All Free Biology MCQs with Answers

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

Explanation: B is correct. As both show reversible inhibition, so X must be competitive because it is binding to the active site whereas Y must be non-competitive because it is binding to the allosteric site.

• A. Acetic acid
• B. Butyric acid
• C. Palmitic acid
• D. Oleic acid

Explanation: Palmitic acid C16H32O2 is a 16 carbon saturated fatty acid as it has no double bonds.

• A. Palmitic acid
• B. Linoleic acid
• C. Oleic acid
• D. Erucic acid

Explanation: Acetic acid, butyric acid, palmitic acid and stearic acid are some examples of saturated fatty acid

• A. Erythrose
• B. Ribulose
• C. Heptose
• D. Ribose

Explanation: "The explanation for this question will be added soon!".This is the correct option because deoxyribose is ribose sugarwhich is oxygen deficient at second carbon (C-2) , so when it is supplemented with oxygen at C-2, ribose is formed.

• A. Oxalosuccinate
• B. Linolenic acid
• C. Oleic acid
• D. α -ketoglutarate

Explanation: Oleic acid is a monounsaturated fatty acid belonging to the omega-9 fatty acid family. It is an 18-carbon fatty acid with one double bond, located at the ninth carbon from the methyl end of the carbon chain. The chemical formula for oleic acid is C18H34O2.Oleic acid is classified as a monounsaturated fatty acid because it has a single double bond in its carbon chain. In chemical terms, oleic acid is classified as a monounsaturated omega-9 fatty acid, abbreviated with a lipid number of 18:1 cis-9, and a main product of Δ9-desaturase. It has the formula CH 3−(CH 2) 7−CH=CH−(CH 2) 7−COOH

• A. Protein moiety of enzyme
• B. Non-protein moiety of enzyme
• C. Complete enzyme
• D. Inactive enzyme

Explanation: Holoenzyme is a complete, functional enzyme, which is catalytically active. It consists of an Apoenzyme and a Cofactor. In order to be functional, an apoenzyme(inactive enzyme) needs to become a holoenzyme(active enzyme). FTB page# 62

• A. Hydrogen
• B. Copper
• C. Oxygen
• D. Carbon

Explanation: Copper is a chemical element with the symbol Cu and atomic number 29. It is a transition metal with a reddish-brown color, and it is known for its excellent conductivity of electricity and heat. Copper serves as a cofactor for several enzymes involved in essential biological processes.

• A. Coordinated catabolic activities
• B. Coordinated anabolic activities
• C. Both catabolic and anabolic activities
• D. None of these

Explanation: The correct answer is that the interconversion of carbohydrates, proteins, and lipids in living cells involves both coordinated catabolic and anabolic activities. In metabolism, catabolic pathways break down molecules to release energy, which is then used in anabolic pathways to build up complex molecules. This coordination is essential for the efficient functioning and energy management of cells.Option A is incorrect because it only addresses the breakdown aspect, while Option B only addresses the building-up aspect. Option D is incorrect because the processes involved are indeed a combination of both catabolic and anabolic activities.

• A. Chemistry
• B. Molecular Biology
• C. Biochemistry
• D. Both A and B

Explanation: The correct answer is biochemistry. Biochemistry is the branch of science concerned with the chemical and physicochemical processes and substances that occur within living organisms. It integrates principles from both biology and chemistry to understand these processes.Chemistry is not specific to living organisms, as it deals with the study of matter in general. Molecular biology focuses more on the molecular mechanisms behind biological processes but does not primarily focus on chemical reactions and compounds. The option "both A and B" is incorrect because neither chemistry nor molecular biology, individually or collectively, addresses the specific focus of biochemical processes in living organisms as biochemistry does.

• A. Brain
• B. Bone
• C. Blood
• D. Liver

Explanation: The correct answer is the brain, which is composed of approximately 85% water. This high water content is essential for its function, as it aids in the transmission of electrical signals. The other options are incorrect because they have less water content: bone is much denser and contains about 20% water, blood is about 83% water, and the liver is approximately 70-75% water.