Answer:
When the required direction of transport is opposed to concentration levels, a cell <u>will </u> expend energy to force<u> ions</u> across its membrane.
Explanation:
If the concentration gradient is opposite to the direction of transport of minerals, then the cell will use energy to transport mineral ions from a lower concentration to a higher concentration. The most common process through which this happens is termed as the active transport.
The process of active transport is opposite to passive transport. In passive transport, molecules move from a higher concentration to a lower concentration.
A pH environment has a significant effect on an enzymes. It can affect the intramolecular forces and change the enzyme's shape -- potentially to the point where it is rendered ineffective. With these effects in mind, typical enzymes have a pH range in which they perform optimally. For example, alpha amylase, which found in the mouth, operates most effectively near a neutral pH. However, lipases operate better at more basic pH levels.