Nokea
Which statement about the fungal mycelium is correct:
- A. It consists of intertwined hyphae
- B. Part of the mycelium goes in the medium and forms the substrate mycelium
- C. Part of the mycelium stays above the medium and forms the aerial mycelium
- D. All of the above
Correct Answer: D
Rationale: Rationale:
- A: The mycelium is indeed made up of intertwined hyphae, which are the branching filaments of fungi.
- B: Part of the mycelium does grow into the medium to acquire nutrients, forming the substrate mycelium.
- C: Some parts of the mycelium remain above the medium to aid in reproduction and spore dispersal, forming the aerial mycelium.
Therefore, all statements (A, B, and C) are correct, making choice D the correct answer. The mycelium exhibits both intertwined hyphae, substrate mycelium, and aerial mycelium to facilitate different functions.
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The specific prevention (by vaccination) of the disease gas gangrene (caused by Clostridium perfringens) is based on:
- A. Killed whole cell vaccine
- B. Anatoxin
- C. There is no specific prevention by vaccination
- D. Alive attenuated vaccine
Correct Answer: B
Rationale: The correct answer is B: Anatoxin. An anatoxin is a toxin that has been rendered harmless while retaining its ability to stimulate an immune response. Gas gangrene is caused by the toxins produced by Clostridium perfringens, not the bacteria itself. Therefore, vaccination with an anatoxin can trigger the immune system to produce antibodies against the toxin, providing immunity against the disease.
A: Killed whole cell vaccine - Gas gangrene is caused by toxins, not the whole bacterium. This type of vaccine may not be effective in preventing the disease.
C: There is no specific prevention by vaccination - This is incorrect, as vaccination with an anatoxin can prevent gas gangrene.
D: Alive attenuated vaccine - Attenuated vaccines contain live, weakened forms of the pathogen. However, for gas gangrene prevention, targeting the specific toxin with an anatoxin vaccine is more appropriate.
Which of the following bacteria is known for producing a capsule that helps it avoid the immune system?
- A. Streptococcus pneumoniae
- B. Escherichia coli
- C. Salmonella enterica
- D. Bacillus subtilis
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is known for producing a capsule that helps it evade the immune system. The capsule acts as a protective barrier, making it difficult for the immune system to recognize and attack the bacteria. Streptococcus pneumoniae is a common cause of pneumonia and meningitis.
Explanation for why other choices are incorrect:
B: Escherichia coli does not typically produce a capsule for immune evasion. It is more commonly associated with gastrointestinal infections.
C: Salmonella enterica also does not produce a capsule for immune evasion. It is known for causing foodborne illness.
D: Bacillus subtilis is a soil bacterium that is not known for producing a capsule to avoid the immune system.
The branch of pharmacology that addresses drug amounts at various sites in the body after drug administration is called:
- A. pharmacodynamics
- B. pharmacokinetics
- C. pharmacotherapeutics
- D. pharmacy
Correct Answer: B
Rationale: The correct answer is B: pharmacokinetics. Pharmacokinetics is the study of drug movement in the body, including absorption, distribution, metabolism, and excretion. It focuses on how the body processes a drug over time. Pharmacodynamics (A) is the study of the effects drugs have on the body. Pharmacotherapeutics (C) involves using drugs to treat diseases. Pharmacy (D) is the practice of preparing and dispensing medications. Pharmacokinetics specifically deals with drug concentrations at different body sites after administration, making it the most appropriate choice for this question.
Which type of bacteria is responsible for causing tuberculosis?
- A. Streptococcus pyogenes
- B. Mycobacterium tuberculosis
- C. Escherichia coli
- D. Bacillus anthracis
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. Mycobacterium tuberculosis is the bacteria responsible for causing tuberculosis. This bacterium has unique cell wall components that make it resistant to the body's immune defenses, allowing it to survive and multiply within the host. Streptococcus pyogenes (Choice A), Escherichia coli (Choice C), and Bacillus anthracis (Choice D) are not associated with tuberculosis. Streptococcus pyogenes is known for causing strep throat and skin infections, Escherichia coli is commonly involved in gastrointestinal infections, and Bacillus anthracis causes anthrax.
Which structure in bacteria allows them to exchange genetic material during conjugation?
- A. Pili
- B. Flagella
- C. Capsule
- D. Ribosomes
Correct Answer: A
Rationale: Pili in bacteria are responsible for conjugation, allowing the transfer of genetic material between cells. They form a bridge between donor and recipient cells, facilitating the exchange of DNA. Flagella are for movement, capsules for protection, and ribosomes for protein synthesis. Pili is the only structure directly involved in genetic material exchange.