Question 1

Which level of protein structure is primarily stabilized by interactions between the peptide backbone, such as hydrogen bonds forming alpha helices and beta sheets?

Accepted Answer

Secondary structure

Question 2

A mutation in the gene encoding hemoglobin changes a single amino acid in the protein sequence. This change most directly affects which level of protein structure?

Accepted Answer

Primary structure

Question 3

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

They speed up reactions by lowering the activation energy without being consumed.

Question 4

In the enzyme-catalyzed breakdown of sucrose, which molecule acts as the substrate?

Accepted Answer

Sucrose

Question 5

Which of the following is NOT a function of proteins listed in the study materials?

Accepted Answer

Energy storage as glycogen

Question 6

What is the correct sequence of events in enzyme action as shown in the provided diagrams?

Accepted Answer

Substrate binds to enzyme, enzyme-substrate complex forms, products are released

Question 7

Which equation correctly represents the formation and breakdown of the enzyme-substrate complex?

Accepted Answer

$E + S \rightarrow E-S \rightarrow E + P$

Question 8

Which property of enzymes allows them to catalyze only specific reactions?

Accepted Answer

Their reaction specificity due to the active site's shape

Question 9

A competitive inhibitor affects enzyme kinetics by:

Accepted Answer

Leaving $V_{max}$ unchanged and increasing $K_m$

Question 10

Which of the following statements about noncompetitive inhibitors is correct?

Accepted Answer

They bind to a site other than the active site and decrease $V_{max}$

Question 11

If an enzyme is exposed to a temperature above its optimum, what is the most likely outcome?

Accepted Answer

The enzyme will denature and lose its function

Question 12

Which protein is responsible for immune defense as listed in the study materials?

Accepted Answer

Immunoglobulin

Question 13

A patient with chronic wasting disease is suffering from a disorder caused by which type of protein?

Accepted Answer

Prion

Question 14

Which protein is primarily involved in cellular transport as described in the study materials?

Accepted Answer

Channels

Question 15

Which of the following best explains why enzymes are sensitive to pH?

Accepted Answer

pH changes can disrupt hydrogen and ionic bonds, affecting the active site

Question 16

Which protein is responsible for storage of iron in the body?

Accepted Answer

Ferritin

Question 17

Which of the following is a gene regulator protein?

Accepted Answer

Transcription factor

Question 18

A misfolded prion protein can cause other normal prion proteins to misfold, leading to which of the following outcomes?

Accepted Answer

Formation of tangled plaques in the brain

Question 19

Which protein is primarily responsible for maintaining osmotic pressure in blood?

Accepted Answer

Serum albumin

Question 20

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzymes are specific to their substrates due to the shape of their active site

Protein Structure, Function, and Enzyme Activity

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