Active transport is the moving of molecules across the membrane of the cell against the concentration gradient with the use of ATP.
Low to high concentration. Concentration gradient is the diffusion (movement of molecules from regions of low concentration) from high to low with the gradient. Active transport is from low to high, against the gradient.
<span>Enzymes are Biological Catalysts. They increase the rate of Metabolic reactions. Almost all Biological Reactions involve Enzymes. All enzymes are Globular Proteins with a specific Tertiary Shape. They are usually specific to only one reaction.</span><span>The part of the Enzyme that acts a Catalyst is called the Active Site. The rest of the Enzyme is much larger and is involved in maintaining the specific shape of of the Enzyme.</span><span>When a reaction involving an Enzyme occurs, a Substrate is turned into a Product. The Substrate can be one or more molecules. The Active Site of an Enzyme is Complementary to the Substrate it catalyses.</span>
Answer:
The membrane is selectively permeable because substances do not cross it indiscriminately.
Explanation:
