Biochemistry : Identifying Biochemical Molecules

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #3 : Identifying Specific Carbohydrate Structures

Glucose and galactose share a chemical formula and are known as epimers.

What is the difference between glucose and galactose?

Possible Answers:

They differ in configuration around the fourth carbon

Glucose is bigger than galactose

Galactose is spread further apart than glucose

Galactose is a ketose

Correct answer:

They differ in configuration around the fourth carbon

Explanation:

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 #1 : Identifying Specific Carbohydrate Structures

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?

Possible Answers:

None of these

Beta-1,6 glycosidic bond

Alpha-1,4 glycosidic bond

Alpha-1,6 glycosidic bond

Beta-1,4 glycosidic bond

Correct answer:

Beta-1,4 glycosidic bond

Explanation:

The beta-1,4 glycosidic bond is not a substrate for any human enzymes, and is thus left untreated.

Example Question #7 : Identifying Specific Carbohydrate Structures

Which of the following enzymes is correctly paired with its products and substrates? 

Possible Answers:

Correct answer:

Explanation:

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 #12 : Identification By Structure

Which of the following enzymes is correctly paired with its products and substrates?

Possible Answers:

Correct answer:

Explanation:

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 #9 : Identifying Specific Carbohydrate Structures

Which of the following enzymes is correctly paired with its products and substrates?

Possible Answers:

Correct answer:

Explanation:

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 #1 : Identifying Specific Carbohydrate Structures

 

 

Which of the following enzymes is correctly paired with its products and substrates? 

 

Possible Answers:

All of these

Correct answer:

Explanation:

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 #11 : Identifying Specific Carbohydrate Structures

Which of the following is a storage polysaccharide of plants?

Possible Answers:

Cellulose

Maltose

Glycogen

Starch

Amylopectin

Correct answer:

Starch

Explanation:

Amylopectin & amylose are joined to make starch. Cellulose is found in the cell wall of plant cells. Glycogen and maltose are not found in plants.

Example Question #71 : Identifying Biochemical Molecules

Identify the given structure.

D galactose

Possible Answers:

D-glucose

D-galactose

D-sucrose

L-galactose

L-glucose

Correct answer:

D-galactose

Explanation:

D-galactose is an aldohexose. Aldo indicates the aldehyde at the first carbon and hexose indicates a six-carbon sugar. The D-isomer is determined by the orientation of the highest number asymmetric carbon, which has a hydroxyl group pointin to the right in this Fischer projection.

Example Question #72 : Identifying Biochemical Molecules

Identify the given structure.

D glucose

Possible Answers:

D-fructose

D-glucose

D-galactose

D-gulose

D-altrose

Correct answer:

D-glucose

Explanation:

D-glucose is an aldohexose, one of the most important carbohydrates in biochemistry. Aldo indicates the aldehyde at the first carbon. Hexose indicates a six-carbon sugar. The D-isomer is determined by the orientation of the highest number asymmetric carbon, which has a hydroxyl group pointing to the right in the Fischer projection.

Example Question #291 : Biochemistry

Identify the given structure.

D fructose

Possible Answers:

D-fructose

L-fructose

D-sorbose

D-tagatose

D-xyulose

Correct answer:

D-fructose

Explanation:

D-fructose is a ketohexos. Keto indicates the ketone present on carbon 2 and hexose indicates a six-carbon sugar. The D-isomer is determined by the orientation of the highest number asymmetric carbon, which has the hydroxyl group oriented to the right in the Fischer projection.

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