AQA Biology GCSE Topic 6: Inheritance, Variation and Evolution Vocabulary

Flashcards covering key vocabulary from AQA Biology GCSE Topic 6: Inheritance, Variation and Evolution.

What is meiosis?

The formation of four non-identical cells from one cell.

What is mitosis?

The formation of two identical cells from one cell.

What are gametes?

Sex cells (sperm and egg in animals, pollen and egg in plants) that contain genetic information from the mother or father.

What is sexual reproduction?

Involves the joining of male and female gametes, resulting in genetic variation in the offspring.

What is asexual reproduction?

Involves one parent, no joining of gametes, and the production of genetically identical clones through mitosis.

What is pollination?

The process by which pollen reaches the egg cells in the female parts of a flower, enabling sexual reproduction in plants.

What is DNA?

The genetic material in the nucleus of a cell, composed of two strands in a double helix structure.

What is a gene?

A short section of DNA on a chromosome that codes for a specific protein.

What is a genome?

All the genes coding for all of the proteins within an organism.

What is a nucleotide?

The building block of DNA, made up of one sugar molecule, one phosphate molecule, and one of the four types of organic bases.

What is complementary base pairing?

In DNA, A bases only connect to T bases, and C bases only connect to G bases.

What is a mutation?

A change in the sequence of bases in DNA.

What is a gamete?

An organism’s reproductive cell (egg in female and sperm in males) which has half the number of chromosomes (23).

What is a chromosome?

A structure found in the nucleus which is made up of a long strand of DNA.

What are alleles?

The different forms of a gene - humans have two alleles for each gene as they inherit one from each parent.

What is a dominant allele?

Only one (out of the two alleles) is needed for it to be expressed.

What is a recessive allele?

Two copies are needed for it to be expressed.

What does homozygous mean?

When both inherited alleles are the same.

What does heterozygous mean?

When one of the inherited alleles is dominant and the other is recessive.

What is a genotype?

The combination of alleles an individual has, e.g. Aa.

What is a phenotype?

The physical characteristics that are observed in the individual, e.g. eye colour.

What is polydactyly?

Having extra digits, caused by a dominant allele.

What is cystic fibrosis?

A disorder of the cell membranes, resulting in thick mucus in the airways and pancreas, caused by a recessive allele.

What is evolution?

A change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.

What is speciation?

The process by which new species arise, when populations can no longer interbreed to produce fertile offspring.

What is selective breeding?

When humans choose which organisms to breed in order to produce offspring with a certain desirable characteristic.

What is genetic engineering?

Modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.

What is cloning?

Creating genetically identical copies of an organism.

What are fossils?

The remains of organisms from many years ago, which are found in rocks.

What is extinction?

When an entire species has died out.

What are resistant bacteria?

Bacteria that are not killed by antibiotics which previously were used as cures against them.

What is the binomial system?

Gives each organism a name which is used worldwide (overcomes language barriers). The first part is their genus and the second part is their species.