Midterm #1 Flashcards
What is Mendel’s first law
- discrete units called genes
- have variants called alleles
- diploidy have 2 copies of the gene
- segregate independently (during meiosis)
- unite at random
What is the genotype ratio and phenotype ratio of a heterozygous cross for a single gene?
Génotype: 1:2:1
Phenotype: 3:1
What is the cross of 2 homozygous in single gene?
All heterozygous
What is the cross of 2 heterozygous?
3: 1 phenotype
1: 2:1 genotype
What is the cross of a homozygous recessive and heterozygous? In single genes?
1: 1 phenotype (50% Aa - 50% aa)
1: 1 genotype
What is mendels second law?
Différent gene combination assort independently in gamete formation and in fertilization (need to multiply probabilities of the genes independently)
In two genes - results of crossing 2 heterozygous genes?
9:3:3:1
In two genes, cross of 1 heterozygousand one homozygous? (Test cross)
1:1:1:1
What is a test cross?
To check if the parent is heterozygous, where the recessive will show up in the progeny
What is a dihybrid cross?
Two heterozygous genes crossing
Probability of two independent events occurring together is the product of their ____
Individual probabilities
Probability of A and B occurring is?
A x B
Probability of A or B occurring is
(P)A + (p)B
How many pairs of chromosomes do humans have?
23
22 autosomal - one sex one
What are the three types of centromeres?
Telocentric (at the end)
Afrocentric (close to end)
Meta centric (center)
What is a dyad? What is the individual chromosome called?
A chromosome pair attached at centromere
A chromatid
What are the stages of the life cycle?
Mitosis
G1
Synthesis
G2
What are the differences between meiosis and mitosis?
Meiosis:
- align from top to bottom where crossing over can occur
- 2 divisions
- results in 4 haploid gametes
Mitosis
- align left to right
- 1 division
- results in identical daughter cells as parents (diploid)
Know the stages of mitosis!!
1
Organelle chromosomes are inherited from
Material gametes
Do not exist in pairs and are similar to bacteria
Do not follow mendel’s 3:1 ratio
When there is a deviation from the 9331 or 1111 ratios ___
Suspect linkage of genes
How do you calculate the % recombinants?
Add all recombinants and divide by their sum
How do you calculate the interference?
1- observed cross over / expected cross over
What is the chi square test for?
Décide if a real data set matches the theoretical