Bio_11_2_DNA inheritance_B_2024

Mitosis

A type of cell division that results in two identical diploid (2n) daughter cells, primarily for growth and tissue repair.

Meiosis

A type of cell division that reduces the chromosome number by half, resulting in four haploid (n) gametes, essential for sexual reproduction.

Somatic Cells

Body cells that undergo mitosis.

Gametes

Sex cells produced through meiosis.

Cytoplasmic Divisions

Mitosis involves 1 division, while meiosis involves 2 divisions.

Chromosome Number

Mitosis maintains the diploid number, while meiosis reduces it to haploid.

Genetic Variability

Introduced during meiosis through processes like crossing over.

Prophase I

The first stage of meiosis I where homologous chromosomes condense and pair up.

Metaphase I

The stage of meiosis I where homologous chromosome pairs align at the cell's equator.

Anaphase I

The stage of meiosis I where homologous chromosomes are separated and move to opposite poles.

Telophase I

The stage of meiosis I where two haploid nuclei form around the separated chromosomes.

Crossing Over

The exchange of genetic material between non-sister chromatids during prophase I, leading to genetic diversity.

Prophase II

The first stage of meiosis II where chromosomes condense again and spindle fibers form.

Metaphase II

The stage of meiosis II where duplicated chromosomes align at the cell's equator.

Anaphase II

The stage of meiosis II where sister chromatids are separated and move to opposite poles.

Telophase II

The final stage of meiosis II where four haploid nuclei are formed.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to aneuploidy.

Alleles

Alternative forms of a gene that determine specific traits.

Dominant Allele

An allele that masks the expression of another allele.

Recessive Allele

An allele whose expression can be masked by a dominant allele.

Phenotype

The observable traits of an organism.

Genotype

The genetic makeup of an organism.

Homozygous

Having two identical alleles for a trait.

Heterozygous

Having two different alleles for a trait.

Principle of Segregation

The concept that alleles segregate independently during gamete formation.

Independent Assortment

The random distribution of alleles during gamete formation, leading to genetic variation.

Monohybrid Cross

A genetic cross involving a single trait.

Dihybrid Cross

A genetic cross involving two traits.

Incomplete Dominance

A genetic scenario where the heterozygous phenotype is intermediate between the two homozygous phenotypes.