plant nutrition

define photosynthesis

the production of sugar in green plants

what is the word equation for photosynthesis

carbon dioxide + water —sunlight + chlorophyll—> glucose +oxygen

what is the chemical equation for photosynthesis

6CO₂ + 6H₂O —sunlight+chlorophyll—> C₆H₁₂O₆ + 6O₂ 

why does photosynthesis require sunlight

Provides the light energy which is converted into chemical energy in the bonds in glucose.  

why does photosynthesis require carbon dioxide

Absorbed from the air and enters the leaf via the stomata 

why does photosynthesis require water

Absorbed from the soil via the root hairs

why does photosynthesis require glucose

It is used in respiration to release energy. 

It is used to make cellulose cell walls.  

Stored as starch in starch grains found in chloroplasts. Starch is insoluble so can be stored in cells without affecting water movement in and out of cells by osmosis. Some plants such as rice and potato store large amounts of starch in parts such as seeds and tubers which are used as a food source. 

Some glucose is converted to sucrose (a double sugar (disaccharide) made from glucose joined to another sugar fructose), this is soluble and is the form in which sugar is transported around the plant. 

Plants can convert glucose to Fructose (monosaccharide) found in fruits. 

Glucose can also be converted to other types of molecules e.g. proteins and lipids  

why does photosynthesis require oxygen

A product of photosynthesis, used in plants for respiration, most is not needed and is given out as a waste product 

why does photosynthesis require chlorophyll

Molecule that captures energy from sunlight. The green pigment present in chloroplasts. Chloroplasts mainly found in the palisade cells; these cells are found towards the upper side of the leaf. 

why does photosynthesis require temperature

To provide the right conditions for the enzymes needed for photosynthesis to work. If it is too cold the enzymes become in active and rate of photosynthesis slows down. If too high enzymes are denatured and photosynthesis does not occur. 

why is photosynthesis important?

Photosynthesis is fundamental to most living organisms on Earth, as most organisms other than plants get their energy from the chemical energy in the food that they eat. 

what are the external adaptations for a leaf

• Leaf is long and broad to give a large surface area to absorb light 

• Leaf is green containing chlorophyll to absorb light 

• The leaf has a network of veins that carry water and other substances to the leaf and glucose away 

• The leaf is thin to allow diffusion to occur (gases into and out of the leaf) 

• The leaf is held to the stem by the petiole, and faces the sun