Nokea
The enzyme used by bacteria to break down hydrogen peroxide is:
- A. Amylase
- B. Catalase
- C. Lipase
- D. Protease
Correct Answer: B
Rationale: The correct answer is B: Catalase. Catalase is the enzyme responsible for breaking down hydrogen peroxide into water and oxygen. This process helps protect the bacteria from oxidative damage caused by hydrogen peroxide. Amylase (A), Lipase (C), and Protease (D) are enzymes that are not involved in breaking down hydrogen peroxide. Amylase is involved in breaking down starch, Lipase breaks down lipids, and Protease breaks down proteins. Therefore, they are not the correct enzymes for the given question.
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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.
For family Rhabdoviridae is true that:
- A. They are enveloped viruses
- B. They cause plague
- C. They have spherical shape
- D. They infect only humans
Correct Answer: A
Rationale: The correct answer is A: They are enveloped viruses. Rhabdoviridae family consists of enveloped viruses, which means they have a lipid envelope surrounding their protein coat. This envelope helps the virus in infecting host cells and evading the immune system. The other choices are incorrect because B: They cause plague is not true as Rhabdoviridae family typically causes diseases like rabies in mammals. C: They have spherical shape is incorrect as rhabdoviruses have a bullet-shaped structure. D: They infect only humans is also incorrect as Rhabdoviridae viruses can infect a wide range of hosts beyond just humans.
A journalist's body temperature has sharply increased in the morning three weeks after his mission in India, it was accompanied with shivering and bad headache. A few hours later the temperature decreased. The attacks began to repeat in a day. He was diagnosed with tropical malaria. What stage of development of Plasmodium is infective for anopheles-female?
- A. Gametocytes
- B. B.Shizontes
- C. C.Merozoites
- D. E.Sporozoites
Correct Answer: D
Rationale: The correct answer is D: Sporozoites. Sporozoites are the infective stage of Plasmodium for the female Anopheles mosquito. Here's the rationale: After being transmitted to a human host through a mosquito bite, the sporozoites travel to the liver where they mature and reproduce asexually as merozoites (not the infective stage for mosquitoes). The merozoites then infect red blood cells, leading to symptoms like fever, headache, and shivering. During the blood stage, some merozoites develop into male and female gametocytes, which are not infective to mosquitoes. When a mosquito bites an infected person, it ingests gametocytes, which then develop into male and female gametes and fuse to form ookinetes. Ookinetes develop into oocysts in the mosquito's gut, releasing sporozoites that migrate to the salivary glands, ready to infect a new human host when the mosquito bites
Bacterial spores are used for:
- A. Protection against phagocytosis
- B. Reproduction
- C. Survival
- D. Nutrient storage
Correct Answer: C
Rationale: The correct answer is C: Survival. Bacterial spores are specialized structures that bacteria form to survive harsh conditions such as extreme temperatures or lack of nutrients. Spores are not used for protection against phagocytosis (A) as they are dormant structures and not actively involved in defense mechanisms. They are not for reproduction (B) as spores are a form of bacterial reproduction but not the primary purpose of spore formation. Spores do not serve as nutrient storage (D) as they are mainly used for survival during unfavorable conditions.
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.