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Which of the following bacteria is responsible for causing syphilis?
- A. Treponema pallidum
- B. Neisseria gonorrhoeae
- C. Chlamydia trachomatis
- D. Escherichia coli
Correct Answer: A
Rationale: Step 1: Treponema pallidum is a spirochete bacterium known to cause syphilis.
Step 2: It is sexually transmitted and can cause various stages of disease.
Step 3: Neisseria gonorrhoeae causes gonorrhea, not syphilis.
Step 4: Chlamydia trachomatis causes chlamydia, not syphilis.
Step 5: Escherichia coli is a common gut bacterium and not responsible for syphilis. Treponema pallidum is the correct answer as it is the specific bacterium known to cause syphilis.
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Antibodies against influenza viruses in a patient's serum can be determined by;
- A. Agglutination reaction
- B. Precipitation reaction in agar gel
- C. Reaction haemagglutination inhibition
- D. Ration haemagglutination
Correct Answer: C
Rationale: The correct answer is C: Reaction haemagglutination inhibition. This method is used to detect antibodies against influenza viruses by measuring the ability of the patient's serum to inhibit haemagglutination. This is a specific and sensitive technique for detecting influenza antibodies.
A: Agglutination reaction is not specific for influenza viruses and may give false positives.
B: Precipitation reaction in agar gel is not typically used for detecting influenza antibodies.
D: Ration haemagglutination is not a standard method for detecting influenza antibodies.
The antigen receptors on the surface of B-lymphocytes are made by proteins:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on the given situation
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: TRUE. B-lymphocyte antigen receptors are made by proteins called immunoglobulins. These proteins are essential for recognizing and binding to specific antigens. They play a crucial role in the immune response. Choice B is incorrect because B-lymphocyte antigen receptors are indeed made by proteins. Choice C is incorrect as well because in this case, the correct answer is that the receptors are made by proteins. Choice D is also incorrect as the receptors are made by proteins.
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.
Which of the following is true regarding gonorrhea symptoms in men?
- A. Testicular pain and epididymal tenderness are often present
- B. Painful urination is always present
- C. 10% of the infected men have no symptoms
- D. Purulent discharge from the urethra is always present
Correct Answer: C
Rationale: The correct answer is C: 10% of the infected men have no symptoms. This is true because gonorrhea can be asymptomatic in some individuals, leading to undiagnosed cases. Testicular pain and epididymal tenderness (choice A) are not typical symptoms of gonorrhea in men. Painful urination (choice B) may or may not be present. Purulent discharge (choice D) is a common symptom but not always present. Therefore, choice C is the most accurate statement regarding gonorrhea symptoms in men.
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.