Overview
This lecture explains respiration as the release of energy from glucose in cells, covering the process, its equation, and how animals and plants obtain and use oxygen and glucose.
What is Respiration?
- Respiration is the release of energy from glucose in cells.
- Respiration happens in the mitochondria of both animal and plant cells.
- It is not the same as breathing; respiration is a chemical process, while breathing is how we obtain oxygen.
Respiration Equation
- Word equation: glucose + oxygen → carbon dioxide + water (plus energy, shown in brackets).
- Symbol equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (plus energy).
- Glucose and oxygen are reactants; carbon dioxide and water are products.
- Energy is produced but not written in the main equation, only in brackets.
Photosynthesis vs Respiration
- Photosynthesis in plants: carbon dioxide + water → glucose + oxygen.
- Respiration is the reverse of photosynthesis.
- Plants make glucose and oxygen for their own respiration and for animals to use.
How Humans Obtain Oxygen and Glucose
- Humans get glucose from food (mainly sugars and carbohydrates).
- We get oxygen by breathing it into our lungs.
- Alveoli are tiny air sacs in lungs where oxygen diffuses into the blood.
- Oxygen binds to red blood cells; glucose travels dissolved in blood plasma.
Transport and Use of Oxygen and Glucose
- Blood carries oxygen (on red blood cells) and glucose (in plasma) to all body cells.
- Both diffuse from blood into cells, especially muscle cells, for aerobic respiration in mitochondria.
- Respiration in cells produces carbon dioxide and water, which diffuse back into the blood to be removed.
Key Terms & Definitions
- Respiration — Release of energy from glucose in cells.
- Mitochondria — Cell structures where respiration takes place.
- Aerobic Respiration — Respiration using oxygen.
- Photosynthesis — Process in plants making glucose and oxygen from carbon dioxide and water.
- Alveoli — Tiny air sacs in the lungs for gas exchange.
- Plasma — Liquid part of blood carrying glucose.
- Red Blood Cells — Blood cells that carry oxygen.
Action Items / Next Steps
- Review the equation for aerobic respiration, including word and symbol forms.
- Remember definitions for key terms.
- Prepare for future learning on anaerobic respiration (respiration without oxygen).