Question 1

The nutritional disease kwashiorkor, in which the body starts to metabolize some of the molecules of its own body, results from a(n)

Accepted Answer

Kwashiorkor is a nutritional disease caused by a lack of protein in the diet. Protein is essential for the building and maintenance of body tissues. Insufficient protein intake can cause the body to start breaking down its own tissues to obtain the necessary amino acids, leading to symptoms such as swelling, muscle wasting, and skin and hair changes. Kwashiorkor is most common in developing countries where there is limited access to protein-rich foods.

Question 2

Supplementation with _______ helps prevent the nutritional deficiency disease called goiter.

Accepted Answer

Goiter is caused by a deficiency of iodine, which is an important mineral required for the production of thyroid hormones. Supplementation with iodine helps prevent and treat goiter. Fluoride is important for healthy teeth but does not prevent goiter. Chromium, zinc, and copper are important trace minerals but are not specifically related to goiter prevention.

Question 3

Which statement about the essential amino acids is true?

Accepted Answer

Certain combinations of plant-based foods, such as beans and corn, provide all eight essential amino acids that are required by humans.

Answer: E
 Both human infants and adults require all the same essential amino acids for growth, repair and maintenance of body tissues.

Question 4

Organisms that derive their energy and molecular nutrients from other organisms are called

Accepted Answer

Heterotrophs depend on other organisms for their energy and nutrient needs. Autotrophs produce their own energy and nutrients through photosynthesis. Herbivores eat only plants, but not all heterotrophs are herbivores. Photosynthetic organisms produce their own energy through photosynthesis and are therefore autotrophs. Protists are a diverse group of eukaryotic organisms and may be either autotrophic or heterotrophic.

Question 5

Numerous organisms in deep-sea thermal vents, far below the surface and away from any light, survive by harvesting the chemical energy stored in the bonds of inorganic molecules that rise from the interior of Earth.These organisms can be described as

Accepted Answer

The organisms described in the passage are not consuming other organisms for energy (heterotrophs or carnivores) nor are they consuming plant material (herbivores). They are instead obtaining their energy from inorganic molecules, which makes them autotrophs.

Question 6

During periods of starvation, stored fuels are used in which order?

Accepted Answer

During periods of starvation, the body prioritizes its use of stored fuels to maintain glucose levels for the brain and other vital organs. Initially, glycogen stores in the liver are broken down to glucose. Once glycogen stores are depleted, the body shifts to breaking down fats into fatty acids and ketone bodies for energy. Proteins are used as a last resort, as their primary function is not energy storage but rather the maintenance and repair of body tissues.

Question 7

The energy content of food is described in terms of calories because

Accepted Answer

The energy in food is ultimately converted into heat through metabolism, so describing the energy content of food in terms of calories, which is a unit of heat energy, makes the most sense.

Question 8

Of the food components listed, which provides the least amount of metabolic energy for animals?

Accepted Answer

Nucleic acids do not provide metabolic energy for animals as they are not easily broken down by the body for cellular respiration.

Question 9

Certain amino acids are essential to the diet of animals because they

Accepted Answer

Essential amino acids are those that cannot be synthesized by animals through the transfer of an amino group to an appropriate carbon skeleton. Therefore, they must be obtained through the diet.

Question 10

Which disease differs from the others in terms of the kind of deficiency that causes it?

Accepted Answer

Goiter is caused by a deficiency of iodine, whereas the other diseases (Pellagra, Rickets, Pernicious anemia, Beriberi) are caused by deficiencies of vitamins or nutrients other than iodine.

Question 11

Which type of food is least likely to help a patient who complains of night blindness?

Accepted Answer

Whole grains are least likely to help with night blindness because they are not a significant source of vitamin A or its precursors like beta-carotene, which are essential for improving night vision. Fruits, vegetables, liver, and dairy products are better sources of these nutrients.

Question 12

Certain amino acids are called essential amino acids because they

Accepted Answer

Essential amino acids cannot be synthesized by the body and must be obtained from the diet. They are necessary for protein synthesis and various physiological functions.

Question 13

Researchers recently reported that the green sea slug, Elysia chlorotica, can incorporate genes from algae, allowing them to use solar energy to meet their energy needs.Sea slugs can therefore be described as

Accepted Answer

The green sea slug, Elysia chlorotica, can incorporate genes from algae to perform photosynthesis, allowing them to produce their own energy from sunlight, which is a characteristic of autotrophs.

Question 14

Vitamins are essential nutrients for cells because they cannot be synthesized by the animal itself, and most

Accepted Answer

Vitamins function as coenzymes or parts of coenzymes, which are necessary for the proper functioning of enzymes in cells.

Question 15

Which statement about energy storage is true?

Accepted Answer

Glycogen, a form of carbohydrate storage, is indeed limited and typically does not exceed a day's worth of energy requirements for the body. This is because glycogen stores in the liver and muscles are finite and are quickly depleted, especially during periods of fasting or intense physical activity. Carbohydrates are stored as glycogen, not glucose. Fat is a crucial form of stored energy, offering the highest energy content per gram among the macronutrients, making statements B and C incorrect. Protein primarily serves as a building block for the body rather than an energy storage component, which makes D incorrect.

Question 16

The major form of stored energy in animal bodies is _______ because it _______.

Accepted Answer

Fat has the highest energy content per gram, making it an efficient long-term energy storage form in animal bodies.

Question 17

Which statement about vitamins is true?

Accepted Answer

Compared to fat-soluble vitamins, water-soluble vitamins are more easily excreted by the body and thus need to be replenished more frequently. Therefore, humans require more water-soluble vitamins than fat-soluble vitamins. The other choices are incorrect.

Question 18

Which statement about undernourishment is true?

Accepted Answer

During starvation, there is a loss of blood proteins, including albumin, which can lead to edema or swelling due to the accumulation of fluid in tissues. This is why the swollen belly is seen in severely malnourished children.

Option A is not correct as the swollen belly is actually due to the accumulation of fluid and gas in the intestine, not fat storage.

Option B is not correct as glycogen reserves can be depleted within a few days of fasting.

Option C is not correct as the duration of survival without food depends on various factors such as the individual's body composition, hydration status, and activity level, and can range from a few days to months.

Option E is not correct as the body usually starts breaking down fat stores before protein reserves when there is a lack of food.

Question 19

Adventurers attempting to recreate the Polynesians' months- or years-long trips across the ocean would likely carry _______ with them to avoid the ascorbic acid deficiency called _______.

Accepted Answer

Citrus fruits, such as oranges and lemons, are a good source of vitamin C, which is needed to prevent scurvy. Adventurers attempting long trips across the ocean would be at risk of developing scurvy due to a lack of access to fresh fruits and vegetables. Other options listed, such as corn, meat, liver, and dairy products, would not be effective in preventing scurvy.

Question 20

Most animals digest dietary proteins into their constituent amino acids and then synthesize new proteins because

Accepted Answer

Foreign proteins are recognized as invaders by the immune system, which is why animals digest dietary proteins into amino acids before using them to synthesize new proteins. This process prevents immune reactions against the consumed proteins.

Quiz 50: Nutrition, Digestion, and Absorption