DNA
A complex molecule containing the genetic information that makes up the chromosomes.
chromosome
structure in a cell's nucleus that contains hereditary material
gene
A segment of DNA on a chromosome that codes for a specific trait
base pairing
principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
allele
one of a number of different forms of a gene
gamete
a mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
sperm
male gamete
ovum
female gamete
zygote
a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.
fertilisation
The fusion of 2 [haploid] gametes to form a [diploid] zygote.
genotype
An organism's genetic makeup, or allele combinations.
phenotype
the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
haploid
An organism or cell having only one complete set of chromosomes.
diploid
An organism or cell having two sets of chromosomes or twice the haploid number
homologous chromosomes
Chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis.
heterozygous
An organism that has two different alleles for a trait
homozygous recessive
Both alleles (factors) for a trait are the same and recessive (aa)
homozygous dominant
Both alleles (factors) for a trait are the same and dominant (AA)
karyotype
the number and visual appearance of the chromosomes in the cell nuclei of an organism or species.
point mutation
gene mutation in which a single base pair in DNA has been changed
chromosomal mutation
A change in the chromosome structure, resulting in new gene combinations.
somatic cells
Any cells in the body other than reproductive cells
F1 generation
the first generation of offspring obtained from an experimental cross of two organisms
nucleotide
A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.