Question 1

Dairy cattle were unknown in Thai culture until recently,and 97% percent of Thai people are lactose intolerant as adults.Which explanation for such widespread lactose intolerance is most likely correct?

Accepted Answer

A)  Allergies are becoming more common in humans as more chemicals are being encountered during longer lifetimes.
B)  Evolutionarily,producing an enzyme to break down a sugar that will never be encountered is wasteful.
C)  The ability to digest sugar in milk is determined by environment,and most humans are not exposed to milk as a food source beyond childhood years.
D)  There is no good explanation for this situation in humans.E) A) and D)
F) A) and C) B

Question 2

What is the major structural difference between starch and glycogen?

Accepted Answer

A)  the types of monosaccharide subunits in the molecules
B)  the type of glycosidic linkages in the molecule
C)  whether glucose is in the α or β form
D)  the amount of branching that occurs in the moleculeE) A) and D)
F) A) and C)

Question 3

Use the following paragraph to answer the corresponding question(s) .
Masatomo Kawakubo et al.reported in Science in August 2004 that the human stomach contains a natural,carbohydrate-based antibiotic that probably protects a large portion of the population from various diseases caused by the bacterium Helicobacter pylori.This bacterium has been linked to peptic ulcers,gastritis,and stomach cancer.This naturally occurring antibiotic is described by Kawakubo as having a terminal α1,4-linked N-acetylglucosamine (NAG) ,and it acts by inhibiting the biosynthesis of a major component of the cell wall in H.pylori.[Source: M.Kawakubo et al. ,Science 305 (2004) : 1003.]
-Refer to the paragraph about Kawakubo's group.Kawakubo's group created a glycoprotein with a terminal NAG (i.e. ,a protein with NAG attached to its end) .Their hypothesis is that the terminal NAG and not the protein component is responsible for the damage to the cell wall in H.pylori.What would be the most appropriate control for testing this hypothesis?

Accepted Answer

A)  Grow H.pylori in a test tube (in vitro) with no glycoprotein.
B)  Destroy the H.pylori by exposing them to a hypotonic solution.Then add the glycoprotein and observe.
C)  Expose other species of bacteria to the glycoprotein.
D)  Grow H.pylori in a test tube with glycoprotein that has its terminal NAG removed.E) None of the above
F) C) and D)

Question 4

The chemical formula for fat is C₁₂H₂₄O₃.The analogous chemical formula for carbohydrates is C₁₂ H ₂₄ O₁₂.Given the differences in their chemical formulas,why do you think that plants generally store their
energy in the form of carbohydrates,but animals generally store their energy in the form of fats?

Accepted Answer

Fats store more energy per unit mass.Ani...

Question 5

You isolate an organic molecule that contains C,H,O,N,and S.This molecule _____.

Accepted Answer

A)  is definitely a sugar
B)  could be a glycoprotein
C)  is definitely a nucleic acid
D)  is definitely a protein that is not glycosylatedE) B) and C)
F) A) and C)

Question 6

Carbohydrates have been shown to form _____.

Accepted Answer

A)  only in biotic conditions (inside living cells) 
B)  in biotic and abiotic conditions,but only if nucleotides and RNA have already formed
C)  in biotic and abiotic conditions,including outer space
D)  only in biotic conditions,when enough free energy is available to allow their formationE) B) and C)
F) None of the above

Question 7

Peptidoglycan forms sheets that stiffen the cell walls of bacteria.How is the formation of sheets possible?

Accepted Answer

A)  The polysaccharides in peptidoglycan are highly branched and form a network.
B)  The glycosidic linkages between monosaccharides in peptidoglycan are extraordinarily strong.
C)  Individual strands are joined by peptide bonds a type of covalent bond.
D)  The polysaccharides in peptidoglycan form helical structures,as in cellulose.E) B) and D)
F) None of the above

Question 8

A glycosidic linkage is analogous to which of the following in proteins?

Accepted Answer

A)  an amino group
B)  a peptide bond
C)  a disulfide bond
D)  a β-pleated sheetE) A) and B)
F) B) and D)

Question 9

Which of the following can vary among monosaccharides?

Accepted Answer

A)  the number of carbon atoms
B)  the presence of a carbonyl group
C)  the presence of hydroxyl groups
D)  all of the aboveE) B) and C)
F) C) and D) A

Question 10

Which of the following carbohydrates contains a peptide bond?

Accepted Answer

A)  Carbohydrates don't contain peptide bonds;only proteins do.
B)  cellulose
C)  chitin
D)  peptidoglycan
E)  glycogenF) None of the above
G) A) and C)

Question 11

Compare the molecular formula of a carbohydrate (CH₂O) n with that of carbon dioxide (CO₂) .What does the presence of hydrogen atoms in carbohydrates indicate?

Accepted Answer

A)  Carbohydrates are more reduced than carbon dioxide.
B)  Carbohydrates are more oxidized than carbon dioxide.
C)  Every carbon atom in a carbohydrate is bonded to four different atoms.
D)  Carbohydrates contain a carbonyl functional group.E) All of the above
F) A) and B)

Question 12

How do the α and β forms of glucose differ?

Accepted Answer

A)  Their ring structures differ in the location of a hydroxyl group.
B)  Their linear structures differ in the location of a hydroxyl group.
C)  The α form can be involved in 1,4 and 1,6 glycosidic linkages;the β form can participate only in 1,4 linkages.
D)  The oxygen atom inside the ring is located in a different position.E) All of the above
F) None of the above

Question 13

Bacteria,insects,and plants use carbohydrates to build structures.Which of the following is true of structural carbohydrates?

Accepted Answer

A)  Different types of pentose monomers form the basis of all carbohydrate-based structures.
B)  Structural carbohydrates show a high degree of branching.
C)  All structural carbohydrates are made from the same monomer,a-glucose.
D)  Structural carbohydrates are long strands of monomers;the strands are chemically linked together to form a network.
E)  None of A,B,C,or D is true.F) A) and D)
G) A) and C)

Question 14

Which of the following structural features is common to cellulose,chitin,and peptidoglycan?

Accepted Answer

A)  They are all composed of glucose in either the α or β form.
B)  They all contain peptide bonds.
C)  They can all form bonds between polymer chains that create parallel strands.
D)  They are all composed of highly branched fibers.E) A) and B)
F) B) and D) C

Question 15

Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?

Accepted Answer

A)  α-1,4-glycosidic linkage
B)  β-1,4-glycosidic linkage
C)  α-1,6-glycosidic linkage
D)  β-1,6-glycosidic linkageE) B) and D)
F) All of the above

Question 16

If you were going to develop a new antibiotic against bacteria,you would probably need to become an expert on which of these carbohydrates?

Accepted Answer

A)  glycogen
B)  chitin
C)  peptidoglycan
D)  cellulose
E)  starchF) A) and C)
G) All of the above

Question 17

Why do plants require sunlight?

Accepted Answer

A)  Sunlight helps plants break down their food products so they can extract the energy stored in them.
B)  Sunlight energy can be used by plants to reduce the carbon atoms in carbon dioxide.
C)  Sunlight oxidizes carbon dioxide and water to form glucose.
D)  Sunlight can be used directly by plants to perform a number of physiological processes.E) A) and B)
F) A) and C)

Question 18

Cell walls are used by many different organisms for protection from their environment and structural support.These cell walls must obviously be insoluble in water;otherwise,they would dissolve the first time the organism got wet.Which of the following carbohydrates would you expect to be the most soluble in water?

Accepted Answer

A)  starch
B)  peptidoglycan
C)  cellulose
D)  chitinE) B) and C)
F) None of the above

Question 19

Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose.Why is this logical?

Accepted Answer

A)  The geometry of the bonds is different,and the shapes of enzyme active sites are highly specific.
B)  Starch is held together by hydrogen bonding,not covalent bonding.
C)  Cellulose molecules are highly branched,and enzymes are too bulky to fit.
D)  Starch is held together by peptide bonds,not glycosidic linkages.E) B) and C)
F) B) and D)

Question 20

Scientists believe polysaccharides played little role,if any,in chemical evolution.Which of the following is true of polysaccharides,which leads scientists to discount them as the first life-forms?

Accepted Answer

A)  They catalyze chemical reactions.
B)  There is complementary pairing between monosaccharides,so they can provide the information for copying themselves.
C)  Glycosidic linkages form spontaneously between monosaccharides.
D)  None of A,B,or C is true-they are all false.E) B) and C)
F) All of the above

Exam 5: An Introduction to Carbohydrates

Dairy cattle were unknown in Thai culture until recently,and 97% percent of Thai people are lactose intolerant as adults.Which explanation for such widespread lactose intolerance is most likely correct?

Correct Answer
verified
B

What is the major structural difference between starch and glycogen?

Correct Answer
verified

Correct Answer
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Correct Answer
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Fats store more energy per unit mass.Ani...
View Answer

You isolate an organic molecule that contains C,H,O,N,and S.This molecule _____.

Correct Answer
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Carbohydrates have been shown to form _____.

Correct Answer
verified

Peptidoglycan forms sheets that stiffen the cell walls of bacteria.How is the formation of sheets possible?

Correct Answer
verified

A glycosidic linkage is analogous to which of the following in proteins?

Correct Answer
verified

Which of the following can vary among monosaccharides?

Correct Answer
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A

Which of the following carbohydrates contains a peptide bond?

Correct Answer
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Compare the molecular formula of a carbohydrate (CH₂O) n with that of carbon dioxide (CO₂) .What does the presence of hydrogen atoms in carbohydrates indicate?

Correct Answer
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How do the α and β forms of glucose differ?

Correct Answer
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Bacteria,insects,and plants use carbohydrates to build structures.Which of the following is true of structural carbohydrates?

Correct Answer
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Which of the following structural features is common to cellulose,chitin,and peptidoglycan?

Correct Answer
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C

Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?

Correct Answer
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If you were going to develop a new antibiotic against bacteria,you would probably need to become an expert on which of these carbohydrates?

Correct Answer
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Why do plants require sunlight?

Correct Answer
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Correct Answer
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Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose.Why is this logical?

Correct Answer
verified

Scientists believe polysaccharides played little role,if any,in chemical evolution.Which of the following is true of polysaccharides,which leads scientists to discount them as the first life-forms?

Correct Answer
verified

Exam 5: An Introduction to Carbohydrates

Dairy cattle were unknown in Thai culture until recently,and 97% percent of Thai people are lactose intolerant as adults.Which explanation for such widespread lactose intolerance is most likely correct?

Correct AnswerverifiedB

What is the major structural difference between starch and glycogen?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedFats store more energy per unit mass.Ani...View AnswerShow Answer

You isolate an organic molecule that contains C,H,O,N,and S.This molecule _____.

Correct AnswerverifiedShow Answer

Carbohydrates have been shown to form _____.

Correct AnswerverifiedShow Answer

Peptidoglycan forms sheets that stiffen the cell walls of bacteria.How is the formation of sheets possible?

Correct AnswerverifiedShow Answer

A glycosidic linkage is analogous to which of the following in proteins?

Correct AnswerverifiedShow Answer

Which of the following can vary among monosaccharides?

Correct AnswerverifiedA

Which of the following carbohydrates contains a peptide bond?

Correct AnswerverifiedShow Answer

Compare the molecular formula of a carbohydrate (CH₂O) n with that of carbon dioxide (CO₂) .What does the presence of hydrogen atoms in carbohydrates indicate?

Correct AnswerverifiedShow Answer

How do the α and β forms of glucose differ?

Correct AnswerverifiedShow Answer

Bacteria,insects,and plants use carbohydrates to build structures.Which of the following is true of structural carbohydrates?

Correct AnswerverifiedShow Answer

Which of the following structural features is common to cellulose,chitin,and peptidoglycan?

Correct AnswerverifiedC

Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?

Correct AnswerverifiedShow Answer

If you were going to develop a new antibiotic against bacteria,you would probably need to become an expert on which of these carbohydrates?

Correct AnswerverifiedShow Answer

Why do plants require sunlight?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose.Why is this logical?

Correct AnswerverifiedShow Answer

Scientists believe polysaccharides played little role,if any,in chemical evolution.Which of the following is true of polysaccharides,which leads scientists to discount them as the first life-forms?

Correct AnswerverifiedShow Answer

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B

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Fats store more energy per unit mass.Ani...
View Answer

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A

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C

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