Question 1

Which amino acid is most likely to be found in the center of a tightly packed, water-soluble globular protein such as myoglobin?

Accepted Answer

Leucine

Question 2

A mutation replaces a leucine residue in the core of myoglobin with aspartate. What is the most likely effect on the protein's structure?

Accepted Answer

The protein will likely misfold or become less stable due to the introduction of a charged residue in the hydrophobic core.

Question 3

Which property of leucine makes it favorable for the interior of globular proteins?

Accepted Answer

It is hydrophobic, minimizing interactions with water.

Question 4

Given the following amino acids: serine, glutamine, leucine, and aspartate, which would most likely be found on the surface of a water-soluble protein?

Accepted Answer

Serine

Question 5

Which of the following best explains why hydrophobic amino acids are buried in the interior of globular proteins?

Accepted Answer

Hydrophobic amino acids minimize unfavorable interactions with water by being buried in the protein core.

Question 6

A researcher is designing a synthetic protein to be highly soluble in water. Which amino acid should be minimized in the protein's sequence?

Accepted Answer

Leucine

Question 7

Which of the following amino acids is most likely to disrupt the hydrophobic core of a globular protein if introduced by mutation?

Accepted Answer

Aspartate

Question 8

The hydrophobic effect is a major driving force in protein folding. Which equation best describes the change in free energy ($$\Delta G) $$associated with protein folding?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 9

Which of the following statements about the structure of myoglobin is correct?

Accepted Answer

The interior is primarily composed of hydrophobic amino acids such as leucine.

Question 10

A patient has a genetic mutation that replaces a hydrophobic amino acid in the core of a globular protein with a polar amino acid. What is the most likely clinical consequence?

Accepted Answer

Decreased protein stability, possibly leading to disease due to protein misfolding.

Question 11

Which of the following best describes the role of hydrophobic amino acids in the tertiary structure of proteins?

Accepted Answer

They are typically found in the protein core, stabilizing the structure by avoiding water.

Question 12

Which amino acid substitution would most likely increase the solubility of a protein in water?

Accepted Answer

Leucine to aspartate

Question 13

Which of the following is a consequence of burying hydrophobic amino acids in the core of a protein?

Accepted Answer

Increased entropy of water molecules surrounding the protein

Question 14

Which amino acid would you expect to find at the interface between a protein and a lipid membrane?

Accepted Answer

Leucine

Question 15

A protein is denatured by heat, causing hydrophobic amino acids to become exposed to water. What is the most likely outcome?

Accepted Answer

The protein will aggregate due to hydrophobic interactions.

Amino Acid Distribution in Globular Proteins

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