Monohybrid inheritance definitons

Chromosome

Thread-like structures carrying genetic information and found in the nucleus of a cell.

DNA

Deoxyribonucleic Acid – the material of inheritance, makes up chromosomes.

Genes

Short sections of DNA carrying genetic information and controlling characteristics of an individual.

Genetic information

Information carried by genes and passed on from one generation to the next.

Nucleus

The largest organelle in a cell, it contains the genetic information.

Gametes

Sex cells, produced during sexual reproduction. E.g. sperm, egg, pollen.

Haploid

Of a sex cell, having one set of chromosomes (i.e. half the usual amount).

Diploid

Of a cell or organism, having two sets of chromosomes (i.e. one set from each parent).

Asexual reproduction

A type of reproduction involving only one parent. The offspring have the same genes as each other and as their parent.

Sexual reproduction

A type of reproduction involving a male and a female parent. The offspring all have different genes (unless they are twins) and are different from the parents.

Allele

A version of a particular gene e.g. the gene for flower colour has a red version and a white version.

Variation

Differences in individuals due to genetic and environmental factors.

Genotype

The genetic make-up of an organism that can determine particular traits.

Phenotype

The physical expression of a trait, it is the result of genes + environment.

Homozygous

An organism that has two identical alleles for a particular gene (e.g. AA or aa).

Heterozygous

An organism that has two different alleles for a particular gene (e.g. Aa).

Recessive allele

A recessive allele is an allele that is only expressed in the phenotype if two copies are present or a dominant allele is not present.

Dominant allele

A dominant allele is an allele that is always expressed in the phenotype if present in the genotype.

Genome

The genome is all the genetic material of an organism.

Trait

A trait is a variation of a characteristic. Traits of the characteristic “hair colour” are, for example, red hair or brown hair.

Characteristic

A characteristic is an observable feature, like, for example, hair colour.