Lactic acid

 

How is lactic acid produced?

Glucose is a substance that gives energy to cells through chemical reactions. When you run fast, your cells use glucose without oxygen. This is called anaerobic respiration. It makes one waste product: lactic acid. Lactic acid has the formula C₃H₆O₃. It has carbon, hydrogen, and oxygen atoms.

 

Lactic acid can cause cramps in your muscles when you run fast. It hurts a lot. After running, you breathe more oxygen. The oxygen breaks down the lactic acid in your muscles. It makes carbon dioxide and water. Then the cramps go away.

 

Some bacteria in your mouth also make lactic acid from glucose and other sugars. Lactic acid in your mouth can cause teeth to decay.

 

🏃 Knowledge Check: Lactic Acid

Test your understanding of anaerobic respiration, muscle fatigue, and oxygen debt.

1. Under what condition is lactic acid produced in the body?

• During deep sleep
• During anaerobic respiration when oxygen is low
• During normal walking when oxygen is plentiful

2. How is glucose broken down during the production of lactic acid?

• It is completely broken down into carbon dioxide
• It is partially broken down
• It is not broken down at all

3. What term is used to describe the buildup of lactic acid causing muscles to feel tired and lack energy?

• Muscle fatigue
• Aerobic boost
• Oxygen surplus

4. What is 'oxygen debt'?

• The oxygen used to create glucose
• The amount of oxygen saved during exercise
• The extra oxygen needed after exercise to break down lactic acid

5. What are the final products once lactic acid is broken down during recovery?

• Glucose and Nitrogen
• Carbon dioxide and water
• Pure oxygen and glucose

Click to Reveal Answers

1. During anaerobic respiration when oxygen is low (Lactic acid is produced when the oxygen supply cannot meet demand).
2. It is partially broken down (Incomplete breakdown of glucose leads to lactic acid formation).
3. Muscle fatigue (The accumulation of lactic acid causes this tired sensation).
4. The extra oxygen needed after exercise (This "debt" must be paid back to clear the lactic acid).
5. Carbon dioxide and water (These are the final waste products after lactic acid reacts with oxygen).

 

Summary:

 

• Anaerobic respiration makes lactic acid as a waste product.
• Lactic acid can build up in your muscles when you run fast, causing cramp.
• Lactic acid can also damage your teeth.