Question 1

Which of the following best describes incomplete dominance as observed in snapdragon flower color inheritance?

Accepted Answer

The heterozygote phenotype is intermediate between the two homozygotes, resulting in a blending of traits.

Question 2

A cross between two snapdragon plants with genotype $$Rr$$ produces offspring with the following phenotypic ratio: 1 red : 2 pink : 1 white. What is the genotypic ratio of the offspring?

Accepted Answer

$$1:2:1 (RR$$:Rr:rr)

Question 3

In the ABO blood group system, which genotype(s) will result in blood group AB?

Accepted Answer

$$I^A I^B$$

Question 4

If two parents are both heterozygous for blood group A ($$I^A I^O) $$and blood group B ($$I^B I^O$$), what is the probability that their child will have blood group O?

Accepted Answer

$$1/4$$

Question 5

Which of the following is an example of polygenic inheritance in humans?

Accepted Answer

Height

Question 6

A child inherits a chromosome deletion from their father, resulting in Prader-Willi syndrome. This is an example of which genetic phenomenon?

Accepted Answer

Genomic (parental) imprinting

Question 7

Which statement best explains why the self-cross of two yellow mice produces a 2:1 ratio of yellow to agouti offspring?

Accepted Answer

Yellow is dominant for hair color but homozygous yellow ($$YY) is $$lethal, so only $$Yy$$ and $$yy$$ survive.

Question 8

In a dihybrid cross of two agouti mice ($$AaCc 	imes AaCc$$), what is the expected phenotypic ratio for agouti : albino : black offspring?

Accepted Answer

$$9:4:3$$

Question 9

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple, seemingly unrelated phenotypic traits.

Question 10

A patient with sickle-cell anemia exhibits symptoms such as anemia, heart failure, and kidney damage. This is an example of:

Accepted Answer

Pleiotropy

Question 11

Which of the following ratios is NOT typically associated with epistatic gene interactions?

Accepted Answer

$$3:1$$

Question 12

In sweet peas, a plant with genotype $$PpCc is $$self-crossed. What is the expected phenotypic ratio of purple to white flowers in the F2 generation?

Accepted Answer

$$9:7$$

Question 13

Which of the following is an example of organelle inheritance?

Accepted Answer

Inheritance of mitochondrial DNA mutations

Question 14

A temperature-sensitive mutation causes a phenotype to be expressed only at certain temperatures. This is an example of:

Accepted Answer

Conditional mutation

Question 15

Which genotype will result in a person with blood group O in the ABO system?

Accepted Answer

$$I^O I^O$$

Question 16

Which of the following best explains why height in humans does not follow Mendelian inheritance?

Accepted Answer

Height is influenced by multiple genes and environmental factors.

Question 17

Which of the following scenarios is an example of codominance?

Accepted Answer

A person with genotype $$I^A I^B$$ expresses both A and B antigens on red blood cells.

Question 18

Which of the following is a modification of Mendelian ratios due to gene interaction?

Accepted Answer

Epistasis resulting in a $$9:4:3$$ ratio

Question 19

A genetic disorder shows increased severity and earlier onset in each successive generation. This phenomenon is known as:

Accepted Answer

Gene anticipation

Question 20

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

The genotype determines the potential for phenotype, but environmental factors can modify expression.

Extensions to Mendelian Inheritance: Modified Ratios, Multiple Alleles, Polygenic Traits, and Gene Interactions

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