Biochem test 3
Cellulose is NOT highly branched because it ________.
Does not have α (1→6) linkages
Enter the product of this Schiff base formation reaction: where R represents attachment to a protein, by editing the reagents given.
Drag the H2N to the O
D-glyceraldehyde and L-glyceraldehyde are...
Enantiomers
In which manner is glycogen is degraded by enzymes?
Enzymes break up glycogen from its nonreducing end one glucose at a time
The Fischer projections of linear D-glucose and D-galactose are shown below. These two molecules are ________.
Epimers
The structures of D-ribose and D-arabinose are shown below. These two molecules are ________.
Epimers
Complete the Fischer projection of the following molecule such that the amino group is adjacent to the topmost carboxylic acid
For dicarboxylic acids, the highest priority carbon is determined by the position of substituents. The carboxylic acid adjacent to the amino group is higher priority.
Amylose differs from amylopectin in that amylose ________.
Forms a helix and no branch points
Which of the following is an example of a monosaccharide?
Galactose
Maltose has a (1→4) α linkage between glucose and ________.
Glucose
If glucose supplies the anomeric carbon atom in a glycosidic link, the resulting compound is classified as a ________.
Glucoside
O-linked glycans are attached to proteins through the side chain of all of the following EXCEPT ________.
Glutamate
Which is a general term indicating a carbohydrate polymer?
Glycan
Monosaccharide derivatives in which an amino group replaces one of the hydroxyl groups may have important roles in ________.
Sialic acid
The storage polysaccharides are ________ in plants and ________ in animals.
Starch Glycogen
The chemical name for table sugar is ________ and it is a ________.
Sucrose disaccharide
Which is TRUE about naturally occurring monosaccharides?
The D-isomers predominate
Synthesis of sugar polymers is enzyme catalyzed and requires activated monomers like ________ in lactose biosynthesis.
UDP-Galactose
Anomers can be interconverted ________.
Via a linear intermediate
The most common carbohydrate, _______, has six carbon atoms.
glucose
Classify the carbohydrate tagatose by both the carbonyl group and the number of carbon atoms.
ketohexose
If a carbohydrate, like xylulose, has five carbon atoms and a carbonyl group on the second carbon, it is called a(n)
ketopentose
Any carbohydrate with the carbonyl group on the second carbon is a(n) _________
ketose
Describe the function of uridine triphosphate (UTP) in carbohydrate metabolism.
uridine diphosphate glucose glucose oligoligosaccharides and polysaccharides
Which is NOT a similarity between glycogen and amylopectin?
**Each has branches of similar chain length.** Each has one reducing end and many nonreducing ends. They each contain about 6000 glucose residues. Each is highly branched.
Complete the Fischer projection of the following molecule:
-The vertical lines represent the carbons going back into the page -The horizontal lines represent atoms coming out of the page.
How many chiral carbon atoms does the monosaccharide glucose have?
4
Carbohydrates are components of the following ________.
-Nucleic acids -The membrane of red blood cells -The bacterial cell wall
Assign the name of each sugar to its corresponding aldose or ketose. 1) D-erythrose A) aldohexose 2) D-glucose B) ketopentose 3) D-ribose C) aldopentose 4) D-xylulose D) aldotetrose
1. D-erythrose D: aldotetrose 2. D-glucose A: aldohexose 3. D-ribose C: aldopentose 4. D-xylulose B: ketopentose
Which of the following represent the function of glycoproteins, a group of biomolecules that contain both protein and carbohydrates? 1. They can serve as hormones. 2. They are involved in cell adhesion and cellular recognition. 3. They can serve structural roles. 4. They can serve as an aid to increase the viscosity of various bodily fluids.
1. They can serve as hormones. 2. They are involved in cell adhesion and cellular recognition. 4. They can serve as an aid to increase the viscosity of various bodily fluids.
Which of the following monosaccharides are ketoses? 1. xylulose 2. idose 3. tagatose 4. psicose
1. xylulose 3. tagatose 4. psicose
Below is the structure for a cyclic D-monosaccharide. Which is the anomeric carbon atom?
2
How many hemiacetal rings with a different connectivity between atoms (ignoring stereoisomers) can be made from glucose, assuming that rings that would generate ring strain (fewer than four atoms or greater than six atoms) are not favored?
4
A ribopyranose contains ________ carbon atoms while a ribofuranose has ________ carbon atoms.
5 5
The structure of D-arabinose is shown below. How many stereoisomers are possible for this molecule (including the one shown)?
8
A person has the blood type A. This person can safely receive blood from which blood group?
A O
Why is a type AB individual considered a universal acceptor?
A type AB individual carries both A and B oligosaccharides, and therefore will not recognize either A or B as foreign in donated blood.
Why is a type O individual considered a universal blood donor?
A type O individual does not produce the antigenic A or B oligosaccharides and hence, can donate blood to any recipient without stimulating an immune reaction.
The compounds α-D-fructofuranose and β-D-fructofuranose are ________.
Anomers
Heparin is a highly-sulphated glycosaminoglycan that acts as an ________.
Anticoagulant
N-linked glycans are attached to proteins through N-acetylglucosamine or N-acetyl galactosamine to the amide side chain of ________.
Asparagine
The bacterial cell wall is sensitive to penicillin because it ________.
Binds to an enzyme which recognizes D-alanine-D-alanine dipeptide
In a Haworth projection for D-glucose, what would be the position (above or below the ring) for the hydroxyl groups at C-2, C-3, and C-4?
C-2: below C-3: above C-4: below
Chitin is all of the following EXCEPT ________.
Composed of linear fibrils like cellulose **Found in plant cell walls** Composed of N-acetylglucosamine subunits Found in insect and crustacean shells
What type of bond links the monomers of a polysaccharide?
Glycosidic bond
A reducing sugar is one that ________.
Has a hemiacetal group
Pentoses and hexoses can form stable ring structures by internal ________ formation.
Hemiacetal
The functional group shown is a(n) ________.
Hemiketal
Examine the Fischer projection below. How is this carbohydrate classified?
L enantiomer; ketopentose
Below is the open-chain structure of the monosaccharide D-tagatose, which is a ketohexose. Like most monosaccharides, it has more than one chiral carbon. Select all of the chiral carbon atoms.
Marked with a 1
Amylose and amylopectin are the principle storage polysaccharides of ________.
Plants
Select the statement that is incorrect.
Polysaccharides are carbohydrates. **All carbohydrates have the general formula Cn(H2O)n.** Simple sugars are carbohydrates. Simple sugars, disaccharides, and polysaccharides contain only carbon, oxygen, and hydrogen atoms.
Indicate whether the structures shown are R or S in the absolute system.
R: Clockwise S: Counterclockwise
Classify each anomer as alpha (α) or beta (β).
The orientation of sugar as alpha or beta impacts the property of the sugar.
What distinguishes an aldonic acid from an alduronic acid?
The oxidation of the aldehyde group in an aldonic acid and the oxidation of the highest numbered carbon in the alduronic acid.
Identify which of the carbons in this molecule are chiral and which are not.
To be chiral, an atom must have four different groups or atoms attached to it.
Identify which of the carbons in this molecule are chiral and which are not. Part B.
To be chiral, an atom must have four different groups or atoms attached to it.
With the carbonyl group on the end of a six-carbon chain, the carbohydrate would be classified as a(n)
aldohexose
A monosaccharide is a(n) ______ if the carbonyl group is on the end of the carbon chain.
aldose
Glyceraldehyde is an example of a(n) _________ because it has three carbon atoms.
aldotriose
