Nokea
What is the function of bacterial ribosomes?
- A. DNA replication
- B. Protein synthesis
- C. Energy production
- D. Cell division
Correct Answer: B
Rationale: The correct answer is B: Protein synthesis. Bacterial ribosomes are responsible for translating the genetic information from mRNA into proteins. This process involves the binding of transfer RNA molecules carrying amino acids to the ribosome and the formation of peptide bonds between the amino acids to create proteins. DNA replication (A) is carried out by DNA polymerase enzymes, not ribosomes. Energy production (C) is primarily the function of mitochondria in eukaryotic cells, and cell division (D) is regulated by a complex network of proteins and signaling pathways, not ribosomes.
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What is the name of the enzyme that allows the bacteria to become resistant to most penicillins?
- A. Beta lactam ring
- B. MRSA
- C. Beta lactamase
- D. Aminoglycoside ring
Correct Answer: C
Rationale: The correct answer is C: Beta lactamase. This enzyme is produced by bacteria to break down the beta-lactam ring structure of penicillins, rendering them ineffective. Beta lactam ring (A) is part of the penicillin molecule, not an enzyme. MRSA (B) stands for methicillin-resistant Staphylococcus aureus, a type of bacteria resistant to certain antibiotics, not an enzyme. Aminoglycoside ring (D) refers to a different class of antibiotics and is not related to penicillin resistance in bacteria.
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 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.
A disease that is generally present in a given population is:
- A. pandemic
- B. epidemic
- C. sporadic
- D. endemic
Correct Answer: D
Rationale: The correct answer is D: endemic. Endemic refers to a disease that is consistently present in a particular population or region at a relatively stable level. This means the disease is always present in that specific area. Pandemic (A) refers to a disease that spreads across multiple countries or continents. Epidemic (B) refers to a sudden increase in the number of cases of a disease above what is normally expected in that population. Sporadic (C) refers to occasional cases of a disease occurring irregularly in a population. Therefore, the correct choice is D as it specifically describes a disease that is generally present in a given population.
Which of the following bacteria is associated with Lyme disease?
- A. Borrelia burgdorferi
- B. Clostridium botulinum
- C. Escherichia coli
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Borrelia burgdorferi. This bacterium is associated with Lyme disease, a tick-borne illness. Borrelia burgdorferi is transmitted to humans through the bite of infected black-legged ticks. It causes a range of symptoms, including fever, rash, joint pain, and neurological problems.
Summary:
B: Clostridium botulinum is associated with botulism, a serious illness caused by a toxin produced by this bacterium.
C: Escherichia coli is a common bacterium found in the intestines of humans and animals, some strains can cause food poisoning.
D: Streptococcus pneumoniae is a bacterium that can cause pneumonia and other respiratory infections, but not Lyme disease.