Massachusetts Comprehensive Assessment System (MCAS) Biology Practice Test

What molecule provides the energy necessary for active transport protein pumps?

1. Glucose

2. ATP

3. NADH

4. ADP

The correct answer is: ATP

The molecule that provides the energy necessary for active transport protein pumps is ATP, or adenosine triphosphate. Active transport is a crucial cellular process in which substances are moved across cell membranes against their concentration gradient, meaning that energy is required to do this. ATP serves as the primary energy currency of the cell. When ATP is broken down into ADP (adenosine diphosphate) and an inorganic phosphate group, a significant amount of energy is released. This energy release is what fuels the protein pumps involved in active transport, allowing them to function effectively and move ions or molecules into or out of the cell as needed. Other options, while they play important roles in cellular metabolism and energy transfer, do not directly provide the energy for active transport. Glucose can be broken down to produce ATP, but it is not used directly by the pumps themselves. NADH is primarily involved in redox reactions and cellular respiration to produce ATP, and ADP is a product of the ATP breakdown and is not an energy source for the pumps. Thus, ATP is essential for the function of active transport protein pumps, making it the correct answer.