Inheritance Glossary
Allele an alternative form of a gene; they are at the same position on homologous chromosomes
Base one of four different structures – A, C, G, T – which contains the genetic code in DNA
Chromosome a strand of DNA that carries many genes
Complementary base pairing used to describe how the bases pair up; A always binds with T, G with C
DNA a molecule that carries genetic information made up of nucleotides
Dominant the allele that is always expressed in the phenotype if it is present
Gamete a sex cell e.g. sperm or egg
Gene A section of DNA that codes for a trait
Genome the DNA content of an individual
Genotype the types of genes in an organism
Heterozygous having two alleles that are different for a particular trait/characteristic; a hybrid
Homologous chromosomes pairs of matching chromosomes; one chromosome of a pair comes from each parent
Homozygous having the same alleles for a particular trait/characteristic; a pure breed
Inherited genetic information received from parents
Natural selection process by which organisms that are best suited to their environment will be more likely to survive and breed
Nucleotide a unit (from which DNA is made) consisting of a base, a sugar and a phosphate group
Phenotype physical expression of an organism's genotype
Punnet square method of working out the possible genotypes of the offspring from the parents' genotypes
Recessive an allele that is only expressed in the phenotype if there are no dominant alleles present i.e. there are two recessive alleles
Trait another word for characteristic
Variation differences in a particular characteristic or an organism which makes each organism unique in a population
X and Y chromosomes chromosomes that determine the gender in humans
Base one of four different structures – A, C, G, T – which contains the genetic code in DNA
Chromosome a strand of DNA that carries many genes
Complementary base pairing used to describe how the bases pair up; A always binds with T, G with C
DNA a molecule that carries genetic information made up of nucleotides
Dominant the allele that is always expressed in the phenotype if it is present
Gamete a sex cell e.g. sperm or egg
Gene A section of DNA that codes for a trait
Genome the DNA content of an individual
Genotype the types of genes in an organism
Heterozygous having two alleles that are different for a particular trait/characteristic; a hybrid
Homologous chromosomes pairs of matching chromosomes; one chromosome of a pair comes from each parent
Homozygous having the same alleles for a particular trait/characteristic; a pure breed
Inherited genetic information received from parents
Natural selection process by which organisms that are best suited to their environment will be more likely to survive and breed
Nucleotide a unit (from which DNA is made) consisting of a base, a sugar and a phosphate group
Phenotype physical expression of an organism's genotype
Punnet square method of working out the possible genotypes of the offspring from the parents' genotypes
Recessive an allele that is only expressed in the phenotype if there are no dominant alleles present i.e. there are two recessive alleles
Trait another word for characteristic
Variation differences in a particular characteristic or an organism which makes each organism unique in a population
X and Y chromosomes chromosomes that determine the gender in humans