The process by which plants synthesise glucose using light energy from the sun. Light energy is converted into chemical energy
Where does photosynthesis take place
Within chloroplasts in leaf palisade cells. They contain chlorophyll a pigment which absorbs light energy
Word equation for photosynthesis
carbon dioxide +water -> glucose +oxygen
Symbol equation for photosynthesis
6CO2 + 6H2O -> C6H12O6 + 6CO2
Is photosynthesis an endothermic or exothermic reaction and why
Endothermic- energy is transferred from the environment to chloroplasts by light
How can you show that a plant give of oxygen during photosynthesis
Using a water plant ,collect gas bubble produced photosynthesis. The gas will relict a glowing splint as it contains oxygen
Give examples of leaf adaptations which maximise the rate of photosynthesis
Broad leaves-maximise surface area
thin leaves -short diffusion distance
chlorophyll present -trap light energy
veins- transport water to leaves viz xylem, remove photosynthesis products via phloem
air spaces -allow CO2 to enter and O2 to leave
guard cells control opening of stomata for gaseous exchange and prevent water loss
What are the four main factors that affect the rate of photosynthesis
Temperature
light intensity
carbon dioxide concentration
amount of chlorophyll
How does temperature affect the rate of photosynthesis
Increasing the temperature increases the rate of photosynthesis as the kinetic energy of particles is increased. The rate decreases past a certain temperature as enzymes become denatured
How does light intensity affect the rate of photosynthesis
Increasing light intensity increases the rate of photosynthesis until another factor becomes limiting
How does carbon dioxide concentration affect the rate of photosynthesis
Increasing the carbon dioxide concentration increases the rate of photosynthesis (until another factor becomes limiting) as CO2 is required to make glucose
How does the amount of chlorophyll affect the rate of photosynthesis
Decreasing the amount of chlorophyll decreases the rate of photosynthesis as chlorophyl is required to absorb light energy
What is a limiting factor
An environmental factor which can restrict the rate of photosynthesis
How can farmers use their knowledge of limiting factors to increase their profits
They can control temperature, light intensity and CO2 concentration to achieve the fastest possible rate of photosynthesis leading to a greater yield
State the law which describes the relationship between the distance of a light source from a plant and light intensity
Inverse square law - light intensity OC 1 / distance2
State 5 uses of the glucose produced during photosynthesis
Respiration
starch for storage
cellulose for strength
amino acid and protein synthesis (combined with nitrates)