Photosynthesis Flashcards
What is the equation for photosynthesis?
Carbon dioxide + water -> glucose + oxygen
Name the two stages of photosynthesis.
Light dependent reaction.
Light independent reaction.
What is the function of chlorophyll?
Absorbs light.
Releases excited electrons.
Where is ATP synthase found in chloroplasts?
Within membranes of thylakoids/grana.
Name the 3 products produced in the photolysis of water.
Protons
Electrons
Oxygen
Where do the light dependent reactions take place?
Thylakoid/grana membranes in the chloroplast.
Where does the light independent reaction take place?
Stroma of chloroplast.
What is release from chlorophyll during photoionisation?
Excited electrons.
Name the enzyme which catalyses the reaction between carbon dioxide and ribulose bisphosphate.
Rubisco
Name the products of the reaction catalysed by rubisco.
2 X glycerate 3 phosphate (GP).
Name the coenzyme needed in photosynthesis.
NADP
How is triose phosphate made in the light independent reaction?
Glycerate phosphate + NADPH + ATP -> Triose phosphate + NADP.
GP is reduced to form TP.
NADPH provides the H+.
ATP provides the energy needed.
What happens to triose phosphate in the Calvin cycle?
5/6 converted to RuBP.
1/6 converted into organic substances eg glucose.
Give two environmental factors that affect the rate of photosynthesis.
Concentration of carbon dioxide.
Light intensity
Temperature
Amount of chlorophyll
Who do fertilisers increase the rate of photosynthesis?
Nitrates/phosphates needed to make chlorophyll.
Describe the quaternary structure of chlorophyll
4 polypeptides are connected to magnesium atom.
Name the technique used go separate the pigments in chlorophyll.
Chromatography.
How is the Rf value of a chlorophyll pigment calculated.
Rf = distance moved by the pigment
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distance moved by the solvent
Name the chemicals produced in the light dependent reactions which are used in the light independent reactions.
NADPH and ATP.
Name the organelle responsible for photosynthesis.
Chloroplast
How are protons moved into the thylakoid space?
Electrons released from chlorophyll move down a series of carrier proteins, losing energy as they go.
Energy is used to actively transport H+ ions from the the stroma into the thylakoid space
How does chemiosmosis produce ATP in the light dependent stage?
H+ ions move down their concentration gradient from the thylakoid space into the stroma via ATP synthase
ADP + Pi –> ATP
What happens to the products of the photolysis of water?
H+ ions - diffuse through ATP synthase to produce ATP
Used to reduce NADP
Electrons - replace those lost from chlorophyll
Oxygen - used for respiration or diffuses out of leaf as a waste gas
How and where is NADPH produced in the chloroplast?
Stroma of chloroplast
NADP combined with 2 H+ and 2 electrons (from photolysis of water) to form NADPH
Catalysed by dehydrogenase enzymes
How many carbon atoms are present in:
RuBP
GP
TP
RuBP = 5
GP = 3
TP = 3
How does the structure of a chloroplast maximise the rate of the light dependent reaction?
Large quantities of Chlorophyll embedded thylakoid membrane
Large surface area of thylakoid membrane for electron transport chain proteins
How does the structure of the chloroplast maximise the rate of the light independent reaction?
DNA and ribosomes in stroma syntheses enzymes and carrier proteins
Concentration of enzymes in stroma high
Name 4 environmental factors that can limit the rate of photosynthesis
Light intensity ( light dependent stage)
Carbon dioxide levels ( light independent stage)
Temperature (enzyme controlled stages)
Mineral/magnesium levels (needed to make chlorophyll)
Outline how paper chromatography can be used to separate and identify photosynthetic pigments
Use mortar and pestle to grind leaf with extraction solvent
Use capillary tube to spot pigment onto origin line
Place chromatography paper in solvent (origin above solvent level)
Allow solvent to run.
Measure distance moved by each pigment and distance moved by solvent
Calculate Rf value
