2.67a

2.67 recall the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf

1) Photosynthesis à O₂ excreted

Leaves absorb light energy, combines with CO₂ and water to form glucose and O₂. O₂ gas is the metabolic waste.

2) Respiration à CO₂ excreted

Plants carry out aerobic respiration where glucose and O₂ are combined together. They go through an enzyme reaction and ATP, water and carbon dioxide are formed. CO₂ is the metabolic waste here. (excretion)