Question 1

Which of the following best describes the difference between an epimer and an anomer in carbohydrate chemistry?

Accepted Answer

Epimers differ at any single chiral center, while anomers differ specifically at the anomeric carbon formed during ring closure.

Question 2

A patient is diagnosed with lactose intolerance. Which enzyme is most likely deficient, and what type of glycosidic bond does this enzyme hydrolyze?

Accepted Answer

Lactase; it hydrolyzes the $$\beta-1$$,4 glycosidic bond in lactose.

Question 3

Which of the following statements about mutarotation is correct?

Accepted Answer

Mutarotation is the conversion between $$\alpha$$ and $$\beta$$ anomers of a monosaccharide through the open-chain intermediate.

Question 4

Which of the following best explains why humans can digest starch but not cellulose, even though both are polymers of glucose?

Accepted Answer

Humans have enzymes that hydrolyze $$\alpha-1$$,4 glycosidic bonds in starch, but lack enzymes to hydrolyze $$\beta-1$$,4 glycosidic bonds in cellulose.

Question 5

Which of the following is a reducing sugar?

Accepted Answer

Maltose

Question 6

A scientist is analyzing a carbohydrate and finds that it is a six-carbon sugar with an aldehyde group. Which class of monosaccharide does this describe?

Accepted Answer

Aldohexose

Question 7

Which of the following best describes the structure of amylose?

Accepted Answer

A linear polymer of $$\alpha-D-$$glucose units linked by $$\alpha-1$$,4 glycosidic bonds.

Question 8

Which of the following is a function of peptidoglycan in bacteria?

Accepted Answer

It provides structural support to the bacterial cell wall.

Question 9

Which of the following best describes the difference between constitutional isomers and stereoisomers?

Accepted Answer

Constitutional isomers have different connectivity of atoms, while stereoisomers have the same connectivity but differ in spatial arrangement.

Question 10

Which of the following statements about vitamin C is correct?

Accepted Answer

Vitamin C acts as an anti-oxidant and is a cofactor for the production of collagen.

Question 11

A solution contains both D-glucose and D-fructose. Which test could be used to distinguish between these two monosaccharides, and what is the key structural difference?

Accepted Answer

Seliwanoff's test; D-glucose is an aldohexose, while D-fructose is a ketohexose.

Question 12

Which of the following best explains why sucrose is a non-reducing sugar?

Accepted Answer

Both anomeric carbons are involved in the glycosidic bond, preventing ring opening and reduction.

Question 13

Which of the following best describes the role of glycosylated proteins in cells?

Accepted Answer

They are involved in cell recognition and signaling, often as membrane-bound or secreted proteins.

Question 14

A carbohydrate sample is found to rotate plane-polarized light to the right. Which of the following statements is correct regarding its D/L configuration?

Accepted Answer

The D/L configuration is unrelated to the direction of optical rotation; D and L refer to the configuration relative to D- and L-glyceraldehyde.

Question 15

Which of the following is true regarding the formation of glycosidic bonds?

Accepted Answer

A glycosidic bond forms when the anomeric carbon of one monosaccharide reacts with a hydroxyl group of another.

Question 16

Which of the following best describes the difference between reducing and non-reducing sugars?

Accepted Answer

Reducing sugars have a free anomeric carbon that can act as a reducing agent, while non-reducing sugars do not.

Question 17

Which of the following is a correct statement about tautomers in carbohydrate chemistry?

Accepted Answer

Tautomers differ by the position of hydrogen and double bond (anomeric carbon) and interconvert, but slowly.

Question 18

Which of the following best describes the function of amylase in human digestion?

Accepted Answer

Amylase catalyzes the hydrolysis of $$\alpha-1$$,4 glycosidic bonds in starch to produce maltose and glucose.

Question 19

A researcher is studying the effect of branching on the osmotic properties of polysaccharides. Which of the following statements is correct?

Accepted Answer

Highly branched polysaccharides have lower osmotic pressure than unbranched ones of the same mass because they form fewer particles in solution.

Question 20

Which of the following best describes the difference between an enantiomer and a diastereomer?

Accepted Answer

Enantiomers are non-superimposable mirror images, while diastereomers are not mirror images and differ at one or more (but not all) chiral centers.

Carbohydrates: Structure, Function, and Biochemical Importance

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