A. inhibition of calcium channels.
B. increased Ca2+ influx into the target cell.
C. inhibition of specialized GABA receptors.
D. increased production of signal transduction chemicals like cyclic AMP.
Catecholamines are naturally occurring amines which function as neurotransmitter and hormones. They include adrenaline, noradrenaline and dopamine. All these function by increasing the production of signal transduction chemicals like cAMP. Adenyly cyclase converts ATP into cAMP. CAMp causes increased heart rate, breakdown of glycogen to glucose and vasodilation.
So option D is correct.
Catecholamines like dopamine activate neurons by ... A. inhibition of calcium channels. B. increased Ca2+ influx...
How is calmodulin activated? A. by binding both calcium and potassium B. by binding Ca2+ when the cytosolic concentration is greater than 500 nM C. by binding to a positively charged helix on another protein D. by binding Ca2+ only when calcium channels are open, allowing Ca2+ efflux from the cell E. None of the answers is correct.
6. Lipid-soluble signaling molecules, such as testosterone, cross the plasma membranes of all cells A) by diffusion but affect only target cells because only target cells retain the appropriate DNA segments. B) by diffusion but affect only target cells because only target cells have the intracellular receptors for testosterone. C) through hydrophilic channels of transmembrane proteins but affect only target cells because only target cells retain the appropriate DNA segments. D) through hydrophilic channels of transmembrane proteins but affect only...
66. Neurons in the control motor reflexes. a. Thalamus b. Spinal cord c. Parietal lobe d. Hippocampus e. B & C 67. The connects the two cerebral hemispheres. a. Limbic system b. Corpus Callosum c. Cerebellum d. Pituitary 68. Where are parasympathetic preganglionic cell bodies located? a. Cerebellum b. Brain Stem c. Dorsal root ganglia d. Skin 69. Patients with ADHD are given which type of medication: a. Anti-Seizure b. Tranquilizer c. SSRI d. Stimulant 70. The structure of peptide...
1. In paracrine signaling, the signaling molecules affects only: Target cells close to the cell from which it was secreted a. b. Target cells distant from its site of synthesis in cells of an endocrine organ Both a. and b. с. d. None of these 2. Below are listed the events that occur in cell to cell communication. Signal transduction occurs 1. 2. Plasma membrane receptor binds with a ligand A cellular response is effected 3. 4. Ligand is released...
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B. It hyperpolarizes the membrane C. t changs he membrane potenatal suh ht voltage-gated Kchambed Na channels are D. It releases calcium from intracellular stores 36. Compared to the cy toplasm, which of the following is generally true about the lumen of the endoplasmie reticulum in our cells? A. It has a more redacing environment B. It bas a moch higher calcium ion concentration. C. It has a higher density of ribosomes. D. All...
1. In allosteric enzyme inhibition, the active site is blocked by another molecule a. True b. False 2. In the second-messenger system of hormonal action, a. The presence of a small amount of one hormone (the second messenger) is essential to permit another hormone (the first messenger) to exert its full effect. b. A tropic hormone (the first messenger) stimulates secretion of another hormone (the second messenger). c. The hormone first binds to a specific surface receptor (the first messenger),...
change pas channels in the volta t ive protein to change shape. This A of the S l e terminal siste oplasmic reticum calcio p r eneule warcoplasm reticulum sodium ions m o nster transverse tubules sarcolemma: calcium ions Saroplasmic reticum: triadsarcolemma: calcium ions sons bind to This causes a change in shape and exposing C D E Calcium vesicle tylcholine action potential Sodium sarcolemma calcium on myosin heads Sodium sacoplasmic reticulum calcium ions actin 15. An attaches to exposed...
46 An electrocardiogram (ECG) provides information about B) the rhythm of heart contractions D) the speed of blood flow through the blood vessels A) the pressure of blood in the heart chambers C) the amount of oxvgen in the blood as it leaves the heart 47 The velocity of blood flow is the lowest in capillaries because A) the capillaries have internal valves that slow the flow of blood B) the diastolic blood pressure is too low to deliver blood...
Which of these statements about the composition of membranes is true?A) All biological membranes contain cholesterol.B) Free fatty acids are major components of all membranes. C) The inner and outer membranes of mitochondria have different protein compositions.D) The lipid composition of all membranes of eukaryotic cells is essentially the same.E) The lipid: protein ratio varies from about 1: 4 to 4: 1Membrane proteins:A) ere sometimes covalently attached to lipid moieties:B) are sometimes covalently attached to carbohydrate moieties.C) are composed of...
Microbiology study guide questions. Please Help!
s. which of the following statements about water activity is not true? a) many fungi can tolerate aw levels of 07-0.8 b) many microorganisms grow well at an aw of 0.98 e sear water has an aw of 0.98 e-xerephiles thrive in dry conditions DNA typically becomes disordered below an a of o.90 Which of the following descriptions about ribosome structure is not true? a) 80s is the size of the intact functional ribosome...