bio energetics Flashcards
where does photosynthesis take place
inside chloroplasts in plants and algae
photosynthesis word equation
602+6h20 —] C6H1206+602
4 key factors affecting the rate of photosynthesis
carbon dioxide concentration
light intensity
temperature
chlorophyll concentration
how does carbon dioxide concentration increase the rate of photosynthesis
increasing the carbon dioxide concentration increases the rate of photosynthesis as it is a reactant in photosynthesis. but above a threshold further increases in the carbon concentration does not increase the rate of photosynthesis because bother factor such as light intensity is limiting the rate of the reaction.
how does light intensity affect the rate of photosynthesis
A greater light intensity means a greater rate of photosynthesis. This is because more energy is being provided.
But, if the light intensity is increased above a certain threshold, the rate of photosynthesis will not increase because another factor (such as temperature) is limiting the rate of the reaction.
how does temperature affect the rate of photosynthesis
Increasing the temperature increases the rate of photosynthesis because more energy is provided.
But, if the temperature is increased to above about 45°C, the enzymes that catalyse (speed-up) the reaction begin to denature (not work anymore).
This causes the rate of the reaction to drop sharply until it stops altogether.
how does chlorophyll concentration affect the rate of photosynthesis
High chlorophyll concentration gives a high rate of photosynthesis.
what does a limiting factor do
restricts the rate of a reaction
uses of glucose
can be converted into starch, fats and oils, proteins and cellulose
how to test for the light intensity rate of photosynthesis
-take a boiling tube and place it 10cm away from an LED light source
-fill the boiling tube with sodium hydrogen carbonate solution which releases carbon dioxide (needed for photosynthesis)
-put a piece of pondweed in the boiling tube, with the cut end on top
-leave for 5 minutes to acclimatise
-start a stop watch and record the number of bubbles produced by the pond weed per minute
-repeat twice more and calculate the mean number of bubbles
-repeat experiment with 20cm,30cm and 40cm
problems with light intensity practical and solutions
number of bubbles can be too fast to count accurately
the bubbles are not always the same size , a large bubble would count the same as a small bubble
measure the volume of oxygen produced instead of counting bubbles by placing pondweed under a funnel and collect the bubbles in a measuring cylinder then use the measuring the cylinder to measure the volume of bubbles produced
what molecule can be joined together to produce starch
glucose
what is aerobic respiration
glucose reacts with oxygen in the mitrochondria of the cell to produce carbon dioxide, water and energy
word equation for aerobic respiration
glucose + oxygen —- carbon dioxide + water (+energy)
formulaic equation for respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O (+ energy)
