All Free Biology MCQs with Answers

• A. Archeotrophication
• B. Eutrophication
• C. Enrichment
• D. Low Trophication

Explanation: Eutrophication is characterized by excessive plant and algal growth due to the increased availability of one or more limiting growth…

• A. Oxides of carbon
• B. Oxides of nitrogen and Sulphur
• C. Oxides of Sulphur
• D. Oxides of nitrogen

Explanation: Nitrogen dioxide acts as a catalyst and reacts with sulphur dioxide to form sulphur trioxide, which is the main culprit of acid rain.

• A. Ultra-violet radiations
• B. Greenhouse gases
• C. Nitrogen oxide
• D. Sulphur oxide

Explanation: The ozone layer absorbs Ultra-violet radiation. Depletion of ozone layer results in increased amount of Ultra-violet radiation reaching…

• A. Water pollution
• B. Air pollution
• C. Eutrophication
• D. Industrial effects

Explanation: Eutrophication is characterized as the excess growth of algae or aquatic plants due to an increase in one or more growth limiting factors…

• A. Increasing levels of nitrogen oxide
• B. Decreasing level of O2
• C. Decreasing level of CFCs
• D. Increasing levels of CFCs

Explanation: An increase in CFC gas is responsible for the deterioration of the ozone layer.

• A. Antibiotics
• B. Pesticides
• C. Disinfectants
• D. Chemotherapeutic agents

Explanation: Pesticides are a class of chemicals that are used to kill crop-eating insects, unwanted weeds etc.

• A. Cysts.
• B. Ribosomes.
• C. Mesosomes.
• D. Spores.

Explanation: These extensions help in the synthesis of the cell wall and replication of DNA

• A. Centrioles
• B. X-chromosome
• C. Plastids
• D. Sieve-tubes

Explanation: Since prokaryotic cells do not indulge in sexual reproduction, they don't have either the X chromosomes or the Y chromosomes.

• A. Campylobacter
• B. Cyanobacteria
• C. Spirochete
• D. Goblet cells

Explanation: Nucleoid is exclusive to prokaryotic cells only where the circular DNA exists without a membrane. Goblet cells are eukaryotic.

• A. Pseudomonas
• B. Campylobacter
• C. Euglena
• D. E.coli

Explanation: Euglena is a genus of single-cell flagellate eukaryotes. All other mentioned organisms are prokaryotes.

• A. Cytoplasmic streaming movement
• B. Ribosome
• C. Binary fission
• D. Nuclear envelope

Explanation: Ribosomes are cellular structures responsible for protein synthesis. They are found in both prokaryotic and eukaryotic cells and play a…

• A. E. Coli
• B. Nostoc
• C. Blue green algae
• D. Cyanobacteria
• E. None of these

Explanation: Mitosis is the process by which a eukaryotic somatic cell divides to produce two genetically identical daughter cells.

• A. Spores
• B. Cyst
• C. Nucleoid
• D. Mesosomes

Explanation: In prokaryotic cells, which lack membrane-bound organelles like mitochondria, the role of generating energy through cellular respiration…

• A. Carbohydrates
• B. Carbohydrates and Proteins
• C. Proteins
• D. Proteins & Lipids

Explanation: The correct answer is Carbohydrates, as prokaryotic cell walls are predominantly composed of peptidoglycan, which is a polymer made from…

• A. Mesosomes
• B. Ribosomes
• C. Storage bodies
• D. Membrane bound organelles

Explanation: Prokaryotic cells, such as bacteria and archaea, lack membrane-bound organelles like a nucleus, mitochondria, or endoplasmic reticulum.

• A. Globular proteins
• B. Fibrous proteins
• C. Glycoproteins
• D. Glycolipids

Explanation: Explanation:This is a fact. Antibiotics are actually Globular proteins.

• A. 11000 atoms
• B. 10000 atoms
• C. 6600 atoms
• D. 6800 atoms

Explanation: Explanation:Each molecule of Haemoglobin is made up of nearly 10,000 atoms and it is 68000 times heavier than a hydrogen molecule.

• A. -C-N
• B. -C-O
• C. -C-P
• D. -C-S

Explanation: The peptide bond is the bond formed when the carboxyl group reacts with an amide group forming a -C-N- bond.

• A. 20
• B. 170
• C. 25
• D. 200

Explanation: Many naturally occurring amino acids have been found however, only 20 of those types are known to be found in the proteins making up the…

• A. R group
• B. Disulfide bond
• C. Amino group
• D. Hydrogen bond

Explanation: The α-helix is a right-handed helix with the peptide bonds present on the inside and the side chains extending outward.