Biochemistry MCQ Quiz Hub

1. Which of the following is incorrect with regard to antigen epitopes?
An epitope may be shared by two different antigens
A protein molecule usually contains multiple epitopes
B cells bind only processed antigen epitopes
Epitopes may be linear or assembled

2. Very low doses of antigen may induce
hypersensitivity
immunological ignorance
low zone tolerance
low zone immunity

3. During the lag period between antigen contact and detection of adaptive immunity,
antigen is hidden from the immune system in macrophages
innate immune effectors are eliminating antigen
innate immunity blocks the activation of adaptive immune effector cells
new B and T cells with the appropriate antigen specificity must be produced in the bone marrow

4. Lymphocytes are activated by antigen in the
blood stream
bone marrow
liver
lymph nodes

5. A pathogen can be a (n)
agent that causes a disease
virus
bacteria
All of these

6. CD antigens
allow leukocytes to recognize antigen
are each expressed on only one cell type
are expressed on immune cells to mark them for separation
function as receptors for cytokine and CAMs

7. A virus vaccine that can activate cytotoxic T cells must contain
a high dose of virus particles
an adjuvant to stimulate T cell division
live virus
virus peptides

8. The ability of an antigen to induce an immune response does not depend on the antigen's
ability to enter the thyroid
degree of aggregation
dose
size

9. The antibiotic penicillin is a small molecule that does not induce antibody formation. However, penicillin binds to serum proteins and forms a complex that in some people induces antibody formation resulting in an allergic reaction. Penicillin is therefore
an antigen
a hapten
an immunogen
both an antigen and a hapten

10. Which of the following immune cells would have an especially low count in a patient with advanced AIDS?
Killer T lymphocytes
Helper T lymphocyte
B lymphocytes
None of these

11. In cellular immunity, T lymphocytes are responsible for the recognition and killing of foreign invaders. The cells
cytotoxic T lymphocytes (CTL)
killer T cells
both (a) and (b)
none of the above

12. Plasma cells produce thousands of __________ that are released into the bloodstream
antigens
antibodies
helper T cells
virus fragments

13. If a person is vaccinated against a disease sometime in the past, which of the following is currently in your body?
The disease organism itself and antigens for the disease organism
A very high level of antibodies against the disease antigens
Memory B lymphocytes for the antigen of this disease organism
All of the above

14. What is a protein produced by host cells infected by viruses?
Interferon
Histamine
Antiserum
Vaccine

15. Polysaccharides on the surface of infecting microorganisms can also activate complement directly in the absence of
antibody via the alternative pathway
antigen via the alternative pathway
antibody via metabolic pathway
none of the above

16. Antibodies bound to an invading microorganism activate the complement system via
classical pathway
metabolic pathway
Embden Meyerhof pathway
Entner-Doudoroff pathway

17. The immune response to a booster vaccine is called a(n)
cellular response
innate response
primary response
secondary response

18. Immunological memory is due to
short lived macrophage that can recognize specific pathogens
long lived B cells that secrete a specific antibody
long lived B cells that secrete a specific antigen
short lived helper T cells that signal macrophage to divide

19. What is the result of an abnormal response of the immune system to part of a person's own body?
Passive immunity
Cancer
An allergic response
An autoimmune disease

20. What are the solutions prepared from weakened or dead microorganisms, viruses, or toxins that provide some immunity from diseases?
Vaccines
Histamines
Drugs
Antibiotics

21. During exposure to a foreign invader, there are more __________ present in the vertebrate body than before exposure
antibodies
lymphocytes
macrophages and antigens
all of these

22. To elicit the best antibodies to mouse MHC I, it should be injected into a
goat
mouse of the same genetic background (strain)
mouse of a different strain
rat

23. To detect a humoral immune response to influenza virus, it is possible to measure
cytotoxicity of virus-infected cells in tissue culture
dividing T cells in the draining lymph nodes
plasma cytokine levels
serum antibody titer

24. Which of the following is in the lymph nodes of a person battling a cold virus?
Huge numbers of white blood cells
Trapped viruses that have been roaming the body
Lymph ducts that enter and exit the nodes and Lymph fluid
All of the above

25. Immunogenicity
depends on the ability of the native antigen to be presented by MHC
is usually a property of self antigens such as eye tissue
is not a property of antibodies
is not a property of haptens

26. The HIV virus infects primarily
brain cells
cells in the immune system
red blood cells
liver cells

27. Chronic granulomatous disease results from a failure to perform oxidative burst. This deficiency would be most likely to interfere with
CTL killing of viruses
dendritic cell activation to become a mature APC
infected cell processing of virus peptides
macrophage intracellular killing of bacteria

28. Difficulties with somatic gene therapy arise from all of the following except
GVHD caused by mature T cells in the transplanted cells
inserting a gene so that it will function properly
limited life span of more mature hematopoietic cells
transducing genetic material into stem cells

29. A monoclonal antibody (mAb) specific for the 2,4-dinitrophenyl (DNP) hapten might also bind
Leu or Ileu
His or Pro
Tyr or Phe
Ser or Thr

30. Retinoblastoma is due to a mutation in a
kinase
tumor supressor
cyclin
viral gene

31. An autoimmune disease is
AIDS
Measles
Lupus
Mumps

32. If Class IIMHC is not expressed in the thymus, the resulting immune deficiencies would include all of the following except reduced
alternative complement activation.
CD8 T cell-mediated cytotoxicity
macrophage activation to vesicular pathogens
IgG synthesis

33. Specific translocations are associated with
colon cancer
breast cancer
pancreatic cancer
some leukemias

34. To treat HIV infections using drugs, the major problem is that
the drugs that are good inhibitors cannot by synthesized
the drugs interfere with normal digestion
the virus particles with altered (mutant) proteases arise
the drugs are rapidly degraded

35. The primary reason for AIDS, a deadly disease is that it
is caused by a virus
is caused by a bacterium
destroys key components of the body's internal defense system
causes a breakdown of the body's inflammatory response

36. A selective IgA deficiency would be expected to result in problems with
bacterial infections
infections following dental work due to bacteria entering the bloodstream
mucosal pathogens
pathogens which can survive inside macrophages

37. Combined cellular and humoral immune deficiencies result from lack of all of the following except
a thymus
class II MHC
HIV infection of CD4+ T cells
transporter of antigen peptides (TAP)

38. An example of an immunodeficiency disorder is
thyroiditis
rheumatic fever
systemic lupus erythematosus
AIDS

39. Bone marrow given to an infant with SCID must
be irradiated to eliminate GVHD
contain mature T cells that can begin making immune responses immediately
come from a donor that shares some MHC alleles with the recipient
come from one of the child's parents

40. X-linked hyper IgM syndrome, resulting in high levels of serum IgM and low levels of serum IgG, is caused by a defect in CD40L expression. The specific immune event that would be prevented by a defective CD40L would be
activation of B cells by T-independent antigens
failure of B cells to provide co-stimulation for Th2 activation
failure of Th2 cells to provide co-stimulation for B cell isotype switching
failure of Th2 cells to provide co-stimulation for B cell proliferation

41. DiGeorge's syndrome is characterized by the lack of a thymus The mouse model closest to this human disease would be a
knock-out mouse for RAG-1 and RAG-2
knock-out mouse for a thymus
nude mouse
recombinant mouse for CD3

42. Which of the Rous sarcoma virus has a homologous cellular protein?
c-src
v-src
v-ha-src
v-ha-ras

43. Infants are most susceptible to bacterial infection due to low circulating levels of IgG
in utero (before birth)
at 0-3 months of age
at 3-12 months of age
at 12-24 months of age

44. The chemical, typically released by the body in an allergic response is
histamine
allergens
antihistamines
perforins

45. Small charged molecules, often biogenic amines function as
hormones
neurotransmitters
both (a) and (b)
none of these

46. SH2 domains specifically bind to
phosphorylated serine residues
phosphorylated tyrosine residues
GDP
Ca2+

47. In paracrine signaling, the signaling molecules affects only
target cells close to the cell from which it was secreted
target cells distant from its site of synthesis in cells of an endocrine organ
both (a) and (b)
none of the above

48. Simple nerve reflexes use signaling molecules called
neurotransmitters
nitric oxides
G proteins
proteases

49. Which of the following is not a type of signaling
Testosterone
Insulin
Thyroxin
Adenylate cyclase

50. Self-phosphorylation is an excellent mechanism for triggering specific catalytic function of the proteins involved in signal cascades because
changes the shape and thus the enzymatic activity of the proteins involved
makes the receptor more likely to capture the signaling, molecule
allows hydrophilic signaling molecules to cross the plasma membrane
None of the above

51. Which of the following statements about G proteins is false?
They are involved in signal cascades
They bind to and are regulated by guanine nucleotides
They become activated when bound to GDP
They must be active before the cell can make needed cAMP

52. When a __________ reaches its __________ , there is a specific means of receiving it and acting on the message. This task is the responsibility of specialized proteins called __________ .
signaling molecule; receptor; G proteins
signaling molecule; target cell; G proteins
signaling molecule; target cell; receptors
kinase; receptor; proteases

53. Why is it that inhaling nitric oxide reduces blood pressure only in the lung tissue and not elsewhere in the body*?
Because other body tissues use a different signaling molecule
Because nitric oxide cannot cross cell membranes and enter the blood
Because nitric oxide breaks down quickly and thus cannot travel far
None of the above

54. Which of the following comes under the category of cell surface receptor?
Enzyme linked receptors
Ion-channel linked receptors
G protein linked receptors
All of these

55. Which of the following is true about a hydrophilic signaling molecule?
Its receptor is located in the cytosol of the target cell
It might trigger a signal cascade that causes some effect in a cell
Since it can enter the cell, it directly affects some specific cell process
It is a steroid

56. cAMP and cGMP are derived from
ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively
GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively
none of the above

57. Nitroglycerin has long been administered to human patients suffering from chronic chest pain (angina). This medication works because it
mimics the action of signal receptors
is broken down into hormones that affect the heart
interferes with chemical cascades that trigger contraction of heart muscle
breaks down into nitric oxide, which increases blood flow to the heart

58. If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?
Nitric oxide would no longer be produced
Smooth muscle cells could not be made to relax
blood flow and reduce blood pressure
All of the above

59. In terms of cell communication, what do bacterial pathogens such as cholera and anthrax have in common?
They destroy the receptors for key signaling molecules
They prevent the production of key signaling molecules
They alter the chemical structure of key signaling molecules
They block the normal functioning of signal transduction mechanisms

60. What is the name of the protein signaling molecule that alters glucose uptake, and where would its receptors be located?
Insulin; many different cell types that use glucose for fuel
Insulin; beta cells of the pancreas
PDGF; the blood
NGF; the nerves involved in simple reflexes

61. In the signal transduction mechanism known as protein phosphorylation
the signaling molecule binds to a surface receptor
receptor kinases play a key role in triggering the signal cascade
phosphorylated proteins act with enzymes to trigger the signal cascade
All of the above

62. Cell signaling can be classified into
three distinct types based on the distance over which the signaling molecules act
two distinct types based on the distance over which the signaling molecules act
three distinct types based on the signaling molecules
none of the above

63. Which of the following statement is correct?
Cell communicate with one another in multicellular organisms using extracellular signaling molecules or hormones
Cell communicate with one another in unicellular organisms using extracellular signaling antigen and antibody
Cell communicate with one another in multicellular organisms using intracellular signaling molecules only
Cell communicate with one another in unicellular organisms using intracellular signaling antigen and antibody

64. In vasodilation, proper nerve signals sent to blood vessels cause
the release of nitric oxide from endothelial cells
relaxation of smooth muscle cells
reduced blood pressure
All of the above

65. A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell?
It is in the heart muscle
It is also the site of production for the signaling molecule
It contains the receptor for the signaling molecule
It is incapable of signal transduction

66. The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is
phosphokinase C
phospholipase C
phosphodiesterase C
lipokinase

67. The binding of ligands to many G-proteins linked receptors leads to shortlived
increase in the concentration of certain intracellular signaling molecules called second messenger
decrease in the concentration of certain intracellular signaling molecules called second messenger
increase in the concentration of certain extracellular signaling molecules called first messenger
decrease in the concentration of certain extracellular signaling molecules called first messenger

68. Which of the following processes involve the combining of a message from one signaling molecule with that of another to either enhance or inhibit a cellular effect?
Signal transduction
Signal reception
Signal integration
Signal amplification

69. A signal cascade induced by adrenaline or thyroxine
must begin with receipt of the signal molecule by a surface receptor
involves the activation of a G protein
results in the activation of a sequence of enzymes needed for the cell effect
all of the above

70. Which of the following is a second messenger?
lnositol 1,4,5-triphosphate
Diacyl glycerol
Phospholipase C
Both (a) and (b)

71. Which of the following statement is incorrect?
The principal lipophilic hormones that binds to receptors located in the plasma membranes are prostaglandins
Prostaglandins are synthesized from arachidonic acid
Prostaglandins act as paracrine signaling molecules
None of the above

72. Two key organizing principles for large multicellular organisms are
prokaryotic cell structure and cell specialization
cell specialization and communication between cells
communication between cells and simple nerve reflexes
simple nerve reflexes and cell specialization

73. Which of the following is a hormone whose action requires a cell surface receptor?
Nitric oxide
Progesterone
Adrenaline
Growth factors

74. The hormone or ligand can be considered as
first messenger
second messenger
both (a) and (b)
none of these

75. The major second messengers are
cAMP
cGMP
DAG
All of these

76. he signaling molecules called steroid hormones
are made in one location of the body but have their effects some distance away
are hydrophilic and so cannot penetrate the plasma membrane
bind to cell surface receptors to trigger chemical cascades
never enter the blood of humans

77. The accepted hypothesis for DNA replication is
conservative theory
dispersive theory
semi-conservative theory
evolutionary theory

78. When DNA polymerase is in contact with guanine in the parental strand, what does it add to the growing daughter strand?
Phosphate
Cytosine
Uracil
Guanine

79. Telomeres are usually rich in which nucleotide?
Adenine
Guanine
Thymine
Cytosine

80. Which is the largest among the followings?
Nucleotide
Nitrogenous base
Phosphate
Carbon