bioenergetics Flashcards
what is photosynthesis?
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 chloroplast in leaf Palaside cells. They contain chlorophyll, a pigment which absorbs light energy.
State the equations for photosynthesis
6co2 + 6H2o —-> C6H12O6 + 6O2
Is photosynthesis an endothermic or exothermic reaction and why?
Endothermic energies transferred from the environment to the chloroplast by light
How can you show that a plant gives off oxygen during photosynthesis?
using a water plant, collect gas bubbles produced during photosynthesis. The gas will relight a glowing splint as it contains oxygen
Give examples of leaf adaptations which maximise the rate of photosynthesis
broadleaves – maximise surface area
Fin leaves – short diffusion distance
Chlorophyll present – trap light energy
Veins – transport water to leaves via xylem, remove photosynthesis products by phloem
airspaces– allows CO2 to enter an O2 to leave
Guard cells – control opening of stomata for gaseous exchange preventing 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 the temperature affect the rate of photosynthesis?
Increasing the temperature increases the rate of photosynthesis as the kinetic energy of the particles is increased. The rate decreases past a certain temperature as enzymes become denatures.
how does light intensity affect the rate of photosynthesis?
Increasing the light intensity increases the rate of photosynthesis until another factor becomes limited
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(eg due a to lack of magnesium) decreases the rate of photosynthesis as chlorophyll is required to absorb light energy
what is a limiting factor?
An environmental factor which can restrict the rate of photosynthesis
eg light intensity
explain how you can calculate the rate of photosynthesis by measuring oxygen production
set up a bubble potometer apparatus (pondweed in a sealed tube of water, attached to a capillary tube and a gas syringe )
Oxygen gas produced causes the bubbles in the capillary tube to move the distance moved by the bubble is used to calculate the volume of oxygen produced 
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 greater yield
State the law which describes the relationship between the distance of light source from a plant and light intensity