UNIT 7: MEIOSIS

Mitosis

Mitosis

Cell division occurring in somatic cells, where one diploid parent cell produces two diploid daughter cells.

Meiosis

Cell division process to produce gametes (sex cells), where one diploid parent cell produces four haploid daughter cells.

Homologous chromosomes

Chromosomes that are members of the same pair, one from each parent.

Sister chromatids

Identical replicated chromatids joined by the centromere.

Replicated chromosomes

Chromosomes containing 2 sister chromatids after the S phase.

Non-replicated chromosomes

Chromosomes containing one chromatid after division.

Haploid

Cell containing one set of chromosomes, half of the normal set.

Diploid

Cell containing two sets of chromosomes.

Meiosis I

Stage where homologous pairs are separated.

Meiosis II

Stage where sister chromatids are separated.

Genetic recombination

Result of crossing over during prophase I and independent assortment during Anaphase I in meiosis.

Fraternal

Resulting from two separate egg cells, having the same genetic variation as other siblings.

Identical

Resulting from an embryo splitting, genetically identical.

Gene

Segment of DNA that codes for a trait.

Allele

Different versions of a gene.

Dominant

Trait that masks the recessive allele.

Recessive

Trait that is masked by a dominant allele.

Homozygous

Possessing two of the same alleles for a trait.

Heterozygous

Possessing two different alleles for a trait.

Genotype

Genetic makeup of an organism.

Phenotype

Physical expression of genes.

Sex-linked traits

Traits carried on sex chromosomes, usually the X chromosome.

Incomplete dominance

Situation where the dominant allele only partially masks the recessive allele.