In which way do cells use glucose during the production of ATP? a. Cells incorporate some of the atoms from glucose molecules into ATP molecules. b. Cells convert glucose molecules entirely into energy, which is then stored in ATP. c. Cells transfer some of the energy stored in glucose’s chemical bonds to ATP. d. Cells directly combine glucose with O2 in the ETC to produce energy for ATP.
The correct answer and explanation is :
The correct answer is c. Cells transfer some of the energy stored in glucose’s chemical bonds to ATP.
Explanation:
Cells use glucose primarily as an energy source during cellular respiration, a multi-step process that occurs in the cytoplasm and mitochondria of the cell. The primary goal of cellular respiration is to produce ATP (adenosine triphosphate), which is the main energy currency of the cell.
- Glycolysis (in the cytoplasm):
The process starts with glycolysis, where one molecule of glucose (C6H12O6) is broken down into two molecules of pyruvate. In this step, a small amount of energy is released. Some ATP is used and some is produced, and high-energy electron carriers (NADH) are generated. - Pyruvate Decarboxylation and the Citric Acid Cycle (in the mitochondria):
After glycolysis, the pyruvate enters the mitochondria and is further processed. It is converted into acetyl-CoA, which enters the citric acid cycle (Krebs cycle). During this cycle, more ATP is produced, and more high-energy electron carriers (NADH and FADH2) are generated, which will be important for the next step. - Electron Transport Chain (ETC) and Oxidative Phosphorylation (in the mitochondria):
The NADH and FADH2 produced earlier donate their high-energy electrons to the electron transport chain (ETC), which takes place across the inner mitochondrial membrane. As electrons move through the ETC, their energy is used to pump protons (H+) across the membrane, creating a proton gradient. The protons flow back through an enzyme called ATP synthase, which uses this energy to add a phosphate group to ADP (adenosine diphosphate), forming ATP. This is known as oxidative phosphorylation.
In essence, glucose’s chemical bonds hold energy, and as glucose is broken down through these steps, the energy released is transferred to ATP molecules. This allows cells to use glucose as a fuel to perform various functions, such as muscle contraction, protein synthesis, and cell division.
Thus, answer c is correct because glucose’s energy is not fully converted into ATP, but rather transferred in a series of steps to produce ATP, the energy currency.