testbank metabolism

CHAPTER 24

Carbohydrate Metabolism

Test Bank

TYPE I MULTIPLE-CHOICE QUESTIONS

In each of the following multiple-choice questions, place the letter of the correct response in the blank at the left. There is only one correct response for each question.

24.1 c The primary site within the human body where carbohydrate digestion occurs is thea) mouth.b) stomach.c) small intestine.d) membranes of intestinal mucosal cells.

24.2 b Which of the following conversions is accomplished by the process of glycolysis?a) glucose to glycogenb) glucose to pyruvatec) starch to glucosed) pyruvate to glucose

24.3 c The first two intermediates in the process of glycolysis are, respectively,a) glucose 6-phosphate and glucose 1-phosphate.b) glucose 1-phosphate and glucose 6-phosphate.c) glucose 6-phosphate and fructose 6-phosphate.d) glucose 1-phosphate and fructose 1-phosphate.

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272 Chapter 24: Carbohydrate Metabolism Test Bank

24.4 b The transition from the C6 stage of glycolysis to the C3 stage involves the conversion of the molecule fructose 1,6-bisphosphate into the C3 species

a) dihydroxyacetone and glyceraldehydes.b) dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.c) glyceraldehyde and 3-phosphoglycerate.d) 3-phosphoglycerate and 2-phosphoglycerate.

24.5 c How many total steps are there in the process of glycolysis?a) sixb) eightc) tend) twelve

24.6 d How many glycolysis intermediates are molecules that contain one or more phosphate groups?

a) twob) fourc) sixd) nine

24.7 c How many steps in the glycolysis pathway have a C3 molecule as the reactant?a) twob) fourc) sixd) eight

24.8 d In the human body, under aerobic conditions and anaerobic conditions, respectively, pyruvate is converted to

a) lactate and ethanol.b) lactate and acetyl CoA.c) ethanol and lactate.d) acetyl CoA and lactate.

24.9 a Accumulation of which of the following substances is the cause of stiff and sore muscles after vigorous exercise?

a) lactateb) pyruvatec) acetyl CoAd) glycerate

24.10 c [Algorithmic]The net yield of ATP from the complete oxidation of one molecule of glucose is

a) 12.b) 24.c) 30.d) 36.

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Test Bank Chapter 24: Carbohydrate Metabolism 273

24.11 a [Algorithmic]The net yield of ATP per glucose molecule during the process of glycolysis is

a) 2.b) 4.c) 8.d) 12.

24.12 b The name of the process in which free glucose is converted to glycogen isa) gluconeogenesis.b) glycogenesis.c) glycogenolysis.d) glycolysis.

24.13 a Which of the following processes require UTP molecules?a) formation of glycogen from glucoseb) degradation of glycogen to glucosec) both the formation and degradation of glycogend) formation of glucose 1-phosphate from glucose 6-phosphate

24.14 c [Algorithmic]Glucose 1-phosphate is converted to glucose 6-phosphate in which of the following processes?

a) gluconeogenesisb) glycogenesisc) glycogenolysisd) glycolysis

24.15 a [Algorithmic]Adding a single glucose unit to a growing glycogen chaina) requires the investment of 2 ATP molecules.b) results in the production of 1 ATP molecule.c) does not require any triphosphate molecules.d) requires NAD+ as an oxidizing agent.

24.16 c [Algorithmic]Which of the following intermediates is involved in gluconeogenesis but not in glycolysis?

a) glucose 1-phosphateb) pyruvatec) oxaloacetated) phosphoenolpyruvate

24.17 a [Algorithmic]Which of the following is a reactant in the first step of gluconeogenesis?

a) carbon dioxideb) molecular oxygenc) glucosed) acetyl CoA



24.18 b Which of the following substances are participants in the reactions encompassed by the Cori cycle?

a) pyruvate and acetyl CoAb) pyruvate and lactatec) lactate and acetyl CoAd) pyruvate, lactate and acetyl CoA

24.19 b [Algorithmic]Which of the following statements concerning the pentose phosphate pathway is incorrect?

a) It is an alternative pathway to glycolysis for the degradation of glucose.b) The major coenzyme produced by the pathway is NADH.c) Pentose derivatives needed for the production of nucleic acids are products of

the pathway.d) In the first stage of the pathway, glucose 6-phosphate is converted to ribulose

5-phosphate.

24.20 a Which of the following hormones promotes the uptake and use of glucose by cells?a) insulinb) glucagonc) epinephrined) adrenaline

TYPE II MULTIPLE-CHOICE QUESTIONS

In each of the following multiple-choice questions, place the letter of the correct response in the blank at the left. There may be more than one correct response (choice d) or no correct response for a question (choice e).

24.21 c Which of the following statements concerning glycolysis is incorrect?a) It is an oxidation process in which no molecular oxygen is used.b) All reactions take place in the cytosol of a cell.c) There are two stages, each of which involves a series of five reactions.d) more than one correct responsee) no correct response

24.22 d In two of the first three steps of glycolysis,a) phosphorylation reactions occur.b) isomerization reactions occur.c) ATP is converted to ADP.d) more than one correct responsee) no correct response



24.23 a Which of the following C6 stage glycolysis intermediates is paired with the correct type of enzyme needed for its production?

a) glucose 6-phosphate; kinaseb) fructose 6-phosphate; dehydrogenasec) fructose 1,6-bisphosphate; mutased) more than one correct responsee) no correct response

24.24 b In which of the following steps of glycolysis does substrate-level phosphorylation occur?

a) production of phosphoenolpyruvateb) production of pyruvatec) production of 2-phosphoglycerated) more than one correct responsee) no correct response

24.25 d Which of the following C3 stage glycolysis intermediates undergoes an isomerization reaction?

a) dihydroxyacetone phosphateb) glyceraldehyde 3-phosphatec) 3-phosphoglycerated) more than one correct responsee) no correct response

24.26 b Intermediates in the glycolysis pathway includea) two glucose derivatives.b) three glycerate derivatives.c) two pyruvate derivatives.d) more than one correct responsee) no correct response

24.27 d The regeneration of NAD+ from NADH occurs during the conversion of pyruvate toa) lactate.b) ethanol.c) acetyl CoA.d) more than one correct responsee) no correct response

24.28 d Carbon dioxide is a product when lactate is converted toa) pyruvate.b) ethanol.c) acetyl CoA.d) more than one correct responsee) no correct response



24.29 b In which of the following processes is glucose the end product?a) glycogenesisb) glycogenolysisc) glycolysisd) more than one correct responsee) no correct response

24.30 d Which of the following is a three-step process?a) conversion of pyruvate to glucoseb) conversion of glucose to glycogenc) conversion of glycogen to glucosed) more than one correct responsee) no correct response

24.31 a The compound glucose 1-phosphate is encountered in which of the following processes?

a) glycogenesis and glycogenolysisb) glycolysis and gluconeogenesisc) glycogenesis and gluconeogenesisd) more than one correct responsee) no correct response

24.32 e The compound glucose 6-phosphate is not encountered in which of the following processes?

a) conversion of pyruvate to glucoseb) conversion to glucose to pyruvatec) conversion of glycogen to glucosed) more than one correct responsee) no correct response

24.33 b The compound oxaloacetate is an intermediate in the conversion ofa) glycogen to glucose.b) pyruvate to glucose.c) pyruvate to acetyl CoA.d) more than one correct responsee) no correct response

24.34 d Which of the following is a product of the first stage of the pentose phosphate pathway?

a) carbon dioxideb) a phosphorylated version of the coenzyme NADHc) ribose 5-phosphated) more than one correct responsee) no correct response



24.35 c Which of the following hormones increases blood glucose levels?a) insulin and glucagonb) insulin and epinephrinec) glucagon and epinephrined) more than one correct responsee) no correct response

MULTIPLE-CHOICE FORMAT TRUE-FALSE QUESTIONS

In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices a) All three statements are true.

b) Two of the three statements are true.c) Only one of the statements is true.d) None of the statements is true.

24.36 c - FTF Statements:(1) The three major monosaccharide products from carbohydrate digestion are

glucose, galactose, and ribose.(2) In glycolysis, two ATP molecules are consumed and four ATP molecules are

produced.(3) The Cori cycle is a process in which glucose is converted to pyruvate which is

then converted back to glucose.

a) All three statements are true.b) Two of the three statements are true.c) Only one of the statements is true.d) None of the statements is true.

24.37 b - FTT Statements:(1) Glycogenesis and glycolysis are “opposite” processes.(2) The focal point for carbohydrate metabolism is the molecule glucose.(3) Production of 30 ATP molecules accompanies the complete oxidation of a

glucose molecule.




24.38 b - FTT Statements:(1) Absorption of monosaccharides through the intestinal wall into the

bloodstream involves passive transport.(2) In the conversion of pyruvate to acetyl CoA, a carbon dioxide molecule is

produced.(3) Glucose degradation occurs in both glycolysis and the pentose phosphate

pathway.


24.39 c - FTF Statements:(1) The process of glycolysis converts a C6 molecules into three C2 molecules.(2) The primary location where gluconeogenesis occurs is the liver.(3) Pyruvate reduction to lactate occurs under aerobic conditions, and pyruvate

oxidation to acetyl CoA results from anaerobic conditions.


24.40 a - TTT Statements:(1) Glucose 1-phosphate is an intermediate in both glycogenesis and

glycogenolysis.(2) Conversion of ATP to ADP occurs in both steps 1 and 3 of glycolysis.(3) In the oxidative stage of the pentose phosphate pathway, a hexose phosphate is

converted to a pentose phosphate and carbon dioxide.


24.41 b - TTF Statements:(1) Gluconeogenesis is a process through which glucose can be synthesized from

noncarbohydrate materials.(2) The process of glycolysis takes place in the cytosol of a cell.(3) Insulin’s function is to increase blood glucose levels by speeding up the

conversion of glycogen to glucose.




24.42 b - TFT Statements:(1) All intermediates in the C3 stage of glycolysis are phosphorylated derivatives

of either glycerol or acetone.(2) The digestion of carbohydrates begins in the mouth, continues in the stomach,

and is completed in the small intestine.(3) The storage form for excess glucose in the body is glycogen produced by

glycogenesis.


24.43 a - TTT Statements:(1) The conversion of glucose 6-phosphate to glucose, the last step of

glycogenolysis, does not occur in muscle and brain cells.(2) The two triose phosphates initially formed in glycolysis are dihydroxyacetone

phosphate and glyceraldehyde 3-phosphate.(3) ATP production during glycolysis occurs via substrate-level phosphorylation.


24.44 d - FFF Statements:(1) The first step of glycolysis involves the phosphorylation of glucose to produce

glucose 1-phosphate.(2) The processing of one glucose molecule via glycolysis produces two acetyl

CoA molecules and two carbon dioxide molecules.(3) The majority of ATP molecules produced during the complete oxidation of

glucose form during the glycolysis phase of oxidation.


24.45 a - TTT Statements:(1) Lactate accumulation is the cause of muscle pain and cramping during

prolonged, strenuous exercise.(2) Lactate production during exercise lowers blood pH, which triggers faster

breathing.(3) The effects of both type I and type II diabetes are the same - inadequate

glucose uptake by cells.




MATCHING QUESTIONSAssign each of the characterizations on the left to one of the metabolic pathways listed in the response list on the right. Responses on the right may be used more than once or need not be used at all.

24.46 d Glucose is converted to two pyruvates.

24.47 b Glycogen is synthesized from glucose.

24.48 c Glycogen is broken down into free glucose units.

24.49 a Glucose is synthesized from pyruvate.

24.50 a Two C3 molecules combine to give a C6 molecule.


Assign each of the reaction characterizations on the left to one of the metabolic pathways listed in the responses on the right. Responses on the right may be used more than once or need not be used at all.

24.51 d Fructose 6-phosphate is the product formed in the second step of this process.

24.52 b Formation of UDP-glucose is part of this process.

24.53 a Oxaloacetate is the product formed in the first step of this process.

24.54 a Two trioses combine to form fructose1,6-bisphosphate as part of this process.

24.55 b Glucose 6-phosphate is converted to glucose1-phosphate as part of this process.


How many steps in glycolysis have the characteristics listed on the left? Respond using the response list on the right. Responses on the right may be used more than once or need not be used at all.

24.56 b ATP is converted to ADP.

24.57 c An isomerization reaction occurs.

24.58 b Substrate-phosphorylation occurs.

24.59 b A bisphosphate molecule is formed.

24.60 c A glycerate derivative is formed.

a) one stepb) two stepsc) three stepsd) four steps



What is the ATP yield per glucose molecule in each of the following processes? Respond using the list on the right. Responses on the right may be used more than once or need not be used at all.

24.61 a Glycolysis

24.62 d Glycolysis plus the common metabolic pathway

24.63 a Glycolysis plus oxidation of pyruvate to acetyl CoA

24.64 a Glycolysis plus reduction of pyruvate to lactate

24.65 a Glycolysis plus reduction of pyruvate to ethanol

a) 2 ATPb) 4 ATPc) 10 ATPd) 30 ATP

For each of the chemical changes on the left, choose from the response list on the right a correct name for the process or the conditions under which it occurs. Responses on the right may be used more than once or need not be used at all.

24.66 b Pyruvate to lactate

24.67 b Pyruvate to ethanol

24.68 a Glucose to pyruvate to lactate to pyruvate to glucose

24.69 c Glucose 6-phosphate to ribulose 5-phosphate

24.70 d Ribulose 5-phosphate to ribose 5-phosphate

a) Cori cycleb) an anaerobic processc) oxidative stage of pentose

phosphate pathwayd) nonoxidative stage of

pentose phosphate pathway


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