Amino Acids and Proteins Quiz

What is the basic monomer unit of proteins?

• Nucleic acids

• Amino acids

• Fatty acids

• Saccharides

Proteins are the most abundant substance in cells after which of the following?

• Lipids

• Water

• Carbohydrates

• Minerals

What percentage of a cell's overall mass do proteins account for?

• 10%

• 15%

• 20%

• 25%

Which element is NOT part of the primary elemental composition of proteins?

• Carbon

• Iron

• Nitrogen

• Oxygen

What is the average nitrogen content by mass in proteins?

• 10.4%

• 12.4%

• 15.4%

• 18.4%

Proteins are naturally occurring polymers. What are the monomer units of proteins?

• Triacylglycerols

• Amino acids

• Carbohydrates

• Nucleosides

What functional groups are present in all amino acids?

• Amino group and hydroxyl group

• Carboxyl group and hydroxyl group

• Amino group and carboxyl group

• Carboxyl group and phosphate group

What distinguishes α-amino acids from other amino acids?

• The presence of a carboxyl group

• The amino group is attached to the α-carbon atom

• The presence of a side chain

• The presence of more than one amino group

How many amino acids are known, and how many of them are considered standard?

• 700 known, 20 standard

• 500 known, 20 standard

• 700 known, 50 standard

• 1000 known, 20 standard

What factors can vary among different amino acids?

• Size, shape, and charge

• Size, shape, charge, and acidity

• Size, shape, charge, acidity, and hydrogen-bonding ability

• Size, shape, and number of carboxyl groups