Question

Adenosine triphosphate (ATP) is used indirectly for which of the following processes?

1) Accumulation of Ca₂⁺ by the sarcoplasmic reticulum (SR)
2) Transport of Na⁺ from intracellular to extracellular fluid
3) Transport of K⁺ from extracellular to intracellular fluid
4) Transport of H+ from parietal cells into the lumen of the stomach
5) Absorption of glucose by intestinal epithelial cells

Answer 1

ATP is indirectly used for several cell processes including the transport of ions like Ca²⁺, Na⁺, K⁺, and H⁺, and the absorption of glucose by cells, by fueling primary and secondary active transport systems.

Step-by-step explanation:

Adenosine triphosphate (ATP) is used indirectly for a variety of processes within the cell. One example is the accumulation of Ca₂⁺ by the sarcoplasmic reticulum (SR) during muscle contraction. ATP provides the energy for the active-transport Ca²⁺ pumps in the SR. Another process is the transport of Na⁺ from intracellular to extracellular fluid and K⁺ from extracellular to intracellular fluid, which occur through the sodium-potassium pump, an action that directly uses ATP for creating gradients. ATP is also indirectly involved in the secondary active transport (co-transport) process that moves other substances, such as glucose, into the cell up their concentration gradient, facilitated by the gradients created by primary active transport systems like the sodium-potassium pump. Additionally, ATP is essential for transporting H⁺ from parietal cells into the lumen of the stomach for digestion.