Q: In Mendel's classic monohybrid cross between pure tall (TT) and pure dwarf (tt) pea plants, what is the expected phenotypic ratio in the F2 generation after selfing the F1 heterozygotes?

$$3 \text{ tall} : 1 \text{ dwarf}$$

Q: A cross between two heterozygous maize plants for the chlorophyll gene (C = normal, c = lethal when homozygous) produces which genotypic ratio among surviving offspring?

$$1 \text{ CC} : 2 \text{ Cc}$$

Q: In rabbits, the coat color gene has multiple alleles: $$c^+ \u003e c$$^{ch}$$ \u003e c^h \u003e c. If a$$ $$c^+c$$ rabbit is crossed with a $$c^{ch}c$ rabbit, what phenotypic ratio is expected in the offspring?

$$1 \text{ agouti} : 1 \text{ chinchilla}$$

Q: In Labrador retrievers, coat color is determined by two genes: $$B ($$black, $$b$$ brown) and $$E ($$pigment deposition, $$e no $$deposition). What is the expected phenotypic ratio in the offspring of two $$BbEe$$ dogs?

$$9 \text{ black} : 3 \text{ brown} : 4 \text{ yellow}$$

Q: In Drosophila, a cross between a homozygous red-eyed male and a homozygous white-eyed female produces all red-eyed F1 offspring. When these F1 are interbred, what is the expected ratio of red-eyed to white-eyed offspring in the F2 generation?

$$2 \text{ red-eyed females} : 1 \text{ red-eyed male} : 1 \text{ white-eyed male}$$

Question 1

In Mendel's classic monohybrid cross between pure tall (TT) and pure dwarf (tt) pea plants, what is the expected phenotypic ratio in the F2 generation after selfing the F1 heterozygotes?

Accepted Answer

$$3 	ext{ tall} : 1 	ext{ dwarf}$$

Question 2

Polydactyly (extra digits) is a dominant trait. If a man with polydactyly (heterozygous) and his wife (normal) have a child, what is the probability that their next child will have extra digits?

Accepted Answer

$$0.5$$

Question 3

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote displays an intermediate phenotype between the two homozygotes.

Question 4

A cross between two heterozygous maize plants for the chlorophyll gene (C = normal, c = lethal when homozygous) produces which genotypic ratio among surviving offspring?

Accepted Answer

$$1 	ext{ CC} : 2 	ext{ Cc}$$

Question 5

Which of the following is an example of pleiotropy?

Accepted Answer

A gene that affects both lung function and digestive enzyme production.

Question 6

In rabbits, the coat color gene has multiple alleles: $$c^+ \u003e c$$^{ch}$$ \u003e c^h \u003e c. If a$$ $$c^+c$$ rabbit is crossed with a $$c^{ch}c$ rabbit, what phenotypic ratio is expected in the offspring?

Accepted Answer

$$1 	ext{ agouti} : 1 	ext{ chinchilla}$$

Question 7

A woman with blood type A ($$I^A i) $$and a man with blood type B ($$I^B i) $$have a child. Which blood type is NOT possible for their child?

Accepted Answer

None of the above

Question 8

Which of the following scenarios describes an example of epistasis?

Accepted Answer

In many mammals, one genotype ($$ee) $$prevents any fur color from developing.

Question 9

In Labrador retrievers, coat color is determined by two genes: $$B ($$black, $$b$$ brown) and $$E ($$pigment deposition, $$e no $$deposition). What is the expected phenotypic ratio in the offspring of two $$BbEe$$ dogs?

Accepted Answer

$$9 	ext{ black} : 3 	ext{ brown} : 4 	ext{ yellow}$$

Question 10

Which of the following best explains why sex-linked recessive disorders are more common in males than in females?

Accepted Answer

Males only need one copy of the allele to express the disorder.

Question 11

A man with hypophosphatemia (an X-linked dominant disorder) marries a normal woman. What is the probability that their daughter will have hypophosphatemia?

Accepted Answer

$$1$$

Question 12

Which chromosomal abnormality is associated with Down syndrome?

Accepted Answer

Trisomy 21 ($$2n+1)$$

Question 13

Which type of chromosomal alteration involves a segment of a chromosome being reversed end to end?

Accepted Answer

Inversion

Question 14

A pedigree shows a trait that skips generations and appears equally in males and females. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 15

Which of the following is a multifactorial disorder?

Accepted Answer

Heart disease

Question 16

In Drosophila, a cross between a homozygous red-eyed male and a homozygous white-eyed female produces all red-eyed F1 offspring. When these F1 are interbred, what is the expected ratio of red-eyed to white-eyed offspring in the F2 generation?

Accepted Answer

$$2 	ext{ red-eyed females} : 1 	ext{ red-eyed male} : 1 	ext{ white-eyed male}$$

Question 17

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes independently affect a single phenotype.

Question 18

Which of the following is NOT a possible result of nondisjunction during meiosis?

Accepted Answer

Polyploidy

Question 19

Which of the following statements about dominant alleles is correct?

Accepted Answer

Dominant alleles mask the effect of recessive alleles in heterozygotes.

Extending Mendelian Genetics: Beyond Simple Inheritance Patterns

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