NUTR101 Protein

How many essential amino acids must come from the diet because the human body cannot make them?

• 11

• 9

• 7

• 12

Proteins are made from how many different amino acids?

• 10

• 20

• 30

• 40

Answer explanation

There are 20 different types of amino acids which can be arranged in different sequences to form proteins.

What element is found in proteins that is not typically found in carbohydrates and lipids?

• Carbon

• Hydrogen

• Oxygen

• Nitrogen

Answer explanation

Proteins contain nitrogen, an element not typically found in carbohydrates and lipids.

Which of the following features distinguishes one type of amino acid from another?

• Amino group

• Carboxyl group

• Side group

• All of the above

Answer explanation

The distinguishing feature of an amino acid's structure is the side group (R group), as it determines the unique characteristics and properties of each amino acid.

What is the role of hydrochloric acid (HCl) in protein digestion in the stomach?

• It breaks down protein into amino acids.

• 
  It activates stomach enzymes and uncoils protein strands.

• 
  It directly absorbs proteins into the stomach lining.

• 
  It neutralises the pH of the stomach contents.

Answer explanation

Hydrochloric acid (HCl) in the stomach denatures proteins, unraveling their structures, and activates pepsinogen into pepsin, which then breaks down proteins into smaller peptides during digestion.

Which of the following is not a product of protein digestion in the small intestine?

• Amino acids

• Tripeptides

• Dipeptides

• Polysaccharides

Answer explanation

Polysaccharides are a type of carbohydrate.

What is the final product of protein digestion before absorption?

• Peptides

• Polypeptides

• Proteases

• Amino acids

Answer explanation

Chains of peptides are broken down into single amino acids for absorption.

What is denaturation of protein in the context of stomach digestion?

• 
  The process where protein is broken down into amino acids.

• 
  The process where protein strands are converted into fats.

• 
  The process where protein structure is changed, making it easier for enzymes to act on it.

• 
  The process where protein is absorbed into the stomach lining.

Answer explanation

Denaturation refers to processes that change the structure of a protein.

Which of the following is NOT an example of protein denaturation?

• Cooking an egg

• Curdling milk

• Folding a peptide chain into a functional shape

• Whipping cream