Biochemistry : Identification by Structure
Study concepts, example questions & explanations for Biochemistry
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Example Questions
Example Question #11 : Identification By Structure
Which of the following are true about phospholipids in structure?
I. Phospholipids consist of a polar group and nonpolar fatty acids, connected by glycerol.
II. Glycerophospholipids are a type of phospholipids and are composed of choline, phosphate, glycerol, and two fatty acids.
III. Sphingolipids, like sphingomyelin, are a type of phospholipids that have choline, phosphate, sphingosine groups and only one fatty acid.
I, II, and III
II only
I and III
I only
II and III
I, II, and III
Phospholipids have two fatty acid chains, with a length of 14-20 carbon atoms each, that attach to the carbons of the glycerol molecule. Examples of glycerophospholipids are phosphatidyl glycerol (PG). Examples of sphingolipids, like sphingomyelin, have choline, phosphate, sphingosine groups and only one fatty acid.
Example Question #1 : Identifying Specific Carbohydrate Structures
Which if the following statements about glucose is false?
None of the other answers is false.
In an aqueous solution, glucose can be found in open-chain, pyranose, or furanose form
It has the same molecular mass as fructose
It cannot isomerize into fructose
The anomeric effect has an influence on glucose’s mutarotation.
It cannot isomerize into fructose
Glucose and fructose have the same constituent atoms, so they have the same molecular mass (about 
Example Question #1 : Identifying Specific Carbohydrate Structures
The molecule sucrose is shown below
What is the full name for this molecule?
None of these
Sucrose is the molecule shown below(in Haworth projection).
We recognize that it's a disaccharide, and that the first molecule is 
Example Question #63 : Identifying Biochemical Molecules
Which of the following sugars is lactose?
Beta-D-glucopyranosyl-1,4-D-glucopyranose
Beta-D-galactopyranosyl-(1,4)-D-glucopyranose
Beta-L-galactopyranosyl-1,4-D-glucopyranose
Alpha-D-galactopyranosyl-(1,4)-D-glucopyranose
Beta-D-galactopyranosyl-(1,4)-D-glucopyranose
Lactose is made by joining a 
Example Question #1 : Identifying Specific Carbohydrate Structures
What is the difference between two carbohydrates that are epimers and two carbohydrates that are anomers?
The location of the change in configuration
The number of carbons that have differences in configuration
The shape of the ring
The number of rings
The location of the change in configuration
A set of anomers will differ in the configurations of their carbonyl carbons only while a set of epimers will differ in configuration in only one carbon that is not the carbonyl carbon.
Example Question #1 : Identifying Specific Carbohydrate Structures
Glucose and galactose share a chemical formula and are known as epimers.
What is the difference between glucose and galactose?
They differ in configuration around the fourth carbon
Galactose is spread further apart than glucose
Galactose is a ketose
Glucose is bigger than galactose
They differ in configuration around the fourth carbon
As a pair of epimers, this means that both glucose and galactose are the same in configuration in all carbons except for one non-carbonyl carbon. To differ in the configuration of the carbonyl carbon makes an anomer not an epimer. Both glucose and galactose are aldoses.
Example Question #71 : Identifying Biochemical Molecules
The following are the common substrates, enzymes and the associated products.
Although cellulose provides the same carbohydrates as maltose, it cannot be broken down by humans. What type of linkage prevents humans from breaking down the polysaccharide?
Alpha-1,4 glycosidic bond
Beta-1,4 glycosidic bond
Beta-1,6 glycosidic bond
None of these
Alpha-1,6 glycosidic bond
Beta-1,4 glycosidic bond
The beta-1,4 glycosidic bond is not a substrate for any human enzymes, and is thus left untreated.
Example Question #4 : Identifying Specific Carbohydrate Structures
Which of the following enzymes is correctly paired with its products and substrates?
An easy way to distinguish the substrate and the product from the enzyme is that the enzyme will end in "ase". The following are the common substrates, enzymes and the associated products.
Example Question #5 : Identifying Specific Carbohydrate Structures
Which of the following enzymes is correctly paired with its products and substrates?
An easy way to distinguish the substrate nd the product from the enzyme is that the enzyme will end in "ase". The following are the common substrates, enzymes and the associated products.
Example Question #6 : Identifying Specific Carbohydrate Structures
Which of the following enzymes is correctly paired with its products and substrates?
An easy way to distinguish the substrate and the product from the enzyme is that the enzyme will end in "ase". The following are the common substrates, enzymes and the associated products.
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