Q- Which of the following organisms is associated with toxic shock syndrome due to exotoxin A?
A- Clostridium perfringens
B- Staphylococcus aureus
C- Streptococcus pyogenes
D- Vibrio cholerae
C- Streptococcus pyogenes- Streptococcus pyogenes produces exotoxin A, a superantigen responsible for streptococcal toxic shock syndrome. Staphylococcus aureus causes toxic shock syndrome as well, but through TSST-1, not exotoxin A.
Q- Which one of the following types of necrosis is most likely associated with myocardial infarction?
A- Caseous
B- Coagulative
C- Fibrinoid
D- Liquefactive
B- Coagulative- Myocardial infarction leads to coagulative necrosis, characterized by preserved tissue architecture with loss of nuclei and increased eosinophilia. Caseous necrosis is seen in tuberculosis, liquefactive in the brain and abscesses, and fibrinoid in immune-mediated vascular injury.
Q- Which of the following conditions is caused by a frameshift mutation?
A- Becker muscular dystrophy
B- Duchenne muscular dystrophy
C- Hereditary nonpolyposis colorectal cancer
D- Sickle cell disease
B- Duchenne muscular dystrophy- Duchenne muscular dystrophy is typically caused by a frameshift mutation in the dystrophin gene, leading to a truncated, nonfunctional protein. Becker muscular dystrophy is due to a non-frameshift mutation. Sickle cell disease is caused by a point mutation, and HNPCC involves mismatch repair defects, not frameshift mutations.
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Thanks all continou
first qus. whay not B ???