Which bacteria is responsible for causing the disease known as tetanus?

Correct Answer: A

Rationale: The correct answer is A: Clostridium tetani. Clostridium tetani is responsible for causing tetanus due to its production of tetanospasmin toxin. This neurotoxin leads to muscle stiffness and spasms characteristic of tetanus. Clostridium perfringens is associated with gas gangrene, not tetanus. Streptococcus pyogenes causes strep throat and skin infections, not tetanus. Escherichia coli is a common gut bacteria and is not responsible for tetanus. Therefore, choice A is the correct answer for causing tetanus.

Correct Answer: D

Rationale: The correct answer is D because all of these symptoms are early signs of rabies. A short period of depression, nausea, and restlessness are common initial symptoms of rabies infection. These symptoms may be followed by more severe manifestations, such as aggression, confusion, and difficulty swallowing. Therefore, option D is the correct choice as it encompasses all the early symptoms of rabies. Options A, B, and C are incorrect as they focus on individual symptoms, whereas rabies typically presents with a combination of these early signs.

Correct Answer: C

Rationale: The correct answer is C: Weakly bound to the cell wall. The glycocalyx in bacteria is a protective layer that can be loosely attached to the cell wall or membrane. This loose attachment allows for flexibility and protection against desiccation and immune responses. Choice A is incorrect because the glycocalyx is not strongly bound to the cell wall, as it needs to be able to be shed easily for bacteria to escape host immune responses. Choice B is incorrect because the glycocalyx is not directly involved in bacterial movement, but rather serves as a protective barrier. Choice D is incorrect as the glycocalyx does play a role in bacterial physiology.

Correct Answer: A

Rationale: The Burri-Gins staining technique is used to identify the presence of capsules around bacteria. Capsules are protective structures that some bacteria produce to evade the immune system. This technique stains the capsule, making it visible under a microscope. Therefore, the correct answer is A: Capsule formation. Incorrect: B: Spore formation - Spores are not typically identified using the Burri-Gins staining technique. C: Acid resistance - This property is not specifically identified by Burri-Gins staining. D: Alkali resistance - This property is not specifically identified by Burri-Gins staining.

Correct Answer: B

Rationale: Correct Answer: B - Plasmids are circular DNA molecules Rationale: 1. Plasmids are extrachromosomal DNA molecules found in bacteria. 2. Plasmids are typically circular in structure, not linear. 3. Circular plasmids are easily replicated and transferred between bacteria. 4. Plasmids can carry genes for antibiotic resistance, making option C incorrect. 5. Not all bacteria have plasmids, making option D incorrect. 6. While plasmids can provide benefits, they are not essential for bacterial survival, making option A incorrect.

Correct Answer: A

Rationale: The correct answer is A: chloroplasts. Algae and plant cells have chloroplasts, which are responsible for photosynthesis. This organelle contains chlorophyll, enabling these cells to convert sunlight into energy. Mitochondria (B) are found in all eukaryotic cells, not specific to algae and plants. Vacuoles (C) are present in plant cells but also in other eukaryotic cells. Vesicles (D) are membrane-bound sacs found in all types of cells for transport and storage purposes, not unique to algae and plants. Therefore, A is the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Propionibacterium shermanii. This bacterium is used in the production of certain types of cheese, such as Swiss cheese, to create the characteristic holes and flavor. Propionibacterium produces carbon dioxide gas during fermentation, forming the holes in the cheese. Acetobacter aceti (B) is used in vinegar production. Giardia (C) is a parasite that causes gastrointestinal issues, not used in cheese production. Fusobacterium (D) is a type of bacteria associated with infections in humans, not used in cheese production.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Metronidazole is a synthetic antiprotozoal drug commonly used for wound infection prevention. 2. It is highly effective against Helicobacter pylori, a bacterium that causes stomach ulcers. 3. Metronidazole works by disrupting DNA structure in bacteria, leading to their death. 4. Chingamin (Chloroquine) is an antimalarial drug, not effective against Helicobacter pylori. 5. Doxycycline hydrochloride is an antibiotic used for bacterial infections, not specifically for H. pylori. 6. Aciclovir is an antiviral drug used for herpes infections, not effective against H. pylori. Summary: Metronidazole is the correct answer as it is specifically effective against H. pylori and commonly used for wound infection prevention. Other choices are incorrect as they target different types of infections.

Correct Answer: B

Rationale: The correct answer is B: Neisseria gonorrhoeae. This bacterium is known to cause gonorrhea, a sexually transmitted infection. Neisseria gonorrhoeae specifically infects the mucous membranes of the reproductive tract in both men and women. It is transmitted through sexual contact. Explanation of other choices: A: Chlamydia trachomatis is a bacterium that causes chlamydia, not gonorrhea. C: Mycoplasma genitalium is associated with non-gonococcal urethritis, not gonorrhea. D: Treponema pallidum is the bacterium that causes syphilis, not gonorrhea. Therefore, Neisseria gonorrhoeae is the correct answer based on its direct association with causing gonorrhea.