Deck 6: Protein: Amino Acids

Question 1

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 synthesized by the body because of a genetic defect

Answer 1

B

Question 2

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

Answer 2

C

Question 3

What is the composition of a tripeptide?

A)one amino acid with three carbons
B)three amino acids bonded together
C)one amino acid with three acid groups
D)three small protein chains bonded together

Answer 3

B

Question 4

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

Question 5

A common genetic variation that causes a change in the amino acid sequence in the structure of hemoglobin leads to the disease ____. ​

A)diabetes
B)marasmus
C)phenylketonuria
D)sickle-cell anemia

Question 6

What class of macromolecule is an enzyme? ​

A)carbohydrate
B)lipid
C)protein
D)nucleic acid

Question 7

What is a ribosome? ​

A)a template for protein synthesis
B)a hard knot of subcutaneous protein mass
C)a structure upon which proteins are assembled
D)an antibody synthesized by specialized immune cells

Question 8

Cells are able to synthesize thousands of different proteins due to the ____.

A)unlimited availability of essential amino acids
B)number of different amino acids
C)availability of amino acids containing sulfur
D)availability of amino acids containing hydroxyl groups

Question 9

Where does protein digestion begin in the human body?

A)mouth
B)stomach
C)small intestine
D)large intestine

Question 10

Protein-hydrolyzing enzymes are commonly known as ____. ​

A)proteases
B)hydrolyzers
C)prodigestins
D)denaturases

Question 11

The weak electrical attractions within polypeptide chains account for the protein's ____ structure.

A)primary
B)secondary
C)tertiary
D)quaternary

Question 12

What is an example of protein denaturation?

A)the formation of a scab over a wound
B)the change occurring in an enzyme to promote catalysis of a chemical reaction
C)the alteration of the protein structure in hydrochloric acid
D)the activation of protein synthesis after changes in gene expression

Question 13

What is the tertiary structure of a protein?

A)the structure of the protein after post-translational modifications have occurred
B)the structure of the protein determined by electrostatic interactions
C)the structure of the protein determined by hydrophobic and hydrophilic interactions
D)the structure of the protein including multiple protein subunits

Question 14

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

Question 15

The process whereby messenger RNA is made from a DNA template is known as ____. ​

A)expression
B)sequencing
C)transcription
D)ribosome assembly

Question 16

What is the chief function of pepsin?

A)​It  e mulsifies dietary proteins.
B)​It  activates hydrochloric acid.
C)​It  activates pancreatic proteases.
D)​It  cleaves proteins into smaller polypeptides.

Question 17

What percentage of dietary protein is hydrolyzed in the mouth? ​

A)​0
B)5-10
C)15-20
D)25-30

Question 18

What is the usual fate of orally ingested enzyme supplements? ​

A)digested by gastrointestinal proteases
B)rapidly degraded by salivary secretions
C)mostly absorbed in original form from the stomach
D)completely absorbed in original form from the jejunum

Question 19

What 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 atoms

Question 20

After digestion of proteins, what products are absorbed into the circulation? ​

A)free amino acids only
B)free amino acids and oligopeptides
C)free amino acids and dipeptides only
D)free amino acids and a few dipeptides and tripeptides

Question 21

What is a characteristic of hormones?

A)inactivate bacteria
B)act as messenger molecules
C)coordinate visual responses
D)act as buffers in the bloodstream

Question 22

What is a consequence of excess protein intake? ​

A)decreased excretion of calcium
B)decreased size of the liver and kidneys
C)increased production and excretion of urea
D)increased protein storage by the liver and kidneys

Question 23

What is the amino acid pool?

A)the total amino acid content derived from a 24-hour dietary intake
B)a measure of the circulating essential amino acid levels available for protein synthesis
C)the total amount of free amino acids in the circulation destined for deamination and excretion
D)a mix of essential and nonessential amino acids derived from protein breakdown and dietary protein intake

Question 24

How do protein rich foods contribute to weight gain? ​

A)High protein diets are also often high in saturated fats, which is what leads to weight gain.
B)High protein diets increase absorption of lipids in the small intestine.
C)High protein diets often prevent fiber from removing excess fats in the small intestine.
D)High protein diets can lead to an excess of amino acid being converted into fat.

Question 25

A patient with acidosis may have a pH of ____.

A)​7.3
B)​7.35
C)​7.4
D)​7.45

Question 26

Your father, who has a high blood ammonia concentration, most likely has a poorly functioning ____. ​

A)liver
B)spleen
C)kidney
D)intestinal tract

Question 27

What are the two products of deamination? ​

A)ammonia and keto acid
B)amino acid and keto acid
C)ammonia and an amino acid
D)urea and a keto acid

Question 28

Edema is caused by ____.

A)a decrease in protein loss
B)an increase in protein synthesis
C)excessive dietary protein
D)negative protein balance

Question 29

How do proteins function as regulators of blood pH?

A)Proteins react with acids to produce uric acid, which can be excreted.
B)Proteins bind hydrogen ions to prevent them from altering blood pH.
C)Proteins attract acids out of the blood stream and into cells.
D)Amino acids that are highly acidic or basic are specifically excreted.

Question 30

What are the products of transamination? ​

A)ammonia and keto acid
B)amino acid and keto acid
C)ammonia and an amino acid
D)urea and a keto acid

Question 31

Why do proteins often function as carriers for lipids in the blood? ​

A)Proteins are required to activate pumps for lipids to gain entry into cells.
B)Proteins prevent the lipids from being recognized as foreign to avert an immune response.
C)Proteins in the carriers begin the digestion process as they move through the blood.
D)Proteins protect the hydrophobic regions of the lipids to allow easy transport through the blood.

Question 32

In the metabolism of amino acids for energy, what is the fate of the amino group? ​

A)excreted as urea
B)burned for energy
C)stored in the liver
D)converted to glucose

Question 33

What amino acid is used to synthesize the neurotransmitter serotonin and the vitamin niacin?

A)glycine
B)tyrosine
C)methionine
D)tryptophan

Question 34

What is opsin?

A)an antigen
B)an antibody
C)light-sensitive protein
D)a blood transport protein

Question 35

A person who is starving is losing ____. ​

A)fat only
B)glycogen only
C)glycogen and fat only
D)glycogen, protein, and fat

Question 36

What is the fate of excess dietary protein? ​

A)After absorption, the liver will store the extra amino acids.
B)After absorption, the extra amino acids will be rapidly degraded.
C)Digestion will be decreased by 30 to 60 percent, resulting in less absorption.
D)After absorption, extra proteins will be synthesized and stored for use when protein intake returns to normal.

Question 37

What is the usual state of nitrogen balance for healthy infants, children, and pregnant women? ​

A)equilibrium
B)metabolic
C)positive
D)negative

Question 38

A result of transamination reactions is the synthesis of ____.

A)essential amino acids
B)nonessential amino acids
C)neurotransmitters and hormones
D)both nonessential and essential amino acids

Question 39

Jason is 35 years old and was recently diagnosed with two failing kidneys. He was advised to decrease the amount of protein he consumes. If Jason cheats by eating an 8-ounce steak for dinner tonight, shortly thereafter there would most likely be an increase in the urea levels of his ____.

A)urine
B)blood
C)stools
D)sweat

Question 40

When amino acids are deaminated, the immediate products are ammonia and often a ____ acid.

A)uric
B)keto
C)folic
D)gluco

Question 41

The cell's proteome consists of ____.

A)all nucleotide bases
B)all the protein in the cell
C)the ratio of DNA to RNA
D)the protein metabolic apparatus

Question 42

What is an assumption made in the formulation of the RDA for protein? ​

A)Dietary protein is of high quality only.
B)Dietary protein is of animal origin only.
C)Dietary carbohydrate and fat intakes are adequate.
D)Dietary protein should represent 12 percent of total energy.

Question 43

Alberta is a 20-year-old who has been a vegetarian for three years. She comes to you for advice after reading some material online by the Meat Promoters of America organization. One of their statements is "...vegetarians are at risk for protein deficiency because they cannot consume all of the essential amino acids necessary for healthy individuals." How should Alberta be advised? ​

A)She should consume dairy and egg products at every meal to protect herself against protein deficiency.
B)She should avoid the "limiting" amino acids because they are limiting her ability to maintain proper protein status.
C)Because the statement is basically true, she should consider eating small quantities of meat every day in order to avoid protein deficiency.
D)Although many foods don't provide all the essential amino acids individually, she could consume complementary proteins throughout the day, which would provide all the essential amino acids she needs.

Question 44

What is the percentage of total energy derived from protein in a diet containing 50 grams of protein and 2000 kcalories? ​

A)​2.5
B)​5
C)​10
D)​20

Question 45

What is a feature of protein nutrition? ​

A)Protein in body tissues is preserved fairly well on low-energy diets.
B)The protein RDA assumes that dietary protein is from a mix of low- and high-quality sources.
C)Many people in the United States and Canada consume somewhat less protein than is needed.
D)Athletes in training benefit from increasing their protein energy intake to 45 to 50 percent of total daily energy.

Question 46

What is a feature of the branched-chain amino acids? ​

A)They are all dispensable amino acids.
B)They suppress ammonia production if taken in large doses.
C)They represent the major energy source for muscle tissue.
D)They may be helpful in treatment of advanced liver failure.

Question 47

The disease phenylketonuria is related chiefly to abnormal metabolism of ____. ​

A)lactose
B)omega-3 fats
C)soy polysaccharides
D)a certain amino acid

Question 48

Which statement describes a relationship between protein intake and calcium metabolism?

A)Calcium excretion falls with increasing intake of animal-derived proteins.
B)Calcium excretion rises with increasing intake of animal-derived proteins.
C)Calcium absorption declines with higher intakes of plant-derived proteins.
D)Calcium absorption increases with higher intakes of animal-derived proteins.

Question 49

What is the percent digestibility of most plant proteins?

A)25-45
B)50-65
C)70-90
D)95-99

Question 50

Which food protein has the best assortment of essential amino acids for the human body? ​

A)egg
B)​rice
C)​corn
D)​gelatin

Question 51

What is a feature of the protein RDA?

A)The recommendations are generous.
B)It is highest proportionately for adult males.
C)It is established at 8 grams per kilogram of ideal body weight.
D)An assumption is made that dietary protein is from animal sources only.

Question 52

Relative to animal proteins, which amino acid is present in lesser amounts in proteins of legumes?

A)alanine
B)isoleucine
C)tryptophan
D)glutamic acid

Question 53

Excessive amounts of homocysteine in the blood are thought to increase the risk for ____. ​

A)cancer
B)diabetes
C)heart disease
D)protein-energy malnutrition

Question 54

What amino acid supplement has been advertised in the popular media for treating herpes infections? ​

A)lysine
B)arginine
C)tryptophan
D)phenylalanine

Question 55

Which statement describes an association between protein intake and kidney function? ​

A)Low-protein diets increase the risk for kidney stone formation.
B)Restricting protein intake may slow the progression of kidney disease.
C)High protein intakes over the long term represent a risk factor for kidney disease.
D)Liberal protein intakes result in high urea production, which increases the long-term efficiency of the kidneys.

Question 56

If protein needs are expressed per kilogram of body weight, what describes the requirements of infants?

A)less than adults
B)similar to adults
C)greater than adults
D)less than adolescents

Question 57

If the diet is lacking an essential amino acid, what will be the course of action? ​

A)Body cells will synthesize it.
B)Protein synthesis will be limited.
C)Health will not be affected as long as other nutrients are adequate.
D)Proteins will be made but they will lack that particular amino acid.

Question 58

Which factor is related to the quality of a food protein? ​

A)essential amino acid balance
B)nonessential amino acid balance
C)total amino acids per gram of food
D)quantity of nonessential amino acids that can be converted to glucose

Question 59

Jim, a college baseball player, tells you that he has started to take glutamine supplements. How would you advise him? ​

A)As long as he keeps the dose under 10 grams per day, the benefits outweigh the costs.
B)Since he plays baseball, he should consider taking alanine supplements instead.
C)Since he plays baseball, he should consider taking tryptophan supplements instead.
D)Since single amino acids do not occur naturally in foods, they offer no benefit to the body and may even be harmful.

Question 60

The study of how food interacts with genes is known as ____. ​

A)nutritional genomics
B)chromosomals
C)nucleotide expression
D)mutagenic expression

Question 70

What dispensable amino acid becomes essential in people with PKU? ​

A)glycine
B)tyrosine
C)arginine
D)glutamine

Question 75

The cellular process of silencing or activating genes is in part accomplished by ____.

A)DNA methylation
B)multigene genomics
C)translational sequencing
D)a transcription-translation cycle