BIOENERGETICS Flashcards
word equation and chemical equation for photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
Carbon dioxide + water (+light) —> glucose + oxygen
-plants get energy from
-What happens in photosynthesis
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-is it exo/ endo thermic
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-where does photosynthesis take place- explain
light
-plant takes in CO2 and water
-energy transferred from environment to chloroplasts by light
- light energy used to turn carbon dioxide and water into glucose + oxygen
-endo thermic, takes in light energy
- in leaves of plant
-leaves have chloroplasts-
-chlorophlasts contain green pigment-chlorophyll
-chlorophyll absorb light energy
LIGHT INTENSITY and rate of photosynthesis
-no light
-increase
-if we increase light intensity and rate of photosynthesis increases, what does it tell us
-when we increase light intensity- rate X increase
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-graph for CO2 concentration and rate of photosynthesis
- x photosynthesis- rate = 0
-rate increases-more light energy to carry out photosynthesis
-light intensity is limiting factor- rate wasn’t as fast bcse X enough
- +ve gradient on graph
-light intensity X longer limiting factor
-graph rises to a point, then levels off
-same as graph for light intensity
4 things that affect rate of photosynthesis and be limiting factor
temp- in winter
light intensity- night
co2 con. - if its warm + bright enough
amount of chlorophyll in leaf
what happens to leaves w/ low amount of chlorophyll
What can affect chlorophyll amount
-leaves trap less light energy, have lower rate of photosynthesis than normal leaves
-disease
-environmental stress eg lack nutrients
TEMP and rate of photosynthesis
- increase temp
-keep increasing
-what temp causes this
rate increases- enzymes work faster
-enzymes denature- rate falls
-around 45 *
how would you get the graph for light intensity-
if u plot distance of lamp from plant- don’t get the specific graph u know
-need to MEASURE light intensity w/ LIGHT METER(or do math w/ results)
uses of glucose from photosynthesis x 5
-for respiration
-converted into insoluble starch for storage
-used to produce fat/ oil for storage
-used to produce cellulose- strengthens cell wall
-used to produce amino acids for protein synthesis
What does resporation do
-why’s glucose converted into starch x3
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why is glucose stored as fats./ oils (lipids)
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how is glucose used in cell wall
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-how is glucose used in terms of protien synthesis
-respiration transfers energy from glucose
-to convert back when photosynthesis isn’t happening eg in winter/ at night
-starch is insoluble- better for storing than glucose
-cell w/ lots of glucose would draw in lots of water and swell up
-to be stored in seeds
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glucose converted into cellulose which gives cell wall strength
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-glucose combined with nitrate ions absorbed from soil to produce amino acids
-amino acids synthesise protiens
RP 6- rate of photosynthesis-
-steps x7 by counting bubbles
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different steps using capillary tube-x4
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-what type of light is used-why
-what if we use normal light bulb
1)put boiling tube 10 cm away from source of WHITE LIGHT -led light
2)fill boiling tube w/ sodium hydrogencarbonate solution- release co2 needed
3)put pondweed in tube,below level of solution, cut end diagonally(steady stream of O2 bubbles)
4)leave for 5 mins- pondweed can acclimatise to conditions in tube + start photosynthesising
5)start stop watch- count no. bubbles from cut end in 1 min
6)repeat a total of 3 times and get a mean no. of bubbles
7)do whole experiment again at 20 cm 30cm, so on
-bubbles will collect in capillary tube.
-use syringe to draw gas up tube alongside a ruler
-measure length of gas bubble
-this is proportional to vol of O2 produced
-led light- X give off much heat-change in heat affect rate
-if we use normal light bulb, place beaker of water btwn light and tube- absorb heat produced by bulb
RP 6 - photosynthesis
-problems x2
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-what’s the independant variable in OG RP
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-dependant variables x3
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-control variables- x3
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how do you make sure no other light effects the practical-
-no. of bubbles too fast to count accurately
-assumed every bubble has same O2 volume- bubbles not all same size
-light intensity
-rate
-no. of bubbles
-vol of gas
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-carbon dioxide conc.
-temp
-type of plant
-turn over head lights off, only light is from lamp
different steps using a funnel
-what do you control on RP6 photosynthesis- x4
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-what if you wanted to discover effect of:
CO2 and
temp on Photosynthesis
-place pondweed under funnel and catch bubbles in measuring cylinder filled w/ water
-use measuring cylinder to measure vol of Oxygen produced
-temp
-time
(+ co2 conc by using same concentration of hydrogen carbonate solution )
-use same length of pondweed and same species
-For testing effect of CO2-
different concentrations of sodium hydrogencarbonate solution
-for testing effect of temp-
put pondweed in water bath at set temp- repeat w/ different temps
RP 6 photosynthesis and light intensity-
what would potentially be plotted on graph x3 options
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-what happens if we double distance of pondweed from light
-what is the relationship btwn light intensity and distance
-equation to show this-
use inverse square law to work out light intensity when distance is 10 cm
Y-axis:
*bubbles per min- when counting
*vol of oxygen per min- with funnel
*length of bubble per min- w/ capillary tub
X-axis:
distance from light source
-distance doubled- number of bubbles falls by factor of 4
-inversely proportional-
DISTANCE INcrease
LIGHT intensity DEcrease
- light intensity ∝ 1/ d²
light intensity ∝ 1/ 10²
= 1/ 100 = 0.01 (a.u= arbitrary units)
what happens to light intensity:
if you do distance/2
if you do distance/3
if you do distance x2
if you do distance x3
A plant is moved from 15cm to 5cm away from led light.
-prove that light intensity becomes 9 times greater
light intensity = x4
light intensity= x9
light intensity= /4
light intensity= /9
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1/ 15² = 0.004444…
1/ 5² = 0.04
0.04 / 0.004444…
= 9
why do farmers control temp, light intensity and co2 concentration in a greenhouse
-how do farmers control:
-temp x3
-light intensity
-co² conc.
-another pro of a greenhouse- x1
-what else farmers do to improve growth x1
- to increase rate of photosynthesis- to increase yield-
-Temp
*greenhouses trap sun’s heat so its X limiting
*use a heater to keep ideal temp
* use shades + ventilation if too hot
Light intensity
-supply artificial light eg at night- more time to photosynthesise
CO₂ conc.
-paraffin heater/ oil burner- give off heat AND also CO₂ as by product
-easier to keep plants free from pests + disease
-farmers can add fertiliser to soil- provide minerals