Chapter 25 - Metabolism and Energetics
A balanced diet should A) include adequate substrates for the production of energy. B) provide essential amino acids and fatty acids. C) contain adequate amounts of vitamins and minerals. D) contain adequate amounts of water. E) All of the answers are correct.
E) All of the answers are correct.
Cells perform catabolism to generate ATP, which can be used for A) muscle contraction. B) ion transport. C) protein synthesis. D) glycogen synthesis. E) All of the answers are correct.
E) All of the answers are correct.
Cells synthesize new organic components for which of the following reasons? A) structural maintenance B) growth and repair C) produce secretions D) store nutrients E) All of the answers are correct.
E) All of the answers are correct.
During glycolysis, A) a molecule of glucose is converted into two molecules of pyruvic acid. B) four molecules of ATP are produced. C) two molecules of ATP are consumed. D) hydrogen atoms are removed from organic molecules. E) All of the answers are correct.
E) All of the answers are correct.
In the electron transport chain, A) NADH and FADH2 donate hydrogen atoms. B) reduced molecules transfer energy to ATP formation. C) oxidative phosphorylation leads to ATP formation. D) generates a concentration gradient by pumping hydrogen ions. E) All of the answers are correct.
E) All of the answers are correct.
In the human body, cholesterol is important because it A) helps waterproof the epidermis. B) is a lipid component of all cell membranes. C) is a key constituent of bile. D) is the precursor of several steroid hormones and vitamin D3. E) All of the answers are correct.
E) All of the answers are correct.
On a tour of African countries, Mark contracts a bad case of traveler's diarrhea. Because he can't eat very much, his body starts to use energy sources other than carbohydrates. This would result in A) increased levels of urea in the blood. B) ketosis and a decreased blood pH. C) increased gluconeogenesis in the liver. D) lipid metabolism. E) All of the answers are correct.
E) All of the answers are correct.
Someone with a total cholesterol level above their optimal range should A) modify their diet. B) lose weight if overweight. C) have annual checkups. D) reduce the amount of saturated fat in the diet. E) All of the answers are correct.
E) All of the answers are correct.
The Dietary Guidelines for Americans recommends many servings a day of dark-green and orange vegetables. Which vitamin is particularly abundant in this food group? A) A B) C C) E D) folic acid E) All of the answers are correct.
E) All of the answers are correct.
The heat-gain center for thermoregulation A) resides in the pre-optic hypothalamus. B) activates shivering thermogenesis. C) activates nonshivering thermogenesis. D) activates skin vasoconstriction. E) All of the answers are correct.
E) All of the answers are correct.
In glycolysis, each molecule of glucose that is catabolized gives a net yield of how many molecules of ATP? A) 2 B) 4 C) 30 D) 36 E) 38
A) 2
The vitamin that plays a role in maintaining epithelia and is required for the synthesis of visual pigments is vitamin A) A. B) B. C) C. D) D. E) E.
A) A.
The vitamin whose deficiency causes beriberi is A) thiamine. B) riboflavin. C) niacin. D) folic acid (folate). E) cobalamin.
A) thiamine.
Impaired fat absorption in the intestine would interfere with the absorption of A) vitamin A. B) vitamin B12. C) vitamin C. D) niacin. E) riboflavin.
A) vitamin A.
Each cytochrome contains a(n) A) lipoprotein. B) metal ion. C) ATP synthase. D) inorganic salt. E) All of the answers are correct.
B) metal ion.
Nitrogen compounds of the body include all of the following except A) amino acids. B) oxaloacetate. C) creatine. D) porphyrin. E) purines.
B) oxaloacetate.
The vitamin that is a constituent of coenzyme A is A) folic acid (folate). B) pantothenic acid. C) pyridoxine (B6). D) riboflavin. E) niacin.
B) pantothenic acid.
The major cation in cytoplasm is A) sodium. B) potassium. C) calcium. D) magnesium. E) iron.
B) potassium.
When NAD+ is ________ it becomes NADH. When NADH is ________ it becomes NAD+. A) phosphorylated; deaminated B) reduced; oxidized C) made; recycled D) phosphorylated; dephosphorylated E) oxidized; reduced
B) reduced; oxidized
The vitamin that is part of the coenzymes FAD is A) thiamine. B) riboflavin. C) niacin. D) folic acid (folate). E) cobalamin.
B) riboflavin.
When the temperature of the preoptic area of the hypothalamus exceeds its thermostat setting, A) peripheral vasoconstriction occurs. B) skin blood flow increases. C) rate and depth of respiration decreases. D) sweat glands are inhibited. E) blood is shunted to deep veins.
B) skin blood flow increases.
The carbon dioxide of respiration is formed during A) glycolysis. B) the citric acid cycle. C) electron transport. D) the formation of pyruvic acid. E) the formation of water.
B) the citric acid cycle.
A cation that is essential for muscle contraction, nerve function, and blood clotting is A) sodium. B) potassium. C) calcium. D) magnesium. E) selenium.
C) calcium.
The strategy of eating starchy foods for several days before an athletic event is known as A) carbohydrate craving. B) the Atkins diet. C) carbohydrate loading. D) glycolysis reaction. E) overeating.
C) carbohydrate loading.
Linoleic acid and linolenic acid are examples of A) transport proteins. B) lipoproteins. C) essential fatty acids. D) essential amino acids. E) vitamins.
C) essential fatty acids.
The nutrients that yield the most energy per gram when metabolized are A) carbohydrates. B) proteins. C) fats. D) nucleic acids. E) vitamins.
C) fats.
The vitamin that is a coenzyme in amino acid and nucleic acid metabolism is A) pantothenic acid. B) pyridoxine (B6). C) folic acid (folate). D) vitamin C. E) vitamin K.
C) folic acid (folate).
An element that is a component of hemoglobin, myoglobin, and cytochromes is A) calcium. B) magnesium. C) iron. D) zinc. E) cobalt.
C) iron.
The presence of ketone bodies in the urine is known as A) polyuria. B) hematuria. C) ketonuria. D) uremia. E) ketosis.
C) ketonuria.
Obesity is defined as a body weight more than ________ percent above the ideal body weight for an individual. A) 5 B) 10 C) 15 D) 20 E) 30
D) 20
How many net ATP molecules are produced by the complete metabolism (all pathways) of one glucose molecule? A) 2 ATP B) 63 ATP C) 500 ATP D) 36 ATP E) 32 ATP
D) 36 ATP
Removal of the amino group from amino acids in the first step of their catabolism requires a coenzyme derived from vitamin A) A. B) C. C) B12. D) B6. E) B9.
D) B6.
Inadequate exposure to sunlight could result in decreased amounts of vitamin ________ in the body. A) A B) B12 C) C D) D E) E
D) D
The vitamin that is required for proper bone growth and for calcium absorption and retention is vitamin A) A. B) B. C) C. D) D. E) E.
D) D.
________ carry excess cholesterol from peripheral tissues to the liver. A) Very-low-density lipoproteins (VLDLs) B) Low-density lipoproteins (LDLs) C) Intermediate-density lipoproteins (IDLs) D) High-density lipoproteins (HDLs) E) Very-high-density lipoproteins (VHDLs)
D) High-density lipoproteins (HDLs)
Lipogenesis generally begins with A) glucose. B) amino acids. C) fatty acids. D) acetyl-CoA. E) succinyl-CoA.
D) acetyl-CoA.
Metabolism of amino acids in the citric acid cycle yields A) more energy than lipid metabolism. B) more energy than carbohydrate metabolism. C) approximately the same energy as lipid metabolism. D) approximately the same energy as carbohydrate metabolism. E) more energy than lipid and carbohydrate metabolism combined.
D) approximately the same energy as carbohydrate metabolism.
The lipoproteins that carry absorbed lipids from the intestinal tract to the bloodstream are A) HDLs. B) VLDLs. C) LDLs. D) chylomicrons. E) coenzymes.
D) chylomicrons.
Wally decides to go on a hunger strike to further one of his favorite causes. After many days with nothing but water, you would not expect to observe A) elevated levels of glucocorticoids. B) ketone bodies in his urine. C) decreased blood pH. D) increased insulin secretion. E) All of the answers are correct.
D) increased insulin secretion.
A cation that often acts as a cofactor for enzymes is A) sodium. B) potassium. C) calcium. D) magnesium. E) zinc.
D) magnesium.
The citric acid cycle occurs in the A) cytosol. B) golgi apparatus. C) mitochondrial intermembrane space. D) mitochondrial matrix. E) ribosome.
D) mitochondrial matrix.
If 8 molecules of NADH from the citric acid cycle entered the ETS, how much ATP would be produced? A) 36 ATP B) 32 ATP C) 3 ATP D) 8 ATP E) 24 ATP
E) 24 ATP
What percent of energy released from catabolism is lost as heat? A) 20 B) 30 C) 40 D) 50 E) 60
E) 60
Compounds that cells can use to make glucose include all of the following, except A) acetyl-CoA. B) glycerol. C) some amino acids. D) lactate. E) pyruvate.
A) acetyl-CoA.
The citric acid cycle A) begins with the formation of a molecule of citric acid. B) directly produces most of the ATP from the catabolism of glucose. C) consumes two moles of carbon dioxide. D) contains enzymes called cytochromes. E) forms acetyl-CoA from glucose-6-phosphate.
A) begins with the formation of a molecule of citric acid.
All of the following occur when the temperature of the preoptic area of the hypothalamus drops below its thermostat setting except A) blood flow to the skin increases. B) shivering thermogenesis occurs. C) nonshivering thermogenesis occurs. D) epinephrine levels rise. E) blood returning from limbs is shunted to deep veins.
A) blood flow to the skin increases.
The end products of aerobic respiration are A) carbon dioxide, water, and ATP. B) pyruvic acid and carbon dioxide. C) carbon dioxide and alcohol. D) oxygen and water. E) NADH and FADH2.
A) carbon dioxide, water, and ATP.
The major anion in body fluids is A) chloride. B) bicarbonate. C) sulfate. D) iodide.
A) chloride.
Oxygen is an important molecule in which of the following? A) citric acid cycle and ETS B) glycolysis, citric acid cycle, and ETS C) citric acid cycle only D) glycolysis only E) ETS only
A) citric acid cycle and ETS
The study of the flow of energy and its transformations is called A) energetics. B) glycolysis. C) cellular respiration. D) thermodynamics. E) metabolism.
A) energetics.
During the postabsorptive state, ________ stimulate(s) lipid catabolism. A) glucocorticoids B) androgens C) insulin D) glucagon E) All of the answers are correct.
A) glucocorticoids
A high uric acid level (above 7.4 mg/dl) can lead to the painful condition known as A) gout. B) rheumatoid arthritis. C) anorexia nervosa. D) lupus. E) ketosis.
A) gout.
All of the following complement the actions of glucocorticoids in the postabsorptive state except A) insulin. B) growth hormone. C) glucagon. D) epinephrine.
A) insulin.
The essential fatty acids are A) linoleic acid and linolenic acid. B) leucine and lysine. C) cholesterol and glycerol. D) HDLs and LDLs. E) glycerol and pyruvic acid.
A) linoleic acid and linolenic acid.
Urea is formed in the A) liver. B) stomach. C) kidneys. D) small intestine. E) large intestine.
A) liver.
Factors that influence an individual's BMR (basal metabolic rate) include all of the following except A) physical exertion. B) age. C) body weight. D) genetics. E) gender.
A) physical exertion.
When the body is relying on internal energy reserves to continue meeting its energy demands, it is in the ________ state. A) postabsorptive B) absorptive C) starvation D) deprivation E) preabsorptive
A) postabsorptive
A vitamin obtained that is a coenzyme in amino acid and lipid metabolism is A) pyridoxine (B6). B) thiamine. C) riboflavin. D) folic acid (folate). E) niacin.
A) pyridoxine (B6).
In an environment that is cooler than your body, you lose heat in a process called A) radiation. B) conduction. C) convection. D) evaporation. E) thermal regulation.
A) radiation.
The function of the citric acid cycle is to A) remove hydrogen atoms from organic molecules and transfer them to coenzymes. B) transfer the acetyl group gained from glycolysis to molecules of pyruvate. C) hydrolyze glucose in the presence of oxygen to obtain two pyruvate molecules. D) produce carbon dioxide to balance the oxygen requirement for cellular respiration. E) produce water.
A) remove hydrogen atoms from organic molecules and transfer them to coenzymes.
The major cation in extracellular fluid is A) sodium. B) potassium. C) calcium. D) magnesium. E) iron.
A) sodium.
During the absorptive state, A) the liver forms glycogen. B) adipocytes release fatty acids to the circulation. C) skeletal muscle breaks down glycogen. D) insulin levels are low. E) skeletal muscle fibers release glucose.
A) the liver forms glycogen.
All of the following occur during the postabsorptive state except that A) glycogenolysis occurs in the liver. B) levels of blood glucose are elevated. C) ketone bodies may be formed. D) fat mobilization occurs. E) gluconeogenesis occurs in the liver.
B) levels of blood glucose are elevated.
Hydrogen atoms from one FADH2 from the citric acid cycle produce how much ATP in the electron transport system? A) 32 ATP B) 2 ATP C) 3 ATP D) 4 ATP E) 1 ATP
B) 2 ATP
The chemical equation that correctly summarizes the overall reaction in oxidative phosphorylation is A) H2 + O2 → H2O + O. B) 2 H2 + O2 → 2 H2O. C) 3 H2 + 2O2 → 3 H2O + 2 O. D) H2 + O2 → H2O. E) P + 3 O → PO3.
B) 2 H2 + O2 → 2 H2O.
The end products of glycolysis are A) ATP, water, and carbon dioxide. B) ATP, NADH, and pyruvic acid. C) ADP and ATP. D) pyruvic acid and citric acid. E) NADH and FADH2.
B) ATP, NADH, and pyruvic acid.
In the ETS, ________ accepts electrons from one molecule and transfers them to another. A) a hydrogen ion B) a coenzyme C) the acetyl group D) ADP E) NAD
B) a coenzyme
Assuming they all weigh the same and maintain the same body temperature, which of the following would lose heat the fastest? A) a short, thickly built person B) a tall, very slender person C) a person of average build D) None of the answers is correct; they would lose heat at an equal rate.
B) a tall, very slender person
In order for glycolysis to proceed, which of the following need not be present? A) glucose B) acetyl-CoA C) ATP D) NAD E) ADP
B) acetyl-CoA
The trace element needed as a cofactor for hemoglobin synthesis is A) zinc. B) copper. C) cobalt. D) iodine. E) silicon.
B) copper.
Most of the ATP from metabolism is produced in the A) citric acid cycle. B) electron transport system. C) cytosol. D) mitochondrial matrix. E) glycolysis.
B) electron transport system.
Although other nutrients can feed into the citric acid cycle, ________ yields energy the quickest. A) glycogen B) glucose C) protein D) fat E) an amino acid
B) glucose
The condition when excessive fluid loss from sweating disrupts thermoregulatory mechanisms is known as A) thermoneogenesis. B) heat exhaustion. C) hydrosis. D) heat stroke. E) hypothermia.
B) heat exhaustion.
During lipolysis, A) triglycerides are converted into molecules of acetyl-CoA. B) triglycerides are broken down into glycerol and fatty acids. C) lipids are converted into glucose molecules. D) lipids are formed from excess carbohydrates. E) lipids are metabolized to yield ATP.
B) triglycerides are broken down into glycerol and fatty acids.
The conversion of ammonia into a less toxic substance produces A) ketone bodies. B) urea. C) nitrate. D) acetyl-CoA. E) water.
B) urea.
For adults, there are ________ essential amino acids. A) 2 B) 6 C) 8 D) 10 E) 20
C) 8
All of the following are true of beta-oxidation except that A) it occurs in the mitochondria. B) fatty acids break down into two-carbon fragments. C) lipids are converted into glycogen molecules. D) it requires coenzyme A, NAD, and FAD. E) it yields large amounts of ATP.
C) lipids are converted into glycogen molecules.
In oxidative phosphorylation, energy for the synthesis of ATP is directly obtained from the A) splitting of oxygen molecules. B) breaking of the covalent bonds in glucose. C) movement of hydrogen ions through channels in the inner mitochondrial membrane. D) combination of two atoms of hydrogen and one atom of oxygen to form water. E) oxidation of acetyl-CoA.
C) movement of hydrogen ions through channels in the inner mitochondrial membrane.
The vitamin that is part of the coenzyme NAD is A) thiamine. B) riboflavin. C) niacin. D) folic acid (folate). E) cobalamin.
C) niacin.
A T4 assay is used to A) determine the number of calories in food. B) directly measure the basal metabolic rate. C) obtain an index of metabolic activity. D) monitor the energy efficiency of metabolism. E) determine the amount of oxygen consumed during metabolism.
C) obtain an index of metabolic activity.
The ________ of the mitochondrion contains large-diameter pores that are permeable to ions and small organic molecules such as pyruvic acid. A) inner membrane B) plasma membrane C) outer membrane D) matrix E) cristae
C) outer membrane
An ion that is a necessary component of high-energy compounds and nucleic acids and a structural component of bone is the ________ ion. A) chloride B) sulfate C) phosphate D) bicarbonate E) iodide
C) phosphate
Reactions within ________ provide most of the energy needed by a typical cell. A) cytoplasm B) the plasma membrane C) the mitochondria D) the endoplasmic reticulum E) nucleus
C) the mitochondria
In transamination, the amino group of an amino acid is A) converted to ammonia. B) converted to urea. C) transferred to a keto acid. D) absorbed by water. E) transferred to acetyl-CoA.
C) transferred to a keto acid.
What is the role of NADH in metabolism? A) convert pyruvic acid into acetyl-coA B) produce bicarbonate ions for a pH buffer C) transport hydrogen atoms to coenzymes D) produce carbon dioxide E) phosphorylate ADP into ATP
C) transport hydrogen atoms to coenzymes
The element that is necessary for the proper function of the enzyme carbonic anhydrase is A) iron. B) cobalt. C) zinc. D) selenium. E) iodine.
C) zinc.
Catabolism of protein is not a practical source of quick energy because of all of the following except that A) proteins are more difficult to break apart than lipids or carbohydrates. B) the energy yield from protein is less than the yield from lipids. C) one of the by-products of protein catabolism is ammonia. D) most individuals have little protein to spare before harming vital organs. E) extensive catabolism of protein threatens homeostasis.
D) most individuals have little protein to spare before harming vital organs.
During starvation, A) carbohydrate utilization increases. B) gluconeogenesis ceases. C) there is a decline in circulating ketone bodies. D) muscle proteins are used as an energy source. E) carbohydrate reserves maintained by metabolizing inorganic compounds.
D) muscle proteins are used as an energy source.
The citric acid cycle is an aerobic process because A) ADP is phosphorylated. B) FADH2 is produced. C) citric acid molecules have oxygen atoms. D) oxygen is needed to remove carbon atoms as carbon dioxide. E) NAH+ is converted into NADH.
D) oxygen is needed to remove carbon atoms as carbon dioxide.
Lipids A) deliver somewhat less energy than an equivalent mass of glucose. B) are difficult to store since they are not water soluble. C) yield quick bursts of energy. D) provide energy for cells with modest energy demands. E) are the primary nutrient metabolized in cells.
D) provide energy for cells with modest energy demands.
The main purpose of the citric acid cycle is to A) produce Acetyl CoA so that the citric acid cycle can continue. B) produce proteins for energy storage. C) phosphorylate glucose molecules. D) supply hydrogen atoms to the Electron Transport System. E) produce citric acid to make vitamin C in the mitochondria.
D) supply hydrogen atoms to the Electron Transport System.
The major steps in oxidative phosphorylation include all of the following except A) removal of hydrogen atoms from a substrate molecule by coenzymes. B) ionization of hydrogen atoms. C) decreasing the energy level of electrons passing through the electron transport chain. D) the breaking of carbon-carbon covalent bonds. E) the acceptance of electrons by oxygen atoms.
D) the breaking of carbon-carbon covalent bonds.
Which of the following statements regarding brown fat is false? A) Brown fat is found in infants. B) Brown fat functions in nonshivering thermogenesis. C) Brown fat contains a rich vascular supply. D) Brown fat is innervated by the sympathetic nervous system. E) Brown fat is concentrated around visceral organs in the adult.
E) Brown fat is concentrated around visceral organs in the adult.
________ are the largest lipoproteins, ranging in diameter up to 0.5 µm, produced by intestinal epithelial cells from the fats in food. A) Very-low-density lipoproteins (VLDLs) B) Low-density lipoproteins (LDLs) C) Intermediate-density lipoproteins (IDLs) D) High-density lipoproteins (HDLs) E) Chylomicrons
E) Chylomicrons
The vitamin that prevents breakdown of vitamin A and fatty acids is vitamin A) A. B) B. C) C. D) D. E) E.
E) E.
The vitamin that is essential for the production of several clotting factors is vitamin A) A. B) B. C) E. D) C. E) K.
E) K.
Which of the following individuals would lose heat the fastest in a cold room? A) an adult man B) an adult woman C) an adolescent male D) a child E) a newborn infant
E) a newborn infant
In the citric acid cycle, a 2 carbon molecule and a 4 carbon molecule combine to produce A) fructose-1, 6-bisphosphate. B) carbon dioxide. C) pyruvic acid. D) NADH. E) citric acid.
E) citric acid.
The sum of all of the biochemical processes going on within the human body at any given time is called A) glycolysis. B) oxidative phosphorylation. C) catabolism. D) anabolism. E) metabolism.
E) metabolism.
In order to determine the LDL level in a patient's blood, it is necessary to measure A) total cholesterol level. B) HDL level. C) triglyceride level. D) triglyceride and monoglyceride levels. E) total cholesterol level, HDL level, and triglyceride level.
E) total cholesterol level, HDL level, and triglyceride level.