BRAINCAKEGenetic Diversity
Revision notes for Genetic Diversity in AQA Biology (7401). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- MutationsAny change in the quantity or base sequence of the DNA of an individual is called a mutation.
- Chromosome MutationsWhole chromosome mutations may occur in which the number or structure of chromosomes in the cell changes.
- Gene MutationsA change in the sequence of DNA is called a gene mutation.
- Substitution of BasesA mutation may arise where one nucleotide base is substituted for another.
- Deletion of BasesBase deletions almost always lead to loss of function of the protein as they involve a shift of the reading frame to the left They are therefore…
- Polyploidy and HybridsModern varieties of wheat are the result of hybridisation of different varieties of wheat over 10,000 years.
- MeiosisMeiosis is a type of nuclear division that halves the number of chromosomes during the formation of gametes and recombines genetic material from…
- The Process of MeiosisMeiosis involves two nuclear divisions: Meiosis I and Meiosis II.
- Genetic Recombination by Crossing OverEach pair of homologous chromosomes have the same genes in the same loci but do not necessarily have the same alleles.
- Independent Segregation of ChromosomesDuring meiosis 1 the 23 homologous chromosomes line up on the equator side by side arranged in a random order.
- Independent Segregation of ChromatidsChromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous…
- Number of Chromosome CombinationsAsexual reproduction results in clones.
- Genetic DiversityGenetic diversity is the total number of alleles found in a population.
- Natural SelectionReproductively successful individuals are able to pass on their alleles to their offspring and the population will continue to have these alleles in…
- Peppered MothsThe peppered moth Biston betularia is a species of night-flying moth.
- Types of SelectionNatural selection is the process by which organisms that are better adapted to their environment survive, reproduce and pass on their alleles to the…
- Directional SelectionThe phenotype of an individual is an observable characteristic of that individual.
- Antibiotic ResistanceSome antibiotics such as penicillin are no longer effective against some bacteria.
- Stabilising SelectionStabilising selection is a type of natural selection that results in phenotypes around the mean being selected for and those phenotypes at the…
On the specification
- 3.4.3 Genetic diversity can arise as a result of mutation or during
- 3.4.4 Genetic diversity and adaptation