Topic 2

Question 1

what is the gametic ratio of a dihybrid cross with independent assortment?

Answer 1

1:1:1:1

Question 2

What is the phenotypic ratio of a dihybrid cross with independent assortment?

Answer 2

9:3:3:1

Question 3

what is the phenotypic ratio of a dihybrid test cross with independent assortment?

Answer 3

1:1:1:1

Question 4

how to calculate the number of gamete types for crosses with multiple genes

Answer 4

2^n (n=num of gene pairs)

Question 5

how do you calculate number of possible genotypes in crosses?

Answer 5

3^n (n=num of gene pairs)

Question 6

how many possible genotypes exist in a trihybrid cross

Answer 6

3^3 (3 gene pairs) = 27

Question 7

what does unlinked genes mean?

Answer 7

genes that are on different chromosomes

Question 8

what does linked genes mean

Answer 8

genes on different loci of the same chromosome

Question 9

how many types of gametes would you get in a dihybrid cross unlinked?

Answer 9

4 (2^n 2^2 2 genes)

Question 10

how many types of gametes would you get in a trihybrid cross unlinked?

Answer 10

8 (2^n 2^3 3 genes)

Question 11

what is the gametic ratio of a test cross with a dihybrid F1

Answer 11

1:1:1:1

Question 12

what is the ratio for independent assortment in a dihybrid meiocite

Answer 12

1:1:1:1

Question 13

how many genotypes are produced with 2 gene pairs?

Answer 13

3^2 = 9

Question 14

how many genotypes are produced with 3 gene pairs?

Answer 14

3^3

Question 15

what is the assumption for testing for whether it is linked or unlinked genes

Answer 15

the assumption is that it is undergoing independent assortment and that the phenotypic ratio is 9:3:3:1

Question 16

how do you calculate degrees of freedom for linkage

Answer 16

num of phenotypes - 1

Question 17

what accounts for Mendel’s first law in meiosis

Answer 17

Segregation of a pair
of homologs by spindle attachment from each pole

Question 18

what accounts for Mendel’s second law in meiosis

Answer 18

The randomness of spindle attachment
throughout the chromosome

Question 19

what is a dihybrid cross

Answer 19

a cross between individiuals that differ with respect for 2 traits (heterozygous for 2 traits)

Question 20

what accounts for mendels second law (law of independent assortment)

Answer 20

in metaphase I, homologous pairs line up at metaphase plate indepenently from others