Cell Respiration and Photosynthesis


2.2  Cell Respiration and Photosynthesis

Respiration can be divide into external respiration and internal respiration.

External respiration: involves exchange of gases between the organism and environment

Cell respiration: oxidation process and break down glucose

Cell Repiration
Glucose + Oxygen \(\rightarrow \) Carbon dioxide + Water + Energy
Carbon dioxide + Water \(\begin{aligned} &\text{Light energy}\\ &\quad\longrightarrow\\&\small\text{Chlorophyll} \end{aligned} \) Glucose + Oxygen 
Cell respiration Photosynthesis
Occur in mitochondria Occurs in chloroplast
Process to release energy Process to absorb energy
Uses chemical energy in food Uses energy from light
Occurs in humans, animals, plants and microorganisms Occurs in plants and microorganisms
Breaks down glucose to produce energy Synthesises glucose
Uses glucose and oxygen to produce carbon
dioxide, water and energy
Uses carbon dioxide and water to produce oxygen and glucose
Occurs at all times Occurs only in the presence of light

The process of cell respiration and photosynthesis complement each other:

  • Plants produce glucose and oxygen
  • All organisms use glucose and oxygen during respiration
  • All organisms produce carbon dioxide and water
  • Plants use carbon dioxide and water during photosynthesis