Author Question: A number of systems for pumping ions across membranes are powered by ATP. Such A (Read 1071 times)

Hawke

  • Hero Member
  • *****
  • Posts: 679
A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they don't often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2, then how is the ATPase acting?
A) ATPase activity must be powering an inflow of calcium from the outside of the cell into the SR.
B) ATPase activity must be transferring  i to the SR to enable this to occur.
C) ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient.
D) ATPase activity must be opening a channel for the calcium ions to diffuse back into the SR along the concentration gradient.
E) ATPase activity must be routing calcium ions from the SR to the cytosol, and then to the cell's environment.



coco

  • Hero Member
  • *****
  • Posts: 739
Try C. I remember this question on my exam.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question

Hawke

  • Hero Member
  • *****
  • Posts: 679
Thanks, and your suggestion was right.



 

Did you know?

After 5 years of being diagnosed with rheumatoid arthritis, one every three patients will no longer be able to work.

Did you know?

According to the CDC, approximately 31.7% of the U.S. population has high low-density lipoprotein (LDL) or "bad cholesterol" levels.

Did you know?

All adverse reactions are commonly charted in red ink in the patient's record and usually are noted on the front of the chart. Failure to follow correct documentation procedures may result in malpractice lawsuits.

Did you know?

One way to reduce acid reflux is to lose two or three pounds. Most people lose weight in the belly area first when they increase exercise, meaning that heartburn can be reduced quickly by this method.

Did you know?

No drugs are available to relieve parathyroid disease. Parathyroid disease is caused by a parathyroid tumor, and it needs to be removed by surgery.

For a complete list of videos, visit our video library