2+ The activity of the Ca 2+ -ATPase is regulated reversibly under normal conditions to maintain homeostatic concentrations of Ca²- inside the sarcomere. However, in a rare genetic disorder, irreversible activation of the Ca 2+ -ATPase can occur. Assuming 37 °C, pH = 7.4, and the steadystate concentrations for ATP, ADP Pi, and Ca2+ (out) given in part (a), calculate the minimum [Ca2+] inside a sarcomere that has irreversibly activated Ca 2+ -ATPase (i.e., the Ca2+-ATPase activity is always “on”). Express your answer to two significant figures and include the appropriate units.

3L9

16c

A one-to-one protein (P)-ligand (L) complexation (P + L PL) has a dissociation equilibrium constant (Kd) value of 100 nM at 25°C, and the Kd remains the same at 37°C. 1) What is AS of binding at 25°C? Assume ACp of the binding is 0 over the temperature range. AS = 1.34E2 kJ/(mol*K) (note the unit!!) (sig. fig =3) 2) What is the concentration of the PL complex formed at equilibrium when you mix 0.20 uM (microM) of Protein and 1.0 uM of Ligand together at 37°C? PL at equilibrium = 8.1E-1 uM (note the unit!!) (sig. fig =2)

The table contains data about how different ASFV mutants affect enzyme activity-- for example the D29A mutant, where the D at position 29 was mutated to an A.  Select three mutants at random, and for each mutant explain how that mutation could affect intermolecular force interactions (an example: hydrogen bonding could be disrupted by this mutation because…

3L6

In considering active transport by Na + -K + -ATPase at body temperature (37 o C), 3 Na+ are pumped out of the cell and 2 K + are pumped in for each ATP that is hydrolyzed to ADP + P i . Given that underyour experimental conditions, the DG for ATP hydrolysis is -10 kcal/mol, and that V is -60 mV, and that the pump maintains the internal Na + at 10mM, external Na + at 120 mM, internal K + at 120 mM and external K + at 8mM, what is the efficiency of the pump (i.e., what fraction of the energy available from ATP hydrolysis is required to drive transport at the provided levels)?

bo Consider a uniport system where a carrier protein transports an uncharged substance A across a cell membrane. Suppose that at a certain ratio of [A] inside to [A] outside, the AG for the transport of substance A from outside the cell to the inside, Macmillan Leaming A outside → Ainside, is 10.7 kJ/mol at 25°C. What is the ratio of the concentration of substance A inside the cell to the concentration outside? [A]inside [A]outside Choose the true statement about the transport of A under the conditions described. Because AG is positive, the ratio [A] inside/[A]outside must be less than one. Increasing [A]outside will cause AG for movement of Aoutside to Ainside to become a larger positive number. Movement of Ainside to Aoutside will be spontaneous. Decreasing the concentration of the uniport protein in the membrane will cause AG to become a smaller positive number.

Refer to the reaction scheme of the GAPDH catalyzed formation of 1,3-BPG. In the reaction, the nucleophile in step (4) is an inorganic phosphate molecule. The enzyme active site is elaborately constructed so that inorganic phosphate, not water, acts as the nucleophile. What advantage is gained by using inorganic phosphate, instead of water, as the nucleophile? Discuss in terms of the energy yield of glycolysis. No need to calculate the total net energy yield of glycolysis.

The Nutrition Facts label on most food products shows % daily values based on a food energy requirement of 8,360 kJ (2,000 kcal) at normal resting state. a) Assuming that the efficiency of converting food energy to ATP is 50%, calculate the mass of ATP (in kg) that is harvested daily by the human body from 8,360 kJ of food energy. A total of 30.5 kJ of energy is needed to synthesize one mole of ATP under standard conditions. The molar mass of ATP is 505 g/mol. b) For an average 68-kg (150 lbs.) human adult, calculate the % mass of extracted ATP (from your answer in 2a) relative to body weight.