Answer:
D. The rate decreases as reactants are used up.
Explanation:
Initially, the rate increases until the reaction is at equilibrium. At equilibrium, the rate is constant.
As the reaction progresses, the rate decreases to zero when reactants are used up ( for irriversible reactions only )
Answer:
a. Remaining at rest requires the use of ATP.
Explanation:
The resting membrane potential is maintained by the sodium-potassium pump. The sodium potassium pump does this by actively pumping sodium ions out of the cell and potassium ions inside the cell in a ratio of 3:2. This movement of ions by the sodium-potassium pump is against their concentration gradient. In a neuron at rest, there are more sodium ions outside the cell than there are inside the cell. Also, there are are more potassium ions inside the cell than there are outside the cell. However, there are ion channels through which these ions enter and leave the cell. Sodium ion channels allow sodium to enter the cell following its concentration gradient, whereas, potassium ion channels allow potassium to leave the cell following its concentration gradient. However, more potassium ions leave the cell than do sodium ions enter the cell because of the higher permeability of the cell to potassium ions.
In order to maintain the resting membrane potential, the sodium potassium pump powered by the hydrolysis of an ATP molecules pumps sodium ions out of the cell and potassium ions into the cell.
<em>Therefore, the correct option is A, as ATP is needed by the sodium-potassium pump in order to maintain the resting membrane potential.</em>
The answer is A. The volume lines on the bottom are just showing the volume of the beaker. The more dense liquid will sink to the bottom
