Chapter 6

Proteins in the body are constantly being broken down and reassembled in a process called:

protein turnover.

A protein that increases the transcription of a gene in response to a specific environmental stimulus BEST exemplifies which type of protein function?

regulation

What is the protein recommendation for elderly individuals to help maintain lean body mass?

1.2 g/kg body weight

A man who weighs 176 lb and has the average intake of protein for men in the United States will consume about _____ grams more protein than his protein RDA.

36

What is the RDA for protein for Renee, a healthy nonathlete who weighs 132 lb?

48 grams

Which of these values is closest to the protein RDA for an adult athlete who weighs 132 lb?

48 grams

What is the RDA for protein for an adult who weighs 143 pounds?

52 g

At a healthy weight of 176 lb, Brian meets his RDA for protein by eating _____ grams of protein.

64

_____ provide(s) the information for the assembly of amino acids into a particular protein.

Deoxyribonucleic acid (DNA)

What distinguishes one protein from another?

Each protein has a unique sequence and type of amino acids.

Which of the following is a TRUE statement about protein denaturation?

It typically destroys the function of proteins.

Which of the following statements about protein digestion is NOT true?

Pepsin, produced by cells lining the small intestine, breaks down the denatured protein into large polypeptide fragments.

Which statement about the protein intake in the United States is true?

Protein intakes are above the RDA for most people in the United States.

What would happen if the diet lacks an essential amino acid?

Protein synthesis is limited.

If the breakdown of body proteins is reused to produce new proteins, why do we need to eat protein?

Some amino acids are metabolized.

Which of the following is TRUE in regard to protein synthesis?

The first step in protein synthesis is transcription.

Which statement about plant proteins is true?

They contain phytochemicals.

Which of the following is NOT true of complementary proteins?

They must be consumed during the same meal.

Which of the following individuals is NOT in positive nitrogen balance?

a 35-year-old man on a high-protein diet with normal levels of physical activity

One month ago, a teenage girl stopped eating animal-derived foods and now only consumes vegetables and fruits. She is now experiencing either a cold and/or an infection. This is probably due to inadequate protein intake for:

synthesizing antibodies.

In times of energy and protein abundance, the body converts the extra amino acids into:

fatty acids.

The overall shape of a protein molecule determines its:

function.

A child with kwashiorkor has a swollen belly appearance due to:

not eating enough protein to synthesize proteins needed to maintain fluid balance or transport fat from the liver.

Which of the following provides approximately 8 grams of protein?

1 cup of milk

Which of the following is NOT true of amino acids?

All amino acids are composed of an acid group, an amino group, and a carbon side chain.

What happens when a person's protein intake is inadequate?

Compounds that are critical for survival will not be synthesized.

A health food store claims that you need to buy enzyme supplements because "your body's ability to make its own enzymes has been compromised by the common diet of overprocessed food." Using your knowledge of digestion, why would it be useless to purchase enzyme supplements?

Enzymes are proteins and would be broken down into amino acids and no longer be functional.

Which statement about protein sources is true?

Essential amino acids can be supplied by consuming two or more complementary protein plant foods.

Joe eats more protein than he needs. What happens to the extra protein?

Excess amino acids are used as an energy source or stored as fat.

What happens when the albumin in the blood gets too low?

Fluid retention occurs in the extremities.

Which of the following is a TRUE statement during protein digestion?

Tripeptides are often digested after they are absorbed by mucosal cells.

Which individual is in negative nitrogen balance?

a person on a weight loss diet

How does the denaturation of protein by stomach acid (hydrochloric acid) promote protein digestion?

allows enzyme access to the peptide bonds

Amino acids consumed in excess of our needs will NOT:

be stored as proteins.

Which of the following conditions will result in negative nitrogen balance?

being confined to bed rest while healing from an injury

Which of the following will NOT cause a loss of skeletal muscle mass?

consuming only plant proteins

Which of the following protein sources will have a limiting amino acid?

corn

Short peptide fragments (about 4 to 8 amino acids in length) are typically:

digested by enzymes produced by small intestinal mucosal cells.

The majority of amino acids supplied in the diet are absorbed as:

dipeptides and tripeptides.

Which of the following would be LEAST likely to increase urea synthesis?

increased protein turnover and resynthesis

All of the following would be likely to increase urea production EXCEPT:

initiation of a weight-lifting program.

All of the following are true regarding marasmus EXCEPT:

it typically causes edema.

When Bryon was weaned from breast milk, he was fed mostly cereal cooked in water. He is at risk for:

kwashiorkor.

An increase in ammonia along with low levels of urea in blood would MOST likely indicate:

liver disease.

All of the following are true of protein turnover EXCEPT:

the diet is the source of most of the amino acids in the amino acid pool.

Two proteins contain the same number of the 20 different amino acids, yet they do not have the same three-dimensional structure and function. This is because:

the proteins differ in the sequence of amino acids in the polypeptide chain.

For which group of individuals is it important to consume complementary proteins each day?

vegans

Saul wants to add 8 grams of protein to his meal. He should select:

½ to ⅔ cup legumes.