Immunobiology Flashcards
(116 cards)
1
Q
What is the main function of the immune system?
A
Resist infections
2
Q
Which pathogens replicate intracellularly?
A
viruses and some bacteria
3
Q
Which immune system is antigen-specific and has immunological memory?
A
adaptive immune system
4
Q
Which cells arise from the myeloid progenitor cell?
A
neutrophils and macrophages
5
Q
Natural killer (NK) cells derive from:
A
lymphoid progenitor cells
6
Q
Which mechanical factor helps keep the air passages and gastrointestinal tract free from microorganisms?
A
cilia movement and peristalsis
7
Q
Which chemical factor in sweat inhibits bacterial growth?
A
fatty acids
8
Q
Lysozyme found in tears and saliva acts by:
A
breaking down bacterial walls
9
Q
What is the role of defensins in the innate immune system?
A
antimicrobial activity in lungs and GI tract
10
Q
The complement system is primarily involved in:
A
Answer: B) Non-specific humoral defense leading to opsonization and lysis of bacteria
11
Q
Which organ primarily synthesizes the complement proteins?
A
liver
12
Q
How does the coagulation system contribute to innate immunity?
A
Answer: B) Increases vascular permeability and acts as a chemotactic agent
13
Q
Beta-lysin, produced during coagulation, kills bacteria by:
A
Answer: B) Acting as a cationic detergent that lyses Gram-positive bacteria
14
Q
Which proteins limit bacterial growth by binding iron?
A
Answer: B) Lactoferrin and transferrin
15
Q
Interferons play an important role in:
A
Answer: B) Limiting virus replication in cells
16
Q
Which humoral factor induces fever and production of antimicrobial acute phase proteins?
A
Interleukin-1
17
Q
Which cells are the primary phagocytes recruited to sites of infection in the innate immune system?
A
neutrophils
18
Q
- What type of cell primarily carries out the humoral immune response?
A
C) B cells
18
Q
Natural killer (NK) cells are important in:
A
Answer: B) Nonspecific killing of virus-infected and tumor cells
19
Q
- Antibodies produced by B cells function by:
A
B) Blocking pathogens from binding to host cells and marking them for destruction
20
Q
- Which cells are responsible for detecting microbes hiding inside host cells and killing infected cells?
A
C) Cytotoxic T cells
21
Q
- Where do T cells develop in the human body?
A
thymus
22
Q
- The primary function of dendritic cells in adaptive immunity is to:
A
C) Present microbial antigens to T cells
23
Q
- Pattern recognition receptors (PRRs) on innate immune cells recognize:
A
B) Microbe-associated molecular patterns (PAMPs) not present in the host
24
8. Regulatory T cells function to:
B) Suppress immune responses and maintain balance
25
10. Adaptive immune responses are mainly activated in:
B) Peripheral lymphoid organs such as lymph nodes and spleen
26
11. What molecule class do antibodies belong to?
B) Immunoglobulins
27
12. Which type of lymphocyte secretes cytokines to activate other immune cells?
C) Helper T cells
28
13. The innate immune system helps activate the adaptive immune system primarily through:
B) Pattern recognition receptors that detect pathogens
29
14. The complement system functions mainly by:
B) Enhancing phagocytosis of pathogens
30
15. Which of the following cells is considered a professional antigen-presenting cell (APC)?
dendritic cells
31
16. After activation, effector B cells mature into:
plasma cells
32
17. What is the main site of B cell development in adult humans?
bone marrow
33
18. Which of the following is true about cytotoxic T cells?
B) They kill infected host cells displaying foreign antigens
34
19. Which lymphoid organ is NOT a secondary (peripheral) lymphoid organ?
thymus
35
20. Toll-like receptors (TLRs) are important because they:
A) Recognize specific pathogen molecules and activate immune signaling
36
1. Where do hematopoietic stem cells (HSCs) reside?
bone marrow
37
2. What is a unique feature of hematopoietic stem cells?
B) They can self-renew and produce all blood cell types
38
3. Which of the following is NOT a blood cell lineage?
A) Erythroid
B) Lymphoid
C) Myeloid
D) Neural
Answer: D
39
4. Lymphocytes develop from which progenitor cells?
B) Common lymphoid progenitors
40
5. Colony-stimulating factors (CSFs) do NOT include:
A) GM-CSF
B) G-CSF
C) Erythropoietin
D) Insulin
Answer: D
41
6. Which transcription factor commits cells to the myeloid lineage?
PU.1
42
7. According to the clonal selection theory, lymphocytes:
B) Are randomly generated with diverse antigen receptors before exposure
43
8. What happens during clonal expansion?
B) Lymphocytes divide and produce many clones specific to an antigen
44
9. What is an epitope?
B) The part of an antigen that binds to an antibody or lymphocyte receptor
45
10. Immunodominant epitopes:
B) Are the parts of the antigen that dominate the immune response
46
11. Which of the following is a characteristic of the secondary immune response?
C) Faster and stronger response than the primary response
47
12. Memory B cells:
C) Respond more rapidly upon re-exposure to the same antigen
48
13. What is the purpose of immunological tolerance?
B) To prevent the immune system from attacking self molecules
49
14. Which mechanism involves lymphocytes changing their antigen receptors so they no longer recognize self-antigens?
B) Receptor editing
50
15. Regulatory T cells suppress the activity of self-reactive lymphocytes in which process?
clonal suppression
51
What causes autoimmune diseases?
B) Breakdown of tolerance mechanisms causing immune cells to attack self
52
In Myasthenia gravis, autoantibodies attack:
B) Acetylcholine receptors on skeletal muscle cells
53
Type 1 diabetes results from immune reactions against:
A) Beta cells in the pancreas that secrete insulin
54
Which of the following is thought to trigger autoimmunity in genetically susceptible individuals?
B) Activation of the innate immune system by infection or tissue injury
55
Antibodies are synthesized exclusively by:
B cells
56
Antibodies are also called:
immunoglobins
57
What percentage of plasma protein do antibodies constitute approximately?
20
58
How many classes of antibodies do mammals have?
5
59
Which antibody is produced first by a developing B cell?
IgM
60
Each B cell clone produces:
B) A single species of antibody with a unique antigen-binding site
61
The hinge region of an antibody:
C) Provides flexibility between the two antigen-binding sites
62
The tail region of an antibody molecule is responsible for:
C) Activating complement and binding to phagocytic cells
63
At which stage do B cells first start making μ (mu) heavy chains?
C) Pro-B cells
64
In B cell development, the μ chains remain in the endoplasmic reticulum until:
C) Surrogate light chains are made
65
What is the function of the surrogate light chain in pre-B cells?
B) To associate with μ chains and allow pre-BCR expression on the membrane
66
The transition from pre-B cells to immature naïve B cells requires:
C) Replacement of surrogate light chains with normal light chains
67
Which immunoglobulin class is the first to appear on the surface of a developing B cell?
IgM
68
The secreted form of IgM is:
a pentamer
69
What is the role of the J (joining) chain in secreted IgM?
C) It links IgM subunits into a pentamer
70
Which antibody class is the major immunoglobulin in blood during secondary immune responses?
IgG
71
IgA is the principal antibody class found in:
C) Secretions such as saliva, tears, and milk
72
Before secretion, IgA is assembled into:
a dimer
73
IgD primarily functions as:
C) An antigen receptor on naïve B cells
74
IgE antibodies bind with high affinity to Fc receptors on:
mast cells and basophils
75
The allergic symptoms such as hay fever and asthma are mainly caused by:
C) Release of histamine from mast cells and basophils bound to IgE
76
Which cells can kill extracellular parasitic worms coated with IgE?
Eosinophils
77
The antigen-binding site of an antibody is formed by:
C) Both variable regions of light and heavy chains
78
How many antigen-binding sites does a secreted IgM pentamer have?
10
79
Antibody light chains come in how many types?
B) Two (κ and λ)
80
The main difference between membrane-bound and secreted antibodies is in the:
B) C-terminus of the heavy chain
81
1. Approximately how many different antibody molecules can a human make before antigen stimulation?
10¹²
82
2. Which antibody classes make up the primary antibody repertoire?
Answer: B) IgM and IgD
83
3. What process allows B cells to switch from producing IgM and IgD to other antibody classes?
class switching
84
4. The process by which antibodies increase their affinity for an antigen over time is called:
Answer: C) Affinity maturation
85
5. Antibody diversity is generated by combining gene segments that encode which parts of the antibody?
Answer: B) Variable regions of light and heavy chains
86
6. Which gene segments combine to form the variable region of the light chain?
Answer: B) V and J segments
87
7. How many V, D, and J segments are approximately available in the human heavy-chain locus?
Answer: A) 40 V, 25 D, and 6 J
88
8. What is the name of the recombination process that assembles V, D, and J gene segments?
Answer: C) V(D)J recombination
89
9. Which region of the antibody encodes the antigen-binding site?
variable region
90
10. After V(D)J recombination, what further genetic processes contribute to antibody diversity upon antigen stimulation?
Answer: B) Mutations increasing affinity and class switching
91
15. How does RNA splicing contribute to antibody production after gene rearrangement?
Answer: A) It removes introns and extra gene segments to form mature mRNA
92
17. Which antibody classes can be produced after class switching?
Answer: B) IgG, IgA, and IgE
93
18. Which part of the antibody gene cluster contains multiple J segments separated from the constant region by an intron?
Answer: A) Germ-line DNA
94
20. What role do enhancers and silencers play in antibody gene expression?
Answer: B) They activate or repress transcription after DNA rearrangement
95
1. What ensures that only appropriate gene segments recombine during V(D)J recombination?
B) Conserved recombination signal sequences (RSS)
96
2. Which genes encode the lymphocyte-specific proteins involved in V(D)J recombination?
B) Rag1 and Rag2
97
3. What enzymatic activity does the RAG complex exhibit during V(D)J recombination?
C) Endonuclease
98
4. Deficiency in Rag genes leads to:
B) Severe combined immunodeficiency (SCID)
99
7. What mechanism allows self-reactive B cells to change their antibody specificity?
receptor editing
100
9. What does allelic exclusion ensure in B cells?
B) Monospecificity of antibody production
101
10. How many antibody loci (heavy and light chains) does a diploid B cell have?
6
102
13. Which enzyme is responsible for somatic hypermutation?
C) Activation-induced deaminase (AID)
103
14. Somatic hypermutation primarily occurs:
B) In peripheral lymphoid organs after antigen stimulation
104
15. What does AID do to cytosine bases in V-region DNA during somatic hypermutation?
B) Converts cytosine to uracil
105
17. Class-switch recombination depends on:
B) Activation-induced deaminase (AID)
106
18. During class-switch recombination, which sequences are targeted for recombination?
B) Switch (S) sequences upstream of constant region genes
107
1. Which type of T cell directly kills infected cells by inducing apoptosis?
cytotoxic T cells
108
2. What do Helper T cells primarily do?
Answer: C) Activate B cells, cytotoxic T cells, macrophages, and dendritic cells
109
3. What is the role of regulatory T cells?
Answer: B) Suppress the activity of effector T cells and maintain self-tolerance
110
4. T cell receptors (TCRs) recognize:
Answer: B) Fragments of foreign proteins presented with MHC proteins
111
5. Which MHC class presents antigens to cytotoxic T cells?
class I MHC
112
6. Which cells typically express Class II MHC proteins?
Answer: B) Dendritic cells, macrophages, and B lymphocytes
113
7. CD8 co-receptor on T cells recognizes:
class I MHC
114
8. Where do peptides presented by Class I MHC proteins primarily originate?
Answer: B) Cytosol (intracellular proteins)
115
10. Which antigen-presenting cell type is most effective in activating naïve T cells?
Answer: C) Dendritic cells
