cells with duplicated chromosomes. Chromosome number is reduced but chromatids remain attached.

The failure of chromosomes to separate properly during meiosis. Can occur during anaphase I or II, disrupting normal separation.

Diploid cells have two sets of chromosomes, haploid cells have one set. Diploid = $2n$, haploid = $n$ chromosome sets.

Anaphase I. Homologous chromosomes separate, distributing alleles to different gametes.