Deck 6: Proteins

Question 1

The chemical bond joining two amino acids is called a(n) ________ bond.

A) glycosidic
B) ionic
C) amino
D) peptide

Answer 1

D

Question 2

The ________ is the site of protein synthesis within the cell.

A) ribosome
B) nucleus
C) Golgi apparatus
D) lysosome

Answer 2

A

Question 3

An essential amino acid

A) can be synthesized in the body if there is a nitrogen source.
B) can be synthesized in the body if caloric intake is adequate.
C) cannot be synthesized in the body in sufficient quantity to meet body needs.
D) can be formed in the body from nonessential amino acids.

Answer 3

C

Question 4

Approximately how many different amino acids are used in the synthesis of body proteins?

A) 5
B) 9
C) 20
D) 29

Question 5

Leucine, isoleucine, and valine are

A) branched-chain amino acids.
B) conditionally essential amino acids.
C) limiting amino acids.
D) complementary amino acids.

Question 6

The basic building block of a protein is called a(n)

A) fatty acid.
B) monosaccharide.
C) amino acid.
D) keto acid.

Question 7

Cooking an egg alters its appearance due to

A) denaturation.
B) emulsification.
C) esterification.
D) detoxification.

Question 8

When an essential amino acid is lacking in the diet,

A) nonessential amino acids will be converted into the missing amino acid.
B) protein synthesis will be limited.
C) glucose will be converted into the missing amino acid.
D) proteins will be made, but they will lack that particular amino acid.

Question 9

Which type of anemia results from an error in the DNA code?

A) Iron-deficiency anemia
B) Megaloblastic anemia
C) Sickle cell anemia
D) Microcytic anemia

Question 10

If a food does not contain the necessary amounts of a certain amino acid to meet a body need, that amino acid is referred to as a(n)

A) complementary amino acid.
B) essential amino acid.
C) limiting amino acid.
D) dispensable amino acid.

Question 11

Which of the following is true about protein?

A) It is unique in that it is the only dietary component that contains selenium.
B) It is important primarily for increasing bone density.
C) It is made up of combinations of approximately 20 amino acids.
D) It is made up of combinations of amino acids and fatty acids.

Question 12

Treating a protein with acid, heat, or agitation will cause ________, meaning that the three-dimensional structure of the protein has been altered.

A) deamination
B) translation
C) transcription
D) denaturation

Question 13

In the case of sickle cell anemia, slight alterations in the DNA code lead to

A) defects in the membranes of red blood cells.
B) changes in the structure of the protein hemoglobin.
C) poor use of glucose for energy.
D) inability of red blood cells to make protein.

Question 14

In proteins, amino acids are joined by ________ bonds.

A) amino
B) peptide
C) proteolytic
D) nitrogen

Question 15

Which of the following is an essential amino acid?

A) Aspartic Acid
B) Cysteine
C) Arginine
D) Tryptophan

Question 16

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 appearance of amino acids in the peptide chain
D) Sequence of events in protein synthesis

Question 17

The disease phenylketonuria (PKU) illustrates how a nonessential amino acid can become conditionally essential as a result of a genetic disease. A person with PKU has a limited ability to metabolize the essential amino acid

A) phenylalanine.
B) lysine.
C) methionine.
D) ascorbic acid.

Question 18

The chemical element found in all amino acids but not found in either carbohydrates or fats is

A) carbon.
B) nitrogen.
C) oxygen.
D) hydrogen.

Question 19

Denaturation refers to

A) alteration of the three-dimensional structure of a protein.
B) digestion of a polypeptide chain into individual amino acids.
C) joining of two amino acids to form a dipeptide.
D) removal of the amino group from an amino acid.

Question 20

A hereditary condition caused by an incorrect amino acid in a protein chain is

A) kwashiorkor.
B) sickle cell anemia.
C) marasmus.
D) edema.

Question 21

Because the ________ diet is recognized as being low in meat, rich in fresh fruit and vegetables, low in added sugar, and low in saturated fat, it has been recommended as a sustainable alternative to the MyPlate dietary pattern.

A) Canadian
B) Mediterranean
C) Asian
D) European

Question 22

When there is a need for increased dietary protein during pregnancy or lactation, which of the following foods would be least desirable?

A) Eggs
B) Dried beans
C) Gelatin
D) Beef

Question 23

Which of the following is a food that provides ample amounts of all of the essential amino acids?

A) Wheat
B) Peanut butter
C) Navy beans
D) Milk

Question 24

When comparing plant sources of protein to animal sources, we could say

A) plant sources tend to be higher in saturated fat.
B) plant sources tend to be higher in cholesterol.
C) animal sources tend to be higher in phytochemicals.
D) plant sources tend to be higher in dietary fiber.

Question 25

Which of the following is true about pepsin?

A) Pepsin breaks down protein into glucose.
B) Pepsin works best in an alkaline environment.
C) Acid activates pepsin in the stomach.
D) Pepsin is secreted by the pancreas.

Question 26

High-quality proteins

A) provide ample amounts of all of the essential amino acids.
B) yield 7 kilocalories per gram.
C) cannot be used to synthesize body proteins.
D) are found only in foods of plant origin.

Question 27

Which of the following is one of the eight most common food allergens?

A) Milk
B) Chocolate
C) Beef
D) Mangoes

Question 28

What enzyme is released by the stomach to digest protein?

A) Pepsin
B) Lipase
C) Amylase
D) Trypsin

Question 29

Amino acids are absorbed via

A) active absorption.
B) passive diffusion.
C) facilitated diffusion.
D) osmosis.

Question 30

Dietary patterns that are high in ________ tend to increase the risk of cardiovascular disease and cancer.

A) legumes
B) fish
C) chicken and turkey
D) red meat

Question 31

Short chain proteins and ________ are the end products of protein digestion that can be taken up by the absorptive cells of the small intestine.

A) amino acids
B) nitrogen
C) polypeptides
D) amino groups

Question 32

Because the DNA cannot leave the nucleus to get to the ribosomes, the genes for proteins must be transcribed into ________ that can leave the nucleus.

A) amino acids
B) chromosomes
C) mRNA
D) tRNA

Question 33

Most plant proteins are ________ proteins, which means that they are low in one or more of the essential amino acids.

A) nonessential
B) complementary
C) incomplete
D) branched-chain

Question 34

Most proteins are ________, which are composed of 10 or more amino acids.

A) dipeptides
B) tripeptides
C) proteases
D) polypeptides

Question 35

Which of the following plant proteins is a complete source of protein?

A) Quinoa
B) Kidney beans
C) Sunflower seeds
D) Oats

Question 36

Amino acids are transported via the ________ vein to the liver.

A) subclavian
B) renal
C) intestinal
D) portal

Question 37

High-protein diets may be harmful for

A) individuals with kidney disease.
B) athletes.
C) the elderly.
D) body builders.

Question 38

Which of the following combinations of plant foods will provide ample amounts of all nine essential amino acids?

A) Garbanzo beans and kale
B) Black beans and rice
C) Wheat bread with sesame seeds
D) Three bean salad

Question 39

Human enzymes digest proteins in which areas of the body?

A) Mouth and stomach
B) Mouth and small intestine
C) Stomach and small intestine
D) Small and large intestines

Question 40

Many legumes are deficient in the essential amino acid ________, while grains are limited in lysine.

A) methionine
B) alanine
C) lysine
D) arginine

Question 41

Which of the following is a function of protein?

A) Absorption of vitamins A, D, E, and K
B) Medium for chemical reactions in the cell
C) The body's preferred source of energy
D) Synthesis of enzymes and hormones

Question 42

The RDA for protein translates into approximately what percentage of total daily calorie needs?

A) 5%
B) 10%
C) 15%
D) 20%

Question 43

The nitrogen from amino acid breakdown is

A) stored in the liver.
B) oxidized to carbohydrate.
C) converted to urea.
D) converted to fat.

Question 44

Food proteins are used most efficiently when we

A) consume a very-low-kilocalorie diet.
B) consume a low-carbohydrate diet.
C) consume enough carbohydrates and fats to meet our kilocalorie needs.
D) consume them with alcohol.

Question 45

How many grams of protein are needed per day by a male nonathlete weighing 87 kilograms?

A) 70
B) 87
C) 174
D) 191

Question 46

Insulin is one example of a protein that acts as

A) an antioxidant.
B) an enzyme.
C) a hormone.
D) an antibody.

Question 47

Edema appears when there is a severe lack of dietary protein because

A) sodium is retained in the body.
B) blood protein levels fall and fluid shifts into extracellular spaces.
C) the blood vessels become more permeable to ions.
D) the kidneys are unable to concentrate urine.

Question 48

A protein that acts as a hormone is

A) insulin.
B) trypsin.
C) pepsin.
D) hemoglobin.

Question 49

Which of the following describes the fate of excess protein?

A) It is stored as glycogen.
B) It is excreted via sweat glands.
C) It is stored as fat.
D) It is used for heat.

Question 50

Proteins that bind to foreign proteins in the body are

A) enzymes.
B) antibodies.
C) hormones.
D) collagen.

Question 51

Which of the following is a true statement about body proteins?

A) Body proteins are in a constant state of breakdown, rebuilding, and repair.
B) Body proteins change very little after age 20.
C) Synthesis of body proteins is directed by antigens, which are present in every cell.
D) Amino acids from dying cells or worn-out cell parts are excreted as a component of bile.

Question 52

Antibodies are

A) chemical messengers produced by glands.
B) catalysts that speed the rate of chemical reactions.
C) compounds that transport lipids through the blood.
D) proteins produced by white blood cells as part of the immune response.

Question 53

The typical American diet supplies approximately what percentage of protein as essential amino acids?

A) 25%
B) 40%
C) 50%
D) 10%

Question 54

Proteins regulate the acid-base balance of the blood by

A) acting as buffers.
B) releasing nitrogen.
C) synthesizing hydrochloric acid.
D) binding sodium ions.

Question 55

If a person does not eat enough carbohydrates to supply the glucose the body needs, which of the following will happen?

A) Fatty acids will be converted to glucose.
B) The pancreas will produce more insulin.
C) The liver will convert amino acids to glucose.
D) The liver will produce more glycogen.

Question 56

The Recommended Dietary Allowance for protein for nearly all adults is ________ g/kg/day.

A) 0.5
B) 0.8
C) 1.6
D) 2.0

Question 57

Which of the following is a true statement about the digestion and absorption of proteins?

A) Polypeptide chains are digested to yield individual amino acids, which can be absorbed into the blood.
B) Polypeptide chains are digested to yield dipeptides, which can be absorbed into the blood.
C) Many whole proteins are absorbed by phagocytosis and enter the blood.
D) The products of protein digestion are first absorbed into the lymphatic system, which empties into the blood.

Question 58

When protein consumption is in excess of body needs and energy needs are met, the excess amino acids are broken down and the energy in the molecule is

A) stored as fat.
B) excreted in the urine.
C) stored as amino acids in muscle.
D) stored as amino acids in the liver.

Question 59

Jackie is an alcoholic. Her liver has been damaged to such a degree that it cannot produce the appropriate blood proteins for fluid balance. She develops a condition called edema, which is

A) extreme thirst.
B) the buildup of fluids in extracellular spaces.
C) loss of muscle mass.
D) cardiovascular disease.

Question 60

If the carbohydrate content of the diet is insufficient to meet the body's needs for glucose, which of the following can be converted to glucose?

A) Urea
B) Fatty acids
C) Amino acids
D) Ketones

Question 61

Plant-based dietary patterns are associated with lower risk of

A) cardiovascular disease.
B) colorectal cancer.
C) diabetes.
D) All of the choices are correct.

Question 62

A vegetarian who excludes animal flesh but consumes milk and eggs is referred to as a(n)

A) lactovegetarian.
B) lactoovovegetarian.
C) vegan.
D) ovovegetarian.

Question 63

A person who does not eat any animal foods and consumes only plant products is called a(n)

A) ovovegetarian.
B) omnivore.
C) lactoovovegetarian.
D) vegan.

Question 64

A child with marasmus

A) has a bloated abdomen due to edema.
B) is hyperactive and irritable.
C) is very susceptible to infections.
D) has bowed legs and a deformed rib cage.

Question 65

Plant-based diets may reduce the risk for cardiovascular disease. This is likely due to the fact that, compared to animal sources of protein, plant sources of protein are lower in

A) dietary fiber.
B) saturated fat and cholesterol.
C) one or more essential amino acids.
D) phytochemicals.

Question 66

The most reliable source of vitamin B-12 for the vegan would be

A) fortified soybean milk.
B) shellfish.
C) cheese.
D) eggs.

Question 67

Which of the following is true about protein intake in the United States?

A) Plant sources of protein predominate in the United States.
B) We eat less animal sources of protein than people in Asia and Africa.
C) About 70% of the protein we eat in the United States comes from animal products.
D) Seafood is our main animal source of protein.

Question 68

Maggie has anorexia nervosa and regularly consumes far less energy and nutrients than she needs. She is likely to be in a state of

A) protein equilibrium.
B) positive protein balance.
C) negative protein balance.
D) positive energy balance.

Question 69

Negative protein balance is likely during

A) growth.
B) pregnancy.
C) starvation.
D) recovery from surgery.

Question 70

A vegetarian who eats only foods of plant origin is a(n)

A) lactoovovegetarian.
B) lactovegetarian.
C) vegan.
D) ovovegetarian.

Question 71

The edema in children with kwashiorkor is the result of fluid leaking into

A) body tissues from the bloodstream because of decreased blood protein levels.
B) body tissues from the bloodstream because of decreased energy levels.
C) the bloodstream from body tissues because of decreased cellular proteins.
D) the bloodstream from body tissues because of decreased energy.

Question 72

The type of malnutrition that results from severely deficient intake of both calories and protein is called

A) kwashiorkor.
B) marasmus.
C) sickle cell anemia.
D) phenylketonuria.

Question 73

Among children with kwashiorkor,

A) calorie intake may be low, but protein intake is severely deficient.
B) intakes of both calories and protein are severely deficient.
C) protein intake may be low, but calorie intake is severely deficient.
D) calorie intake may be low, but carbohydrate intake is severely deficient.

Question 74

Kwashiorkor appears in children between the ages of 2 and 5 years. The reason is that

A) growth needs are low.
B) children have been weaned from breast milk to starchy gruels.
C) by this time, adequate exposure to other children allows them to catch it.
D) protein intake has been high for a long enough time to cause kidney damage.

Question 75

Jack weighs 176 pounds. What is his RDA for protein?

A) 10 grams
B) 64 grams
C) 80 grams
D) 27 grams

Question 76

Donovan has been consuming large quantities of food and in violation of safe rules of athletic training is injecting testosterone. He has been seeing large temporary gains in muscle mass. He is in a state of

A) negative protein balance.
B) positive protein balance.
C) energy equilibrium.
D) protein toxicity.

Question 77

Recent research shows that older adults need ________ the current RDA for protein for adults.

A) more than
B) less than

Question 78

Which of the following is true about protein intake of people in the United States?

A) Most do not consume enough protein.
B) Most consume approximately the amount of protein needed to balance losses.
C) Athletes generally do not get enough protein without supplements.
D) Most consume more protein than is needed.

Question 79

Kwashiorkor and marasmus are two forms of

A) protein-energy malnutrition.
B) protein overload.
C) genetic diseases.
D) anemia.

Question 80

Which of the following conditions would describe a child with kwashiorkor?

A) Bowed legs
B) Visible eczema and cold sores
C) Edema in the abdomen and legs
D) Skin-and-bones appearance