Nokea
The oxidation-reduction pairs X/XHâ‚‚ and Y/YHâ‚‚ have reduction potentials of -50 and +75 millivolts, respectively. This means that electrons would most likely be removed from ______ to reduce ______.
- A. XHâ‚‚, Y
- B. Y, XHâ‚‚
- C. YHâ‚‚, X
- D. Y, YHâ‚‚
Correct Answer: A
Rationale: The correct answer is A: XHâ‚‚, Y. This is because the reduction potential of -50 mV for X/XHâ‚‚ indicates that X is more likely to lose electrons compared to Y with a reduction potential of +75 mV. Therefore, electrons would be removed from XHâ‚‚ (X) to reduce Y. Choice B is incorrect because Y has a higher reduction potential than XHâ‚‚, so electrons would not be removed from Y to reduce XHâ‚‚. Choices C and D are also incorrect as they do not consider the relative reduction potentials of X/XHâ‚‚ and Y/YHâ‚‚.
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Determine the following diseases that are not thought to be an autoimmune disease.
- A. Rheumatoid arthritis
- B. Multiple sclerosis
- C. Cancer of the bone marrow
- D. Insulin-dependent diabetes
Correct Answer: C
Rationale: The correct answer is C, Cancer of the bone marrow. Autoimmune diseases occur when the immune system mistakenly attacks healthy cells. Rheumatoid arthritis, multiple sclerosis, and insulin-dependent diabetes are autoimmune diseases where the immune system targets specific tissues or organs. Cancer of the bone marrow, on the other hand, is a result of uncontrolled cell growth and division, not a malfunction of the immune system attacking the body's own tissues. Therefore, it is not considered an autoimmune disease.
The joints most commonly involved with rheumatoid arthritis include:
- A. Symmetrical involvement of major joints.
- B. Small joints of hands and feet.
- C. Spine,from the sacrum upward to cervical.
- D. Slightly movable joints of the axial skeleton.
Correct Answer: B
Rationale: Rheumatoid arthritis primarily affects small joints symmetrically, especially those in the hands and feet. Major joints and axial skeleton involvement occurs but is less characteristic of early disease presentation.
The activation of naïve T cells takes place in:
- A. Germinal centers
- B. Primary lymphoid tissues
- C. Secondary lymphoid tissues
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C: Secondary lymphoid tissues. Naïve T cells are activated in secondary lymphoid tissues such as lymph nodes and spleen. These tissues are where T cells encounter antigen-presenting cells, receive co-stimulatory signals, and undergo clonal expansion to differentiate into effector T cells. Germinal centers are primarily for B cell responses. Primary lymphoid tissues (bone marrow and thymus) are where T cells mature but not where activation occurs. Choice D is incorrect as naïve T cell activation does occur in secondary lymphoid tissues.
VDJ gene rearrangement takes place in
- A. Germinal Centers
- B. Lymph Nodes
- C. Bone marrow
- D. Spleen
Correct Answer: C
Rationale: Rationale: VDJ gene rearrangement occurs during lymphocyte development to generate diverse antigen receptors. This process occurs in the bone marrow, specifically in the early stages of B cell development. In the bone marrow, B cell precursors undergo VDJ recombination to create unique antibody specificity. Germinal centers are sites for B cell activation and proliferation, not gene rearrangement. Lymph nodes and spleen are secondary lymphoid organs where mature lymphocytes are activated, not where VDJ recombination occurs.
Which condition is an example of Type IV hypersensitivity?
- A. Multiple sclerosis
- B. Grave's disease
- C. Anaphylaxis
- D. Eczema
Correct Answer: A
Rationale: The correct answer is A: Multiple sclerosis. Type IV hypersensitivity involves T cell-mediated immune reactions, leading to tissue damage. In multiple sclerosis, myelin sheath destruction is caused by activated T cells attacking self-antigens.
Incorrect choices:
B: Grave's disease is an example of Type II hypersensitivity involving autoantibodies targeting specific cells.
C: Anaphylaxis is a Type I hypersensitivity reaction mediated by IgE antibodies causing rapid and severe allergic reactions.
D: Eczema is a chronic inflammatory skin condition involving complex immune mechanisms not specific to Type IV hypersensitivity.