MDS PREP
There are some enzymes that cause protein to coagulate rather than to produce simpler compund These are known as
1. lab enzymes
2. coagulase
3. proteolytic enzymes
4. wenmycin
Microbiology
Answer: 1
There are some enzymes that cause protein to coagulate rather than to produce simpler compund These are known as lab enzymes
1. Coagulase:
Definition: Coagulase is an enzyme produced by certain
bacteria, most notably Staphylococcus aureus. It catalyzes the
conversion of fibrinogen (a soluble plasma protein) into fibrin (an
insoluble protein), leading to the clotting of blood.
Function: The production of coagulase is a virulence
factor for Staphylococcus aureus, as it helps the bacteria evade
the host's immune system by forming a protective clot around the bacterial
cells. This clot can shield the bacteria from phagocytosis and other immune
responses.
Clinical Relevance: Coagulase is used in laboratory
tests to differentiate between pathogenic Staphylococcus aureus (coagulase-positive)
and non-pathogenic staphylococci (coagulase-negative).
2. Proteolytic Enzymes:
Definition: Proteolytic enzymes, also known as
proteases or peptidases, are enzymes that catalyze the breakdown of proteins
into smaller peptides or amino acids by cleaving the peptide bonds between
amino acids.
Function: These enzymes play crucial roles in various
biological processes, including digestion, protein turnover, cell signaling,
and immune responses. They are found in many organisms, including humans,
where they are involved in the digestion of dietary proteins in the stomach
and small intestine.
Types: Proteolytic enzymes can be classified based on
their mechanism of action (e.g., serine proteases, cysteine proteases,
aspartic proteases, and metalloproteases) and their substrate specificity.
Wenmycin is an antibiotic that is derived from the
bacterium Streptomyces wenyangensis. It belongs to the class of
compounds known as macrolide antibiotics, which are
characterized by their large lactone ring structure. Wenmycin has been studied
for its antimicrobial properties, particularly against certain types of
bacteria.
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.
What is the role of the Vi antigen in the pathogenesis of typhoid fever?
1) It aids in colonization of the intestinal mucosa.
2) It confers resistance to antibiotics.
3) It is involved in the production of toxins.
4) It allows the bacteria to evade the host's immune response by inhibiting phagocytosis.
General Microbiology Answer: 4The role of the Vi antigen in the pathogenesis of typhoid fever is it allows the bacteria to evade the hosts immune response by inhibiting phagocytosis: The Vi antigen is a polysaccharide capsule found in some strains of S. typhi that helps the bacteria avoid phagocytosis by host immune cells. This contributes to the bacterias ability to survive and proliferate within the human body.
The chemical nature of bacterial exotoxins is, a
1. low molecular weight polypeptide
2. lipopolysaccharide complex
3. protein
4. complex carbohydrate
Microbiology
Answer: 2
The chemical nature of bacterial exotoxins is, a
lipopolysaccharide complex
What is the typical microscopic finding in amoebic dysentery?
1) Numerous pus cells
2) Abundant Charcot-Leyden crystals
3) Many motile bacteria
4) Abundant pyknotic bodies
The typical microscopic finding in amoebic dysentery includes numerous pus cells and abundant Charcot-Leyden crystals.
What type of antibodies are known as "coproantibodies"?
1) IgA
2) IgM
3) IgG
4) Antibodies found in feces
General Microbiology Answer: 4Copro antibodies are antibodies found in feces These are typically IgA antibodies that are produced in response to infections in the gastrointestinal tract, including typhoid fever. They can be detected in stool samples and are used in diagnostic tests.
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.
The bacterial population in the gingival sulcus or the pocket that influences the course of periodontal disease has been found to involve
1 bacteria indigenous to the oral cavity
2. essentially a pure culture
3. essentially the same organisms found in the healthy sulcus
4. mostly aerobic bacteria
Microbiology
Answer: 3
The bacterial population in the gingival sulcus or the pocket that influences the course of periodontal disease has essentially the same organisms found in the healthy sulcus