Reproduction key terms

insertions

Insertions are mutations where one or more nucleotide bases are added into the DNA sequence, potentially altering the protein produced.

deletions

Deletions are mutations where one or more nucleotide bases are removed from the DNA sequence, which can lead to changes in the resulting protein.

Gamete

A haploid reproductive cell (sperm or egg) that contains one complete set of chromosomes and fuses with another gamete during fertilisation.

Chromosome

A thread‑like structure made of DNA and protein that carries genes and determines the genetic information passed from parent to offspring.

allele

In Genetic inheritance, allele means the specific Unit 4.6 idea used to answer this objective: students must explain the terms allele, dominant and recessive. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use allele as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.

dominant

In Genetic inheritance, the term dominant has a specific definition boundary role in Unit 4.6. Use dominant when students must explain the terms allele, dominant and recessive. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use dominant as a vague inheritance word or as a synonym for a neighbouring term; link it to Reproduction, Genetic inheritance, and the exact role it plays in AQA GCSE Biology. Revision cue 1: When asking about DNA, test molecular structure, base sequence, nucleotides, or genetic information storage.

homozygous

In Genetic inheritance, homozygous means the specific Unit 4.6 idea used to answer this objective: students must explain the terms homozygous and heterozygous. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use homozygous as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.

heterozygous

In Genetic inheritance, the term heterozygous has a specific definition boundary role in Unit 4.6. Use heterozygous when students must explain the terms homozygous and heterozygous. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use heterozygous as a vague inheritance word or as a synonym for a neighbouring term; link it to Reproduction, Genetic inheritance, and the exact role it plays in AQA GCSE Biology. Revision cue 1: When asking about DNA, test molecular structure, base sequence, nucleotides, or genetic information storage.

genotype

The genetic constitution of an individual, representing the specific alleles inherited from both parents.

phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

single-gene characteristics

Traits that are determined by the expression of a single gene, such as fur color in mice and red-green color blindness in humans.

allele

Different forms of a gene that can exist at a specific locus on a chromosome, influencing single-gene characteristics.

Allele

In Genetic inheritance, Allele means the specific Unit 4.6 idea used to answer this objective: students must explain that different forms of a gene are called alleles. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use Allele as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.

Gene

In Genetic inheritance, the term Gene has a specific definition boundary role in Unit 4.6. Use Gene when students must explain that different forms of a gene are called alleles. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use Gene as a vague inheritance word or as a synonym for a neighbouring term; link it to Reproduction, Genetic inheritance, and the exact role it plays in AQA GCSE Biology. Revision cue 1: When asking about DNA, test molecular structure, base sequence, nucleotides, or genetic information storage.

Genotype

The complete set of alleles present in an individual’s genome that determines the genetic potential for a trait.

Phenotype

The observable physical or biochemical characteristics of an individual resulting from the interaction of its genotype with the environment.

dominant allele

An allele that is expressed in the phenotype when at least one copy is present in the genotype.

genotype

The genetic constitution of an individual, specifically the alleles present for a particular gene.

recessive allele

A form of a gene that is only expressed when an individual has two copies and no dominant allele is present.

dominant allele

A form of a gene that is expressed when at least one copy is present, masking the effect of a recessive allele.

gene

In Genetic inheritance, gene means the specific Unit 4.6 idea used to answer this objective: students must explain that most characteristics result from multiple genes interacting rather than single-gene inheritance. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use gene as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.

polygenic

In Genetic inheritance, the term polygenic has a specific definition boundary role in Unit 4.6. Use polygenic when students must explain that most characteristics result from multiple genes interacting rather than single-gene inheritance. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use polygenic as a vague inheritance word or as a synonym for a neighbouring term; link it to Reproduction, Genetic inheritance, and the exact role it plays in AQA GCSE Biology. Revision cue 1: When asking about DNA, test molecular structure, base sequence, nucleotides, or genetic information storage.

Gene

In Genetic inheritance, Gene means the specific Unit 4.6 idea used to answer this objective: students must use probability to predict the results of a single-gene cross. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use Gene as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.

Probability

The likelihood of a particular genotype or phenotype occurring in the offspring of a single-gene cross, expressed as a ratio or percentage.

Direct proportion

A relationship in which the ratio of two quantities remains constant, used to predict the relative frequencies of genotypes or phenotypes in a genetic cross.

Simple ratio

A comparison of two or more numbers expressed as a fraction or whole numbers, applied to describe the expected proportions of outcomes in a genetic cross.

Punnett square

A diagram used to predict the outcome of a genetic cross by showing all possible combinations of alleles from the parents.

genetic cross

The mating of two organisms to analyze the inheritance of specific traits based on their genetic makeup.

Punnett square

A diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles from the parents.

probability

A measure of the likelihood that a particular genetic outcome will occur, often expressed as a fraction or percentage.