BIOCHEMISTRY-LE-8 (2024) Flashcards
- The class of immunoglobulins which can cross the placenta is:
A. IgM
B. IgG
C. IgA
D. IgD
IgG
- Self-reactive antibodies are not found in significant concentration in normal serum because:
A. It is impossible to generate a self-reactive antibody
B. Self-reactive B cells are killed by CD8 T cells
C. B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide
D. Self-reactive B cells switch to lgA which is all secreted and not present in serum
B cells that are stimulated via their surface bound antibody in the absence of T cell help to commit suicide
- Simulation of which of the following will lead to appearance of first antibody to appear following stimulation by an antigen?
A. IgM
B. IgA
C. IgE
D. IgG
IgM
- Antigen binding sites of an immunoglobulin are located in:
A. Light chain alone
B. Heavy chain alone
C. Fc region of the antibody
D. Fab regions of the antibody
Fab regions of the antibody
- Which of the following mediates Type I hypersensitivity reaction?
A. IgE
B. IgG
C. IgM
A. IgD
IgE
- Which of the following theory of antibody production is most widely accepted?
A. Side chain theory
B. Clonal selection theory
C. Direct template theory
D. Indirect template theory
Clonal selection theory
- Which is the most efficient complement fixing class of antibody?
A. IgE
B. IgA
C. IgM
D. IgG
IgM
- The class of immunoglobulin, most abundant in body is:
A. IgD
B. IgE
C. IgG
D. IgM
IgG
- Which is not a function of IgG?
A. Major antibody inserum
B. First antibody type produced against an antigen during the primary antibody response
C. Activates or fixes complement
D. Involved in opsonisation
First antibody type produced against an
antigen during the primary antibody response
- J chain is present in:
A. IgA
B. IgG
C. IgD
D. IgE
IgA
- Heat-labile class of immunoglobulins include:
A. IgA
B. IgE
C. IgG
D. IgM
IgE
- Which of the following is the phylogenetically oldest immunoglobulin?
A. IgE
B. IgM
C. IgG
D. All are similar
IgG
- The secretary component of sigA is:
A. Made by plasma cells that secrete dimeric IgA
B. Added to dimeric IgA by the M cell
C. Formed by cleavage of an epithelial cell receptor used to transport the dimeric IgA across the epithelial cell
D. Made by T cells
Formed by cleavage of an epithelial cell receptor used to transport the dimeric IgA across the epithelial cell
- Anti-Rh antibodies are:
A. IgG type
B. IgA type
C. IgE type
D. IgD type
IgG type
- Which is not a function of IgA?
A. Protect mucosal surfaces
B. Fix complement
C. Protect eyes
D. Agglutinate antigen
Fix complement
- Which immunoglobulin is the principal one found in secretions such as milk?
A. IgG
B. IgM
C. IgA
D. IgE
IgA
- Which of the following statements best characterizes an antibody:
A. It contains high molecular weight RNA as its basic structure
B. Is composed of protein and cannot be distinguished from the albumin fraction of the serum proteins
C. Is composed of four identical protein subunits which may be caused to dissociate by treatmentwith urea
D. Contains protein as its major chemical component and its synthesis may be elicited by the administration of a foreign protein or polysaccharide
Contains protein as its major chemical component and its synthesis may be elicited by the administration of a foreign protein or polysaccharide
- The immunoglobulin class which is the least abundant in the normal adult is:
A. IgG
B. laA
C. IgD
D. IgE
IgE
- Light chains are:
A. Specific for each class of antibody
B. Not specific for each class of antibody
C. Reactive with antigen
D. Have only a constant region
Not specific for each class of antibody
- Which of the following statement is true regarding F region:
A. Fragment crystallization and is the constant region
B. Fragment constant and is the variable region
C. Fragment crystallization and is the variable region
D. Fragment crystallization and has both variable and constant region
Fragment crystallization and is the constant region
- Fab region:
A. Has a hypervariable region that binds with antibody
B. Has a hypervariable region that binds with antigen
C. Has a hypervariable region that binds with other immune cells
D. All of the choices
Has a hypervariable region that binds with antigen
- The ability of antigen to stimulate antibody production is termed:
A. Affinity
B. Antigenicity
C. Elicitation
D. None of the choices
Antigenicity
- Monomers of certain immunoglobulins are joined by:
A. Variable chain
B. Constant chain
C. J-chain
D. All of the choices
J-chain
- The two identical light chains of an antibody belongs to:
A. Kappa only
B. Lambda only
C. Lambda or kappa
D. None of the above
Kappa only
- The hypervariable region of antibody consists of:
A. Amino acids that form antigen binding site
B. Phospholipids that form antigen binding site
C. Oligosaccharides that form antigen binding site
D. A part of the constant region of heavy and light chains
Amino acids that form antigen binding site
- True of xenobiotics:
A. They are alternative sources of ATP in the absence of macronutrients
B. They are excreted by the body unchanged
C. They do not undergo first pass metabolism
D. Catabolism by CytP450 makes them more water soluble
Catabolism by CytP450 makes them more water soluble
- What is/are the principal site/s for xenobiotic metabolism?
A. Lungs
B. Liver
C. Kidneys
D. Liver and kidneys
Liver
- In general, xenobiotic drugs are manufactured as which of the following to facilitate absorption?
A. Water-soluble
B. Fat-soluble
C. Highly polar
D. Hydrophilic
Fat-soluble
- The main goal of xenobiotic metabolism:
A. Render the molecule water-soluble
B. Avoid liver catabolism to enable a higher bioavailability
C. Excrete the xenobiotic via the fecal route
D. Increase the lipophilic character of the xenobiotic for better cellular absorption
Render the molecule water-soluble
- Which organ is least involved in xenobiotic metabolism?
A. Intestine
B. Brain
C. Kidney
D. Liver
Brain
- True of cytochrome P450.
A. It catalyzes phase II of xenobiotic metabolism
B. It is a selenium-containing enzyme
C. It helps synthesize steroid hormones
D. It inactivates Vitamin D
It helps synthesize steroid hormones
- How are cytochrome P450 enzymes related to drug interactions?
A. They induce the lungs to volatilize drugs that enter the bloodstream
B. Some drugs are catabolized by the sameCytP450 enzymes
C. Because of their monomorphic nature, only one CyP450 breaks down drugs that enter the bloodstream
D. The hemeproteins in Cyt450 are responsible for promoting antibiotic resistance
Some drugs are catabolized by the sameCytP450 enzymes
- All of the following are true of free radicals EXCEPT:
A. Increasing intake of antioxidants will halt free radical synthesis
B. They are formed even in normal conditions
C. They cause damage to nucleic acids, proteins, and lipids
D. Formation of free radicals can cause self-perpetuating chain reactions
Increasing intake of antioxidants will halt free radical synthesis
- The reaction 02 + 2H* -> H202 is catalyzed by:
A. Catalase
B. Glutathione peroxidase
C. Superoxide dismutase
D. Cytochrome P450
Superoxide dismutase
- Which of the following is an important cofactor for vitamins C, E, and Glutathione Peroxidase in the neutralization of free radicals?
A. NADPH
B. Bioflavinoids
C. Selenium
D. Copper
NADPH
- What is the adduct that attaches to red blood cells in HbA1C that is used as a diagnostic marker?
A. Fructose
B. Alanine
C. Heme
D. Glucose
Glucose
- This phytochemical is usually found in grapes:
A. Resveratrol
B. EGCG
C. Curcumin
D. Ferulic acid
Resveratrol
- What DNA repair mechanisms is used to correct DNA damage caused by the formation of thymine-thymine dimers due to ultraviolet light?
A. Base excision
B. Nucleotide excision
C. Single strand break
D. Homologous recombination
Nucleotide excision
- This is a toxic protein aggregate that is the hallmark of diseases such as Parkinson’s and Alzheimer’s disease:
A. Schiff base
B. Amyloid
C. Amylopectin
D. Amadori intermediate
Amyloid
- What is the role of telomeres in the aging process?
A. Telomeres cause a progressive slowing down of an individual’s heart rate when they accumulate with age
B. Telomeres shorten after every cell division until senescence sets in
C. Telomeres generate Okazaki fragments, which are not detected by DNA polymerases during cell replication of DNA
D. In theory, telomeres generate protein aggregates which when expressed will cause DNA damage
Telomeres shorten after every cell division until senescence sets in