Proteins

The DRI committee set an upper limit for protein of no more than ________ percent of total calories. a. 10 b. 35 c. 25 d. There is no upper limit for protein.

35.The DRI committee set an upper limit for protein intake of no more than 35 percent of total calories, an amount significantly higher than average intakes. See page 206

Using the DRI recommendation of 0.8 g/kg, calculate the protein requirement of a 150-pound individual. a. 120 grams b. 54 grams c. 150 grams d. Not enough information to calculate.

54 grams. By converting pounds to kilograms (dividing pounds by 2.2 first and then multiplying by 0.8), you can determine the total grams of protein recommended. See page 206

Typical vegetarian diets contain adequate amounts of ________. a. vitamin B12 b. fiber c. zinc d. iron

As discussed on page 222, a typical vegetarian diet contains an adequate amount of carbohydrate, fiber, thiamin, folate, vitamin B6, vitamin C, vitamin A, and vitamin C. However, vegetarian diets may be low in protein, iron, zinc, calcium, vitamin D, vitamin B12, and omega-3 fatty acids.

How much protein per day should a 180-pound, 20-year-old individual who is not a vegetarian and who is no longer growing in a vertical direction consume to meet their daily needs? a. about 144 grams b. about 317 grams c. about 65 grams d. about 82 grams

As explained on page 205, the recommended need for protein is 0.8 grams of protein per kilogram of body weight. Since there are 2.2 pounds per kilogram: (180 pounds / 2.2 kg per pound) x 0.8 gr of protein per kg of body weight = 65 gr of protein..

What type of protein helps to maintain electrolyte balance in the body? a. clotting proteins b. antibodies c. enzymes d. transport protein

As explained on pages 201-202, transport proteins help with electrolyte balance by moving these substances in and out of cells to maintain the composition of body fluids.

All of the following individuals are in nitrogen equilibrium EXCEPT: a. a young retiree. b. a teacher. c. a college student. d. a child.

Child. Growing children add new blood, bone, and muscle cells to their bodies every day, so children must have more protein and therefore more nitrogen at the end of each day, making them in positive nitrogen balance. See pages 208-209

All of the following are correct about protein digestion and enzymes EXCEPT: a. Protein digestion doesn't begin until it reaches the stomach. b. Once absorbed, amino acids are carried to the liver. c. Enzymes from the pancreas and the intestine split peptide strands into tripeptides, dipeptides, and amino acids. d. Enzyme pills can be taken to aid digestion of foods.

Enzyme pills can be taken to aid digestion of foods.

Where in a cell are the directions for making every protein? a. proteins b. cytoplasm c. DNA d. RNA

Every cell nucleus contains the DNA for making every protein. See page 194

Recommendations for protein intake assume a diet that consists of animal protein only. a. True b. False

False

Every cell in the body makes every human protein possible. a. True b. False

False. Cells are specialized in synthesizing particular types of proteins. See page 190

In general, amino acids from plant proteins are most easily digested and absorbed. a. True b. False

False. In general, amino acids from plant proteins vary in digestibility and absorption from 70 to 90 percent, compared to amino acids from animal proteins at over 90 percent. See page 209

All hormones are proteins. a. True b. False

False. Some hormones, but not all, are proteins or are made from amino acids. See page 200

Which of the following CANNOT denature a protein? a. heat b. mercury c. stomach acid d. freezing

Freezing does not denature proteins. Consider the effects of freezing on animal proteins. See page 196

All of the following are true concerning protein and amino acid supplements EXCEPT: a. No level of amino acid supplementation can be assumed safe. b. Protein supplements do not improve athletic performance beyond the gains from well-timed meals of ordinary foods. c. In the skilled hands of clinical dietitians, formulas with supplemental protein or amino acids may help to reverse malnutrition in some critically ill patients. d. People with chronic or acute mental or physical illnesses should take amino acid supplements

Protein supplements do not improve athletic performance beyond the gains from well-timed meals of ordinary foods

In which of the following situations are amino acids NOT wasted? a. The body has too much of any single amino acid, such as from a supplement. b. The diet supplies sufficient protein of high-quality essential amino acids. c. The body does not have enough energy from other sources. d. The body has more protein than it needs

The diet supplies sufficient protein of high-quality essential amino acids.

How does the body use amino acids to build proteins? a. Inside a cell, tRNA brings amino acids to a ribosome and lines them up in the sequence dictated by mRNA, so that they can be strung together to make a protein. b. Inside a cell, mRNA brings amino acids to a ribosome and lines them up in the sequence dictated by tRNA, so that they can be strung together to make a protein. c. Inside a cell's nucleus, tRNA brings amino acids to a ribosome and lines them up in the sequence dictated by mRNA, so that they can be strung together to make a protein. d. Inside a cell, ribosomes bring amino acids to mRNA and lines them up in the sequence dictated by tRNA, so that they can be strung together to make a protein.

The functions of mRNA and tRNA are mixed up in this choice. mRNA is manufactured in a cell's nucleus, using DNA as a template, as illustrated in Figure 6-6 (page 196). The mRNA then leaves the nucleus and attaches to ribosomes. tRNA carries amino acids to the ribosomes, where they are bonded to one another by an enzyme to form a growing protein. mRNA specifies the specific sequence of amino acids in the protein being manufactured.

All of the following are correct concerning proteins and protein structure EXCEPT: a. standard amino acid sequences exist for each protein. b. strands of protein do not remain a straight chain. c. some protein strands cluster together in order to become functional. d. peptide bonds give the protein molecule its unique character.

The side chains of amino acids bristle out from the backbone of the structure, giving the protein molecule its unique character. A peptide bond connects one amino acid with another, forming a link in a protein chain. See pages 190-191

Protein-energy malnutrition is the most widespread form of malnutrition in the world today. a. True b. False

True.

In human beings, a high-protein diet worsens existing kidney problems. a. True b. False

True. Overconsumption of proteins offers no benefits and may pose health risks for the heart, for weakened kidneys, and for bones. See page 213

There is a possible correlation between high intakes of meats and some types of cancers. a. True b. False

True. While the effects of protein on cancer causation cannot be easily separated from the various foods providing protein, some population studies suggest a moderate increased risk between well-cooked red meats and processed meats and cancers of the colon and rectum. See page 214

When kwashiorkor occurs, the victim's belly often bulges with a fatty liver and edema. a. True b. False

True.Edema and an enlarged liver secondary to a fatty liver are characteristic of kwashiorkor. See pages 211-212

Kwashiorkor may result from too little protein to support body functions. a. True b. False

True.Kwashiorkor is a disease related to protein malnutrition, with a set of recognizable symptoms, such as edema. See pages 210, 211-212

The body can use the amino acid tryptophan as the starting point for the manufacture of ________. a. vitamin C b. zinc c. niacin d. ATP

Tryptophan can be used to make the neurotransmitter serotonin and the vitamin niacin.

Which of the following will occur if an essential amino acid is unavailable for more than a day? a. The cells will increase their use of amino acids for fuel. b. The cells will increase the breakdown of their working protein. c. The cells will limit the breakdown of their working protein and reduce their use of amino acids for fuel. d. The cells will make the amino acid.

Within a single day of restricted intakes of an essential amino acid, the cells begin to conserve it by limiting the breakdown of their working proteins and by reducing the use of amino acids for fuel. See page 208

All of the following are true concerning vegetarian diets EXCEPT: a. Pregnant women following a vegan diet can easily meet their B12 requirements through a variety of legumes and nuts. b. Vegetarians have significantly lower rates of certain cancers than the general population. c. Vegetarians tend to weigh less than nonvegetarians. d. People consuming plant-based diets die less often from heart disease than do meat-eating people.

a. Vitamin B12 is found naturally only in animal-derived foods, such as meats, milk, and eggs, foods that vegans do not consume. For a reliable supply, vegans would use vitamin B12-fortified foods. See page 221

Proteins must be digested to ________ for absorption across the small intestine to occur. a. amino acids b. tripeptides c. monosaccharides d. dipeptides

amino acids. The cells along the small intestine absorb single amino acids. See pages 198, 199

Before an amino acid is converted to glucose or broken down for energy, the ________ must be removed. a. acid group b. amino group c. side chain d. phosphate group

amino group. when protein is broken down for energy or used to make glucose, the nitrogen-containing amino groups of their amino acids are removed.

Which of the following would, by itself, meet a person's essential amino acid need? a. rice b. beans c. legumes d. an egg

an egg

Which is NOT an example of mutual supplementation? a. minestrone soup (noodles and legumes) b. beans and tortillas c. a peanut butter sandwich d. bagel and jam

bagel and jam. Jam is a carbohydrate and provides no protein to complement the amino acids found in the bagel. See pages 208, 209

In addition to enzymes, the digestion of lipids requires ________ and the digestion of proteins requires ________. a. acid; bile b. bile; bile c. acid; acid d. bile; acid

bile; acid

Under low-carbohydrate conditions the body converts protein to glucose to primarily serve the needs of ________. a. the brain b. the large intestine c. muscle d. enzymes

brain. Protein can be converted to glucose as to meet the brain's need for this source of energy.

Why must proteins be denatured during the digestion process? a. Because they are water insoluble and will clump together in watery body fluids b. Because the peptide bonds holding amino acids together are extremely strong c. Because the strands of amino acids in a protein are coiled and folded into a complex structure d. Because the food proteins that are enzymes help to digest other proteins

c. As explained on pages 196-197, the enzymes in foods (or dietary supplements) cannot aid digestion because they are completely broken down into amino acids before they are absorbed, not absorbed whole. In fact, the denaturation that occurs when such proteins reach the stomach destroys their functionality, which depends on their shape. As discussed on page 191 and seen in Figure 6-3 (page 192),the amino acids in proteins are first strung into chains, and then coil and fold into distinct shapes as the amino acids in different segments of the chain are attracted to or repelled from one another. As discussed on pages 196-197, the first step in the digestion of a protein is to denature it, to open up the coiled/folded shape, so that digestive enzymes can get at the peptide bonds between the amino acids and cleave them.

In contrast to meat-eaters, both lacto-ovo vegetarians and vegans are at lower risk of ________. a. PEM b. cancer c. kwashiorkor d. anemia

cancer. As discussed on pages 220-221, people who eat meat, especially red meat, are at greater risk of cancer than those who do not eat meat.

Which of the following is NOT, primarily, composed of amino acids? a. enzymes b. antibodies c. cell membranes d. hair

cell membranes

Which of the following foods has the highest amount of protein? a. 1/2 cup corn b. 1/2 cup strawberries c. 2 oz. chicken breast d. They all have the same amount of protein.

chicken breast. A 2 oz. serving of chicken breast, like most meats, contains 15 grams of protein. See pages 214-215

We can state with a high degree of confidence that ________ the consumption of protein in amounts well above current recommendations. a. cancer is a consequence of b. adult bone loss is a consequence of c. kidney damage is a consequence of d. there are no specific adverse health consequences that can be directly attributed to

d. there is evidence for adverse consequences when most of the protein is from red meat and/or dairy products. However, it is not known if this is due to the protein itself or the types of fat that are associated with these foods.

Which of the following would NOT be eaten by a lactovegetarian? a. milk b. beans c. nuts d. eggs

eggs. The only animal proteins consumed by lactovegetarians are dairy products. See page 219

Which of these is/are the healthiest animal or animal product source of protein? a. kale b. red meat c. fish or eggs d. pork chops and pork ribs

fish or eggs. While consuming red meat will meet the need for protein such meals are usually accompanied by a high intake of fat, with much of the fat being saturated fat. (The same is true for pork.) As discussed on pages 213-214, people who consume animal flesh and animal products such as eggs usually do not have difficulty meeting their need for protein nor do they have difficulty meeting their essential amino acid needs. In addition, recall from Chapter 5 that fish are an excellent source of essential fatty acids. Of the choices listed, fish and eggs are the healthiest animal protein sources.

In contrast to lacto-ovo vegetarians, vegans are at greater risk of not meeting their need(s) for ________. a. vitamin C b. iron, zinc, and vitamin B12 c. folate d. vitamin A

iron, zinc and vitamin B12. As seen in Figure 2-5 (page 38), the fruit and vegetable groups are good sources of vitamin C, so a vegan would not be at a greater risk of vitamin C deficiency. On the other hand, plant products, unlike animal products, are not rich in iron, zinc, or vitamin B12, making these problem nutrients for vegans but not lacto-ovo vegetarians.

All of the following are characteristics of a vegetarian diet EXCEPT: a. it provides more phytochemicals. b. it promotes a leaner body type. c. it provides more antioxidant nutrients and fiber. d. it provides more saturated fat.

it provides more saturated fat. Vegetarian diets rich in whole grains, legumes, nuts, fruits, and vegetables provide less saturated fat. See page 220

Most of the products of the digestion of lipids are absorbed into ________; the products of protein digestions are absorbed into ________. a. lymph; capillaries b. capillaries; capillaries c. lymph; lymph d. capillaries; lymph

lymph; capillaries

Both lacto-ovo vegetarians and vegans are at risk of not having sufficient ________ in their diet. a. fiber b. magnesium c. omega-3 fatty acids d. potassium

omega-3 fatty acids. As discussed on page 222, vegetarian diets may be lacking in omega-3 fatty acids. Good vegetarian sources of omega-3 fatty acids include soybeans, canola oil, and sea vegetables.

When carbohydrate is lacking the body can convert ________ into glucose. a. proteins b. vitamins c. fatty acids d. minerals

proteins

All of the following are important roles proteins play in the body EXCEPT: a. maintaining acid-base balance. b. maintaining fluid and electrolyte balance. c. serving as antibodies. d. providing an unlimited supply of energy.

providing an unlimited supply of energy. Glucose is the body's preferred source for energy; protein helps to maintain a steady blood glucose level and serve the glucose need of the brain only under the conditions of inadequate energy or carbohydrate. See page 203

Which of the following is the richest source of amino acids? a. apples b. broccoli c. red meats d. whole-grain bread

red meats

The variable part of an amino acid is the: a. acid group. b. side chain. c. amino group. d. backbone.

side chain. Each amino acid has a distinctive chemical side chain attached to the center carbon of the backbone that gives identity and chemical nature to each amino acid. See page 190

Most lipid digestion occurs in the ________ and most protein digestion occurs in the ________. a. mouth; small intestine b. small intestine; large intestine c. small intestine; small intestine d. large intestine; large intestine

small intestine; small intestine

When carbohydrate and fat are lacking in the diet the body is forced to break down protein for energy. Which of the following is first to be broken down for energy? a. pancreatic proteins b. large muscle proteins c. liver proteins d. small proteins from the blood and muscle

small proteins from the blood and muscle. small proteins from the blood and muscle are the first to be broken down when the body is starved for energy and/or the diet lacks carbohydrate and fat. Breaking down small proteins in the blood and muscle conserves the structural proteins of the heart and other organs.

Which of the following foods contains proteins with the same quality as meat? a. whole-wheat bread b. soy c. rice d. broccoli

soy. For practical purposes, the quality of soy protein can be considered equivalent to that of meat. See page 215

By consuming ________ a vegan can meet their protein needs. a. black beans b. soybean products c. rice d. legumes

soybean. As discussed on page 208, most soybean products contain enough of the essential amino acids to meet the needs of a vegan.

Enzymes are a type of protein that function ________. a. as structural components of lipoproteins b. as structural components of cells c. to transport substances within the blood d. to speed up the rate of chemical reactions

to speed up the rate of chemical reactions

To which of the following individuals are complementary proteins important? a. vegans b. lacto-ovovegetarians c. lacto-vegetarians d. partial vegetarian

vegans?

All of the following are correct concerning iron intakes of vegetarians EXCEPT: a. the DRI committee suggests that vegetarians need 1.8 times the amount of iron recommended for the general population. b. vegetarians experience iron deficiency more than non-vegetarians do. c. iron absorption can be enhanced by vitamin C. d. the iron in plant foods is poorly absorbed.

vegetarians experience iron deficiency more than non-vegetarians do. Vegetarians suffer no more iron deficiency than other people do. See pages 222-223