🧬 AP Biology Unit 5 (copy)

Somatic cells

A normal 'body' cell that contains the full set of chromosomes.

Gametic Cells

Egg or sperm cells in humans, which have half the total number of chromosomes.

Haploid Cell

A cell with half the normal amount of chromosomes, possessing a single set of chromosomes.

Diploid Cell

A cell that contains two homologous sets of chromosomes.

n

Notation for the number of chromosomes in a cell; haploid cells have n chromosomes, diploid cells have 2n.

Syngamy

The fusion of two gametes during fertilization.

Zygote

A fertilized egg that is diploid.

Allele

Variations of a gene that determine specific traits.

Loci/Locus

The specific position where a gene or allele is located on a chromosome.

Sex Chromosomes

Chromosomes that determine the sex of an organism, categorized as X or Y in humans.

Monosomy

A condition resulting from nondisjunction during meiosis, where a cell has only one chromosome instead of a pair.

Tetrad

A pair of homologous chromosomes that forms during meiosis.

Meiosis

The process of reduction division that results in four genetically different daughter gametes.

Crossing Over

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

Independent Assortment

The random alignment of chromosomes during Metaphase I, leading to genetic diversity.

Mendelian Genetics

Genetic inheritance patterns based on dominant and recessive alleles as illustrated by Gregor Mendel.

Phenotype

The physical expression or characteristics of a genetic trait.

Genotype

The specific set of alleles an organism possesses for a certain trait.

True Breeding

The crossing of two homozygous organisms resulting in offspring of identical phenotypes.

Monohybrid Cross

A genetic cross between organisms that are heterozygous for one trait.

Dihybrid Cross

A genetic cross between two organisms that are heterozygous for two traits.

Pleiotropy

When one gene controls multiple phenotypic traits.

Epistasis

An interaction where one gene affects the expression of another gene.

Polygenic Inheritance

Inheritance pattern in which one trait is controlled by multiple genes.

Sex-Linked Trait Inheritance

Traits whose genes are located on sex chromosomes, showing different patterns in males and females.

Phenotypic Plasticity

The ability of an organism to change its phenotype in response to environmental conditions.

Epigenetics

The study of changes in gene expression that do not involve alterations to the DNA sequence.