Chapter 6: Protein: Amino Acid

Which of the following is not an essential amino acid in human nutrition? a. Proline b. Threonine c. Methionine d. Tryptophan

a. Proline

Which of the following is the primary factor that differentiates one amino acid from another? a. The side group b. The central carbon atom c. The number of oxygen atoms d. the number of nitrogen

a. The side group

When two amino acids are chemically joined together, the resulting structure is called a a. dipeptide b. diglyceride c. polypeptide d. disaccharide

a. dipeptide

What digestive enzyme would be most affected in people who are unable to produce hydrochloric acid? a. pepsin b. transaminase c. pancreatic protease d. intestinal peptidase

a. pepsin

Which of the following is a feature on an essential amino acid? a. It is not necessary in the diet b. It must be supplied by the diet c. It can be made from fat in the body d. It can be made from glucose in the body

b. It must be supplied by the diet

Which of the following elements is found in certain amino acids? a. Iron b. Sulfur c. Calcium d. Potassium

b. Sulfur

What is the composition of a tripeptide?

b. Three amino acids bonded together

Any of the following can be used by the body for the synthesis of nonessential amino acid except: a. a fragment of fat b. an essential mineral c. an essential amino acid d. a fragment of carbohydrate

b. an essential mineral

A dispensable amino acid is one that a. is not needed by the body b. can be synthesized by the body c. can be used to synthesize an indispensable amino acid d. cannot be synthsized by the body because of a genetic defect

b. can be synthesized by the body

What process results in the hardening of an egg when it is exposed to heat? a. solidification b. denaturation c. condensation d. protein interaction

b. denaturation

What is the simplest amino acid? a. valine b. glycine c. alanine d. methionine

b. glycine

How many different kinds of amino acids make up proteins?

d. 20

Which of the following would be classified as a polypeptide? a. 1 amino acid b. 3 amino acids bonded together c. 9 fatty acids bonded together d. 20 amino acids bonded together

d. 20 amino acids bonded together

What type of reaction is required to bind two molecules of glycine together and release a molecule of water? a. Hydrolysis b. Deamination c. Denaturation d. Condensation

d. Condensation

What element is found in proteins but not in carbohydrates and fats? a. Carbon b. Oxygen c. Calcium d. Nitrogen

d. Nitrogen

In what organ is pepsin active

stomach

Protein-hydrolyzing ensymes are commonly known as a. proteases b. hydrolyzers c. prodigestins d. denaturases

...

In comparison to the well-defined structure of starch, which of the following is the most important factor that allows for the synthesis of thousands of different proteins? a. number of cell ribosomes b. number of different amino acids c. availability of amino acids containing sulfur d. availability of amino acids containing hydroxyl groups

b. number of different amino acids

The weak electrical attractions within polypeptide chains account for the protein's a. primary structure b. secondary structure c. tertiary structure d. quaternary structure

b. secondary structure

After a hamburger is eaten, in what organ is the hydrolysis of its proteins initiated? a. mouth b. stomach c. small intestines d. large intestines

b. stomach

The following amino acids are linked together: glycine- lysine- valine. This compound is a a. dipeptide b. tripeptide c. polypeptide d. oligopeptide

b. tripeptide

What amino acid is classified as conditionally essential when dietary intake of phenylalanine is insufficient or the body cannot normally metabolize phenylalanine? a. cysteine b. tyrosine c. glutamine d. isoleucine

b. tyrosine

Approximately how many different amino acids are used in the synthesis of body proteins? a. 5 b. 10 c. 20 d. 35

c. 20

Which of the following is a feature of hemoglobin? a. It has not tertiary structure b. It holds the mineral calcium c. It is constructed of 4 polypeptide chains d. It has no primary or secondary structure

c. It is constructed of 4 polypeptide chains

In comparison to the composition of carbohydrates and fats, which element found in proteins makes them unique? a. Carbon b. Oxygen c. Nitrogen d. Hydrogen

c. Nitrogen

All of the following are contained in an amino acid except? a. an acid group b. an amino group c. an aldehyde group d. a central carbon atom

c. an aldehyde group

The application of heat or acid to a protein that causes its shape to change is known as a. stiffening b. condensation c. denaturation d. destabilization

c. denaturation

what is the process by which heat or acidity disrupts the noral shape of the protein chain? a. digestion b. condensation c. denaturation d. hydrogenation

c. denaturation

An example of a protein with quaternary polypeptide structure is a. insulin b. typtophan c. hemoglobin d. disulfide bridges

c. hemoglobin

What is meant by the amino acid sequence of a protein? a. number of side chains in the protein b. folding arrangement of the peptide chain c. order of amino acids in the peptide chain d. order of only the essential amino acids in the protein

c. order of the amino acids in the peptide chain

Terms used to classify amino acids in the diet include all of the following except a. essential b. nonessential c. partially essential d. conditionally essential

c. partially essential

What is the name of the inactive form of the protein- splitting enzyme in the stomach? a. peptidase b. propepsin c. pepsinogen d. propeptidase

c. pepsinogen