Q: Which equation represents the Central Dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote expresses an intermediate phenotype between the two homozygotes.

Question 2

A cross between two snapdragon plants, one with red flowers (RR) and one with white flowers (rr), produces all pink flowers (Rr) in the F1 generation. What is the expected phenotypic ratio in the F2 generation?

Accepted Answer

1 red : 2 pink : 1 white

Question 3

Which equation represents the Central Dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 4

In the ABO blood group system, which genotype results in the AB blood type?

Accepted Answer

$$I^A I^B$$

Question 5

A rabbit with genotype $$C^{ch}C$ is crossed with a rabbit with genotype C$$^{ch}$$C^{ch}$. What is the expected phenotypic ratio in the offspring?

Accepted Answer

1 full color : 1 chinchilla

Question 6

Which of the following best describes a dominant negative mutation?

Accepted Answer

A mutation that interferes with the function of the wild-type allele, often in multimeric proteins.

Question 7

If a gene has three alleles ($$A_1$$, $$A_2$$, $$A_3) in a $$population, how many possible genotypes can be formed?

Accepted Answer

6 (using $$\frac{n(n+1)}{2}$$ where $$n=3)$$

Question 8

Which of the following is an example of codominance?

Accepted Answer

A flower with some petals red and some petals white.

Question 9

A mouse with genotype $$A^Y A^Y$$ does not survive. What type of allele is $$A^Y$$?

Accepted Answer

Recessive lethal allele

Question 10

Which of the following best describes a leaky (hypomorphic) mutation?

Accepted Answer

A mutation that produces a reduced amount of gene product.

Question 11

In a cross between two heterozygous yellow mice ($$A^Y A$$), what is the expected ratio of agouti to yellow offspring?

Accepted Answer

1 agouti : 2 yellow

Question 12

Which of the following is true about temperature-sensitive alleles, such as the Himalayan allele in rabbits?

Accepted Answer

The enzyme is functional at lower temperatures, resulting in pigment on extremities.

Question 13

Which formula would you use to calculate the number of possible genotypes for a gene with $$n$$ alleles?

Accepted Answer

$$\frac{n(n+1)}{2}$$

Question 14

Which of the following best describes a gain-of-function mutation?

Accepted Answer

A mutation that produces a novel gene activity or increased gene activity.

Question 15

A plant with genotype $$T_1T_2$$ flowers at an intermediate time compared to $$T_1T_1 ($$early) and $$T_2T_2 ($$late). What type of dominance is this?

Accepted Answer

Incomplete dominance

Question 16

Which of the following is a real-world example of a gain-of-function mutation?

Accepted Answer

A mutation that increases hemoglobin affinity for oxygen in high-altitude populations.

Question 17

Which of the following best describes sex-limited traits?

Accepted Answer

Traits that are only expressed in one sex, even though both sexes carry the gene.

Question 18

Which of the following best describes sex-influenced traits?

Accepted Answer

Traits that are influenced by the sex of the individual and can be expressed differently in males and females.

Question 19

Which of the following is a characteristic of late-onset dominant lethal mutations, such as Huntington disease?

Accepted Answer

Symptoms appear after reproductive age, allowing the mutation to persist in the population.

Question 20

Which of the following best describes the molecular basis of dominance in the context of enzyme activity?

Accepted Answer

Dominance occurs when one copy of the wild-type allele produces enough enzyme to result in the wild-type phenotype.

Gene Interactions: Variations in Dominance and Allelic Relationships CH4 Pt1 NEW SEM

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