Question

17. In a dihybrid cross for two traits (DdGg), what is the probability of obtaining an offspring with the homozygous recessive genotype (ddgg)?

a. 1/4

b. 1/16

c. 9/16

d. 3/16

19. Blood type is controlled by two genes, I and H. The I gene alleles include: i, IA, and IB. The H gene alleles include: H and h. Blood type determination is therefore an example of which genetic principle(s)?

a. multiple alleles and codominance.

b. Pleiotropy and epistasis.

c. Multiple alleles, codominance, and epistasis.

d. Multifactorial traits and codominance.

35. Which of the following could be used as evidence that sleep has an inherited component?

a. MZ twins have more similar sleep patterns than DZ twins.

b. People who report insomnia frequently are over age 50.

c. Siblings tend to have different sleep patterns.

d. DZ twins have less similar sleep patterns compared to siblings.

46. Which of the following makes epigenetics difficult to study?

a. It does not depend on the nucleotide sequence of the DNA.

b. It is hard to sequence the entire human genome.

c. It is not heritable.

d. DNA sequences mutate too quickly to tractk changes.

41. Which of the following is TRUE about RNA?

a. RNA nucleotides have the bases thymine and uracil.

b. RNA is more stable than DNA.

c. RNA controls the expression of genetic information.

d. RNA is double stranded.

Answer 1

17. In a dihybrid cross for two traits (DdGg), what is the probability of obtaining an offspring with the homozygous recessive genotype (ddgg)?

a. 1/4

b. 1/16

c. 9/16

d. 3/16

Answer: Option a, 1/4 is the correct option here.

This cross is essentially a test cross between heterozygous DdGg and homozygous recessive ddgg and will give a 1:1:1:1 ratio. Therefore every possibility will have a 25% probability, that is, 1/4.

19. Blood type is controlled by two genes, I and H. The I gene alleles include i, IA, and IB. The H gene alleles include: H and h. Blood type determination is, therefore, an example of which genetic principle(s)?

a. multiple alleles and codominance.

b. Pleiotropy and epistasis.

c. Multiple alleles, codominance, and epistasis.

d. Multifactorial traits and codominance.

Answer: multiple alleles and codominance

ABO blood group is a great example of multiple alleles as blood grouping is controlled by three alleles iA, iB and i allele on the same locus on the chromosome. It also shos codominance as bot the A and the B alleles are dominant over O type, thus if an offspring inherits iA from his mother and iB from his father, the resulting blood group will show co-dominance as both the alleles will be expressed simultaneously and the blood group would be AB.

35. Which of the following could be used as evidence that sleep has an inherited component?

a. MZ twins have more similar sleep patterns than DZ twins.

b. People who report insomnia frequently are over age 50.

c. Siblings tend to have different sleep patterns.

d. DZ twins have less similar sleep patterns compared to siblings.

Answer: MZ twins have more similar sleep patterns than DZ twins

Various studies on sleep and dream patterns and have been conducted that suggest that MZ twins will have more similar patterns as compared to DZ twins as inheritance in Monozygotic twins are quite comparable.

46. Which of the following makes epigenetics difficult to study?

a. It does not depend on the nucleotide sequence of the DNA.

b. It is hard to sequence the entire human genome.

c. It is not heritable.

d. DNA sequences mutate too quickly to track changes.

Answer: a. It does not depend on the nucleotide sequence of the DNA

Epigenetics does not alter the DNA sequence but still alter the phenotype. These involve factors like DNA methylation or other chemical modifications that can influence gene expression.

41. Which of the following is TRUE about RNA?

a. RNA nucleotides have the bases thymine and uracil.

b. RNA is more stable than DNA.

c. RNA controls the expression of genetic information.

d. RNA is double-stranded.

Answer: c. RNA controls the expression of genetic information

Gene expression is regulated through transcription to from RNA sequence and then its translation into proteins. Thus it is the RNA that controls the expression of genetic material.

All other options are clearly incorrect as,

RNA does not contain Thymine,

RNA is single-stranded, and

DNA is much more stable than RNA