All Free Biology MCQs with Answers

• A. All are eukaryotes
• B. They are multicellular
• C. Non-motile organisms
• D. Are heterotrophs

Explanation: Plants are classified as autotrophs. Autotrophs are organisms that produce their own food using inorganic substances, usually through the…

• A. Datura stramonium
• B. Datura alba
• C. Solanum nigrum
• D. Nicotiana tabacum

Explanation: This is the correct scientific name for Thorn apple. It's a poisonous flowering plant in the nightshade family (Solanaceae).

• A. Sycopodium phlogmaria
• B. Anthocoros fusiform
• C. Ginkgo biloba
• D. Datura alba
• E. Agaricus bisporus

Explanation: The scientific name of Thorn Apple is Datura stramonium. Thorn Apple is a common name for this plant, and it is also known by various…

• A. Endothecium produces the microspores
• B. Tapetum nourishes the developing pollen
• C. Hard outer layer of pollen is called intine
• D. Sporogenous tissue is haploid

Explanation: A microsporangium is generally surrounded by four wall layers - the epidermis, endothecium, middle layers and the tapetum.

• A. Suspensor
• B. Egg
• C. Synergid
• D. Zygote

Explanation: Filliform apparatus is a mass of finger like projections of the wall into the cytoplasm.

• A. Spirochete
• B. Seudomonas
• C. E.coli
• D. Campylobacter

Explanation: Campylobacter is a genus of bacteria that are mostly microaerophilic, i.e. they require a very low concentration of oxygen to survive.

• A. Prokaryotes generate sodium gradients across their nuclear membranes
• B. Prokaryotes do not generate energy
• C. Prokaryotes produce energy via photosynthesis
• D. Prokaryotes generate proton gradients across their plasma membranes

Explanation: Although prokaryotes lack mitochondria and other membrane-bound organelles, they are able to generate a proton gradient across their cell…

• A. Coccus
• B. Vibrio
• C. Spirillum
• D. Bacillus

Explanation: Option C is correct as bacteria classified as "spirillum" are spiral in shape.

• A. Pilli
• B. Flagella
• C. Both A and B
• D. None of these

Explanation: Flagella help in locomotion whereas pilli help in attachment.

• A. Gram-positive
• B. Both Gram-positive and Gram-negative
• C. Gram-negative
• D. Capsule

Explanation: If lipopolysaccharides (LPS) did not appear in the wall of bacteria on staining, it would be known as Gram-positive bacteria

• A. Peptidoglycans
• B. Flagellin
• C. Bacteriorhodopsin
• D. Chitin

Explanation: Chitin is found in fungal cell walls 1 arthropod exoskeletons, not in bacteria or archaea, whereas peptidoglycan, flagellin, and…

• A. Single cell
• B. Chain of bacilli
• C. Pairs of bacilli
• D. All of Above

Explanation: It is a genus of facultatively anaerobic gram-negative rod-shaped bacteria (family Fusobacteriaceae) in which the individual cells are…

• A. Plasmid
• B. Nucleotide
• C. Mesosomes
• D. All of these

Explanation: Plasmids often contain drug-resistant, heavy metals, disease, and insect-resistant genes on them.

• A. Cell membrane
• B. Chromatin
• C. Ribosome
• D. Capsule

Explanation: Not all bacteria have capsules present. They all have a slime layer but this is only classified as a capsule when visible under the…

• A. Readily incorporate cloned DNA
• B. Capable of autonomous replication
• C. Capable of being isolated from genomic DNA
• D. All of these

Explanation: All of these characteristics collectively make plasmid DNA a valuable tool for researchers, as they enable the introduction, replication…

• A. Heterotrophic bacteria
• B. Saprotrophic bacteria
• C. Chemosynthetic bacteria
• D. Parasitic bacteria

Explanation: Parasitic bacteria are those which obtain nutrients from the host they live on, they rely on the host for their food.

• A. Bacilli
• B. Strephylobaccilus
• C. Bacillus
• D. Diplobacilli

Explanation: A. Rod shaped bacteria (plural)B. Chain of bacilliD. Pair arrangement

• A. Mesosome
• B. Ribosomes
• C. Golgi bodies
• D. Mitochondria

Explanation: The correct answer is 'Ribosomes.' In bacteria, which are prokaryotic organisms, ribosomes are present and essential for protein…

• A. Cocci
• B. Bacilli
• C. Spirilla
• D. Vibrio

Explanation: Bacteria are classified according to their shape, which is an essential characteristic for identification.

• A. Cytoplasmic matrix
• B. Cytoplasm
• C. Protoplasm
• D. Cell Structure

Explanation: The correct answer is 'Protoplasm'. In the context of bacteria, the protoplasm is the term used to describe all the living contents within…