Meiosis- two-stage cell division in which the chromosome number of the parental cell is reduced by half. Meiosis is the process by which gametes are formed.
Gametes- Sex cells that have a haploid chromosome number.
Haploid- Refers to the number of chromosomes in a gemete.
Diploid- Refers to twice the number of chromosomes in a gamete. Every cell in the body, except sex cells, have a diploid number.
Zygote- A cell resulting from the union of a male and female sex cell,
until it divides and then it is called an embryo.
Tetrad- A pair of homologous chromosomes, each with two chromatids.
Synapsis- The pairing of homologous chromosomes.
Sex Chromosome- The pair of chromosomes that have a role in the sex of an individual.
Karyotype Chart- A picture of chromosomes arranged in a homologous pair. Shown on left.
Sister Chromosome- Two duplicated chromosomes attached by the centromere.
Alleles- Two or more alternaive forms of a gene.
Dominant- Alleles of this type determine the expression of the genetic trait in offspring.
Recessive- Alleles of this type are overruled by dominent alleles, which determine the genetic trait.
Phenotype- The observable traits of an organism (from the interaction between genes).
Heterozygous- A genotype where the alleles of a pair are different.
Homozygous- A genotype in which noth alleles of a pair are the same.
Punnet square- A chart to show possible combinations of alleles in offspring.
Cytokinesis- The division of the cytoplasm.
Autosomes- The chromosomes not involved in sex determination
Homologous Chromosome- Similar in shape, size, gene arrangement, and gene information.
Trisomy- The zygote will have three chromosomes in place of a normal pair.
Monosomy- The zygote will only have one chromosome instead of a homologous pair.
Nondisjunction- Occurs when two holomogous chromosomes move to the same pole during meiosis.
Genotype- The alleles an organism contains.
Monohybrid Cross- A cross that involves one allele , pair of contrasting traits.
