Free Biodiversity and Variety of Life MCQs with Answers

2381. Cyanobacteria help in nitrogen fixation since they have:

• A. Heterocyst
• B. Hormogonia
• C. Akinetes
• D. Mesosomes

Explanation: Nitrogen fixation occurs through heterocycts.

2382. Protein named as pilin is present in:

• A. Flagella
• B. Pili
• C. Capsule
• D. Slime

Explanation: Pilli are tubular extensions of cell membrane and project through the cell wall.They are composed of pillin protein.

2383. Periplasmic space is absent in:

• A. Gram positive bacteria
• B. Gram negative bacteria
• C. Both A and B
• D. None

Explanation: Periplasmic space is a region that exists between the inner and outer membranes in gram-negative bacteria. It is not present in gram-negative bacteria.

2384. Which part of bacteria is most delicate and can damage bacterial cell immediately?

• A. Cell wall
• B. Cell membrane
• C. Slime
• D. Capsule

Explanation: Just beneath the cell wall is the cell membrane or plasma membrane. It is very thin, lexible and completely surrounds the cytoplasm. Plasma membrane is very delicate in nature any damage toit results in death of the organism. Bacterial membranes difer from eukaryotic membranes in lacking sterols such as cholesterol. Cell membrane regulates the transport of proteins, nutrients, sugar and electrons or othermetabolites. The plasma membranes of bacteria also contain enzymes for respiratory metabolism.

2385. Which is present in every bacterium?

• A. Cell wall
• B. Slime
• C. Cell membrane
• D. Capsule

Explanation: Correct option is C cell membrane, The cell membrane, also known as the plasma membrane, is a semipermeable barrier that surrounds the cytoplasm of bacterial cells. It consists of a lipid bilayer with embedded proteins. The cell membrane is crucial for regulating the movement of substances in and out of the cell, maintaining the cell's internal environment, and providing structural support. It also plays a role in communication and signal transduction.

2386. Cyanobacteria are related to eukaryotes in having:

• A. PSI
• B. PSII
• C. Both A and B
• D. None

Explanation: Correct Option C: This option is correct. Cyanobacteria are related to eukaryotes in having both PSI (Photosystem I) and PSII (Photosystem II). Both of these photosystems are crucial for capturing and utilizing light energy during photosynthesis, and their presence in cyanobacteria and eukaryotes is one of the reasons these two groups are related in the context of photosynthetic capabilities.

2387. Which organelle is of prokaryotic origin?

• A. Mitochondria
• B. Chloroplast
• C. Both A and B
• D. None of the above

Explanation: Option C is correct. Both mitochondria and chloroplasts are believed to be of prokaryotic origin, and their presence in eukaryotic cells supports the endosymbiotic theory.

2388. Spores are resistant to:

• A. Antibodies
• B. Environmental stress
• C. Disinfectants
• D. All of these

Explanation: Option D is correct. Spores are resistant to antibodies, environmental stress, and many disinfectants, making them highly durable and capable of surviving in challenging conditions.

2389. Cyanobacteria move by:

• A. Gas vesicle
• B. Gliding motility
• C. Flagella
• D. Both A and B

Explanation: Option D is correct. Cyanobacteria can move by utilizing gas vesicles to control their buoyancy in the water column and by gliding motility to move along surfaces.

2390. Purple non-sulphur is an example of:

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

Explanation: Purple non-sulfur bacteria are photosynthetic bacteria that perform anoxygenic photosynthesis using organic compounds other than water as an electron donor.