State whether the following statements are true or false. When not enough oxygen gets to muscle cells during a sprint, energy is provided by glycolysis of glucose to pyruvic acid and then conversion of these molecules to lactic acid.

Answer

To determine whether the statement is true or false, we can break it down into several steps:

### Step-by-Step Solution:

1. **Understanding the Context**: The statement refers to a scenario where muscle cells are not receiving enough oxygen during intense physical activity, such as sprinting.

2. **Glycolysis Process**: Glycolysis is the metabolic pathway that converts glucose into pyruvic acid. This process occurs in the cytoplasm of cells and does not require oxygen. It is the first step in both aerobic and anaerobic respiration.

3. **Formation of Pyruvic Acid**: During glycolysis, one molecule of glucose is broken down to produce two molecules of pyruvic acid. This is a key point in the statement.

4. **Insufficient Oxygen Conditions**: When oxygen levels are low (insufficient oxygen), cells cannot perform aerobic respiration efficiently. Instead, they undergo anaerobic respiration.

5. **Conversion to Lactic Acid**: In muscle cells, when there is insufficient oxygen, the pyruvic acid produced from glycolysis is converted into lactic acid. This process allows for the regeneration of NAD+, which is necessary for glycolysis to continue and produce ATP (energy).

6. **Conclusion**: The statement claims that energy during a sprint is provided by glycolysis of glucose to pyruvic acid and then conversion of these molecules to lactic acid. Since this accurately describes the process that occurs in muscle cells under low oxygen conditions, the statement is true.

### Final Answer:
The statement is **True**.

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