Genetics Flashcards
What are the 4 types of bases?
- Adenine
- Cytosine
- Thymine
- Guanine
Which bases bind to each other?
- Adenine - Thymine
- Guanine - Cytosine
What is the human diploid number?
46
What is the human haploid number?
23
Homozygous
Definition
Having 2 identical alleles for a particular characteristic
Dominant allele
Definition
An allele that has an effect in both heterozygous and homozygous conditions
Genotype
Definition
The genes/ alleles that an organism possesses
Recessive allele
Definition
An allele which only has an effect in the homozygous condition
Phenotype
Definition
An organisms outward appearance/ characteristics
Heterozygous
Definition
Having 2 different alleles for a particular characteristic
Allele
Definition
Different forms of the same gene
Homozygous Recessive
Definition
Having 2 copies of identical, recessive alleles
Homozygous Dominant
Definition
Having 2 copies of identical, dominant alleles
Homologous Pairs
Definition
- A pair of chromosomes that have the same genes at the same loci
- The alleles may be different
Expressed
Definition
The gene is switched on and the protein is made and the characteristic is seen in the phenotype
Pure-breeding
Definition
An organism is homozygous and can only pass on 1 type of allele to offspring
Test Cross
Definition
Breeding an organism with dominant characteristics with one that has recessive characteristics to analyse th offspring yo find the genotype of the original organism
Punnet Square
Definition
Shows the possible genotypes and phenotypes that could form following a cross between parents with particular alleles for a gene
Is a type of genetic diagram
Polygenic
Definition
When many genes are involved to cause a phenotype
Genetic Variation
Definition
Differences in alleles
Environmental Variation
Definition
- Some of the variation is caused by how the environment affects the individual
- e.g. height, weight, skin colour
Continuous Variation
Definition
- When the characteristic can take any value in the data set
- Represented using a line graph or histogram
- e.g. hair length
Discontinuous Variation
Definition
- Where the characteristic can only take oone of a limkited set of values in a data set
- Represented using a bar chart
- e.g. number of legs, eye colour, blood groups
