MDS PREP
Which of the following is a feature of the immune response involving HLA class I antigens?
1) They activate B cells
2) They present antigens to CD4+ T cells
3) They are involved in graft rejection
4) They are only present in the thymus
General Microbiology Answer: 3HLA (Human Leukocyte Antigen) class I antigens are crucial in the immune response to infections and also play a significant role in graft rejection. They present antigens to CD8+ T cells (cytotoxic T cells), which then target and destroy infected or foreign cells. While they do not directly activate B cells or CD4+ T cells, they are involved in the recognition of cells by the adaptive immune system and thus are important in the overall immune response.
What is the standard diagnostic procedure for Infectious Mononucleosis?
1) ELISA
2) Paul-Bunnel test
3) Latex agglutination
4) Nucleic acid probes
General Microbiology Answer: 2The Paul-Bunnel test is a classic heterophile antibody test used to diagnose infectious mononucleosis, primarily caused by Epstein-Barr virus (EBV). It detects heterophile antibodies that are typically present in patients with this condition. While ELISA and other tests can also be used, the Paul-Bunnel test is historically significant and widely recognized for this diagnosis.
Which of the following is NOT a characteristic of the spore formation in C1. Perfringens?
1) Central or equatorial spores, giving the bacillus a spindle shape
2) Subterminal spores, causing the bacillus to appear club shaped
3) Oval and terminal spores, resembling a tennis racket
4) Spherical and terminal spores, resulting in a drumstick appearance
General Microbiology Answer: 3
C1. Perfringens forms subterminal spores, which cause the bacillus to appear club-shaped under the microscope. The tennis racket appearance is not a characteristic of C1. Perfringens spore formation.
Which test uses live Treponema pallidum as the antigen?
1) TPA test
2) TPI test
3) FTA test
4) TPHA test
General Microbiology Answer: 2
TPI test: The Treponema pallidum immobilization (TPI) test involves using live T. pallidum as an antigen to detect antibodies in the patient's blood serum.
The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a
1. significant increase in number of oral bacteria
2. shift towards a more acidogenic microflora
3 significant decrease in number of oral bacteria
4 shift towards a more aerobic micro flora
Microbiology
Answer: 2
The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a shift towards a more acidogenic microflora
What disease is associated with inhalation of dust from infected wool?
1) Cutaneous anthrax
2) Pulmonary anthrax
3) Gastrointestinal anthrax
4) None of the above
Pulmonary anthrax is associated with inhalation of dust from infected wool.
What is the primary target of antibodies in neutralizing the action of exotoxins?
1) Cell wall components
2) Lipopolysaccharides
3) Protein components of the toxin
4) Enzymes involved in toxin production
General Microbiology Answer: 3
Antibodies neutralize exotoxins by binding to their protein components, preventing them from interacting with host cells and causing damage. This immune response is critical for protecting the host from the harmful effects of these toxins.
What is the typical macroscopic appearance of the stool in cases of amoebic dysentery compared to bacillary dysentery?
1) Amoebic dysentery stool is small and odorless, while bacillary dysentery stool is copious and offensive.
2) Both amoebic and bacillary dysentery stools are copious and offensive.
3) Amoebic dysentery stool is dark red and acidic, while bacillary dysentery stool is bright red and alkaline.
4) Amoebic dysentery stool is bright red and alkaline, while bacillary dysentery stool is dark red and acidic.
Amoebic dysentery stool is typically dark red and acidic, while bacillary dysentery stool is bright red and alkaline.