Nokea
For the viral structure of rubella virus is true that
- A. does not have glycoprotein spikes
- B. does not have an envelope
- C. is ssDNA virus
- D. has icosahedral type of symmetry
Correct Answer: D
Rationale: The correct answer is D because the rubella virus has icosahedral symmetry, meaning it has a spherical shape with 20 equilateral triangular faces. This symmetry is common in many viruses and allows for efficient packaging of genetic material.
Choice A is incorrect because the rubella virus does have glycoprotein spikes on its surface. These spikes help the virus attach to host cells.
Choice B is incorrect because the rubella virus does have an envelope derived from the host cell membrane. This envelope plays a role in viral entry into host cells.
Choice C is incorrect because the rubella virus is an ssRNA virus, not ssDNA. Its genetic material is single-stranded RNA, not DNA.
In summary, the rubella virus has icosahedral symmetry and possesses glycoprotein spikes, an envelope, and ssRNA genetic material, making choices A, B, and C incorrect.
You may also like to solve these questions
Non-gonococcal urethritis and cervicitis can be caused by
- A. Mycoplasma hominis
- B. Mycoplasma genitalium
- C. Ureaplasma urealyticum
- D. all of them
Correct Answer: D
Rationale: The correct answer is D because Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum are all known to cause non-gonococcal urethritis and cervicitis. These organisms can infect the urogenital tract and lead to inflammation and symptoms in both males and females. Each of these bacteria has been identified as a common cause of these conditions through research and clinical studies. Therefore, since all three organisms are capable of causing non-gonococcal urethritis and cervicitis, the correct answer is D. The other choices (A, B, and C) are incorrect because each of them alone can cause these conditions, making option D the most comprehensive and accurate choice.
Viruses can infect
- A. plants.
- B. bacteria.
- C. animals.
- D. all organisms.
Correct Answer: D
Rationale: The correct answer is D because viruses have the ability to infect all organisms, including plants, bacteria, animals, and even fungi. Viruses are non-living entities that require a host cell to replicate and spread. They can infect a wide range of organisms by attaching to specific receptors on the host cell's surface. Therefore, the correct answer is D as viruses have the capability to infect all living organisms. Choices A, B, and C are incorrect because viruses can infect not only plants, bacteria, and animals but also other organisms, making choice D the most comprehensive and accurate option.
Chlorhexidine:
- A. Is characterised by strong human toxicity
- B. Belongs to the group of alcohols and is widely used for disinfection of surfaces and sanitary facilities
- C. Belongs to the group of biguanides and is widely used for disinfection hands, skin and mucous membranes
- D. Is a disinfectant with limited application
Correct Answer: C
Rationale: Step 1: Chlorhexidine belongs to the group of biguanides, which are commonly used for disinfecting hands, skin, and mucous membranes.
Step 2: It is known to have broad-spectrum antimicrobial activity against various pathogens.
Step 3: The usage of chlorhexidine in healthcare settings for preoperative skin preparation and surgical hand scrub is well-established.
Step 4: The effectiveness and safety profile of chlorhexidine make it a preferred choice for disinfection purposes.
Summary:
- Option A is incorrect as chlorhexidine is not characterized by strong human toxicity.
- Option B is incorrect as chlorhexidine is not classified as an alcohol and is primarily used for disinfecting hands, skin, and mucous membranes.
- Option D is incorrect as chlorhexidine has a wide range of applications in disinfection, especially in healthcare settings.
The territory of an old burial ground for animal refuse that hasn't been used for over 50 years is meant for house building. But soil investigation showed the presence of viable spores of a causative agent causing a very dangerous disease. What microorganism might have been preserved in soil for such a long period of time?
- A. Bacillus anthracis
- B. Francisella tularensis
- C. Brucella abortus
- D. Yersinia pestis
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. This bacterium is known to form highly resistant spores that can survive for long periods in soil. Bacillus anthracis causes anthrax, a dangerous disease that can be transmitted to humans and animals. The other choices, Francisella tularensis, Brucella abortus, and Yersinia pestis, do not form spores as resistant as Bacillus anthracis. Therefore, only Bacillus anthracis is likely to have survived in the soil of the old burial ground for animal refuse for over 50 years.
Conidiospores that bud off from a vase-shaped spore-bearing cell are referred to as:
- A. arthrospores
- B. porospores
- C. phialospores
- D. blastospores
Correct Answer: C
Rationale: The correct answer is C: phialospores. Phialospores are conidiospores that bud off from a vase-shaped spore-bearing cell called a phialide. This structure is characteristic of fungi in the genus Penicillium. Arthrospores (A) are formed by the fragmentation of hyphae, porospores (B) are not a recognized term in mycology, and blastospores (D) are produced by budding from yeast cells. Therefore, C is the correct choice based on the specific description provided in the question.