Genetics Flashcards
Continuous variation
Characteristics that change over time / variation with a high range of values
Discontinous variation
Characteristics which are wither one of the other e.g. you can either roll you tounge or you can’t. There is no in-between.
The structure of a DNA
Two linked strands that wind around each other to resemble a twisted ladder. (Double helix)
Made up of phos[hates, sugars and bases.
There are 4 kinds of bases: A(Adenine) T(Thymine) C(Cytosine) G(Guanine)
A pairs with T, C pairs with G
Where is DNA in a cell?
In the nucleus
State the base pairing rule
A pairs with T, C pairs with G
Define chromosomes
They are made up of many genes and are located inside the nucleus of every cell
How many chromosomes does a human have?
46 chromosomes, 23 pairs
What chromosomes does a male and female have?
Males has one X chromosome and one Y chromosome, while females have two X chromosomes.
Define a gene
A section of DNA that codes for a characteristic and traits
Define alleles
Different forms of a gene, one from the mother and one from the father e.g. brown and blue eyes
Define dominant
The allele that is always expressed (represented by the capital letter) e.g. B = brown eyes
Define Recessive
The allele which is only expressed if the dominant is absent. Represented with a lower case letter. (b = blue eyes)
Define Homozygous
When both alleles are the same e.g. BB or bb
Define Heterozygous
When the two alleles are different e.g. Bb
Define Genotype
What the alleles look like in an individual e.g. Bb or BB or bb
