GENETICS Flashcards
Gene
A section of DNA that contains the coded information for making polypeptide chains and functional RNA
Allele
One of a number of an alternative form of a gene
Codon
A functional sequence of 3 codons that codes for a specific amino acid.
Genome
Complete set of genes in a cell.
Proteome
Full range of proteins produced by the genome.
Chromatin (chromatid)
Condensed chromosomes
What is codominance?
2 inherited alleles are equally dominant and expressed in the phenotype.
How many alleles of a gene does a person have?
Every person has 2 alleles of a gene
What is the Hardy Weinberg principle used for?
Used to work out the frequencies of an allele in a population
What 5 things must be true of the Hardy Weinberg principle?
1) No mutations
2) No immigration/emigration
3) A large population
4) No selection
5) Random mating
What is the equation for Hardy Weinberg principle?
p^2 + 2pq +q^2
p= frequency of dominant allele q= frequency of recessive allele p+q= 1
What are the types of selection?
1) Directional selection- occurs when there has been a change in environmental conditions.
2) Stabilising selection- when environmental conditions have remained the same.
3) Disruptive selection- it will favour individuals with extreme phenotypes further from the mean of the population.
What is the definition of a species?
Individuals that can breed and produce FERTILE offspring
What is speciation?
The evolution of a new species from an existing one.
How does geographical isolation affect speciation? (ALLOPATRIC SPECIATION)
1) Natural events over many years separate a species into two different populations
2) The type in frequency of the alleles in the 2 gene pools may differ over time until they become so different they are a different species. (ALLOPATRIC SPECIATION)
