Free Biodiversity and Variety of Life MCQs with Answers

2801. Unlike eukaryotes, prokaryotes have no membrane-bound organelles. How, then, are prokaryotes able to generate energy?

• 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 membranes, and thus produce ATP by chemiosmosis.

2802. Which of the following bacteria are thick rigid and spiral?

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

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

2803. Which of the following structure primarily helps in attachment of bacteria on various surfaces?

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

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

2804. If lipopolysaccharides did not appear in the wall of bacteria on staining, then it will be known as_:

• 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

2805. All of the following are examples of substances found in bacteria or archaea except :

• 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 bacteriorhodopsin are found in bacteria/archaea.

2806. Streptobacillus is basically a

• 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 often joined in a chain.

2807. Which of the following contains genes for drug and disease resistance in bacteria?

• 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. Plasmids are small, circular, double-stranded DNA molecules that are separate from the chromosomal DNA in bacterial cells. They are commonly found in many bacterial species and can carry genes that provide various advantages to the host bacterium.

2808. Which of the following structure is not present in all the bacteria?

• 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 microscope.

2809. Which of the following characteristics make plasmid DNA useful for researchers?

• 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, and isolation of specific DNA sequences for various applications in molecular biology and genetic engineering.

2810. Those bacteria which are fully dependent upon their host for nutrition are called?

• 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.