B8 photosynthesis Flashcards
what is the word equation for photosynthesis
carbon dioxide + water = glucose + oxygen
what is photosynthesis
an endothermic reaction in which energy is transferred from the
environment to the chloroplasts by light
how does temperature affect photosynthesis
temperature increase means that the rate of photosynthesis increases because more energy is provided for the reaction
how does carbon dioxide concentration affect photosynthesis
as the concentration of CO2 increases so does the rate of photosynthesis because CO2 is needed for the reaction
after reaching certain point an increase in CO2 has no effect because its no longer the limiting factor
how does light intensity affect photosynthesis
increase leads to increase in photosynthesis because more energy is provided
after a certain point an increase has no further affect
how does chlorophyll concentration affect photosynthesis
does not vary in short term but may change if plants are gown in soil without enough minerals to make chlorophyll
what is a limiting factor
the factor that stops the reaction going any further
how do limiting factors affect greenhouse gases
greenhouse gases can be used to increase rate of photosynthesis
controls lighting
temperature and carbon dioxide
what is inverse square law
doubling distance between lamp and pondweed will reduce the light intensity by a quarter
what are the uses of glucose in photosynthesis
- used for respiration
- used to produce cellulose, which strengthens the cell wall
- used to produce amino acids for protein synthesis.
what is the independent variable in the photosynthesis practical
light intensity
what is the dependent variable in the photosynthesis practical
the number of bubbles in one minute
what are the control variables in the photosynthesis practical
temperature
concentration of carbon dioxide
how to carry out the photosynthesis practical
Set up a boiling tube containing 45 cm3 of sodium hydrogencarbonate solution . Allow the tube to stand for a few minutes and shake to disperse any air bubbles that might form.
Cut a piece of the pondweed. The pondweed should be 8 cm long.
Use forceps to place the pondweed in the boiling tube carefully. Make sure that you don’t damage the pondweed, or cause the liquid to overflow.
Position the boiling tube so that the pondweed is 10 cm away from the light source. Allow the boiling tube to stand for five minutes. Count the number of bubbles emerging from the cut end of the stems in one minute. Repeat the count five times and record your results.
Calculate the average number of bubbles produced per minute. Repeat the experiment at different distances away from the light source.
