MLT GlobeMOH exam preparation (UAE) – page 12
700 practice MCQs for the MOH medical laboratory exam. Level: Basic to intermediate.
The paratope, the antigen-binding site, is found on which molecule?
The paratope is part of the antibody variable region; it binds the epitope on the antigen.
Which statement about IgE is FALSE?
IgE neither crosses the placenta (IgG does) nor activates complement. It binds mast cells, causing allergy and anti-parasite responses.
What is true of kappa and lambda light chains?
Kappa or lambda light chains may pair with any heavy-chain class. Light chains have both variable and constant domains.
Which is NOT true of antibodies?
Antibodies are made by B cells and plasma cells, not T cells.
Which is NOT a type of immune disorder?
Tolerance is the normal lack of response to self antigens.
An exaggerated immune reaction to harmless antigen, such as pollen, that damages the host is called:
Hypersensitivity is an excessive response to foreign antigen. Autoimmunity targets self antigen.
Wheal-and-flare and bronchospasm in type I hypersensitivity are chiefly caused by release of:
Mast cell degranulation releases histamine, which causes vasodilation, increased permeability and smooth muscle contraction.
HIV mainly infects and depletes which cells?
HIV binds CD4 with a chemokine co-receptor and depletes CD4 T cells. Monitoring uses CD4 counts.
Interferon-alpha and -beta are proteins released mainly by:
Type I interferons are released by virus-infected cells and induce an antiviral state in neighbouring cells.
Which blood cell is a professional phagocyte?
Neutrophils ingest and kill bacteria. NK cells kill by cytotoxicity and plasma cells secrete antibody.
Redness, heat, swelling and pain after tissue injury form a response called:
Inflammation involves vasodilation, increased permeability and leukocyte recruitment. Phagocytosis is one part of it.
A small molecule that elicits antibody only when attached to a carrier protein is a(n):
Haptens are antigenic but not immunogenic alone. Adjuvants non-specifically enhance immune responses.
The part of an antigen that binds an antibody is the:
The epitope is the antigenic determinant; the paratope is on the antibody.
Which immunoglobulin is co-expressed with IgM on naive B cells?
Naive B cells co-express IgM and IgD with the same specificity.
Which pair of immunoglobulins activates the classical complement pathway?
IgM and IgG bind C1q. IgA and IgE do not activate the classical pathway.
The membrane attack complex is formed by:
C5b-9 forms the membrane pore. C4b2a is the classical C3 convertase.
Complement proteins in plasma:
Complement circulates as inactive zymogens activated in cascade.
C3a and C5a cause:
C3a and C5a are anaphylatoxins; they cause mast cell degranulation and increased permeability.
Plasma cells arise from:
Activated B cells differentiate into plasma cells.
Which is an example of natural passive immunity?
Maternal IgG crossing the placenta is natural passive immunity. Recovery from infection gives natural active immunity.