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Question 1
Incorrect
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Telomerase is active in all of the following cells, except:
Your Answer: Stem cells
Correct Answer: Certain liver cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. A somatic cell is any biological cell forming the body of an organism, other than a gamete, germ cell, gametocyte or undifferentiated stem cell. i.e. liver cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Physiology
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Question 2
Incorrect
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The following occurs as a result of 2,3 Bisphosphoglycerate binding to deoxyhaemoglobin
Your Answer: An increase in deoxyhaemoglobin's affinity for oxygen
Correct Answer: A reduction in deoxyhaemoglobin's affinity for oxygen
Explanation:2,3-BPG acts as a heteroallosteric effector of haemoglobin, lowering haemoglobin’s affinity for oxygen by binding preferentially to deoxyhaemoglobin. An increased concentration of BPG in red blood cells favours formation of the T, low-affinity state of haemoglobin and so the oxygen-binding curve will shift to the right.
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This question is part of the following fields:
- Haematology
- Physiology
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Question 3
Incorrect
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Which of the following conditions results from chromosomal ‘non-disjunction’?
Your Answer: Klinefelter’s syndrome
Correct Answer: All of the options
Explanation:Non-disjunction can result in aneuploidy i.e. abnormal number of chromosomes in a cell. It results due to uneven division of chromosomes in the meiosis 1 or 2 phase. All the above mentioned examples are of non-disjunction.
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This question is part of the following fields:
- Genetics
- Physiology
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Question 4
Incorrect
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Question 5
Incorrect
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Which ventral (motor) root is responsible for triceps?
Your Answer: C5
Correct Answer: C7
Explanation:Of the nerve fibers that make up the brachial plexus, C7 mainly forms the radial nerve to innervate the triceps muscle, thus innervating the shoulders, elbow, wrist and hand. C7 is responsible for the triceps reflex.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 6
Incorrect
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Question 7
Incorrect
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Which part of the neuron has the highest concentration of sodium channels per square millimetre of the cell membrane?
Your Answer: Axon terminals 20-75
Correct Answer: Nodes of Ranvier
Explanation:The nodes of Ranvier contain Na+/K+ ATPases, Na+/Ca2+ exchangers and a high density of Na+ channels. The estimated concentration of sodium channels in the node is of ∼1500/μm2.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 8
Correct
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Myocardial oxygen consumption is increased by:
Your Answer: An increase in after load
Explanation:Cardiac oxygen consumption is directly related to the amount of tension that develops in the ventricles. It is increased by an increased size of heart, increased afterload, increased contractility and increased heart rate.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Correct
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An important hormone controlling the differentiation of monocytes to osteoclasts, by inhibiting the RANKL/ RANK interaction is called?
Your Answer: Osteoprotegerin
Explanation:Osteoprotegerin, also known as osteoclastogenesis inhibitory factor (OCIF) is a glycoprotein that acts as a cytokine receptor. It works as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoclast differentiation factor, thus inhibiting the differentiation of osteoclasts, which are capable of resorbing bone. Osteoprotegerin has been proposed as a therapeutic agent for osteoporosis.
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This question is part of the following fields:
- Endocrinology
- Physiology
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Question 10
Incorrect
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Stem cell characteristics include the following except
Your Answer: Ability to proliferate / differentiate outside the bone marrow in an adult during times of stress/disease of the bone marrow
Correct Answer: Differentiation and proliferation into progenitor cells committed to multiple cell lines
Explanation:The classical definition of a stem cell requires that it possess two properties:Self-renewal: the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.Potency: the capacity to differentiate into specialized cell types. In the strictest sense, this requires stem cells to be either totipotent or pluripotent to be able to give rise to any mature cell type
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This question is part of the following fields:
- Haematology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
