BIOCHEM C785 Final Exam Latest update With Complete Solution

BIOCHEM C785 Final Exam

Which mRNA sequence results in a polypeptide that contains three amino acids?

Correct answer- 5' - CUU GAU ACU UAG - 3'

Which RNA sequence would end in the following polypeptide?

Phe-Thr-Val-Stop

Correct answer- 5' - UUC ACA GUA UAA - 3'

What is the complementary sequence for the following DNA sequence?

5' - GCC ATC TCG AAT - 3'

Correct answer- 5' - ATT CGA GAT GGC - 3'

Assuming 100% reaction efficiency, how many DNA copies are created after the

completion of four complete PCR cycles?

Correct answer- 16

What is the function of DNA polymerase in the process of PCR?

Correct answer- It recognizes the primers and uses the available dNTPs to replicate the

template DNA sequence.

5' - [...] ATT CGC TAG GGC [...] - 3' − Normal DNA

5' - [...] ATT CGC GAG GGC [...] - 3' − Mutant DNA

Which type of mutation and outcome characterizes the Mutant DNA?

Correct answer- A missense mutation leading to a longer protein

In sickle-cell disease, the glutamic acid (Glu) at position number seven is mutated to

valine (Val).

What change in codons corresponds to this mutation?

Correct answer- GAA to GTA

What are possible blood types of the parents of a patient with blood type AB?

Correct answer- A and B

Which pair of chromosomes accurately depicts the genotype of a person with an

autosomal recessive mutant HBB allele and sickle cell anemia?

Correct answer- option 3- 2 mutant genes on chromosome 11

Which pair of chromosomes accurately depicts the genotype of a person with an Xlinked recessive mutant ALAS2 allele and sideroblastic anemia?

Correct answer- option 3, mutated allele

Studies have shown that increased expression of two genes called SIRT1 and SIRT2 is

associated with chronic exposure to cocaine and contributes to drug addiction.

What difference in the regions of the SIRT1 and SIRT2 genes in people addicted to

cocaine increases their expression?

Correct answer- The nucleosomes become more widely spaced.

Mice with low levels of agouti gene expression tend to have yellow fur and are obese,

while mice with higher levels of expression are brown and of normal weight. Studies

show that expression of the agouti gene in mice can be controlled by epigenetics.

Mice with low levels of agouti gene expression tend to have yellow fur and are obese,

while mice with higher levels of expression are brown and of normal weight. Studies

show that expression of the agouti gene in mice can be controlled by epigenetics.

What scenario describes epigenetic regulation of the agouti gene?

Correct answer- Mother mice fed methyl-rich diets during pregnancy give birth to

offspring with decreased agouti gene expression compared to those fed a methyl-poor

diet.

Oxidative damage to DNA can often result in the alteration of a single nucleotide.

Which DNA repair mechanism would repair this type of damage?

Correct answer- Base excision repair

Xeroderma pigmentosum (XP) is a recessive genetic disease that occurs when one or

more of the genes that perform nucleotide excision repair are nonfunctional.

Why do XP patients have a much higher incidence of skin cancer than the general

population?

Correct answer- The mutation rate of all other genes is higher due to failure to repair.

Which reaction is responsible for the formation of polypeptides?

Correct answer- Dehydration

Which portion of the amino acid is inside the box?

Correct answer- Carboxyl group

Which amino acid side group is polar?

Correct answer- option 2-one with charge

When placed within a polypeptide chain, which amino acid would interact most

favorably with nonpolar amino acids?