Mendel's laws and exceptions

Question 1

What is a homozygous genotype?

Answer 1

A genotype where both alleles of a gene are the same (e.g., AA or aa).

Question 2

What is a heterozygous genotype?

Answer 2

A genotype where the alleles of a gene are different (e.g., Aa).

Question 3

Define phenotype.

Answer 3

Observable characteristics or traits of an organism.

Question 4

Define genotype.

Answer 4

he genetic makeup of an organism that determines its traits.

Question 5

What is dominance in genetics?

Answer 5

A dominant allele is always expressed when present, even in a heterozygous state.

Question 6

What is recessiveness in genetics?

Answer 6

A recessive allele is expressed only in the homozygous state (e.g., aa).

Question 7

What are true-breeding lines?

Answer 7

Descendants obtained after inbreeding for several generations, producing uniform traits.

Question 8

What is inbreeding?

Answer 8

The process of crossing genetically related individuals.

Question 9

What is a monohybrid cross?

Answer 9

A genetic cross focusing on a single trait.

Question 10

What is the phenotypic ratio for a monohybrid F2 generation?

Answer 10

3:1 (3 dominant, 1 recessive).

Question 11

What is the genotypic ratio for a monohybrid F2 generation?

Answer 11

1:2:1 (1 homozygous dominant, 2 heterozygous, 1 homozygous recessive).

Question 12

What is a dihybrid cross?

Answer 12

A genetic cross focusing on two traits simultaneously.

Question 13

What is the phenotypic ratio for a dihybrid F2 generation?

Answer 13

9:3:3:1 (9 dominant for both traits, 3 dominant for one, 3 dominant for the other, 1 recessive for both).

Question 14

What is the purpose of a Punnett square?

Answer 14

To predict the genotypes and phenotypes of offspring from a genetic cross.

Question 15

What is polygenic inheritance?

Answer 15

A single trait influenced by two or more gene pairs, resulting in a spectrum of phenotypes.

Question 16

Define epistasis.

Answer 16

A form of gene interaction where one gene masks or modifies the expression of another gene.

Question 17

What is recessive epistasis?

Answer 17

When a recessive allele at one locus masks the effect of alleles at another locus (e.g., coat color in mice).

Question 18

What is dominant epistasis?

Answer 18

When a dominant allele at one locus masks the effect of alleles at another locus (e.g., fruit color in squash).

Question 19

What is the phenotypic ratio for recessive epistasis?

Answer 19

9:3:4 (e.g., Agouti, black, albino mice).

Question 20

What is the phenotypic ratio for dominant epistasis?

Answer 20

12:3:1 (e.g., white, yellow, green squash).