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BIOCHEM MODULE 4 EXAM QUESTIONS WITH CORRECT ANSWERS
"lactose is made from linking galactose and glucose. when this happens: a. a polysaccharide is formed b. gas is eliminated c. an epimer is formed d. an anomeric carbon is formed on carbon-
e. lactose forms by a condensation reaction - CORRECT ANSWER e. lactose forms by a
condensation reaction" "lactose is made from linking galactose and glucose. when this happens: a. gas is eliminated b. an anomeric carbon is formed on carbon- c. water is released d. an epimer is formed
e. an aldose is formed - CORRECT ANSWER c. water is released"
"which statement about starch and glycogen is false? a. both have beta-D-glucose monomers b. both starch and glycogen are energy storage polysaccharides c. both are homopolymers of glucose d. glycogen is more extensively branched that starch
e. both have O-glycosidic linkages - CORRECT ANSWER a. both have beta-D-glucose monomers
*starch and glycogen have alpha-D-glucose monomers"
"what is an anomeric carbon? - CORRECT ANSWER the new chiral center formed in ring
closure; it was the carbon containing the carbonyl in the straight-chain form attached to an -OR group, -OH group, C, and H"
"which arrow correctly identifies the atom that will become the anomeric carbon? - CORRECT
ANSWER carbon-1, which is at the top of the Fischer structure"
"the polysaccharide cellulose is most chemically similar to:
a. glycogen b. dextrose c. glucose d. chitin
e. starch - CORRECT ANSWER d. chitin"
"which of the following is the most common monosaccharide on earth? a. ribose b. cellulose c. chitin d. sucrose
e. glucose - CORRECT ANSWER e. glucose"
"the "D" in D-carbohydrates stands for: a. 3-dimensional b. dextrorotatory c. derivative d. design
e. double - CORRECT ANSWER b. dextrorotatory"
"table sugar is also known as: a. sucrose b. dextrose c. glucose d. galactose
e. glycogen - CORRECT ANSWER a. sucrose"
"amylopectin has alpha 1-->6 branching about every ___ residues. a. 1 to 10 b. 8 to 12 c. 10 to 30 d. 24 to 30
e. no branching - CORRECT ANSWER d. 24 to 30"
"besides C, H, and O, what other element is found in the structure of chitin?
B) Is this molecule D or L? - CORRECT ANSWER A) Carbon D, the penultimate carbon,
determines if the molecules is D or L. In the case of glucose, this would be carbon-5. B) The monosaccharide is L because the -OH group is on the left side." "on a Fischer projection, what is the carbon that is the second furthest away from the carbonyl
group is termed? - CORRECT ANSWER the penultimate carbon"
"What is the difference between amylose and amylopectin? - CORRECT ANSWER Amylose is a
linear chain of glucose joined together in alpha 1-->4 bonds in one continuous chain with no branching. These chains have a few thousand to a million glucose molecules bonded together and are referred to as the main chain. Like amylose, amylopectin has a long chain of glucose bonded together, but it also has branches every 24 to 30 glucose molecules apart from the main chain. These branches then have large numbers of residues connected by alpha 1-->4 connections. The branch points permit amylopectin to form larger compounds."
"what is the difference between epimer and anomer? - CORRECT ANSWER Epimers are
monosaccharides that differ in the orientation at only one carbon position. Anomers are the alpha and beta forms that differ only in the -OH orientation about the anomeric carbon that forms the hemiacetal group."
"polysaccharide vs. oligosaccharide - CORRECT ANSWER Polysaccharides are LONG chains of
20 or more monosaccharides joined together. Oligosaccharides consists of SHORT chains of monosaccharides joined together."
"what is a non-reducing end? - CORRECT ANSWER the end without a free anomeric carbon
that contains an o-glycosidic linkage" Which of the following monosaccharides is a ketose? Dihydroxyacetone Galactose Glucose Glyceraldehyde
Idose - CORRECT ANSWER dihydroxyacetone"
"When two carbohydrates are epimers:
One is a pyranose, the other a furanose One is an aldose, the other a ketose They differ in length by one carbon They differ only in the configuration about one carbon atom
They react differently with iodine - CORRECT ANSWER They differ only in the confirmation
about one carbon atom"
" - CORRECT ANSWER D.) alpha-D-glucose and beta-D-glucose"
"Lactose is made from linking galactose and glucose. When this happens, _____. Gas is eliminated An anomeric carbon is formed on carbon- Water is released An epimer is formed
An aldose is formed - CORRECT ANSWER water is released"
"Amylose and amylopectin are both polymers of: A) α-D-glucose B) β-D-glucose C) Galactose D) Idose
E) Maltose - CORRECT ANSWER A.) alpha-D-glucose"
"Which statement about starch and glycogen is false? A) Both have β-D-glucose monomers B) Both starch and glycogen are energy storage polysaccharides C) Both are homopolymers of glucose D) Glycogen is more extensively branched than starch
E) Both have O-glycosidic linkages - CORRECT ANSWER A.) both have beta-D-Glucose
monomers" "Which monosaccharide is not a six-carbon monosaccharide? Fructose Ribose
"identify the hemiacetal bond - CORRECT ANSWER includes the anomeric carbon, H, OH, and
O in the ring"
"tell the difference between alpha beta and D and L configurations - CORRECT ANSWER D & L:
look at the penultimate carbon L=left D=right alpha and beta. Alpha is the OH on the top of the anomeric carbon Beta is under the anomeric carbon" "Table sugar is also known as: Sucrose Dextrose Glucose Galactose
Glycogen - CORRECT ANSWER sucrose"
"Amylopectin has α1 → 6 branching about every________ residues. 1 to 10 8 to 12 10 to 30 24 to 30
No branching - CORRECT ANSWER 24 to 30"
"What element besides C, H, and O is found in the chitin? Br N P S
Cl - CORRECT ANSWER N"
"The word saccharide means ___________. Sugar Carbohydrate Energy molecule Sucrose
Starch - CORRECT ANSWER sugar"
"What is the difference between amylose and amylopectin? - CORRECT ANSWER amylose is a
single chain of glucose molecules connected by alpha 1 to 4 linkages. However, amylopectin also contains a main chain connect by alpha 1 to 4b linkages but it branches every 24 to 30 glucose residues. the branches are a different type of linkage called alpha 1 to 6 linkages however within the branched they contain alpha 1 to 4 linkages." "A) Which carbon in the following molecule determines if the molecule is D or L? Indicate the letter corresponding the correct carbon ("A",
"B", etc.) and explain. B) Is this molecule D or L? - CORRECT ANSWER the penultimate carbon
is the carbon that determines whether the molecule is D or L. In this scenario, the monosaccharide is D." Which of the following monosaccharides is a ketose? Dihydroxyacetone Galactose Glucose Glyceraldehyde
Idose - CORRECT ANSWER Dihydroxyacetone"
"Which of the following monosaccharides is not an aldose? Erythrose Dihydroxyacetone Glucose Glyceraldehyde
Ribose - CORRECT ANSWER Dihydroxyacetone"
"When two carbohydrates are epimers: One is a pyranose, the other a furanose One is an aldose, the other a ketose They differ in length by one carbon They differ only in the configuration about one carbon atom
They react differently with iodine - CORRECT ANSWER They differ only in the configuration
about one carbon atom" "Which pair is anomeric? A) D-glucose and D-fructose B) D-glucose and L-fructose C) -D-glucose and β-D-glucoseβ
D) ⍺-D-glucose and β-L-glucose - CORRECT ANSWER C.) ⍺-D-glucose and β-D-glucose"
Anomers Aldoses Ketoses Epimers
Pentoses - CORRECT ANSWER Epimers"
"The two monosaccharides shown below could best be described as: Anomers Ketoses Aldoses Pentoses
Epimers - CORRECT ANSWER Aldoses"
"Which arrow correctly identifies the atom that will become the anomeric carbon? - CORRECT
ANSWER A"
"The polysaccharide cellulose is most chemically similar to: Glycogen Dextrose Glycogen Chitin
Starch - CORRECT ANSWER Chitin"
"Which of the following is the most common monosaccharide on earth? Ribose Cellulose Chitin Sucrose
Glucose - CORRECT ANSWER Glucose"
"The "D" in the D-carbohydrates stands for: Derivation Double Disaccharide 3-dimensional
Dextrorotatory - CORRECT ANSWER Dextrorotatory"
"Which compound does not fit the formal definition of a carbohydrate? A. C6H12O B. C7H10O C. C8H16O D. C3H6O
E. C4H8O4 - CORRECT ANSWER B. C7H10O7"
"Identify the hemiacetal bond - CORRECT ANSWER includes the anomeric carbon, H, OH, and
O in the ring"
"Tell the difference between alpha beta and D and L configurations - CORRECT ANSWER D & L:
look at the penultimate carbon L=left D=right alpha and beta. Alpha is the OH on the top of the anomeric carbon Beta is under the anomeric carbon" "Table sugar is also known as: Sucrose Dextrose Glucose Galactose
Glycogen - CORRECT ANSWER Sucrose"
"Amylopectin has α1 → 6 branching about every________ residues. 1 to 10 8 to 12 10 to 30 24 to 30
No branching - CORRECT ANSWER 24 to 30"
"What element besides C, H, and O is found in the chitin? Br N P S
A) How many monosaccharide units are furanoses and how many are pyranoses? B) What is the linkage between the monosaccharides?
C) Is this a reducing sugar? - CORRECT ANSWER a.) 2 pyranoses and 0 furanoses
b.) beta 1 to 4 c.) yes because it has a free anomeric carbon" "A hiker is lost in the wilderness and without food. He runs across several beetles with hard chitin
exoskeletons. Would he get nutrition in the form of glucose from eating these beetles? Explain. -
CORRECT ANSWER Chitin is made with β1—>4 bonds, however humans can't break this bond
as they can only break down alpha 1 to 4. The hiker wouldn't consume glucose and shouldn't eat the beetles."
"What is the difference between amylose and amylopectin? - CORRECT ANSWER Amylose is a
single chain of glucose with no branching. Amylopectin is a long chain of glucose with branching every 24 to 30 molecules." "A) Which carbon in the following molecule determines if the molecule is D or L? Indicate the letter corresponding the correct carbon ("A", "B", etc.) and
explain. B) Is this molecule D or L? - CORRECT ANSWER The penultimate carbon is the carbon
that determines whether the molecule is D or L. In this scenario, the monosaccharide is L." "Glycogen has ⍺1--->6 branching about every _____ residues. 1 to 10 8 to 12 10 to 30
24 to 30 - CORRECT ANSWER 8 to 12"
"What is the configuration of the following compound? - CORRECT ANSWER "L""
"How are oligosaccharides and polysaccharides similar in their structure? How are they
different? - CORRECT ANSWER Oligosaccharides are polymers of 2 to 20 monosaccharides
joined together. Polysaccharides are more than 20 monosaccharides joined together. Polysaccharides can have branches, while oligosaccharides don't." “which of the following monosaccharides is not an aldose? a. erythrose b. dihydroxyacetone c. glucose
d. glyceraldehyde
e. ribose - CORRECT ANSWER b. dihydroxyacetone"
"when two monosaccharides are epimers: a. they differ only in the configuration about the penultimate carbon b. one is an aldose, the other a ketose c. they differ only in the configuration about one carbon atom d. they form o-glycosidic bonds
e. they are oligosaccharides - CORRECT ANSWER c. they differ only in the configuration about
one carbon atom" "which pair is anomeric? a. D-glucose and D-fructose b. D-glucose and L-fructose c. D-glucose and L-glucose d. alpha-D-glucose and beta-D-fructose
e. alpha-D-glucose and beta-D-glucose - CORRECT ANSWER e. alpha-D-glucose and beta-D-
glucose" "chitin and cellulose are both polymers of: a. alpha-D-glucose b. galactose c. beta-D-glucose d. idose
e. maltose - CORRECT ANSWER c. beta-D-glucose
*starch, glycogen, amylose, and amylopectin = alpha-D-glucose" "amylose and amylopectin are both polymers of: a. alpha-D-glucose b. beta-D-glucose c. galactose d. idose
e. maltose - CORRECT ANSWER a. alpha-D-glucose
*cellulose and chitin = beta-D-glucose *starch, glycogen, amylose, and amylopectin = alpha-D-glucose" "which statement about starch and glycogen is false?
"the following monosaccharides are covalently bonded. what type of bond unites them? -
CORRECT ANSWER alpha 1-->6"
"which statement about cellulose is true? a. cellulose is found in plants b. cellulose in the primary storage polysaccharide of animal cells c. cellulose is found in DNA d. the glucose residues of cellulose contain the same configuration as the glucose residues of amylose
e. cellulose is an epimer of chitin - CORRECT ANSWER a. cellulose is found in plants"
"which statement about cellulose is true? a. cellulose is the primary storage polysaccharide of animal cells b. cellulose is a highly branched polysaccharide c. cellulose is a homopolysaccharide d. the glucose residues of cellulose contain the same configuration as the glucose residues of amylose
e. cellulose is an anomer of chitin - CORRECT ANSWER c. cellulose is a homopolysaccharide"
"which compound does not fit the formal definition of a carbohydrate? a. C6H12O b. C7H10O c. C8H16O d. C3H6O
e. C4H8O4 - CORRECT ANSWER b. C7H10O7"
"what is a hemiacetal bond? - CORRECT ANSWER a functional group that contains an
anomeric carbon bonded to an -OR group, -OH group, alkyl chain, and H"
"what is the difference between alpha/beta and D/L configurations? - CORRECT ANSWER
alpha = -OH on top of the anomeric carbon beta = -OH under the anomeric carbon D = -OH on right of penultimate (second to last) carbon L= -OH on left of penultimate (second to last) carbon" "sucrose is also known as: a. lactose
b. milk sugar c. chitin d. table sugar
e. glycogen - CORRECT ANSWER d. table sugar"
"A) How many monosaccharide units are furanoses, and how many are pyranoses? B) What is the linkage between the monosaccharides?
C) Is this a reducing sugar? - CORRECT ANSWER A) 0 furanoses and 2 pyranoses
B) beta 1--> C) Yes, this is a reducing sugar because a true anomeric carbon is present."
"Table sugar dissolves easily in water. Given its structure, explain why this is. - CORRECT
ANSWER Sucrose contains -OH groups, which can form hydrogen bonds with H2O. These
noncovalent interactions of the hydrogen bonds allows table sugar to dissolve in water through the formation of an aqueous solution." "The following oligosaccharide interacts favorable with water. What is the source of the ability of
the interaction between H2O and this carbohydrate. - CORRECT ANSWER The -OH groups of
the following oligosaccharide form hydrogen bonds with water molecules. These noncovalent interactions permit solubility of the oligosaccharide in water by forming an aqueous solution."
"Explain in molecular terms why humans cannot use cellulose as a nutrient. - CORRECT
ANSWER Humans cannot use cellulose as a nutrient because human enzymes cannot
breakdown the bonds associated with it. Cellulose contains a beta 1-->4 linkage, and human enzymes can only split alpha 1-->4 linkages. Because cellulose linkages cannot be broken down by the human body, it cannot be used as a nutrient." "A hike is lost in the wilderness and without food. He runs across several beetles with hard chitin
exoskeletons. Would he get nutrition in the form of glucose from eating these beetles? Explain. -
CORRECT ANSWER The exoskeleton of beetles are composed of chitin. Chitin is made of
glucose residues with beta 1-->4 linkage, however, human enzymes cannot breakdown this type of linkage. Human enzymes are able to breakdown alpha 1-->4 linkages only. Therefore, the hiker will not intake glucose or get nutrition from the beetle and should not eat it." "How are oligosaccharides and polysaccharides similar in their structure? How are they
different? - CORRECT ANSWER Oligosaccharides and polysaccharides are both composed of
monosaccharides, which are the functional unit of carbohydrates. However, oligosaccharides consist of shorts chains of monosaccharides joined together, and polysaccharides consists of long chains of 20 or more monosaccharides joined together. Polysaccharides form linear structures as well as highly branched structures."
The glucose residues of cellulose contain the same configuration as the glucose residues of amylose
Cellulose is an anomer of chitin - CORRECT ANSWER cellulose is a homopolysaccharide"
"Some carbohydrates form a(n)___________ structure, which resembles a structure in proteins. A) αform B) β-turn C) βeta-sheet D) D-configuration
E) α-helix - CORRECT ANSWER E.) alpha- helix"
"The equilibrium between _________ structures is called mutarotation. A) Anomer and epimer B) α andβ C) L and D D) Helix and beta sheet
E) None of the above - CORRECT ANSWER B.) alpha and beta"
"Consider the functions of carbohydrates. Which of the following is not a function of these molecules? Structure Energy storage Enzyme structure Both A and B
Both A and C - CORRECT ANSWER enzyme structure"
"Table sugar dissolves easily in water. Given its structure, explain why this is. - CORRECT
ANSWER Surcrose contains -OH groups which can form hydrogen bonds with H2O. these non-
covalent interactions allow solubility by permitting carbs to interact with H2O and become an aqueous solution." "A) In the above structure, how many monosaccharide units are furanoses and how many are pyranoses? B) What is the linkage between the monosaccharides?
C) Is this a reducing sugar? - CORRECT ANSWER a.) 2 pyranoses and 0 furanoses
b.) beta 1 to 4 c.) yes because it has a free anomeric carbon"
"A hiker is lost in the wilderness and without food. He runs across several beetles with hard chitin
exoskeletons. Would he get nutrition in the form of glucose from eating these beetles? Explain. -
CORRECT ANSWER Chitin is made out glucose residues with the beta 1 to 4 bond however
human enzymes cannot break down this specific glucose residue because they can only act upon the alpha 1 to 4. so the hiker will not intake any glucose from eating the beetles and he should not eat the beetles." "Based on the form of the cyclic sugar below in a Haworth projection, which Fischer projection
formula could have formed this structure? - CORRECT ANSWER D"
"The organic molecule that is produced abundantly by photosynthesis is Ribose Glucose Cellulose Chitin
Sucrose - CORRECT ANSWER Glucose"
"The following monosaccharides are covalently bonded. What type of bond unites them? -
CORRECT ANSWER A glycosidic bond unites them."
"Which statement about cellulose is true? Cellulose is the primary storage polysaccharide of animal cells Cellulose is a highly branched polysaccharide Cellulose is a homopolysaccharide The glucose residues of cellulose contain the same configuration as the glucose residues of amylose
Cellulose is an anomer of chitin - CORRECT ANSWER Cellulose is a homopolysaccharide"
