Bio 30 Ch. 16.3 & 16.4

Meiosis

A type of cell division that produces four daughter cells with half the number of chromosomes as the parent cells.

Haploid

Daughter cells in meiosis have fewer chromosomes than parent cells, meaning they are haploid.

Genetic Variation

Daughter cells in meiosis have chromosomes with different combinations of genes compared to parent cells, resulting in genetic variation.

Prophase I

The stage of meiosis where chromatin condenses, spindle fibers form, and homologous chromosomes align.

Crossing Over

The process of genetic material exchange between homologous chromosomes during prophase I of meiosis.

Metaphase I

The stage of meiosis where spindle fibers attach to the centromere of each chromosome and homologous chromosomes line up as pairs.

Anaphase I

The stage of meiosis where spindle fibers shorten and homologous chromosomes separate.

Telophase I

The stage of meiosis where homologous chromosomes uncoil, a nuclear membrane forms, and cytoplasm divides, resulting in two haploid cells.

Meiosis II

The second round of cell division in meiosis, which does not involve DNA replication, resulting in four haploid daughter cells.

Independent Assortment

The random orientation of homologous chromosome pairs during metaphase I of meiosis, leading to a greater diversity of gametes.

Spermatogenesis

The process of meiosis in males that results in the formation of four viable sperm cells.

Oogenesis

The process of meiosis in females that results in the formation of one viable ovum and three polar bodies.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during meiosis, resulting in gametes with too few or too many chromosomes.

Monosomy X (Turner Syndrome)

A genetic disorder caused by the fertilization of a normal egg by a sperm lacking an X chromosome due to nondisjunction in meiosis II.

Trisomy 21 (Down Syndrome)

A genetic disorder caused by the fertilization of an egg with an extra chromosome 21 due to nondisjunction in meiosis I.

Reproductive Strategies

Different approaches organisms use for reproduction, including sporophyte and gametophyte stages.

Asexual Reproduction

A reproductive process where a parent organism produces genetically identical offspring without the involvement of gametes.

Sexual Reproduction

A reproductive process involving the production of gametes by meiosis and the fusion of genetically distinct parental gametes to produce genetically diverse offspring.

Fragmentation

A form of asexual reproduction where a parent organism breaks into fragments, each of which can develop into a new individual.

Sporophyte

The spore-making body in plants that produces multiple haploid spores, which develop without fertilization.

Gametophyte

The gamete-making body in plants that produces male and female gametes, which develop into a new sporophyte upon fertilization.

Binary Fission

A method of asexual reproduction used by bacteria, allowing for rapid growth.

Conjugation

A process in bacteria where plasmids are transferred between cells, creating new genetic combinations.

Budding

A form of asexual reproduction where a miniature version of the parent organism grows out and separates once mature.

Vegetative Reproduction

A form of asexual reproduction in plants that involves the growth of new individuals from nodes, crown runners, or clones without the use of spores or seeds.

Parthenogenesis

A form of asexual reproduction where an unfertilized egg develops into an adult organism.

Spores

A form of asexual reproduction that allows parents to disperse their offspring over long distances, and can be haploid or diploid.

Alteration of Generations

The life cycle of some plants that consists of two generations - a diploid sporophyte and a haploid gametophyte.

Diploid Sporophyte

The diploid generation in the life cycle of plants that produces haploid spores through meiosis.

Haploid Gametophyte

The haploid generation in the life cycle of plants that produces male and female gametes, which develop into another sporophyte upon fertilization.