Q: Which equation correctly represents the relationship between hydrogen ion concentration and pH?

$$\text{pH} = -\log_{10}[\text{H}^+]$$

Q: Which of the following is the correct sequence for the central dogma of molecular biology?

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

Question 1

Which of the following statements best explains why water is considered the 'universal solvent' in biological systems?

Accepted Answer

Water's polarity allows it to surround and stabilize ionic and polar solutes, keeping them in solution.

Question 2

A patient presents with blood pH of 7.28. Which acid-base disorder is most likely present, and what is the physiological consequence?

Accepted Answer

Acidosis; disruption of protein structure and enzyme function

Question 3

Which equation correctly represents the relationship between hydrogen ion concentration and pH?

Accepted Answer

$$	ext{pH} = -\log_{10}[	ext{H}^+]$$

Question 4

Amino acids act as excellent buffers in biological systems. Which property allows them to resist changes in pH?

Accepted Answer

They can both accept and donate hydrogen ions due to their amino and carboxyl groups.

Question 5

Which of the following best describes the structural difference between DNA and RNA?

Accepted Answer

DNA is double-stranded with deoxyribose sugar; RNA is single-stranded with ribose sugar.

Question 6

Which of the following is the correct sequence for the central dogma of molecular biology?

Accepted Answer

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

Question 7

A frameshift mutation occurs in the HEXA gene. What is the most likely biochemical consequence?

Accepted Answer

Production of a non-functional enzyme due to altered reading frame, leading to GM2 ganglioside accumulation.

Question 8

Which of the following best explains why increasing substrate concentration can overcome competitive inhibition but not non-competitive inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, so excess substrate outcompetes the inhibitor; non-competitive inhibitors alter the enzyme's shape at a different site.

Question 9

Which of the following is NOT a function of proteins in the human body?

Accepted Answer

Storage and transmission of genetic information

Question 10

During DNA synthesis, why are deoxynucleotide triphosphates (dNTPs) used instead of deoxynucleotide monophosphates (dNMPs)?

Accepted Answer

dNTPs contain three phosphate groups, providing energy for phosphodiester bond formation.

Question 11

Which of the following best describes the effect of a nonsense mutation in the CFTR gene?

Accepted Answer

Production of a truncated, unstable protein that cannot reach the cell surface.

Question 12

Which of the following is a correct description of a zwitterion?

Accepted Answer

A molecule with both positive and negative charges, but overall neutral.

Question 13

Which enzyme class catalyses the joining of two molecules using energy from ATP?

Accepted Answer

Ligases

Question 14

Which of the following best describes the induced-fit model of enzyme-substrate interaction?

Accepted Answer

The enzyme's active site changes shape to better fit the substrate, stabilizing the transition state.

Question 15

Which of the following amino acid side chain groups is responsible for forming disulfide bonds in proteins?

Accepted Answer

Sulfur-containing

Question 16

A protein is exposed to high temperature and extreme pH. What is the most likely outcome?

Accepted Answer

The protein is denatured, losing its secondary, tertiary, and quaternary structure, but the primary structure remains intact.

Question 17

Which of the following best explains why silent mutations do not affect protein function?

Accepted Answer

The genetic code is degenerate, so multiple codons can code for the same amino acid.

Question 18

Which of the following is a real-life example of irreversible enzyme inhibition?

Accepted Answer

Aspirin permanently inhibits cyclooxygenase (COX), preventing prostaglandin synthesis.

Question 19

Which of the following best describes the process of translation in protein synthesis?

Accepted Answer

Ribosomes read mRNA codons, tRNA delivers amino acids, and peptide bonds are formed to produce a polypeptide.

Foundations of Biochemistry: Body Fluids, Biomolecules, Proteins, Enzymes, and Nucleic Acids

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