Nokea
What is the function of bacterial pili?
- A. Provide motility
- B. Aid in adhesion
- C. Form spores
- D. Synthesize proteins
Correct Answer: B
Rationale: The function of bacterial pili is to aid in adhesion. Pili are hair-like structures on the bacterial surface that help the bacteria attach to surfaces or other cells. This adhesion is crucial for colonization and infection. Pili do not provide motility, as that is typically done by flagella. Bacteria form spores for survival under harsh conditions, and protein synthesis is carried out by ribosomes, not pili. Thus, the correct answer is B, aiding in adhesion.
You may also like to solve these questions
Disinfection with chemicals acting on cell surface:
- A. Soaps
- B. Phenols
- C. Amines
- D. Polymyxin
Correct Answer: B
Rationale: The correct answer is B: Phenols. Phenols act on the cell surface by disrupting cell membranes and denaturing proteins, leading to cell death. Soaps (A) work by lifting dirt and microbes off surfaces, not directly acting on cell surfaces. Amines (C) are typically used as disinfectants targeting specific enzymes in microbes, not cell surfaces. Polymyxin (D) is an antibiotic that works by disrupting cell membranes internally, not on the cell surface.
Poxviruses are DNA viruses that replicate in the cytoplasm.
- A. TRUE
- B. FALSE
- C. Partially
- D. Not Sure
Correct Answer: A
Rationale: Step 1: Poxviruses are indeed DNA viruses, confirmed by scientific research.
Step 2: Poxviruses replicate entirely in the cytoplasm, unlike most DNA viruses.
Step 3: Cytoplasmic replication is a unique characteristic of poxviruses.
Step 4: The replication process of poxviruses in the cytoplasm is well-documented.
Step 5: Therefore, option A (TRUE) is correct, as poxviruses replicate in the cytoplasm exclusively.
Which statement for immunomodulators is correct
- A. they can only stimulate the incomplete humoral and immune response
- B. Isoniazid is a very effective immunomodulator
- C. they can be natural and artificial compounds
- D. they can only suppress the incomplete humoral and immune response
Correct Answer: C
Rationale: Rationale:
Choice C is correct because immunomodulators can indeed be natural (e.g., cytokines) or artificial compounds (e.g., synthetic peptides). They work by modulating the immune response, enhancing or suppressing it as needed.
Choice A is incorrect because immunomodulators can stimulate both humoral and cellular immune responses.
Choice B is incorrect as isoniazid is primarily an antibiotic used to treat tuberculosis, not an immunomodulator.
Choice D is incorrect because immunomodulators can have varying effects on the immune response, not just suppress it.
Which of the following microorganisms can cause skin infections?
- A. Candida albicans
- B. All are correct
- C. Staphylococcus aureus
- D. Streptococcus pyogenes
Correct Answer: B
Rationale: The correct answer is B: All are correct. Candida albicans can cause skin infections such as candidiasis. Staphylococcus aureus and Streptococcus pyogenes are common bacteria that can also cause skin infections. Therefore, choice B is correct as all three microorganisms listed can cause skin infections. Choices A, C, and D are incorrect because individually, each of the microorganisms listed can cause skin infections.
Which of the following transport mechanisms transports water across the plasma membrane?
- A. osmosis
- B. facilitated diffusion
- C. phagocytosis
- D. exocytosis
Correct Answer: A
Rationale: Osmosis is the correct answer because it is the process by which water molecules move across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This movement occurs passively, driven by the concentration gradient. Facilitated diffusion (B) involves the transport of specific molecules with the help of carrier proteins, not water. Phagocytosis (C) is a process where cells engulf solid particles, not water molecules. Exocytosis (D) is the process of releasing substances from a cell by fusion of vesicles with the cell membrane, not the transport of water across the membrane.