genetics yr11 mid topic test

Genetics

The study of the variation and inheritance of genes.

Gene

A section of DNA that codes for a protein that determines a particular trait.

Allele

An alternative version of a gene.

DNA

A chemical that carries genetic instructions, stored as chromosomes inside the nucleus of a cell.

Chromosome

An organised structure of DNA found inside the nucleus of a cell.

Homologous Chromosomes

Pairs of chromosomes that are the same length and carry the same genes at the same loci.

Mutation

A random permanent change in the base sequence of DNA.

Point Mutation

Occurs when a single base or a few bases is changed, affecting only a single gene.

Substitution Mutation

A type of point mutation where a base is replaced by another base.

Deletion Mutation

A type of point mutation where a base is removed from the DNA sequence.

Insertion Mutation

A type of point mutation where an extra base is added to the DNA sequence.

Asexual Reproduction

A type of reproduction in which a new offspring is produced by a single parent, and the offspring are genetically identical to each other.

Sexual Reproduction

A type of reproduction in which a new offspring is produced by two parents, resulting in genetically different offspring.

Fertilisation

The process of combining a male and female gamete to form a new zygote.

Meiosis

A cell division process that produces genetically unique gametes with half the number of chromosomes.

Population Genetics

The field of biology that studies the genetic makeup of populations and how they change over time.

Gene Pool

All the alleles available to a population.

Allele Frequency

The percentage of each allele in a gene pool.

Gene Flow

The movement of alleles between populations due to migration.

Natural Selection

The process whereby individuals with beneficial phenotypes survive and reproduce more successfully, passing these alleles to their offspring.

Genetic Drift

The change in allele frequencies in a population due to random chance.

Founder Effect

Occurs when a small number of individuals from a larger population establish a new, isolated population.

Bottleneck Effect

Occurs when there is a significant reduction in population size due to an environmental event or human activity, leading to reduced genetic diversity.

Crossing Over

The process during meiosis where homologous pairs exchange sections of DNA.

Independent Assortment

The random arrangement of homologous chromosomes during meiosis that leads to genetic variation.