Genetics Definitions Flashcards
Homozygous recessive
two recessive alleles, aa
Homozygous dominant
two dominant alleles, AA
Heterozygous
two different alleles, Aa
DNA
carries the genetic information
Gene
a short segment of DNA that codes for a protein/trait
Allele
an alternative form of a gene
Genotype
the alleles present
Phenotype
the physical characteristic expressed
Chromosome
condensed DNA
Inheritable
can be passed on, occurs in the gametes
Non-inheritable
can not be passed on, occurs in somatic cells
Somatic Cells
body cells
Gametes
sex cells (egg and sperm)
Pure Breeding
homozygous for a trait
Homologous Chromosomes
pair of chromosomes (one from each parent)
Sexual reproduction
involves two parents
Asexual reproduction
involves one parent (creates identical offspring/clone)
Fertilisation
fusing of egg and sperm (gametes) to form a zygote
Crossing over
homologous chromosomes exchange genetic information
Independent assortment
homologous chromosomes line up independently along equator (middle of cell)
Meiosis
cell division in gametes produces 4 unique daughter cells
Variation
differences/diversity within a population
Mutation
permanent change in the base sequence of DNA, produces new allele
Test Cross
a cross between an unknown genotype and homozygous reccessive
