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Question 1
Correct
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The chemosensitive area in the medulla responds to:
Your Answer: High hydrogen and high carbon dioxide
Explanation:The chemosensitive area in the medulla responds mainly to high pH levels and carbon dioxide levels. Baroreceptors in the carotid and aortic body respond mainly to oxygen and carbon dioxide partial pressure in blood.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Incorrect
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Antibiotic resistance may happen by:
Your Answer: By transformation when resistance is transferred from 1 bacteria to another
Correct Answer: By enzymes which inactivate the drug
Explanation:The three main mechanisms of antibiotic resistance are, enzymatic degradation of antibacterial drugs, alteration of bacterial proteins that are antimicrobial targets, and changes in membrane permeability to antibiotics.
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This question is part of the following fields:
- Infectious Diseases
- Physiology
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Question 3
Incorrect
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The processing of NH3 to urea occurs in:
Your Answer: Rough endoplasmic reticulum
Correct Answer: Mitochondria and cytoplasm
Explanation:The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea ((NH2)2CO) from ammonia (NH3). The urea cycle consists of four enzymatic reactions: one mitochondrial and three cytosolic.
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This question is part of the following fields:
- Cell Biology
- Physiology
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Question 4
Incorrect
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Cyclic AMP activates the following enzyme
Your Answer: Adenylyl cyclase
Correct Answer: Protein Kinase A
Explanation:Cyclic AMP works by activating protein kinase A (PKA, or cAMP-dependent protein kinase). Protein kinase A can also phosphorylate specific proteins that bind to promoter regions of DNA, causing increases in transcription.
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This question is part of the following fields:
- Cell Biology
- Physiology
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Question 5
Incorrect
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If both the noradrenergic and the cholinergic systems are blocked in the heart, the rate will be approximately:
Your Answer: 50/ min
Correct Answer: 100/min
Explanation:The normal heart beat is about 70/min. This is due to a predominant parasympathetic activity. If sympathetic activity was unopposed the heart rate would have been 150/min. When both the noradrenergic and cholinergic systems are blocked the heart rate is 100/min. This is the normal firing rate of the SA node.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 6
Correct
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Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Physiology
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Question 7
Incorrect
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Which cell secretes parathyroid hormone?
Your Answer: Parafollicular cells
Correct Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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This question is part of the following fields:
- Endocrinology
- Physiology
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Question 8
Incorrect
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Which of the following statements is not true regarding ion channels?
Your Answer:
Correct Answer: Ion channels provide a charged, hydrophobic pore through which ions can diffuse across the lipid bilayer.
Explanation:Ion channels are pore-forming protein complexes that facilitate the flow of ions across the hydrophobic core of cell membranes. They are present in the plasma membrane and membranes of intracellular organelles of all cells, and perform essential physiological functions. They provide a charged, hydrophilic pore through which ions can move across the lipid bilayer. They are selective for particular ions and their pores may be opened or closed. Because of this ability to open and close, ion channels allow the cell to have the ability to closely control the movement of ions across the membrane. Gating refers to the transition between an open and closed ion channel state, and is brought about by a conformationational change in the protein subunits that open or close the ion-permeable pore. Ion channels can be: 1. voltage-gated these are regulated according to the potential difference across the cell membrane or 2. ligand-gated – these are regulated by the presence of a specific signal molecule.
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This question is part of the following fields:
- Cell Biology
- Physiology
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Question 9
Incorrect
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A 24-year-old athlete drinks a 500 ml hypertonic sports drink before an endurance event he participates in. Which of the following effects will this cause?
Your Answer:
Correct Answer: The interstitial fluid becomes more concentrated
Explanation:Osmosis is the passive movement of water across a semipermeable membrane from a region of low solute concentration to a region of higher solute concentration. When hypertonic fluid is ingested: The plasma becomes CONCENTRATED. The cells lose water and shrink The intracellular fluid becomes more concentrated. Water and ions move freely from the plasma into the interstitial fluid and the interstitial fluid becomes more concentrated. The increased osmotic potential draws water out of the cells.
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This question is part of the following fields:
- Cell Biology
- Physiology
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Question 10
Incorrect
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Where is retinol mainly stored?
Your Answer:
Correct Answer: Liver
Explanation:Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene). The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin A (1–2 years’ supply), vitamin D (1–4 months’ supply), vitamin B12 (3–5 years’ supply), vitamin K, iron, and copper.
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This question is part of the following fields:
- Haematology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
