All Free Biology MCQs with Answers

• A. Glycosidic Bond
• B. Hydrogen Bond
• C. Peptide Bond
• D. Disulphide

Explanation: A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group.

• A. Carboan, water and oxygen
• B. Carbon, Sulphur and hydrogen
• C. Carbon, calcium and hydrogen
• D. Carbon, ahydrogen and oxygen

Explanation: Carbohydrates are organic molecules, which are built out of carbon, hydrogen and oxygen molecules

• A. β-D-glucose
• B. α--glucose
• C. γ-D-glucose
• D. α-L-glucose

Explanation: Starch is a polysaccharide composed of repeating units of alpha-glucose molecules joined together through glycosidic bonds.

• A. Waxes
• B. Glycerol
• C. Starch
• D. Cellulose

Explanation: Cellulose is the most abundant carbohydrate in nature due to its role as a structural component in the cell walls of plants.

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: This structure shows a six-membered ring (pyranose form) with the OH group on the anomeric carbon (carbon-1) pointing down relative to the…

• A. Glycosidic Bond
• B. Keto group
• C. Maltose
• D. Fructose

Explanation: Monosaccharides are polyhydroxy aldehydes or polyhydroxy ketones. This implies that monosaccharides contain either an aldehyde group or a…

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

Explanation: When starch is ultimately broken down into glucose molecules, this occurs after further hydrolysis of maltose or other intermediates.

• A. They are both polymers of glucose
• B. They are geometric isomers of each other
• C. They can both be digested by humans
• D. They are both used for energy storage in plants

Explanation: The statement that is true regarding both starch and cellulose is that they are both polymers of glucose.Both starch and cellulose are…

• A. Glucopyranose
• B. Ribofuranose
• C. Glyceraldehyde
• D. Acetaldehyde

Explanation: When most monosaccharides are in a solution, they tend to form ring structures.

• A. Hydrolysis
• B. Oxidation
• C. Condensation
• D. Glycolysis

Explanation: Condensation is a chemical reaction in which two molecules combine to form a larger molecule, releasing a small molecule, often water, as…

• A. Fructose
• B. Glucose
• C. Ribose
• D. Deoxyribose

Explanation: Typically, glucose forms a six-membered ring called a pyranose. This ring consists of five carbon atoms and one oxygen atom.

• A. It sends out electrical impulses to ventrictes to contract.
• B. It is present at upper end of the left atrium
• C. It consists of small number of diffusely oriented cardiac fibers
• D. It sends out electrical impulses to atrial muscles causing both atria to contract.

Explanation: Explanation:SA node or the pacemaker is located in the right atrium and it sends out impulses causing both Atria to contract.

• A. It sends out electrical impulses to atrial muscles causing both atria to contract
• B. It consists of small number of diffusely oriented cardiac fibres
• C. It sends out electrical impulses to ventricular muscles causing both ventricles to contract
• D. It is present at upper end of left atrium

Explanation: Option [a] The Sinoatrial node, also known as the pacemaker, is responsible for initiating the heartbeat.

• A. Ventricular systole
• B. Atrial systole
• C. Diastole
• D. Recovery systole

Explanation: The QRS complex represents depolarization of the ventricles and is followed by ventricular contraction which is collectively known as the…

• A. Glycolysis.
• B. ETC.
• C. Krebs cycle.
• D. Calvin cycle.

Explanation: Krebs cycle (or citric acid cycle) breaks down the pyruvic acid to carbon dioxide.

• A. Alcoholic fermentation.
• B. Lactic acid fermentation.
• C. Glycolysis.
• D. Pyruvic acid oxidation.

Explanation: The product of this reaction is lactic acid. This builds up in muscles causing pain and tiredness, which can lead to cramp.

• A. Fructose-6-phosphate
• B. Glucose-1-phosphate
• C. Fructose-1, 6-bisphosphate
• D. Glucose-6-phosphate

Explanation: Explanation:When glucose enters the Cytoplasm, the first reaction of Glycolysis is addition of a phosphate molecule into the glucose…

• A. 32 F
• B. 313 K
• C. 46 C
• D. 37 C

Explanation: This optimal temperature is usually around human body temperature (37 oC) for the enzymes in human cells

• A. Phenylalanine hydroxylase
• B. Phenylalanine oxidase
• C. Phenylalanine phosphate
• D. None of these

Explanation: Explanation:Phenylalanine hydroxylase is an enzyme that converts the amino acid phenylalanine to tyrosine.

• A. Not produced in complete form
• B. It does not work efficiently at that time
• C. Quite capable of destroying cells internal structure
• D. None of the above

Explanation: Explanation:Pepsin is a protein-digesting enzyme and is capable of destroying cells' internal structure, as a result, it is secreted in an…