Nokea
Bacteriophages are:
- A. White blood cells that kill bacteria
- B. Bacteria that invade other bacteria
- C. Viruses that infect bacteria
- D. Bacteria that infect fungi
Correct Answer: C
Rationale: The correct answer is C: Bacteriophages are viruses that infect bacteria. Firstly, bacteriophages are viruses, not white blood cells or bacteria. They specifically target and infect bacteria, not fungi. This is known as a bacteriophage cycle where the virus injects its genetic material into the bacterial cell to replicate and eventually lyse the cell. This process is specific to bacteria and distinguishes bacteriophages from other microorganisms. Therefore, the correct answer is C as it accurately describes the nature and function of bacteriophages.
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Resident microflora is found in
- A. blood
- B. lung
- C. urethra
- D. cerebro-spinal fluid
Correct Answer: C
Rationale: The correct answer is C: urethra. Resident microflora refers to the normal, beneficial bacteria that inhabit a specific area of the body without causing harm. The urethra is one of the locations where resident microflora are commonly found. These bacteria play a vital role in maintaining a healthy balance and preventing harmful pathogens from colonizing the urethra. Blood (A), lung (B), and cerebro-spinal fluid (D) are not typical locations for resident microflora as these areas are usually sterile or have very limited microbial presence to prevent infections.
The most important fungi that cause diseases of the skin, hair, and nails are called:
- A. Plasmodium
- B. sporozoites
- C. dermatophytes
- D. nematodes
Correct Answer: C
Rationale: Correct Answer: C: dermatophytes
Rationale:
1. Dermatophytes are fungi that specifically infect the skin, hair, and nails.
2. They are the most common fungi causing such infections in humans.
3. Plasmodium and sporozoites are parasites causing malaria, not skin diseases.
4. Nematodes are a type of roundworm and do not typically cause skin, hair, or nail infections.
In summary, dermatophytes are the correct answer because they are specialized fungi that commonly cause skin, hair, and nail diseases, distinguishing them from the other choices.
Molds belong to which of the following groups of eukaryotic organisms?
- A. Protozoans
- B. Archaea
- C. Fungi
- D. Algae
Correct Answer: C
Rationale: The correct answer is C: Fungi. Molds are a type of fungi, which are eukaryotic organisms characterized by having cell walls made of chitin. Fungi are distinct from protozoans (single-celled eukaryotes), archaea (prokaryotes), and algae (photosynthetic eukaryotes). Fungi, including molds, obtain nutrients through absorption and play crucial roles in decomposition and nutrient cycling. Therefore, molds belong to the group of eukaryotic organisms known as fungi.
The key diagnostic feature of Corynebacterium diphtheriae is:
- A. formation of spores
- B. presence of metachromatic granules
- C. production of coagulase
- D. beta-hemolysis on blood agar
Correct Answer: B
Rationale: The correct answer is B: presence of metachromatic granules. This is because Corynebacterium diphtheriae is known for containing metachromatic granules, which are characteristic of this species. These granules can be observed under a microscope and aid in the identification of the bacteria.
Explanation of other choices:
A: formation of spores - Corynebacterium diphtheriae does not form spores. Spore formation is more commonly seen in bacteria such as Bacillus and Clostridium species.
C: production of coagulase - Coagulase production is a characteristic of Staphylococcus aureus, not Corynebacterium diphtheriae.
D: beta-hemolysis on blood agar - Corynebacterium diphtheriae does not exhibit beta-hemolysis on blood agar. This type of hemolysis is more typical of Streptococcus pyogenes.
During bacteriological examination of the purulent discharge obtained from a postoperative wound an inoculation on meat infusion agar has been performed. The inoculation has resulted in large colorless mucous colonies that in 24 hours with exposure to sunlight developed green-blue pigmentation and smell of honey or jasmine. Bacterioscopy revealed gram-negative lophotrichea. What bacterial culture is contained in purulent discharge?
- A. Pseudomonas aeruginosa
- B. Proteus vulgaris
- C. Klebsiella osaenae
- D. Streptomyces griseus
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is a gram-negative bacterium known for its green-blue pigmentation and sweet, fruity odor. The large colorless mucous colonies that develop green-blue pigmentation and honey or jasmine smell point towards Pseudomonas aeruginosa. The bacterioscopy revealing gram-negative lophotrichea further supports this identification. Proteus vulgaris and Klebsiella osaenae do not typically exhibit the described characteristics. Streptomyces griseus is a soil bacterium known for its antibiotic production and is not commonly associated with wound infections.