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Meiosis
Cell division where 4 haploid gametes are formed from one parent cell. The gametes are genetically different.
Haploid
A cell has half the total number of chromosomes required for the organism.
Complimentary base pairs
Adenine with Thymine, Guanine with Cytosine.
Genome
All the DNA in an organism.
Gene
A section of DNA that codes for a specific protein - can be 1000s of bases long.
Allele
Different types of a gene.
Zygote
A fertilised egg.
Homozygous
Two alleles the same in a chromosome pair.
Heterozygous
Two alleles that are different on the chromosome pair.
Expressed
Where the gene makes the protein and the characteristic is present.
Genotype
The two alleles that are present for a gene.
Phenotype
The combination of alleles expressed to form a characteristic - which can be seen.
Dominant
Where only one allele is required in the genotype for it to be the phenotype.
Recessive
Where both alleles must be present in the genotype for the phenotype to be expressed.
Mutation
A change in the base sequence of an allele - this cause new alleles to come about
How do mutations cause variation?
Mutations change the pool of genes in population by introducing new alleles (many don’t give any advantage).
Two types of variation
Genetic and environmental.
Discontinuous variation
Where data on variation can only take a limited set of values.
Continuous variation
Where data can be any value on a range.
Normal distribution
Where continuous data is spread in a bell shape.
What are the strands of DNA made of?
Sugar-phosphate backbone.
Shape of DNA?
Double-helix.
How are DNA strands linked?
Hydrogen bonds.
How many divisions in mitosis?
One.
Divisions in meiosis?
Two.
Number of daughter cells in mitosis
Two.
Number of daughter cells in meiosis
Four.
Type of cell produced in mitosis and meiosis
Mitosis: diploid
Meiosis: haploid
What did the human genome project do?
Sequenced all the genes and alleles in the human gene pool.
HGP impact in medicine
Genetic disorders can be diagnosed.
Helps predict the risk of a person getting a disease - preventative treatment.
Medicines can be given or not based of of if it will actually help them (with their specific DNA) or just cause an issue
