Organic Chemistry Multiple Choice Questions on “Carbohydrates”.
1. Which Biomolecules simply refers as “Staff of life” in the given macromolecules?
a) Protein
b) Lipids
c) Carbohydrate
d) Vitamins
Answer: c
Clarification: Carbohydrates belong to a group of complex biomolecules commonly regarded as the “staff of life.” They are the most abundant organic compounds in living organisms and are among the four major classes of biomolecules. During photosynthesis, carbohydrates are produced from the reaction of carbon dioxide with water. Carbohydrates go by several common names, including sugars, starches, saccharides, and polysaccharides.
2. In carbohydrates which are the main functional groups are present?
a) Alcohol & Carboxyl groups
b) Aldehyde & Ketone groups
c) Hydroxyl groups & Hydrogen groups
d) Carboxyl groups & Others
Answer: a
Clarification: Carbohydrates are often represented by the chemical formula Cx(H2O)y, where the numerical values of x and y range from 3 to 12, and functional groups are Alcohol & Carboxyl groups.
3. Majority of the monosaccharides found in the human body are of which type stereoisomer?
a) L-type
b) D-type
c) neutral
d) racemic mixture
Answer: b
Clarification: Majority of the monosaccharides found in the human body are of D-type stereoisomer. The D-isomer of glucose predominates in nature and it is for this reason that the enzymes in our body have adapted to binding this form only.
4. Which is the simplest carbohydrate?
a) Dihydroxy acetone
b) Glycerldehyde
c) Glucose
d) Gulose
Answer: b
Clarification: Glyceraldehyde (glyceral) is a triose monosaccharide with chemical formula C3H6O3. It is the simplest of all common aldoses.
5. Which of the following is the examples of Epimers?
a) Glucose & Galactose
b) Glucose & Ribose
c) Mannose & Glucose
d) fructose and glucose
Answer: a
Clarification: In stereochemistry, an epimer is one of a pair of stereoisomers. The two isomers differ in configuration at only one stereogenic center. All other stereocenters in the molecules. The sugars glucose and galactose are epimers. In glucose, the -OH group on the first carbon is in the axial position, the direction opposite the -OH group on carbon C-4. In galactose, the -OH group is oriented in the same direction, the equatorial position.
6. Which of the following is true about Turanose?
a) Reducing disaccharides of glucose and fructose
b) Non-reducing disaccharide
c) 7-methyl sugar
d) a deoxy sugar
Answer: a
Clarification: Turanose educing sugar (3-O-α-D-glucosyl-D-fructose), an isomer of sucrose, naturally exists in honey.
7. Which of the following is not a disaccharide?
a) Sucrose
b) Maltose
c) Lactose
d) Galactose
Answer: d
Clarification: Sucrose, maltose and lactose are disaccharide and galactose is a monosaccaride.
8. Which sugars are present in Sucrose?
a) Fructose and glucose
b) Glucose and glucose
c) Glucose and galatose
d) Fructose and galatose
Answer: a
Clarification: Sucrose is commonly known as table sugar and is obtained from sugar cane or sugar beets contain fructose and glucose as monomers.
9. Which of the following carbohydrate do not have any essential nutritional value?
a) Sucrose
b) Cellulose
c) Dextrin
d) Glycogen
Answer: c
Clarification: Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch or glycogen. Dextrins are mixtures of polymers of D-glucose units linked by α-(1→4) or α-(1→6) glycosidic bonds. Dextrin Function. Dextrin is a source of energy; it contains 3.8-4.1 Calories per gram. Dextrin is not an essential nutrient, so you do not need to get it from food to be healthy.
10. Which of the following will not be reactive towards seliwanoff reagent?
a) Maltose
b) Inulin
c) Fructose
d) Sucrose
Answer: a
Clarification: Maltose is an aldose sugar and only ketoses give a positive Seliwanoof’s test. Sucrose, Inulin and fructose contain a ketose, and maltose does not. Only Therefore, sucrose, Inulin and fructose will give a positive Seliwanoof’s test, but maltose will not.