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Photosynthesis
40 cards·by aden
Where does photosynthesis take place?
Leaves
What is the equation for photosynthesis?
C6H12O6+6CO2-6O2+6H20
How do animals obtain glucose?
By eating plants or other animals that have eaten plants, then respire the glucose to release
energy
How do plants release energy?
Energy is stored in glucose until plants release it by respiration
What is a metabolic pathway? give an example
Processes that occur in a series of small reactions controlled by enzymes, e.g. respiration
Give the equation for aerobic respiration
C6H12O6+6O2-6CO2+6H20
What are the products of anaerobic respiration in plants and yeast? in humans?
plants and yeast produce ethanol and carbon dioxide then release energy where as humans
produce lactate then release energy
How are plants adapted to photosynthesis? (LATTNAN)
Large SA, Arrangement of leaves, Thin, Transparent cuticle, Numerous stomata, Air space in
mesophyll, Network of xylem and phloem
In respiration, what is the energy released from glucose used to make?
ATP because a cell cant get its energy directly from glucose
Where does the light dependent stage of photosynthesis take place?
Thylakoids
Where does the light-independent stage of photosynthesis take place?
Stroma
What is an oxidation reaction?
Loss of electrons, loss of hydrogen and gain of oxygen
What is a reduction reaction?
Gain of electrons, gain of hydrogen, loss of oxygen
What are photosystems and what are they linked by?
Thylakoid membranes are attached to a protein to create a photosystem, linked by electron
carriers
How is light energy absorbed and what does it cause?
Chlorophyll molecule in PSII which excited the electrons in chlorophyll giving them more
energy
What happens when the excited electron moves to a higher energy level?
Moves out of the chlorophyll molecule which is now ionised (photoionisation) down the
electron transport chain to reduce an electron carrier
What happens at stage 2 of the light dependent reaction?
Photolysis of water
How is lost energy replaced?
Energy is released when water molecules are split by light to produce protons, electrons and
oxygen
How is lost energy used?
Used to transport protons into the thylakoid so that the thylakoid has a higher concentration
of protons than the stroma
State on other factor that increases the concentration of protons in the thylakoid
photolysis of water (produces protons)
How do protons from the thylakoid move into the stroma?
move down their concentration gradient into the stroma through ATP synthase channel
proteins which is embedded in the thylakoid membrane
What is the energy from this movement used to make?
ATP from ADP and Pi
What happens at stage 4 of the light dependent reaction?
The excited electron from PSI and protons from the stroma are transferred to NADP which is a
coenzyme
What is another name for the light independent reaction and where does it take place?
Calvin cycle and stroma
What is produced in the light independent reaction?
Triose phosphate
what can triose phosphate be used to make?
Organic substances such as glucose
What diffuses into the stroma of the chloroplast?
carbon dioxide
What does c02 react with and what enzyme catalyses this reaction?
RuBP and rubisco
What is produced when c02 combines with RuBP
2 molecules of Glycerate-3-phosphate
How is triose phosphate produced?
Hydolysis of Atp and oxidation of NADPH reduces GP into TP
Where does the reformed NADP go?
Back to the light dependent reaction to be reduced again by accepting more protons
What fraction of TP molecules are converted to organic substances?
1/6
What fraction of TP molecules are used to regenerate ribulose biphosphate?
5/6
How many times must the calvin cycle turn to make one hexose sugar?
six times
How many ATP's and NADPH's does six turns of the cycle need?
12 ATP's and 18 NADPH's
State 4 limiting factors in photosynthesis?
Carbon dioxide, temperature, light intensity, water
How does light intensity affect photosynthesis?
Light is needed to provide energy for the light dependent reaction- the higher the light
intensity the more energy it produces
How does temperature affect photosynthesis?
below 10 enzymes become inactive, greater than 40 enzymes denature and stomata close to
prevent water loss, so less c02
How does carbon dioxide affect photosynthesis?
higher c02 conc, higher rate of photosynthesis
How does water affect photosynthesis?
too much water makes soil water logged which reduces the uptake of magnesium which is needed to
make chlorophyll a