Biology - plant nutrition, photosynthesis

Photosynthesis

The process by why plants synthesise carbohydrates from raw materials using energy from light

Word equation of photosynthesis

—light and chlorphyll—

carbon dioxide + water —→ glucose + oxgyen

Chlorophyll

Green pigment found in chloroplasts that transfers light energy into chemical energy

What ways are glucose produced by photosynthesis are used?

Used and stored in different ways including - sucrose, starch, cellulose and nectar

Uses of sucrose

Transported in phloem vessels to parts of the plant that don’t photosynthesise.

Uses of Starch

Converted from glucose and stored in chloroplast, in cells of stems and roots and in tubers. Starch is used to store energy because it can pass freely through cell membranes.

Uses of Cellulose

A tough fibrous material that makes up the cell wall of plants

Uses of glucose

To produce energy through respiration

Uses of nectar

produced by flowering plants to attract pollinators.

Balanced chemical equation for photosynthesis

6CO₂ + 6H₂O —→C₆H₁₂O₆ + 6O₂

Plants also synthesis their own…

Chlorophyll (magnesium ions from the soil are needed to make it)

Amino acids (nitrogen ions from the soil are needed to make it, they join together to build proteins)

Limiting factor

Something that is present in the environment that limits life processes due to it’s short supply.

Limiting factors of photosynethesis

Light intensity, temperature, carbon dioxide concentration and water avaliability.

How can light intensity be a limiting factor?

• For plants that grow on the forest floor

• In winter when days are short

Artifical light can be used to remove light as a limiting factor

How can temperature be a limiting factor?

• Plants that grow in cold climates

• In winter when temperatures fall

Uses of greenhouses

To remove temperature as a limiting factor and raise carbon dioxide levels to increase rate of growth.