Nokea
Matrix formed outside the plasma membrane is referred to as:
- A. cytoplasm
- B. glycocalyx
- C. exoplasm
- D. cell wall
Correct Answer: B
Rationale: The correct answer is B: glycocalyx. The glycocalyx is a matrix formed outside the plasma membrane that consists of glycoproteins and glycolipids. It plays crucial roles in cell-cell recognition, protection, and immune response. Cytoplasm (A) is the gel-like substance inside the cell, not outside. Exoplasm (C) is not a recognized term in biology. Cell wall (D) is a rigid structure found in plant cells, not outside the plasma membrane in all cells.
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The term “infectious process†means “all biological processes carried out after…â€
- A. The attachment and penetration of microbes into the microorganism
- B. The attachment and penetration of microbes into the microorganisms regardless of whether or not there is clinical manifestation
- C. The penetration of microbes into the macroorganism and always manifest clinically
- D. No correct answer
Correct Answer: B
Rationale: The correct answer is B because the term "infectious process" refers to all biological processes that occur after the attachment and penetration of microbes into the host organism, regardless of whether there are clinical manifestations. This includes the colonization, multiplication, and spread of the microorganisms within the host.
Explanation:
A: Incorrect because it only mentions the attachment and penetration of microbes into the microorganism, missing the subsequent processes.
C: Incorrect because it is too specific, stating that the penetration of microbes always manifests clinically, which is not always the case.
D: Incorrect because there is a correct answer, which is B, as explained above.
A worker of a cattle farm consulted a surgeon about fever up to 40oC, headache, weakness. Objective examination of his back revealed hyperaemia and a dark red infiltration up to 5 cm in diameter with black bottom in the center and some pustules. What disease are these presentations typical for?
- A. Anthrax
- B. Plaque
- C. Tularemia
- D. Furuncle
Correct Answer: A
Rationale: The correct answer is A: Anthrax. The symptoms of fever, headache, weakness, and the skin lesion described (hyperemic with a dark red infiltration, black center, and pustules) are characteristic of cutaneous anthrax. The black center is known as an eschar. Anthrax is caused by the bacterium Bacillus anthracis, commonly found in cattle. Plague (choice B) typically presents with swollen lymph nodes (buboes) and is caused by Yersinia pestis. Tularemia (choice C) presents with fever, ulcer at the site of infection, and lymphadenopathy, caused by Francisella tularensis. Furuncle (choice D) is a localized skin infection typically caused by Staphylococcus aureus, presenting as a red, swollen, and painful bump.
Which of the following is a key feature of Mycobacterium tuberculosis?
- A. Produces spores
- B. Gram-negative
- C. Acid-fast cell wall
- D. Produces toxins
Correct Answer: C
Rationale: The correct answer is C: Acid-fast cell wall. Mycobacterium tuberculosis is characterized by its unique cell wall composition, containing high levels of mycolic acids which make it acid-fast. This property allows it to resist decolorization during acid-fast staining procedures. This distinguishes it from other bacteria.
A: Producing spores is not a key feature of Mycobacterium tuberculosis. Spore formation is more commonly associated with bacterial species such as Bacillus and Clostridium.
B: Mycobacterium tuberculosis is not Gram-negative. It is classified as acid-fast Gram-positive.
D: Mycobacterium tuberculosis does not produce toxins as a key feature. Its pathogenicity is more closely related to its ability to evade host immune responses and persist in host tissues.
During examination of the patient's oral cavity a dentist noticed deformation of the teeth and a crescent indentation of the upper right incisor. The teeth are undersized, barrel-shaped – tooth cervix is wider than its edge. The patient uses a hearing aid, suffers from visual impairment. What type of syphilis affects teeth in such way?
- A. Primary
- B. Early congenital
- C. Neurosyphilis
- D. Late congenital
Correct Answer: D
Rationale: The correct answer is D, Late congenital syphilis. This is because the patient presents with Hutchinson's teeth, which are a characteristic feature of late congenital syphilis. Hutchinson's teeth are small, barrel-shaped teeth with a wider cervix and notched incisors. The patient's history of visual impairment and hearing aid use also support the diagnosis of late congenital syphilis, as these are common manifestations of this stage of the disease.
Choice A, Primary syphilis, is incorrect because it typically presents with a painless sore at the site of infection, not dental abnormalities. Choice B, Early congenital syphilis, is incorrect as dental abnormalities in this stage are usually more severe, such as mulberry molars. Choice C, Neurosyphilis, is incorrect as it primarily affects the central nervous system and does not typically present with dental abnormalities.
A fetus infected with rubella virus produces which of the following antibodies that can then be detected in the umbilical cord?
- A. IgA
- B. IgM
- C. IgG
- D. IgD
Correct Answer: B
Rationale: The correct answer is B: IgM. IgM antibodies are the first type of antibodies produced in response to an infection, indicating an active or recent infection. In the case of a rubella virus infection in a fetus, IgM antibodies can be detected in the umbilical cord blood, confirming the presence of the virus. IgA antibodies are mainly found in mucosal areas, IgG antibodies indicate past infection or immunity, and IgD antibodies play a role in B cell activation but are not typically detected in this context.