ORGANIC & BIOCHEMISTRY EXAM 4

Conversion of dihydroxyacetone phosphate to D-glyceraldehyde 3-phosphate is a(an) ________. a. isomerization b. oxidation c. reduction d. esterification e. condensation

A

Exergonic reactions are those that are ________ and that ________ liberate free energy. a. spontaneous; do b. nonspontaneous; do c. spontaneous; do not d. nonspontaneous; do not e. none of the above

A

High density lipoproteins contain a greater amount of ________ than do low density lipoproteins. a. protein b. lipids c. triglycerides d. cholesterol e. fatty acids

A

The common features of catabolism of all amino acids include a. removal of the amine group and conversion of the carbon skeleton to intermediates which can enter the citric acid cycle. b. hydrolysis of peptide linkages and production of CO2 as waste. c. hydrolysis of peptide linkages and production of urea as waste. d. diversion of the carbon skeletons into gluconeogenesis. e. diversion of the carbon skeletons into ketogenesis.

A

The conversion of glucose 6-phosphate to fructose 6-phosphate in the second step of glycolysis is a(an) ________ reaction. a. isomerization b. reduction c. oxidation d. phosphorylation e. dehydration

A

The formation of acetyl coenzyme A is an example of a(an) ________ reaction. a. esterification b. redox c. addition d. acid / base e. elimination

A

The mitochondria are the location where ________ takes place and most ________ is produced. a. citric acid cycle; ATP b. digestion; acetyl coenzyme A c. digestion; ATP d. citric acid cycle; acetyl coenzyme A e. digestion; fatty acid

A

The pain and cramps that occur during physical exhaustion are associated with the formation of excess a. lactate. b. pyruvate. c. acetyl-CoA. d. acetaldehyde. e. glucose.

A

The process of converting ADP to ATP in the mitochondrion takes place by a process known as a. oxidative phosphorylation. b. chemiosmosis. c. respiration. d. reductive phosphorylation e. chemiosmotic phosphorylation.

A

An essential amino acid is one that a. is required for the synthesis of all proteins. b. must be obtained in the diet because the human body cannot synthesize it. c. can safely be omitted from the diet because the human body can produce it in unlimited amounts. d. must be provided in the diet for individuals with specific hereditary enzyme deficiencies. e. has a relatively simple carbon skeleton.

B

Endergonic reactions are those that have a ________ value of ΔG and ________ spontaneous. a. positive; are b. positive; are not c. negative; are d. negative; are not e. none of the above

B

PKU, phenylketonuria, is caused by a defect in the enzyme that converts a. alanine to serine. b. phenylalanine to tyrosine. c. tryptophan to tyrosine. d. alanine to phenylalanine.

B

The abbreviation ATP stands for a. adenine + three phosphates. b. adenosine triphosphate. c. adenosine tetraphosphate. d. anabolic triple phosphate. e. alanine triphosphate.

B

The common molecule produced from all foods at the second stage of catabolism is a. ADP. b. acetyl-SCoA. c. glucose. d. citric acid. e. carbon dioxide.

B

The complete metabolism of one molecule of myristic acid, a fatty acid with 14 atoms of carbon, would produce ________ molecules of acetyl-SCoA. a. 6 b. 7 c. 12 d. 14 e. 16

B

The formation of malonyl CoA from acetyl CoA and CO2 also requires the presence of a. cyclic AMP. b. ATP. c. glucose. d. FAD.

B

The major products of carbohydrate digestion are a. monosaccharides and disaccharides b. monosaccharides c. acetyl CoA d. pyruvic acid

B

Which of the following processes is important when new amino acids are produced in the body? a. deamination b. transamination c. urea cycle

B

A metabolic pathway in which a series of steps, each using different enzymes, regenerates one of the early reactants, is a(an) ________ pathway. a. anabolic b. catabolic c. cyclic d. linear e. spiral

C

All of the following are possible metabolic fates of the acetyl-SCoA intermediate except a. synthesis of cholesterol. b. the citric acid cycle and production of ATP. c. gluconeogenesis. d. lipogenesis. e. ketogenesis.

C

All of the following chemicals except ________ provide protection against potentially harmful oxygen species. a. beta-carotene b. catalase c. hydrogen peroxide d. vitamin C e. vitamin E

C

Digestion of lipids begins in the ________, in a process catalyzed by ________. a. mouth; salivary amylase b. stomach; hydrochloric acid c. small intestine; pancreatic lipases d. large intestines; bile acids e. adipocytes; triacylglycerol lipase

C

Entry of monosaccharides other than glucose into the glycolysis pathway initially involves a. breakdown into pyruvate. b. oxidation into acetyl groups. c. conversion into phosphates. d. reduction of carbonyl groups. e. hydrolysis of 2-carbon units.

C

Glycerol produced as a byproduct of metabolism of lipids is converted to ________, which can be isomerized to a compound that can enter glycolysis or gluconeogenesis. a. fatty acids b. citrate c. dihydroxyacetone phosphate d. acetone e. carbon dioxide

C

Harmful byproducts of biochemical oxidation include a. superoxide dismutase and catalase. b. vitamins A, C, and E. c. superoxide ions and hydroxyl free radicals. d. ATP. e. coenzyme Q.

C

In steps 3 and 4 of the citric acid cycle, successive oxidations produce ________ as a waste product and the four-carbon carrier ________. a. CO2; oxaloacetate b. ADP; oxaloacetate c. CO2; succinyl-SCoA d. ADP; succinyl-SCoA e. CO2; malate

C

In the anabolism of amino acids, ________ is the source of the amine group. a. aspartate b. urea c. glutamate d. arginine e. phenylalanine

C

Ketone bodies are primarily produced in ________ cells. a. brain b. heart c. liver d. kidney e. red blood

C

The chemical resulting from steps 3-5 of glycolysis which is oxidized in step 6 is a. glucose. b. acetyl-SCoA. c. glyceraldehyde 3-phosphate. d. citrate. e. oxaloacetate.

C

The conversion of nitrogen derivatives to urea takes place in the a. blood. b. kidneys. c. liver. d. brain. e. intestines.

C

The driving force which provides the energy for synthesis of ATP in the fourth stage of metabolism is a. the exergonic conversion of ADP to ATP. b. the energy difference between reduced carbon atoms and oxidized carbon atoms. c. the concentration gradient of hydrogen ions between the two sides of the inner mitochondrial membrane. d. the concentration difference in oxygen between the cell and the intercellular fluid. e. none of the above

C

The enzyme that removes an amine group from an amino acid and moves it to α-ketoglutarate is classified as a a. ligase. b. phosphatase. c. transaminase. d. dehydrogenase. e. kinase.

C

The pathway followed by glucose when energy is needed is a. gluconeogenesis. b. glycogenesis. c. glycolysis. d. lipogenesis. e. the pentose phosphate pathway.

C

The process of oxidative deamination of an amino acid produces which of the following? a. urea b. CO2 and H2O c. NH4+ d. aspartate e. glutamate

C

The synthesis of fatty acids a. takes place by simply the reverse reactions of the fatty acid spiral. b. takes place in the same location within a cell as the fatty acid spiral. c. takes place by different reactions than the reverse of the fatty acid spiral and in a different cellular location. d. More than one response is correct. e. No response is correct.

C

The urea cycle is ________ because it ________. a. exergonic; costs 3 ATP b. exergonic; releases 3 ATP c. endergonic; costs 3 ATP d. endergonic; releases 3 ATP e. neither exergonic nor endergonic; consumes 3 ATP in an early step and releases 3 ATP in a later step

C

Two key amino acids in the catabolism of nitrogen atoms in amino acids are a. aspartate and phenylalanine. b. aspartate and tyrosine. c. aspartate and glutamate. d. glutamate and asparagine. e. alanine and valine.

C

Where do the first chemical changes in the digestion of dietary fats take place? a. mouth b. stomach c. small intestine d. large intestine e. liver

C

Which chemical is produced from pyruvate when it is metabolized in muscle cells under aerobic conditions? a. lactate b. ethanol c. acetyl-SCoA d. phosphoenol pyruvate e. glucose

C

Which lipoprotein transports cholesterol to the liver to be recycled or excreted? a. chylomicrons b. ultra-high-density lipoproteins c. high-density lipoproteins d. low-density lipoproteins e. very low-density lipoproteins

C

Which of the following is not used as an energy source in metabolism? a. ATP b. UTP c. UTC d. GTP e. More than one choice is correct.

C

Which of the following substances are produced from hydrolysis of dietary fats in the small intestine? a. bile salts b. triglycerides c. fatty acids d. amino acids e. monosaccharides

C

Which statements are true for the process of β-oxidation? I. It occurs in the mitochondria. II. Acyl carrier proteins are involved. III. NADPH is the coenzyme. IV. The molecule increases in length by two carbons. V. Energy is released in the process. a. I, III, V b. II, IV c. I, V d. I, II, III, IV, V e. II, III, IV

C

Which type of molecule is the major form for long term storage of chemical energy in the body? a. carbohydrates b. proteins c. triglycerides d. steroids e. waxes

C

A high energy phosphate molecule involved in gluconeogenesis is ________. a. UDP b. UTP c. GDP d. GTP e. ADP

D

All of the chemicals below are associated with the pentose phosphate pathway except a. glucose 6-phosphate. b. NADPH. c. ribose. d. pyruvate. e. NADP.

D

Amino acids that can be synthesized in the body are called ______ amino acids. a. essential b. glycogenic c. ketogenic d. nonessential

D

Endergonic reactions are those that are ________ and that ________ liberate free energy. a. spontaneous; do b. nonspontaneous; do c. spontaneous; do not d. nonspontaneous; do not e. none of the above

D

Gluconeogenesis occurs mainly in the a. cytosol of all cells. b. mitochondria of all cells. c. muscle. d. liver. e. brain.

D

Glycogen is most commonly found in ________ cells and ________ cells. a. red blood; white blood b. red blood; liver c. muscle; white blood d. muscle; liver e. bone; white blood

D

High concentrations of ketone bodies in the bloodstream may indicate a. diabetes mellitus. b. starvation. c. a decrease in the pH of the blood. d. All responses are correct. e. No responses are correct.

D

In addition to producing ATP, the citric acid cycle produces ________ as high energy molecules and ________ as its major chemical waste product. a. oxidized coenzymes; H2O b. oxidized coenzymes; CO2 c. reduced coenzymes; H2O d. reduced coenzymes; CO2 e. ADP; O2

D

In the first step of glycolysis, the conversion of glucose to glucose 6-phosphate is known as a. isomerization. b. reduction. c. oxidation. d. phosphorylation. e. dehydration.

D

The amino acid pool is the collection of a. all amino acids available from the diet. b. amino acids produced from breakdown of proteins and available for reuse. c. essential amino acids available from the diet or from breakdown of other proteins. d. all free amino acids in the body. e. all amino acids in the body, whether free or part of proteins.

D

The correct order for these three processes leading from a fatty acid molecule in a cell needing energy to high energy molecules capable of meeting the energy need is I. activation by reaction with coenzyme A II. oxidation to acetyl-SCoA and reduced coenzymes III. transport from cytosol into mitochondrial matrix a. I, II, III. b. II, III, I. c. III, I, II. d. I, III, II. e. III, II, I.

D

The enzymes of the oxidative phosphorylation system are located in the a. cytosol. b. nucleus. c. matrix of the mitochondria. d. cristae of the mitochondria. e. endoplasmic reticulum.

D

The hormones ________ and ________ control the release of energy from stored triacylglycerol. a. insulin; cortisone b. adrenalin; glucagon c. norepinephrine; cortisone d. insulin; glucagon e. adrenalin; norepinephrine

D

The sum of all the biochemical reactions occurring in an organism is a. anabolism. b. catabolism. c. digestion. d. metabolism. e. respiration.

D

Which is the correct order for the steps in digestion and absorption of proteins? I. hydrolysis by pancreatic lipases II. denaturation by stomach acid III. hydrolysis by pepsin IV. active transport into the bloodstream a. I, II, III, IV b. IV, II, III,I c. II, I, III, IV d. II, III, I, IV e. III, II, IV, I

D

Which of the following are produced as a net result of glycolysis? I. NADH II. NAD+ III. ADP IV. ATP a. I and II b. III and IV c. I and III d. I and IV e. II and III

D

Which of the following carbohydrates can also be used as fuel in glycolysis? a. glucose b. glucose and fructose c. fructose and galactose d. galactose, fructose, and mannose e. fructose

D

Which of the following statements about free radicals is incorrect? a. They are a by-product of oxygen-consuming redox reactions. b. Their unpaired electron makes them extremely reactive. c. They can disrupt covalent bonds in biomolecules. d. B vitamins provide protection from their harmful effects. e. Superoxide catalase is one of the specific enzymes that can provide protection from their harmful effects.

D

All of the following chemicals are involved in the citric acid cycle except a. acetyl-SCoA. b. isocitrate. c. succinate. d. malate. e. ascorbate.

E

If nitrogen is to be excreted from the body, it is converted to which chemical? a. ammonia b. arginine c. glycine d. α-ketoglutarate e. urea

E

The purpose of coupling two biochemical reactions is to a. lower the activation energies of both reactions. b. convert an endergonic reaction to an exergonic one. c. convert an exergonic reaction to an endergonic one. d. use an endergonic reaction to drive an exergonic reaction. e. use an exergonic reaction to drive an endergonic reaction.

E

When a cell's need for NADPH or ribose-6-phosphate exceeds its need for ATP, glucose-6-phosphate is metabolized by a. gluconeogenesis. b. glycogenesis. c. glycolysis. d. glycogenolysis. e. the pentose phosphate pathway.

E

When energy is needed and adequate oxygen is available, pyruvate is converted to ________. a. glucose b. glycogen c. lactate d. ethanol e. acetyl-SCoA

E

When glutamate acts as the source of an amino group, the enzyme involved is a a. transferase. b. lipase. c. pepsin. d. synthetase. e. dehydrogenase.

E

Which factor is the same in both lipogenesis and β-oxidation of fatty acids? a. They occur in the same location in the cell. b. They use the same enzymes. c. They both involve NADPH and FAD. d. They both depend on coenzyme A e. They both occur two carbon atoms at a time.

E

Which is the correct term for the micelle-like structures which transport triglycerides in the bloodstream after digestion? Question 10 options: a. very low-density lipoproteins b. low-density lipoproteins c. high-density lipoproteins d. liposomes e. chylomicrons

E

Which of the following is not a product of digestion? a. amino acids b. fatty acids c. glucose d. glycerol e. pyruvate

E

Which of the following types of compounds do not require nitrogen for their biosynthesis? a. purines b. pyrimidines c. neurotransmitters d. urea e. All of these require nitrogen.

E

Which statements are true for the process of lipogenesis? I. It occurs in the mitochondria. II. Acyl carrier proteins are involved. III. NADPH is the coenzyme. IV. The molecule increases in length by two carbons. V. Energy is released in the process. a. I, III, V b. II, IV c. I, III d. I, II, III, IV, V e. II, III, IV

E

All of the following are reactions in the oxidation of glucose which produce energy except a. glycolysis. b. glycogenolysis. c. oxidation of pyruvate to acetyl-SCoA. d. the citric acid cycle. e. reaction of reduced coenzymes in the electron transport chain.

B

When fats are metabolized, the fatty acids enter the reactions of the a. electron transport chain. b. citric acid cycle. c. glycolysis pathway. d. β-oxidation process. e. gluconeogensis.

D

Which of the following is the usual reactant in the urea cycle? a. NH4+ b. glutamate c. pyruvate d. carbamoyl phosphate e. CO2

D

All of the carbon backbones from amino acids end up as intermediates in the ________. a. citric acid cycle b. urea cycle c. β-oxidation sequence d. both A and C e. none of the above

A

Fatty acids are activated for breakdown by conversion to ________. a. fatty acid SCoA's b. triacylglycerides c. fatty acid glycerol phosphates d. fatty acid alkyl esters e. none of the above

A

Glucogenic amino acids can be converted into which of the following? a. glucose b. fatty acids c. acetyl CoA d. ketone bodies e. They can be converted into all of the above.

A

Glycolysis occurs mainly in the a. cytosol of all cells. b. mitochondria of all cells. c. muscle. d. liver. e. brain.

A

In many catabolic processes the principal product is ________ to be processed in the ________. a. acetyl coenzyme A, citric acid cycle b. acetyl coenzyme A, electron transport chain c. ATP, electron transport chain d. ATP, citric acid cycle e. ADP, electron transport chain

A

Overproduction of insulin causes ________, a state in which the concentration of blood sugar is ________ than normal. a. hypoglycemia; lower b. hypoglycemia; higher c. hyperglycemia; lower d. hyperglycemia; higher e. none of the above

A

Photosynthesis is an ________ process because the free energy of the products is ________ the free energy of the reactants. a. endergonic; greater than b. exergonic; greater than c. endergonic; less than d. exergonic; less than e. equilibrium; the same as

A

Pyruvate is converted to lactate under anaerobic conditions because ________. a. reduction of pyruvate provides NAD+ which is needed for glycolysis b. lactate releases oxygen upon conversion to acetyl-CoA c. reduction of pyruvate provides NADH which is needed for gluconeogenesis d. lactate is storage for of pyruvate for use later when more ATP is needed e. none of the above

A

The action of yeast on pyruvate is a process referred to as a. alcoholic fermentation. b. aerobic oxidation. c. glycolysis. d. anaerobic reduction. e. substrate-level phosphorylation.

A

The biochemical process in which simple molecules are combined to make larger ones and energy is consumed is referred to as a. anabolism. b. catabolism. c. digestion. d. metabolism. e. respiration.

A

The cellular organelle that is responsible for most cellular catabolic redox reactions is the a. mitochondria b. chloroplast c. peroxisome d. ribosome

A

The complete metabolism of one molecule of myristic acid, a fatty acid with 14 atoms of carbon, would require ________ turns of the beta-oxidation cycle. a. 6 b. 7 c. 12 d. 14 e. 16

A

The enzyme that catalyzes cleavage of fructose 1,6-bisphosphate to dihydroxyacetone phosphate and D-glyceraldehyde-3-phosphate is ________. a. aldolase b. D-glyceraldehyde-3-phosphatase c. phosphofructokinase d. hexokinase e. none of the above

A

The major function of the pentose phosphate pathway when energy for anabolic reactions is a priority is a. producing NADPH. b. producing ribose. c. meeting the need for large amounts of ATP. d. providing intermediates for the citric acid cycle. e. providing intermediates for glycogenesis.

A

The most important monosaccharide for energy production is a. glucose. b. galactose. c. fructose. d. ribose. e. mannose.

A

The process by which the cell produces ATP in the mitochondria is called a. oxidative phosphorylation b. hydrolysis c. substrate-level phosphorylation d. electron transport

A

When blood sugar levels are lower than normal, this condition is called a. hypoglycemia. b. hyperglycemia. c. glucosuria. d. diabetes mellitus.

A

When fatty acid metabolism creates more acetyl-CoA than can be handled in the citric acid cycle, the excess acetyl-CoA is converted into ________. a. ketone bodies b. amino acids c. cholesterol d. fatty alcohols e. glycerol

A

Which chemical is produced from pyruvate when it is metabolized in muscle cells under anaerobic conditions? a. lactate b. ethanol c. acetyl-SCoA d. phosphoenol pyruvate e. glucose

A

Which of the following is considered to be the so-called "good cholesterol"? a. HDL b. LDL c. VLDL d. Chylomicrons

A

Which of the following lipoproteins is used solely for the transport of lipids in the blood? a. chylomicrons b. ultra-high-density lipoproteins c. high-density lipoproteins d. low-density lipoproteins e. very low-density lipoproteins

A

Which statement is true concerning the relationship between NAD+ and NADH? a. NAD+ is the oxidized form of NADH. b. NAD+ is the reduced form of NADH. c. The conversion of NAD+ to NADH is an acid/base reaction. d. The conversion of NAD+ to NADH is a cyclization reaction. e. none of the above

A

α-ketoacids are produced as a result of a transamination reaction with ________ acting as the donor molecule. a. glutamate b. aspartate c. urea d. ornithine e. oxaloacetate

A

A cyclic metabolic sequence can best be described as one in which a. the product of the first reaction is the starting material for the next reaction, and so on. b. a series of reactions regenerates the initial reactant. c. the various reactions have virtually no connection to one another. d. the same set of enzymes progressively builds up a molecule. e. the same set of enzymes catalyses the same reaction in both the forward and reverse directions.

B

After O2 has been reduced in the electron transport chain, the oxygen atoms are part of what molecules? a. ATP b. water c. carbon dioxide d. acetate e. acetyl-SCoA

B

After digestion and absorption, the molecules from dietary fats and oils are transported in the bloodstream as a. glycerol. b. fatty acids. c. cholesterol. d. citric acid. e. enzymes.

B

Each oxidation during fatty acid catabolism directly produces one molecule of ________ and a fatty acid molecule that has been shortened by ________ carbon atom(s). a. ATP; two b. acetyl-SCoA; two c. ATP; one d. acetyl-SCoA; one e. CO2; three

B

Fatty acids from triacylglycerols can be ________ when energy is plentiful or ________ when energy is needed. a. oxidized to produce acetyl-SCoA; stored as triacylglycerols in adipose tissue b. stored as triacylglycerols in adipose tissue; oxidized to produce acetyl-SCoA c. stored as cholesterol derivatives in adipose tissue; oxidized to produce glucose d. reduced to hydrocarbons; isomerized to lower energy forms e. diverted to gluconeogenesis; hydrolyzed to smaller molecules

B

If a glucose tolerance test shows an abnormally high level of glucose in the blood after several hours, the person is possibly a. hypoglycemic. b. diabetic. c. anemic. d. overweight.

B

If lipid catabolism produces more acetyl-SCoA than the citric acid cycle can consume, but there is still a need for energy, the process of ________ takes over. a. gluconeogenesis b. ketogenesis c. lipogenesis d. steroid synthesis e. transamination

B

In a pair of coupled reactions, if the favorable reaction releases more energy than the amount required by the unfavorable reaction, the excess energy is a. reabsorbed by the favorable reaction to be used later. b. released as heat and used to maintain body temperature. c. used by the unfavorable reaction to create more products than normally expected. d. converted to high energy ATP. e. used to produce reduced coenzymes.

B

In steps 5-8 of the citric acid cycle, the high-energy molecules ________, ________, and ________ are produced, and ________ is regenerated to begin another turn of the cycle. a. GDP; FADH2; NADH/H+; oxaloacetate b. GTP; FADH2; NADH/H+; oxaloacetate c. ATP; FADH2; NADH/H+; citrate d. ADP; FAD; NAD+; oxaloacetate e. GDP; FADH2; NADH/H+; isocitrate

B

The cellular organelle associated with energy production is the a. nucleus. b. mitochondrion. c. Golgi apparatus. d. endoplasmic reticulum. e. lysosome.

B

The complete metabolism of one molecule of stearic acid, a fatty acid with 18 atoms of carbon, would produce ________ molecules of acetyl-SCoA. a. 8 b. 9 c. 10 d. 16 e. 18

B

The diseases identified as diabetes are primarily associated with a malfunction of the hormone a. glucagon. b. insulin. c. epinephrine. d. cortisone. e. sorbitol.

B

The molecule that is a precursor to the other ketone bodies is a. acetone. b. acetoacetate. c. 3-hydroxybutyrate. d. malonyl-ACP. e. malonyl-SCoA.

B

The products of glycolysis important in metabolism are a. acetyl-SCoA and ATP. b. pyruvate, ATP, and NADH. c. CO2, ATP, and NADH. d. pyruvate, ADP, and NAD+. e. CO2 and H2O.

B

What percentage of a healthy adult's energy need is met by metabolism of protein? a. less than 5 b. 10-20 c. 35-45 d. 65-75 e. more than 90

B

When energy from stored triacylglycerols is needed, they are ________, and then transported in the bloodstream via ________ as fatty acids. a. hydrolyzed; high-density lipoproteins b. hydrolyzed; albumins c. oxidized; chylomicrons d. oxidized; albumins e. polymerized; high-density lipoproteins

B

When the amine group of glutamate is replaced with a carbonyl group, the process is called a. hydrolysis. b. oxidative deamination. c. reductive deamination. d. oxidative decarboxylation. e. phosphorylation.

B

Which chemical is produced from pyruvate when it is metabolized by yeast cells? a. lactate b. ethanol c. acetyl-SCoA d. phosphoenol pyruvate e. glucose

B

Which conversion is accomplished during glycolysis? a. glucose to glycogen b. glucose to pyruvate c. starch to glucose d. pyruvate to glucose e. glycogen to glucose

B

Which of the following enzymes is not involved in the digestion of proteins? a. pepsin b. amylase c. trypsin d. carboxypeptidase e. chymotrypsin

B

Which pathway produces glucose from its storage form in animals? a. glycolysis b. glycogenolysis c. gluconeogenesis d. glycogenesis e. lipogenesis

B

Which statement best summarizes the digestion of proteins? a. Amine groups are removed from all amino acids. b. All peptide linkages are hydrolyzed to produce a mixture of amino acids. c. Proteins are denatured by stomach acid. d. Amino acids are combined to produce proteins or enzymes. e. none of the above

B

Which statement is true concerning the relationship between FAD and FADH2? a. FADH2 is the oxidized form of FAD. b. FADH2 is the reduced form of FAD. c. The conversion of FADH2 to FAD is an acid/base reaction. d. The conversion of FADH2 to FAD is a cyclization reaction. e. none of the above

B

All of the following are energy strategies used in biochemical reactions except a. ATP is produced as a means of transferring energy. b. exergonic reactions are used to drive unfavorable reactions. c. chemical reactions occur in pairs in order to change the value of ΔG for one of the reactions. d. coenzymes which can exist in oxidized or reduced forms are used to transfer electrons. e. ADP is transformed into a higher energy molecule when coupled to an exergonic reaction.

C

Exergonic reactions are those that have a ________ value of ΔG and ________ spontaneous. a. positive; are b. positive; are not c. negative; are d. negative; are not e. none of the above

C

How many molecules of NADH are produced by the oxidation of a 10-carbon fatty acid? a. 6 b. 10 c. 4 d. 3 e. 15

C

The activation of a fatty acid prior to entering into the beta-oxidation cycle requires the presence of what coenzyme? a. malonyl CoA b. FAD c. ATP d. cyclic AMP

C

The proton translocating ATP synthase complex is located in the a. cytosol. b. outer membrane of the mitochondria. c. inner membrane of the mitochondria. d. matrix. e. intermembrane space.

C

When a person is deprived of food, in which order does the body use the following sources to produce glucose? I. protein breakdown to amino acids used for gluconeogenesis II. conversion of glycogen to glucose III. catabolism of lipids a. I, II, III b. III, II, I c. II, I, III d. II, III, I e. III, I, II

C

A lack of insulin causes ________, a state in which the concentration of blood sugar is ________ than normal. a. hypoglycemia; lower b. hypoglycemia; higher c. hyperglycemia; lower d. hyperglycemia; higher e. none of the above

D

A metabolic pathway that can be illustrated as A → B → C → D is said to be a(an) ________ pathway. a. anabolic b. catabolic c. cyclic d. linear e. spiral

D

A spiral metabolic sequence can best be described as one in which a. the product of the first reaction is the starting material for the next reaction, and so on. b. a series of reactions regenerates the initial reactant. c. the various reactions have virtually no connection to one another. d. the same set of enzymes progressively builds up or breaks down a molecule. e. the same set of enzymes catalyses the same reaction in both the forward and reverse directions.

D

All of the following statements concerning digestion are correct except a. the major chemical reaction in digestion is enzyme-catalyzed hydrolysis of large molecules. b. digestion begins in the mouth, continues in the stomach, and is completed in the small intestine. c. digestion can be considered a catabolic process in which bulk food is broken down into individual small molecules. d. the same enzymes are used in the digestion of carbohydrates, lipids, and proteins. e. the major physical processes in digestion are mixing, softening, and grinding of food.

D

Which sequence illustrates the order of the steps from food to biochemically useful energy? a. digestion; citric acid cycle; ATP production; acetyl-SCoA production b. digestion; citric acid cycle; acetyl-SCoA production; ATP production c. citric acid cycle; digestion; acetyl-SCoA production; ATP production d. digestion; acetyl-SCoA production; citric acid cycle; ATP production e. digestion; acetyl-SCoA production; ATP production; citric acid cycle

D

A metabolic pathway in which a molecule is progressively built up by repeated interaction with the same set of enzymes is a(an) ________ pathway. a. anabolic b. catabolic c. cyclic d. linear e. spiral

E

All of the following chemicals are part of the urea cycle except a. carbamoyl phosphate. b. citrulline. c. arginine. d. fumarate. e. acetyl-SCoA.

E

Complementary sources of protein are a. single foods that contain all of the essential amino acids. b. single foods that contain all of the nonessential amino acids. c. single foods that contain none of the essential amino acids. d. single foods that contain none of the nonessential amino acids. e. combinations of foods that provide all of the amino acids, both essential and nonessential.

E

Which group of compounds includes only low-energy molecules? a. ATP, acetyl-SCoA, NADH, FADH2 b. ADP, acetyl-SCoA, NAD+, FAD c. ATP, CO2, NADH, FADH2 d. ADP, CO2, NADH, FADH2 e. ADP, CO2, NAD+, FAD

E

Which statement concerning coenzymes and redox reactions is incorrect? a. Oxidation can be considered as loss of hydrogen or gain of oxygen. b. Reduction can be considered as gain of hydrogen or loss of oxygen. c. NAD+ is the oxidized form of NADH. d. An oxidation reaction cannot occur unless a reduction reaction also occurs. e. FAD is the reduced form of FADH2.

E