Question

Which of the following statements about transport of Ca₂⁺ from the cytosol (low Ca₂⁺ concentration) into the endoplasmic reticulum (high Ca₂⁺ concentration) is true?

1) Ca₂⁺ is transported against its concentration gradient
2) Ca₂⁺ is transported by facilitated diffusion
3) Ca₂⁺ is transported by active transport
4) Ca₂⁺ is transported by simple diffusion

Answer 1

Ca²⁺ is transported by active transport

Step-by-step explanation:

In the context of transporting Ca²⁺ from the cytosol to the endoplasmic reticulum, the correct statement is that Ca²⁺ is transported by active transport.

In active transport, substances are transported against their concentration gradient, requiring energy expenditure. This process is uni-directional, with one substance being transported into the cell while another is transported out.

Therefore, option 3) Ca²⁺ is transported by active transport is the correct statement.