Nokea
Which of the following organisms is used in the production of cheese?
- A. Propionibacterium shermanii
- B. Acetobacter aceti
- C. Giardia
- D. Fusobacterium
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.
You may also like to solve these questions
The lysozyme hydrolyzes:
- A. The glycoside bonds between the N-acetylmuramic acid and the N-acetylglucosamine in the peptidoglycan of the cell wall
- B. The phosphate bonds between the carbon atoms in the phospholipids
- C. The disulfide bonds in the immunoglobulin molecule
- D. The hydrogen bonds between the monosaccharides in the bacterial capsules
Correct Answer: A
Rationale: The correct answer is A: The lysozyme hydrolyzes the glycoside bonds between the N-acetylmuramic acid and the N-acetylglucosamine in the peptidoglycan of the cell wall. This is because lysozyme is an enzyme that specifically targets the peptidoglycan layer of bacterial cell walls, breaking down the structure by cleaving the glycosidic bonds between these two specific sugar molecules. This action weakens the cell wall, leading to bacterial cell lysis. The other choices are incorrect because lysozyme does not target phosphate bonds in phospholipids (B), disulfide bonds in immunoglobulins (C), or hydrogen bonds in bacterial capsules (D).
The laboratory for especially dangerous infections conducts microscopic examination of pathological material from a patient with suspected plague. The sample was stained by Burri-Gins technique. What property of the causative agent can be identified by this technique?
- A. Capsule formation
- B. Spore formation
- C. Acid resistance
- D. Alkali resistance
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.
A patient has roundish ulcers on his face, inflammation and enlargement of lymph nodes. These symptoms turned up as a result of mosquito bites. Laboratory examination of discharge from the ulcers revealed unicellular aflagellar organisms. What is the most probable diagnosis?
- A. Dermatotropic leishmaniasis
- B. Toxoplasmosis
- C. Scabies
- D. Trypanosomiasis
Correct Answer: A
Rationale: The most probable diagnosis is Dermatotropic leishmaniasis. The roundish ulcers, lymph node enlargement, and presence of unicellular aflagellar organisms in discharge are characteristic of this parasitic infection transmitted by sandfly bites. Leishmania parasites cause skin lesions and lymphadenopathy. Toxoplasmosis (B) presents with flu-like symptoms, not ulcers. Scabies (C) causes intense itching and burrows, not ulcers. Trypanosomiasis (D) presents with fever, not ulcers. In this case, the symptoms align closely with Dermatotropic leishmaniasis, making it the most likely diagnosis.
Before a surgery the patient was prescribed a synthetic antiprotozoal drug for prevention of wound infection. The prescribed drug is highly effective against Helicobacter pylori. Name this drug:
- A. Metronidazole
- B. Chingamin (Chloroquine)
- C. Doxycycline hydrochloride
- D. Aciclovir
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.
Some of the viruses have a cubic type of symmetry, which in the shape of:
- A. Icosahedral structures
- B. Hexahedral structure
- C. Tetrahedral structure
- D. Dodecahedral structure
Correct Answer: A
Rationale: The correct answer is A: Icosahedral structures. Icosahedral symmetry is commonly found in viruses due to its efficient way of packing genetic material. The icosahedron has 20 equilateral triangular faces, making it ideal for viral capsids. The other choices, B: Hexahedral, C: Tetrahedral, and D: Dodecahedral structures, do not accurately describe the cubic type of symmetry seen in viruses. Hexahedral refers to a six-faced polyhedron, tetrahedral to a four-faced polyhedron, and dodecahedral to a twelve-faced polyhedron, none of which align with the structure commonly observed in viruses.