CHAPTER 4 Test Your Knowledge
DRIVING QUESTION 1
What are the macronutrients and micronutrients provided by food?
By answering the questions below and studying Infographics 4.2 and 4.3 and Table 4.1, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
A macronutrient is
a. a nutrient with a large molecular weight.
b. a nutrient that is abundant in the diet.
c. a nutrient that is required in large amounts.
d. a nutrient that is stored in large amounts in the body.
e. a nutrient that the body makes in large quantities.
c
Which of the following is/are macronutrient(s)?
a. protein
b. iodine
c. vitamin C
d. fats
e. all of the above
f. a and d
f
A multivitamin supplement is a(n) ___________ supplement.
a. macronutrient
b. micronutrient
c. mineral
d. enzyme
e. a and b
b
Which of the following foods is a rich source of protein?
a. lean meat, such as chicken breast
b. whole grains (e.g., whole wheat bread)
c. olive oil
d. leafy greens
e. berries (e.g., blueberries and raspberries)
a
USE IT
5 Explain the difference between macronutrients and micronutrients.
Macronutrients are needed in large amounts from the diet for health. Micronutrients are also critical for health, but are needed only in small amounts from the diet.
A typical multivitamin supplement contains vitamin A, vitamin C, vitamin D, vitamin E, vitamin K, vitamin B1, vitamin B2, vitamin B6, biotin, calcium, iron, magnesium, zinc, selenium, copper, manganese, and chromium. Explain your answers to the following questions.
a. Are all of these vitamins? If there are ingredients that are not vitamins, what are they?
b. Are all of these micronutrients?
a: Not all of these are vitamins. Calcium, iron, magnesium, zinc, selenium, copper, manganese and chromium are minerals. b: Yes. They are all micronutrients (nutrients needed only in small quantities in the diet).
DRIVING QUESTION 2
What are essential nutrients?
By answering the questions below and studying Infographics 4.3 and 4.5 and Table 4.1, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
What subunits are proteins broken down into during digestion?
a. fatty acids
b. amino acids
c. glycerol
d. nucleotides
e. simple sugars
b
Where (or how) do we obtain essential amino acids?
a. from carbohydrates in our diet
b. by synthesizing them from other amino acids
c. from oils in our diet
d. from bright orange fruits and vegetables
e. from protein in our diet
e
USE IT
Our bodies cannot synthesize vitamin C, but requires it. Therefore, vitamin C is
a. an essential micronutrient.
b. an essential mineral.
c. an essential macronutrient.
d. a nonessential vitamin.
e. a nonessential amino acid.
a
Which component of peanut butter RUTF supplies essential amino acids?
a. milk powder
b. peanut butter
c. sugar
d. vegetable oil
e. powered vitamins and minerals
f. a and c
a
Corn lacks the essential amino acids isoleucine and lysine. Beans lack the essential amino acids tryptophan and methionine. Soy contains all the essential amino acids.
a. Could someone survive on a diet with a corn-based protein alone? Why or why not?
b. Why do many traditional diets combine corn (e.g., tortillas) with beans?
c. Why did one of the home-based feeding therapies in Malawi combine soy flour with corn flour?
a: No. They would be lacking the essential amino acids isoleucine and lysine, which our bodies cannot make. b: Traditional diets that combine corn and beans (e.g., in a meal of tortillas and beans) provide all the essential amino acids. The beans provide the essential amino acids lacking in corn, and the corn provides the essential amino acids lacking in beans. c: Corn and soy are traditional foods in Malawi, and so would be familiar. Also, while soy contains all the essential amino acids, the starchy corn flour adds another source of carbohydrates.
DRIVING QUESTION 3
What are enzymes, and how do they work?
By answering the questions below and studying Infographics 4.4, 4.5, and 4.6, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
The substrate of an enzyme is
a. an organic accessory molecule.
b. the molecule(s) released at the end of an enzyme-facilitated reaction.
c. the shape of the enzyme.
d. one of the amino acids that makes up the enzyme.
e. what the enzyme acts on.
e
Compare and contrast enzyme cofactors and coenzymes.
Both help enzymes speed up their reaction rates. Cofactors are typically inorganic metals, while coenzymes are organic molecules, such as vitamins.
Enzymes speed up chemical reactions by
a. increasing the activation energy.
b. decreasing the activation energy.
c. breaking bonds.
d. forming bonds.
e. releasing energy.
b
How is folate (folic acid) best described?
a. as a substrate of an enzyme
b. as a nucleotide
c. as an organic cofactor (coenzyme)
d. as an enzyme
e. a and b
c
USE IT
If the shape of an enzyme's active site were to change, what would happen to the reaction that the enzyme usually speeds up?
If the shape of the active site were to change, the reaction would likely decrease (or completely slow to 0). If the active site changes shape, the substrate cannot properly enter the active site, and the enzyme cannot catalyze the reaction.
Considering the function of folate (folic acid) given in Infographic 4.6, why would you say pregnant women (and women who could become pregnant) should ensure that they have adequate levels of folate in their diets?
Folate is essential for DNA replication, and DNA must be replicated every time a cell divides. An embryo (and later fetus) grows from a single fertilized egg through many rounds of cell division, each round adding new cells to the growing embryo. If the mother is folate deficient, the embryo will not grow properly, and so folate deficiency can lead to birth defects.
DRIVING QUESTION 4
What are the consequences of a diet lacking sufficient nutrients?
By answering the questions below and studying Infographics 4.1, 4.6, and 4.7 and Table 4.1, you should be able to generate an answer for the broader Driving Question above.
KNOW IT
When vitamins are consumed:
a. Why are there no problems of excess for vitamin C but there are for vitamin E?
b. If you were to take a supplement with a high amount of vitamin C, what would happen to all that vitamin C? Would it all be used? Would some of it be stored in your body?
a: Vitamin C is water soluble, so any excess is removed from the body in the urine. Vitamin E is fat soluble, so excess is stored in fatty tissues in the body, possibly accumulating to toxic levels. b: High levels of vitamin C supplementation will not lead to storage of vitamin C in the body. Any excess over what is needed is excreted from the body, dissolved in the urine.
What ingredients in RUTF peanut paste specifically help bone growth? (Hint: Refer to Table 4.1.)
a. calcium
b. vitamin D
c. potassium
d. all of the above
e. a and b
e
INTERPRETING DATA
Infographic 4.7 shows the results of a study examining three different home-based therapies for malnourished children.
a. From the data shown, how many of all the children in the study reached full catch-up growth?
b. What percentage of the children in the study does this number represent? How does this compare to previous recovery rates of 25%–40% for children who had received standard hospital therapy?
The children who received the RUTF were given enough of it to supply 730 kJ of energy per kg of body weight. This is sufficient energy to meet their needs.
c. A malnourished 2-year-old girl weighs a mere 6 kg (~13 pounds). If she had been in the RUTF group in the study, how many daily kJ would she have obtained from the RUTF?
d. If the same malnourished 2-year-old had been in the RUTF supplement group, she would have received 2,100 kJ per day from the supplement. What percentage of her daily energy needs would this represent? (Hint: Use your answer to part c.)
e. Children in the RUTF supplement group ate a traditional diet of corn/soy flour to make up the rest of their diet. Corn/soy flour contains 4 kJ per gram. How many grams of the traditional mix would this 2-year-old need to consume (on top of the RUTF supplement) to meet her daily needs?
a: (95% of 69 = 69) + (78% of 96 = 75) + (78% of 117 = 91) = 232. Overall, 232 children reached full catch-up growth. b: 232 children reaching catch-up growth out of 282 children in the study represents ~82% of the children in this study. This rate is between two and three times higher than the 25%–40% rate for standard hospital therapy. c: She would have received (6 kg × 730 kJ/kg) = 4380 kJ per day of the RUTF. d: 2100 kJ from a supplement is only 47.9% of her daily energy needs. e: She would need to obtain another 2280 kJ per day from the corn/soy flour to meet her energy needs. This represents 570 g of the soy/flour per day on top of the RUTF supplement.
MINI CASE
A college student returns home at the end of the school year. His mother is shocked by the large number of unhealed scrapes and sores on his knees and arms. She also notices that he has put on a few pounds. The student tells his mother that the scrapes are just left over from a skateboarding mishap a few weeks ago and that he guesses he could cut back on some of his snacks. A week after coming home, he goes to the dentist for his yearly checkup. The dentist is alarmed by his bleeding and swollen gums. When asked about his diet, the student notes that he and some of his friends challenged one another to see who could go the longest eating nothing but eggs, mac “n' cheese, and toast with butter. He proudly announces that he had stayed on this diet for 6 months.
a. Could this student be suffering from malnutrition? Explain your answer.
b. What mineral(s) or vitamin(s) (or both) are you most concerned about, given the symptoms noted by the dentist?
c. What dietary recommendations would you make for this student?
a: Yes. While his caloric intake is sufficient, he is more than likely missing essential micronutrients (and probably fiber as well). b: The bleeding gums and wounds that are slow to heal are consistent with scurvy, which results from a deficiency of vitamin C. This is consistent with his current diet, which appears not to provide any fruit or vegetables. c: This student needs to increase his intake of most micronutrients. In the short term, he should consider a multivitamin/mineral supplement. In the longer term, a more varied diet that includes more fruits and vegetables (and more colors in general) will help provide micronutrients needed for good health.
BRING IT HOME
Is malnutrition solely a problem in developing countries? Do some investigative research on at least two food-aid programs, local, federal, or international. What criteria would you consider before deciding to donate money to a food-aid program? Explain your answer.
Malnutrition is not limited to developing countries. According to Johns Hopkins Children’s Center, approximately 1% of children in the United States are chronically malnourished. Answers about donations will vary with respect to specific programs and criteria for donations.