Term 2 - Variance And Inheritance Flashcards
What is a gene
Gene code for something
These genes join to make chromosome
Chromosome pairs with another chromosome and there’s 23 pairs
These 23 pairs make DNA
What is meiosis
Type of cell division.
Involved in reproductive organs
R daughter cells diploid to haploid
Genetically different to parent cells
Production of gametes
What is a diploid
Double chromosome
what is a haploid
Half the amount of chromosomes
Process of meiosis
- DNA unravels and replicates - 2 copies of each chromosome called chromatids
2.DNA condenses to form double armed chromosomes - Chromosomes arrange themeselbes into homologous pairs
4.these pairs are separated , halving the chromosome - The pairs of sister chromatids that make up each chromosome are separate
- Four haploids cells genetically different from each other have been produced
What happens during meiosis 1
Homologous chromosomes come together and pair up the chromatids twist around each other and bits of chromatids swap over
Who is Mandel
He grew peas
Found something interesting about the pods
He coined the terms recessive and dominant
Phenotype
Characteristics and appearance etc
Who decided when the baby is girl or boy
The father
What are pairs of matching chromosomes called
Homologous pairs - one from the mum one from the dad
What are homologous pairs
Both chromosome are the same size and the same genes
But different alleles
Example
Eye colour is a gene
Colours of the eyes like blue , brown etc - is allele
What is zygosity
One chromosome is inherited from the mother and one from the father
What is phenotype
Characteristic or the trait - hair colour , blood types , height etc
What is genotype
Something that is not visible
What is complete dominance
One allele completely masks another
What is cystic fibrosis
A recessive gene disease caused by one gene
What is codominance - blood groups
Neither the allele can mask the expression of the other allele
The gene controlling human. ABO blood groups had 3 alleles
A and B are not dominant over each other but are dominant over O
What is the hardy - Weinberg equation
Allele frequency :
P + q= 1
P is the frequency of one allele usually the dominant one
Q = the frequency of the other allele usually the recessive one
Genotype frequency:
P2 +2pq +q2 = 1
P2 = homozygous dominant genotype
2pq = frequency of homozygous genotype
Q2 = frequency of homozygous recessive genotype
Chi - squared test equation
X 2 = E (‘sum of ) x (O ( observed value )- E2 (‘expected value )/ E
Hypothesis
H0 = no statistically significant difference between observed frequency and the expected frequency
