Free Carbohydrates MCQs with Answers

• A. Heterotrophs
• B. Autotrophes
• C. Carnivores
• D. Saprotrophs

Explanation: Insectivorous plants carry out photosynthesis and make their own carbohydrates, so they remain autotrophs.

• A. Trioses
• B. Hexoses
• C. Tetroses
• D. Pentoses

Explanation: Tetroses are four-carbon monosaccharides and are relatively rare, occurring in some bacteria and in a few metabolic pathways.

• A. 1 to 3 thousand
• B. 3 to many thousand
• C. 3 to 5 thousand
• D. 5 to 9 thousand

Explanation: In the general formula Cx(H2O)y for carbohydrates, x may begin at 3 in trioses and extend to many thousands in polysaccharides.

• A. CO
• B. C-COO-C
• C. HCOH
• D. HOH

Explanation: A keto group contains a carbonyl group within the carbon chain and is represented as C=O, commonly shortened in such options to CO.

• A. Glucose
• B. Starch
• C. Sucrose
• D. Glycogen

Explanation: Starch is the main carbohydrate obtained by animals from plant-based foods such as cereals, potatoes and legumes; digestion breaks it down…

• A. Silk
• B. Wool
• C. Cotton
• D. Paper

Explanation: Cotton fibres are composed almost entirely of cellulose, a polymer of beta-glucose units, making cotton the usual example of relatively…

• A. Chitin
• B. Cellulose
• C. Lignin
• D. Proteins

Explanation: The cell walls of oomycetes are chiefly made of cellulose and other glucans, unlike true fungi, whose walls are mainly chitin.

• A. Algae
• B. Amoeba
• C. Fungi
• D. Bacteria

Explanation: Fungi can grow in environments with high external osmotic pressure because their rigid cell walls and compatible-solute mechanisms help…

• A. Starch
• B. Glycogen
• C. Cellulose
• D. None of these

Explanation: Animals store excess glucose mainly as glycogen, a highly branched polysaccharide found especially in liver and skeletal muscles.

• A. Starch
• B. Glycogen
• C. Cellulose
• D. Polysaccharide

Explanation: Iodine forms a blue to blue-black complex with the helical structure of amylose in starch.

• A. Starch
• B. Glycogen
• C. Cellulose
• D. None of these

Explanation: Glycogen is called animal starch because it is the main storage polysaccharide in animals, especially in liver and muscles.

• A. Phosphodiester bond
• B. Peptide bond
• C. Glycosidic Bond
• D. Ionic bond

Explanation: A glycosidic bond joins two monosaccharides through a condensation reaction, in which a water molecule is removed.

• A. Starch
• B. Glycogen
• C. Amylose
• D. Amylopectin.

Explanation: Amylose, the mostly unbranched component of starch, can dissolve in hot water and forms a colloidal solution.

• A. Monosaccharide
• B. Oligosaccharide
• C. Polysaccharide
• D. None of these

Explanation: A monosaccharide is already a single sugar unit, so it cannot be hydrolysed into smaller carbohydrates.

• A. 0.80%
• B. 0.08%
• C. 1.80%
• D. 8%

Explanation: Normal blood glucose is about 80 mg per 100 mL, which is 0.08 g per 100 mL, or approximately 0.08%.

• A. Maltose
• B. Sucrose
• C. Fructose
• D. Glucose

Explanation: Starch, cellulose and glycogen are polysaccharides made from repeating glucose units, so complete hydrolysis releases glucose.

• A. Trioses
• B. Tetroses
• C. Pentose
• D. Hexose

Explanation: Ribose contains five carbon atoms, making it a pentose sugar. The common mistake is choosing hexose by confusing ribose with glucose or…

• A. Monosaccharides
• B. Oligosaccharides
• C. Polysaccharides
• D. None of these

Explanation: Polysaccharides are the most complex carbohydrates because they contain long chains of many monosaccharide units.

• A. Lipid
• B. Carbohydrate
• C. Protein
• D. Carotein

Explanation: Carbohydrates are polyhydroxy aldehydes or ketones, or substances that yield these compounds on hydrolysis.

• A. Monosaccharide
• B. Oligosaccharide
• C. Polysaccharide
• D. None of these

Explanation: Polysaccharides such as starch and cellulose are generally tasteless because their large molecules do not stimulate sweet taste receptors…