Fichas
Photosynthesis
Fichas del conjunto (19)
- 15 features of leaf structure?. large surface area
. arrangement of leaves that minimises overlapping
. short diffusion path length
. high conc. of chloroplasts in upper mesophyll
. numerous stomata that open and close in response to changes in light intensity to control gaseous exchange - 2Basic photosynthesis equation?6H20 + 6CO2
= (LIGHT) =
C6H12O6 + 6O2 - 3What are thylakoids? (4 points of information about them). Found in the grana
. Stacks of membrane full of chlorophyll that increase surface area
. Site of light-dependent reaction
. Inter-granal lamellae running between adjacent grana - 4Two special features of the grana that enables it to carry out the light-dependent reaction affectively?. Enzymes attached to granal membrane to aid in the manufacture of ATP
. DNA and ribosomes to manufacture any proteins needed for the light-dependant reaction - 5Explain/describe the light-dependant reaction (4 points). Light energy absorbed and collected by photosystems in grana
. two chlorophyll molecules ionised, each releasing two high energy electrons
. electrons travel down electron transport chains = release energy as they go: energy from one pair e- condenses ADP + Pi into ATP, energy from other pair creates molecule of reduced NADP using H+ ions from photolysis
. ATP and reduced NADP enter stroma for use in calvin cycle/light-independant reaction - 6What does the photolysis of water produce? What are the products used for?H2O
=
. 2H+ (to reduce NADP)
. 2e- (to replace electrons lost from chlorophyll in photosystem one)
. 1/2 O2 (by-product of photosynthesis - 7What is the stroma? Adaptations of the stroma that make it particularly useful for light-independent reaction/calvin cycle?. Fluid filled matrix in the chloroplast
. Contains all enzymes needed for calvin cycle
. Surrounds the grana so products of light-dependant reaction can readily diffuse in
. Contains both DNA and ribosomes so any proteins needed for reaction readily made - 84 stages of the calvin cycle/light-independant reaction?1. Fixation
2. Reduction
3. Product synthesis
4. Regeneration - 9light-independant reaction: what happens in fixation?CO2 fixed into initial substrate of calvin cycle, RuBP, to form GP
- 10light-independant reaction: what happens in reduction?GP reduced to TP using products of light-dependant reaction: ATP and reduced NADP
- 11light-independant reaction: what happens in product synthesis?Some TP is used to synthesise glucose and other carbohydrates
- 12light-independant reaction: what happens in regeneration?Most TP used to regenerate RuBP:
1. TP converted to RP
2. RP converted to RuBP using inorganic Pi from an ATP molecule - 132 ways by which rate of photosynthesis is measured?. volume of oxygen released by a plant
. volume of carbon dioxide taken up by a plant - 14What happens to the carbon dioxide and oxygen volumes as light intensity is increased? What is it called?the volume of oxygen produced and the volume of carbon dioxide released will become equal to that of the oxygen taken up for respiration and the carbon dioxide taken up for photosynthesis = no net exchange of gases in and out of the plant
. the light compensation point - 15What happens is light intensity is increased beyond the light compensation point?At a particular point, the rate of photosynthesis will level off, due to another limiting factor
- 16What is the law of limiting factors?"At any given moment, the rate of a physiological process is limited by the factor that is at its least favourable value"
- 17Why is it important that the temperature does not get too high for plants?Because enzymes involved in their metabolic pathways can denature
- 18Carbon dioxide concentration affects enzyme activity. Which enzyme in particular?The enzyme that catalyses the fixation of CO2 to RuBP in the light-independant reaction
- 19Explain/describe how the rate of photosynthesis is measured (6 points). completely air-tight apparatus set up
. water bath used to maintain constant temp
. potassium hydrogencarbonate solution surrounds plant in test tube = supply of CO2
. apparatus kept in dark room (2 hours before), apart from variable light source
. light source turned on, timer started: oxygen produced enters funnel/capillary tube/syringe, causing syringe to move along = volume of O2 produced measured in mm3
. process repeated four or five times at same light intensity to produce average volume of oxygen produced per hour at that particular light intensity (apparatus left in dark between each repeat)
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- Fichas sobre Photosynthesis , creado por gracemanson64 el 09/04/2015.
- Creado por
- gracemanson64 · abr 2015
- Actualizado
- 19 feb 2016
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