Topic 3: Mendelian Genetics

Question 1

why did Mendel choose peas for his experiment?

Answer 1

1. flowers have male and female structures
2. self-fertilise
3. can use artificial cross-fertilization
4. short life cycles

Question 2

what are test crosses ALWAYS crossed with?

Answer 2

homozygous recessive x F1

Question 3

what is the genotypic ratio for a monohybrid cross? phenotypic?

Answer 3

1:2:1, 3:1

Question 4

what is Mendel’s first law?

Answer 4

Law of Segregation, two alleles from the same gene separate from one another during the formation of gametes (meiosis I, occurs during anaphase I)

Question 5

self-fertilization of the F2 produces a ____ phenotypic ratio

Answer 5

3:1

Question 6

dihybrid crosses support Mendel’s second law, what is it?

Answer 6

Independent assortment (the segregation of alleles of one gene are independent of the other, occurs during metaphase)

Question 7

dihybrid crosses: crossing the F1 heterozygotes produce a _____ phenotypic ratio in the F2

Answer 7

9:3:3:1

Question 8

____: two independently assorting traits

Answer 8

dihybrid cross

Question 9

____: three independently assorting traits

Answer 9

trihybrid cross

Question 10

_____: the probability that 2 independent outcomes will BOTH occur

Answer 10

product rule (multiply them)

Question 11

_____: the probability that either one or the other of two independent outcomes will occur

Answer 11

sum rule (two traits are mutually exclusive)

Question 12

________: suggests that there is no statistically significant difference between the observed outcome and the expected outcome

Answer 12

H0, null hypothesis

Question 13

________: suggests that there is a statistically significant difference between the observed outcome and the expected outcome

Answer 13

Ha, alternative hypothesis

Question 14

step 1: define H0 and Ha
step 2: define alpha value (0.05)
step 3: calculate observed numbers, expected numbers, chi-square value, and degrees of freedom
step 4: compare those numbers to critical value
step 5: draw conclusions

these are all steps of which test?

Answer 14

chi-square analysis