Nokea
The structure used for bacterial motility is:
- A. Fimbriae
- B. Capsule
- C. Flagella
- D. Pili
Correct Answer: C
Rationale: The correct answer is C: Flagella. Flagella are the structures used for bacterial motility, allowing bacteria to move towards or away from stimuli. They are long, whip-like appendages that rotate to propel the bacteria. Fimbriae (A) are short, hair-like structures used for attachment, not movement. Capsules (B) are protective layers surrounding bacteria. Pili (D) are used for adherence and conjugation, not motility. In summary, flagella are specifically designed for bacterial movement, making them the correct choice.
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Which of the following bacteria is capable of forming spores to survive in extreme conditions?
- A. Staphylococcus aureus
- B. Clostridium botulinum
- C. Escherichia coli
- D. Neisseria gonorrhoeae
Correct Answer: B
Rationale: The correct answer is B: Clostridium botulinum. This bacterium is capable of forming spores as a survival mechanism in harsh conditions. Spore formation allows it to remain dormant until conditions become favorable for growth again. Staphylococcus aureus (A), Escherichia coli (C), and Neisseria gonorrhoeae (D) do not form spores and rely on other mechanisms for survival. Staphylococcus aureus is a common skin bacterium, Escherichia coli is a gut bacterium, and Neisseria gonorrhoeae is a sexually transmitted bacterium.
Which structure is used by bacteria for movement?
- A. Pili
- B. Flagella
- C. Capsule
- D. Fimbriae
Correct Answer: B
Rationale: The correct answer is B: Flagella. Flagella are whip-like appendages used by bacteria for movement. They rotate in a corkscrew motion to propel the bacteria through their environment. Pili (choice A) are hair-like structures used for attachment, not movement. Capsules (choice C) are protective layers around bacteria, not involved in movement. Fimbriae (choice D) are also used for attachment and biofilm formation, not for movement. Therefore, the correct choice is B as flagella are specifically adapted for bacterial motility.
Which of the following bacteria is associated with food poisoning caused by improperly canned foods?
- A. Clostridium botulinum
- B. Escherichia coli
- C. Salmonella enterica
- D. Vibrio cholerae
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium is associated with food poisoning from improperly canned foods due to its ability to produce botulinum toxin, a potent neurotoxin that causes botulism. Improper canning allows spores of Clostridium botulinum to survive and germinate, producing the toxin in anaerobic conditions. The other choices are incorrect because Escherichia coli, Salmonella enterica, and Vibrio cholerae are not typically associated with food poisoning from improperly canned foods. Escherichia coli and Salmonella are more commonly linked to contaminated water or undercooked food, while Vibrio cholerae causes cholera primarily through contaminated water sources.
The movement of molecules through a membrane from an area of high hydrostatic pressure to an area of lower hydrostatic pressure is:
- A. filtration
- B. exocytosis
- C. simple diffusion
- D. simple diffusion
Correct Answer: D
Rationale: The correct answer is D: simple diffusion. In simple diffusion, molecules move from an area of high concentration to low concentration without the need for energy input. Hydrostatic pressure is a form of passive transport that drives molecules to equalize concentration. Filtration (A) involves the movement of solutes through a membrane under pressure. Exocytosis (B) is the process by which cells release substances outside the cell using energy. Osmosis (C) is the movement of water molecules across a selectively permeable membrane. Therefore, simple diffusion is the most appropriate choice in this scenario.
How would you interpret the study results?
- A. Water is safe to be consumed
- B. Water is of doubtful quality
- C. Water is of highly doubtful quality
- D. Water is contaminated
Correct Answer: D
Rationale: Step-by-step rationale:
1. The study results indicate water contamination.
2. Contaminated water poses health risks.
3. Therefore, the correct interpretation is that water is contaminated.
Summary:
- Choice A is incorrect as safety is not confirmed.
- Choice B is too mild given the severity of contamination.
- Choice C is also incorrect, as it does not accurately reflect the study findings.