Q: A cross between a true-breeding red-flowered snapdragon (CRCR) and a true-breeding white-flowered snapdragon (CWCW) produces all pink-flowered offspring (CRCW). When these F1 plants are self-fertilized, what phenotypic ratio is expected in the F2 generation?

$$1 \text{ red} : 2 \text{ pink} : 1 \text{ white}$$

Q: A woman with blood type A has a daughter with blood type B. Which of the following genotypes could the father have?

$$I^B I^B$$ \, \text{or} \, I^B i$

Question 1

A cross between a true-breeding red-flowered snapdragon (CRCR) and a true-breeding white-flowered snapdragon (CWCW) produces all pink-flowered offspring (CRCW). When these F1 plants are self-fertilized, what phenotypic ratio is expected in the F2 generation?

Accepted Answer

$$1 	ext{ red} : 2 	ext{ pink} : 1 	ext{ white}$$

Question 2

Which of the following best describes the inheritance pattern of cystic fibrosis?

Accepted Answer

Autosomal recessive

Question 3

A woman with blood type A has a daughter with blood type B. Which of the following genotypes could the father have?

Accepted Answer

$$I^B I^B$$ \, 	ext{or} \, I^B i$

Question 4

Which of the following is an example of codominance in humans?

Accepted Answer

ABO blood group, type AB

Question 5

A cross between two heterozygous tall bean plants (Tt) produces offspring that are all taller than the dwarf parent but shorter than the tall parent. What is the most likely explanation for this observation?

Accepted Answer

Incomplete dominance

Question 6

Which of the following best explains why most mutant alleles are recessive?

Accepted Answer

Their product usually does not function, but one wild-type allele is sufficient to provide needed product

Question 7

In Labrador retrievers, coat color is determined by two genes: B (black pigment) and E (pigment deposition). A yellow lab has genotype $$bb\,ee. If a $$true-breeding black lab ($$BB\,EE) is $$crossed with a yellow lab, what will be the phenotype of all F1 offspring?

Accepted Answer

All black

Question 8

Which of the following is an example of a pleiotropic effect?

Accepted Answer

A single gene mutation causing multiple symptoms in cystic fibrosis

Question 9

A Manx cat is heterozygous for a dominant allele that causes a shortened tail. When two Manx cats are crossed, the ratio of Manx to normal-tailed kittens is 2:1. What is the best explanation for this ratio?

Accepted Answer

Homozygosity for the Manx allele is lethal

Question 10

Which of the following describes a genetic interaction where the expression of one gene is masked by another gene at a different locus?

Accepted Answer

Epistasis

Question 11

A woman with genotype $$I^A i$$ and a man with genotype $$I^B i$$ have a child with blood type O. What is the genotype of the child?

Accepted Answer

$$ii$$

Question 12

Which of the following is an example of a sex-influenced trait?

Accepted Answer

Scurs in cattle, dominant in males and recessive in females

Question 13

Which of the following best describes incomplete penetrance?

Accepted Answer

Not all individuals with a particular genotype express the expected phenotype

Question 14

Which of the following is a likely explanation for variable expressivity?

Accepted Answer

Modifier genes or environmental factors affect the phenotype

Question 15

A cross between two true-breeding white-flowered plants produces all purple-flowered offspring. What genetic phenomenon does this illustrate?

Accepted Answer

Complementation

Question 16

Which of the following is true about mitochondrial inheritance?

Accepted Answer

It is transmitted only through the maternal line

Question 17

In a dihybrid cross involving two genes with simple dominance, what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 18

Which of the following best describes the Bombay phenotype in humans?

Accepted Answer

A mutation at a different locus prevents expression of ABO antigens, resulting in type O phenotype regardless of genotype

Question 19

Which of the following is an example of gene redundancy?

Accepted Answer

Two genes have the same function, so a mutation in one does not cause a phenotype

Question 20

Which of the following is a real-world example of a multifactorial disease?

Accepted Answer

Celiac disease, which involves multiple genes and environmental triggers

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