Plant structures and their functions

Photosynthesis

• Takes place in the chloroplasts found in plants and algae. 
• Reaction is endothermic
• Sunlight is trapped by chlorophyll 
• Photosynthesis converts carbon dioxide and water into oxygen and glucose

Rates of photosynthesis

The four key factors affecting the rate of photosynthesis are:

• Light intensity
• Chlorophyll concentration
• Carbon dioxide concentration
• Temperature

Limiting Factors

A limting factor restricts the rate of reaction. The limiting factor is dependant on the condition of the plant.

• Mineral-deficient soil- chlorophyll is the limting factor
• Winter- temperature is limiting
• Warm and bright- Carbon dioxide is limiting
• Night- light intensity is limiting

Photosynthesis Test

• The effect light intensity has on the rate of photosynthesis can be investigated by using an aquatic plant like pondweed. You would need to change the distance between the lamp and the pondweed and count the number of bubbles produced. Light intesity is the independant variable and the number of bubbles is the dependant variable.
• Bubbles indicate the rate of photosynthesis, the bubbles released are oxygen, a waste product of photosynthesis

The Inverse Square Law

The inverse square law is an equation that links light intesity to the distance from a light source.

L= 1/d^2

Plant Transport

Root hair cell

• Specialised
• Structure allows the plant to take in more water and take in the minerals it needs to survive.
• They have no chloroplast because they're located underground (no light for photosynthesis)
• Long projections- increase the surface area that a plant can use to absorb water and minerals 

Xylem Cell

• Open ended- allows water to move…