Classic Classic Quiz Cardiology : Tropomyosin by Tommymoran Tommymoran 3 played - 10 yrs ago A proteinate quiz QUIZ 26 QUESTIONS expert 1 Troponin I is... The tropomyosin binding subunitThe calcium binding subunitThe inhibiting subunitA and C 2 A cross bridge is... A buffer solution in a galvanic cellA myosin-actin interactionA troponin-myosin interactionAn actin-troponin interaction 3 The conformation shift in the adjacent troponin complex due to a tropomyosin shift from calcium binding is termed... Troponin Binding ComplexCo-operativityCa-troponin binding affinityTropomyosin Binding Cascade 4 What is the chance that cross-bridging will induce the formation of another forming... 01. 5-2. 54. 0-6. 08. 5-10. 0 5 What is the limiting factor in a functioning heart... Ca+K+Na+Cl- 6 What is the "blocked-state? " Troponin-tropomyosin complex blocks actin-myosin interactionCalcium is bound to troponin-CTroponin-I has dissociatedA andC 7 Progression to the closed-state after Ca+ binding to troponin-C is... Highly favoredHighly unfavorableEqually reversibleNot important. 8 The closed-state (weakly bound state)'s interaction is analogous to... The first grip of a rock-climberThe thistles of a plantThe melting of snowflake hitting a warm surfaceA glass vase shattering 9 In a disease heart, the contraction may fail because... It contracts before myosin readjusts to the strong-stateTroponin-C and Troponin-I amalgamateMyosin heads exploded into spaghettiNone of the above 10 ATP propels the myosin head forward from the strong-state (10-15nm), and may... Displaces it so it goes back to its pre-active stateDisplaces it so it goes back to the blocked stateLeaves it intact with the actin moleculeA and B 11 The inefficiency of contracting from the weak state is... ATP, because the contraction is shorterGTP, because the contraction is shorterMyosin, because the complex dissociatesNothing. It's great! Try it. 12 In regulating myofilament, what increases cycling rate? Phosphorylation of troponin subunits by PKA at sites Tnl-S23/S24Phosphorylation of troponin subunits by PKA at sites Tnl-S123Phosphorylation of of actin by PKAA and C 13 What conformational change specifically allows for cycling to increase? Releasing myosin head from ATP-bound state is fasterBinding of calcium fasterShift of tropomyosin complexA and B 14 What is the lifetime risk of heart failure? 20%40%60%80% 15 What is systolic heart failure? The heart doesn't contract appropriatelyThe heart doesn't relax properlyA and BNone of the above 16 Increasing HR to compensate for poor contractility is... A good idea?A really bad idea.Sometimes ok.Grrrrrrrreeeeaaattt! 17 Calcium sensitizers... Enhance the ability of troponin-C to bind Ca+Indirectly reduce the energy expended by SERCAImprove the efficiency of ATP expenditureAll of the above 18 Pimobendan is... An effective calcium sensitizersAn infective calcium sensitizersAvailable in Japan and in vet clinicsA and C 19 Omecativ Mecarbil is a myosin activator that... Improves the ability of the weak-to-strong stepReduced HR that has increased to compensate for weak contractionsRequires more calciumA and B 20 Fractional shortening... Is an indication of how well the muscle is contractingEnchanced by positive ionotropesEnchanced by Omecativ MecarbilAll of the above 21 What is the largest protein in humans? MyosinActinTropomyosinTitin 22 What is the function of titin? Anchors myosin to Z-linesSpring-elastic effect that induces recoil to compensate for cell stretching during ventricular fillingStiffens in a diseased state, problematic for filling and contractingAll of the above 23 PKA and PKG phosphorylate titin to... Decrease stiffenessAllow ventricles to fill more easilyIncrease stiffnessA and B 24 PKC may be involved in a diseased state because... It acts to stiffen titinIs problematic for ventricle fillingIs problematic for contractionAll of the above 25 B-adrenergic receptor can't be targeted in-face of stiffened titin because it is often down-regulated in heart failure. What is a viable downstream target of PKA or PKG? Phosphodiesterase (degrades cGMP)Adenylyl cyclaseGuanylyl cyclaseA and B 26 What drug helps to increase titin phosphorylation, and decrease titin stiffness, in experiments on dogs? Sildenafil (Viagra)DigoxinJvt632876All of the above A mistake in this Quiz ? Contact the author Commentaires
