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Bchm 2300 Test III
Biochemistry 2300 — Elements of Human Nutrition
Test III Proteins & Lipids
Thursday, November 12, 2009
Each question has only one proper answer.
Mark your answers on provided answer sheet using pencil only.
1. What is the chemical composition of fats?
a.
Hexose polymers
b.
Glycogen granules
c.
Fatty acids and glycerol
d.
Combinations of long chain fatty acids
2. What is the simplest fatty acid found in the diet?
a.
Oleic acid
b.
Acetic acid
c.
Linoleic acid
d.
Palmitic acid
3. Which of the following describes a fatty acid that has one double bond?
a.
Saturated
b.
Hydrogenated
c.
Monounsaturated
d.
Polyunsaturated
4. Lipids differ in their degree of saturation or unsaturation due to their number of
a.
amino acids.
b.
double bonds.
c.
saccharide units.
d.
peptide linkages.
5. What type of fatty acid is found in high amounts in olive oil?
a.
Saturated
b.
Monounsaturated
c.
Polyunsaturated
d.
Partially hydrogenated
6. Which of the following is a common dietary saturated fatty acid?
a.
Oleic acid
b.
Stearic acid
c.
Linolenic acid
d.
Arachidonic acid
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7. Which of the following is a source of medium-chain fatty acids?
a.
Fish oils
b.
Beef products
c.
Vegetable oils
d.
Dairy products
8. Which of the following chemical characteristics of fatty acids determines their susceptibility to spoilage
by oxygen?
a.
Chain length
b.
Number of double bonds
c.
Position of first saturated bond
d.
Size of adjacent fatty acids on the triglyceride molecule
9. Which of the following is a polyunsaturated fatty acid in foods?
a.
Oleic acid
b.
Acetic acid
c.
Stearic acid
d.
Linoleic acid
10. Of the following foods, which has the highest percentage of its fat in saturated form?
a.
Butter
b.
Soybean
c.
Coconut
d.
Beef tallow
11. Of the following foods, which has the highest percentage of its fat in polyunsaturated form?
a.
Butter
b.
Soybean
c.
Coconut
d.
Beef tallow
12. Which of the following is considered a major source of polyunsaturated fat?
a.
Corn oil
b.
Palm oil
c.
Peanut oil
d.
Chicken fat
13. Which of the following is a feature of polyunsaturated fats?
a.
Low melting point
b.
High melting point
c.
Solid at room temperature
d.
Solid at refrigerator temperature
14. All of the following are rich sources of polyunsaturated fatty acids except
a.
palm oil.
b.
fish oils.
c.
soybean oil.
d.
safflower oil.
Bchm 2300 Test III
15. Which of the following characteristics is shared by olive oil and canola oil?
a.
Neither is liquid at room temperature.
b.
Neither contains saturated fatty acids.
c.
Both contain high levels of polyunsaturated fatty acids.
d.
Both contain high levels of monounsaturated fatty acids.
16. When stored at room temperature in loosely capped containers, which of the following dietary lipids
would turn rancid in the shortest time?
a.
Lard
b.
Peanut oil
c.
Soybean oil
d.
Coconut oil
17. Characteristics of hydrogenated oils include all of the following except
a.
they are stored in adipose tissue
b.
they lower HDL and raise LDL cholesterol in the body.
c.
some of their fatty acids change shape from cis to trans.
d.
products containing them become rancid sooner, contributing to a shorter
shelf life.
18. Which of the following is a feature of phospholipids?
a.
Resistant to digestion
b.
Soluble in both water and fat
c.
Highly susceptible to oxidation
d.
Found naturally only in animal foods
19. What is the usual fate of dietary lecithin?
a.
Unabsorbed and passes out in the feces
b.
Absorbed intact and incorporated into tissues
c.
Absorbed intact and broken down by the liver
d.
Hydrolyzed by the intestinal enzyme lecithinase
20. What is the major sterol in the diet?
a.
Palm oil
b.
Lecithin
c.
Cholesterol
d.
Arachidonic acid
21. Which of the following is a characteristic of cholesterol?
a.
It is absorbed directly into the blood.
b.
It is a precursor for bile and vitamin D synthesis.
c.
It is not formed in the body when provided by the diet.
d.
It is found in abundance in tropical fats such as palm oil.
22. Which of the following foods contains cholesterol?
a.
Corn
b.
Olives
c.
Roasted turkey
d.
Roasted peanuts
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23. Among the following, which would be the least effective method to control blood cholesterol levels?
a.
Control body weight
b.
Eat more insoluble fiber
c.
Consume less saturated fat
d.
Exercise intensely and frequently
24. How is soluble fiber in the diet thought to help lower blood cholesterol level?
a.
It denatures cholesterol in the stomach.
b.
It hydrolyzes cholesterol in the intestinal tract.
c.
It traps cholesterol in the intestinal tract and thus inhibits its absorption.
d.
It enhances excretion of bile leading to increased cholesterol turnover.
25. What part of the gastrointestinal tract is the predominant site of dietary fat hydrolysis?
a.
Mouth
b.
Stomach
c.
Small intestine
d.
Large intestine
26. In the digestion of fats, emulsifiers function as
a.
enzymes.
b.
hormones.
c.
detergents.
d.
chylomicrons.
27. Which of the following substances cannot be absorbed directly into the blood?
a.
Glycerol
b.
Long-chain fatty acids
c.
Short-chain fatty acids
d.
Medium-chain fatty acids
28. After a meal, most of the fat that eventually empties into the blood is in the form of particles known as
a.
micelles.
b.
chylomicrons.
c.
low-density lipoproteins.
d.
very-low-density lipoproteins.
29. Which of the following lipoproteins contains the highest percentage of cholesterol?
a.
Chylomicron
b.
Low-density lipoprotein
c.
High-density lipoprotein
d.
Very-low-density lipoprotein
30. What lipoprotein is largest in size?
a.
Chylomicron
b.
High-density lipoprotein
c.
Low-density lipoprotein
d.
Very-low-density lipoprotein
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31. A low risk of cardiovascular disease correlates with high blood levels of
a.
triglycerides
b.
free fatty acids
c.
high-density lipoproteins
d.
very-low-density lipoproteins
32. Which of the following is used by the body to synthesize arachidonic acid?
a.
Oleic acid
b.
Linoleic acid
c.
Palmitic acid
d.
Linolenic acid
33. Which of the following is an omega-3 fat?
a.
Acetic acid
b.
Palmitic acid
c.
Linoleic acid
d.
Docosahexaenoic acid
34. All of the following foods contain liberal amounts of eicosapentaenoic and docosahexaenoic acid
except
a.
tuna
b.
salmon
c.
human milk
d.
soybean oil
35. Which of the following vegetable oils is a good source of omega-3 fatty acids?
a.
Corn
b.
Canola
c.
Sesame
d.
Coconut
36. Studies show that regular consumption of fatty fish leads to
a.
lower blood pressure
b.
higher blood cholesterol
c.
greater tendency of the blood to clot
d.
decreased storage of omega-3 fatty acids
37. A meal providing 1200 kcalories contains 10 g of saturated fats, 14 g of monounsaturated fats, and 20 g
of poly-unsaturated fats. What is the percentage of energy supplied by the lipids?
a.
22
b.
33
c.
44
d.
55
38. 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
Bchm 2300 Test III
39. Which of the following 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
40. Approximately how many different amino acids are used in the synthesis of body proteins?
a.
5
b.
10
c.
20
d.
35
41. Terms used to classify amino acids in the diet include all of the following except
a.
essential
b.
nonessential
c.
partially essential
d.
conditionally essential
42. What is the simplest amino acid?
a.
Valine
b.
Glycine
c.
Alanine
d.
Methionine
43. Which of the following is not an essential amino acid in human nutrition?
a.
Proline
b.
Threonine
c.
Methionine
d.
Tryptophan
44. What amino acid is classified as conditionally essential when dietary intake of phenylalanine is
insufficient or the body cannot normally metabolize phenylalanine?
a.
Cysteine
b.
Tyrosine
c.
Glutamine
d.
Isoleucine
45. When two amino acids are chemically joined together, the resulting structure is called a
a.
dipeptide.
b.
diglyceride.
c.
polypeptide.
d.
polysaccharide.
46. 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 amino acids in the peptide chain
d.
Order of only the essential amino acids in the protein
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47. In comparison to the well-defined structure of starch, which of the following is the most important
factor that allows for the synthesis of thousands of different proteins?
a.
Number of cell ribosomes
b.
Number of different amino acids
c.
Availability of amino acids containing sulfur
d.
Availability of amino acids containing hydroxyl groups
48. What is the process that results in the hardening of an egg when it is exposed to heat?
a.
Solidification
b.
Denaturation
c.
Condensation
d.
Protein interaction
49. Upon eating a hamburger, in what organ is the hydrolysis of its proteins initiated?
a.
Mouth
b.
Stomach
c.
Small intestine
d.
Large intestine
50. 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
51. What is the chief function of pepsin?
a.
Emulsifies dietary proteins
b.
Activates hydrochloric acid
c.
Activates pancreatic proteases
d.
Cleaves proteins into smaller polypeptides
52. 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 some dipeptides and tripeptides
53. 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 stomach
d.
Completely absorbed in original form from jejunum
54. Protein hydrolyzing enzymes are commonly known as
a.
proteases
b.
hydrolyzers
c.
prodigestins
d.
denaturases
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55. The function of a protease is to
a.
hydrolyze proteins.
b.
synthesize proteins.
c.
hydrolyze ribosomes.
d.
synthesize ribosomes.
56. What protein is intimately involved in the formation of scar tissue in wound healing?
a.
Albumin
b.
Thrombin
c.
Collagen
d.
Hydroxyproline
57. What is the relationship between body proteins and water?
a.
Proteins attract water.
b.
Water attracts proteins.
c.
Water degrades proteins.
d.
Proteins form polymers of water.
58. Proteins, because they attract hydrogen ions, can act as
a.
acids.
b.
buffers.
c.
enzymes.
d.
antibodies.
59. Which of the following processes is regulated primarily by the buffering action of proteins?
a.
pH balance
b.
Fluid balance
c.
Blood clotting
d.
Synthesis of visual pigments
60. Which of the following proteins inactivates foreign bacteria and viruses?
a.
Enzymes
b.
Hormones
c.
Antibodies
d.
Lipoproteins
61. Which of the following is involved in the clotting of blood?
a.
Opsin
b.
Fibrin
c.
Collagen
d.
Transferrin
62. Which of the following are precursors of urea synthesis?
a.
All amino acids
b.
Animal proteins only
c.
Essential amino acids only
d.
Nonessential amino acids only
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63. 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
64. Which of the following illustrates a deamination reaction?
a.
Removal of the amino group from an amino acid
b.
Separation of an amino acid from a peptide chain
c.
Addition of an amino group to form a new amino acid
d.
Addition of an amino acid to form a larger peptide chain
65. 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%, resulting in less absorption.
d.
After absorption, extra proteins will be synthesized and stored for use when
protein intake returns to normal.
66. What is the chief factor that governs the quality of a food protein?
a.
Fat content
b.
Essential amino acid content
c.
Complex carbohydrate content
d.
Nonessential amino acid content
67. In general, the protein quality in grains would be most improved by the addition of a plant protein rich
in
a.
lysine.
b.
tryptophan.
c.
phenylalanine.
d.
glutamic acid.
68. Which of the following animal-derived proteins is classified as a poor-quality protein?
a.
Fish
b.
Cheese
c.
Gelatin
d.
Turkey
69. In general, the protein quality of legumes would be most improved by the addition of a plant
protein rich in
a.
lysine.
b.
tryptophan.
c.
methionine.
d.
glutamic acid.
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70. Which of the following 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.
71. In relation to the range of protein intake as a percentage of energy intake, what would be the highest
safe level of protein intake for a 60 kg adult ingesting 2,500 kcalories?
a.
48 g
b.
96 g
c.
120 g
d.
219 g
72. If proteins needs are expressed per kilogram of body weight, which of the following describes the
requirements of infants?
a.
Less than adults
b.
Similar to adults
c.
Greater than adults
d.
Less than adolescents
Bchm 2300 Test III
Keys for test III – lipids and proteins
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