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
consideration when using a green house- x3
-must enhance conditions to get max rate of photosynthesis while maintaining profit
-extra cost should be justified by increase in yield
-eg don’t provide more light/ heat ect than plant needs otherwise money is wasted.
-how do we get energy- what process-
-is this exo/ endo thermic
-where does it occur
-what happens in aerobic respiration
-why is it important
- cellular respiration
-exothermic- releases energy
-all living cells
-glucose + O₂= CO₂ and water
and energy is released
-the energy transferred in respiration supplies all the energy needed for living processes
respiration transfers energy due to the….
-what happens to the glucose molecule
breakdown of glucose
-fully oxidised- which is why alot of energy is released
where in a cell does aerobic respiration happen
-word equation for anaerobic respiration in muscles
-what do muscle cells neede energy for
-is energy given off in anaerobic respiration- how much
-why
in mitrochondria
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glucose—>lactic acid
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contraction
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yes-much less than aerobic
-because in anaerobic respiration, oxidation of glucose is INCOMPLETE
why can anaerobic respiration happen in muscle cells
vigorous excercise- body can’t supply enough oxygen to muscles
3 places anaerobic respiration takes place
plant cells
yeast cells
muscle cells
word equation for anaerobic respiration in plant/yeast cells
-anaerobic respiration in yeast cells is called-
-why is this important
glucose —> ethanol + carbon dioxide
-energy given off
-fermentation
-has economic importance in manufacture of bread and alcoholic drinks
-how is fermentation important in:
-alcoholic drinks
-in bread
-is yeast uni/multicellular
the alcohol in the drinks is the ethanol produced by fermentation
-carbon dioxide produced by fermentation creates bubbles in dough-make bread rise
-single celled organisms
what do organisms need energy for x3
-chemical reactions to build larger molecules (eg protiens from amino acids)
-movement- allow muscle cells to contract
-keeping warm-mammals and birds keep body temp steady in colder surroundings
during excercise the body reacts to the…….
explain why-
increased demand for energy-
-muscles need energy from respiration to contract
-muscles contract more than normal
- need more energy
what 3 things increase when exercising
-overall why
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and specifically why for each thing
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why does anaerobic respiration increase-
-heart rate,
-breathing rate,
-breath volume
* to supply muscles w/ more oxygenated blood
-breathing rate, breathing volume increase(more frequent breathing and deeper breaths)
*more oxygen in blood stream
-heart rate increases
*to pump oxygenated blood around body faster
-anaerobic respiration increases bcse body cells need more oxygen
faster heart rate gets o2 blood around body faster but also…..
-why does anaerobic respiration happen in humans- 3 points
removes CO2 quicker
-if insufficient oxygen is supplied to muscles
-normally during vigorous exercise
- anaerobic respiration takes place in muscles
-what does anaerobic respiration cause- 3 points
-The incomplete oxidation of glucose
-causes a build up of lactic acid
-and creates an oxygen debt
-what happens to our muscles during long periods of vigorous exercise
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-what is the oxygen debt
lactic acid causes muscles to become fatigued AND so they stop contracting efficiently
(After resorting to anaerobic respiration and u stop exercising, you’ll have an oxygen debt)
-oxygen debt is amount of extra O2 body needs after exercise to react with accumulated lactic acid and remove it from cells
-what happens to lactic acid in muscles after you’ve finished exercising- 3 points
-blood flowing through muscles
-transports lactic acid to liver
-where it’s converted back into glucose
2 ways your body deals with lactic acid build up
-blood transports lactic acid to liver where it’s converted into glucose
-you ‘repay’ the oxygen- breath hard after exercise to get more o2 in blood- o2 reacts w/ lactic acid in muscle cells to form CO2 and water
how do you measure:
breathing rate
heart rate
- why does pulse rate increase the more intense exercise is-
-how can you reduce random errors when plotting a bar graph on pulse rate/breath count and type of exercise-
-count breaths
-taking the pulse
(2 fingers on inside of wrist/neck-count no. of pulses in 1 min)
-body needs to get more oxygen to muscles and take more CO2 away
(-co2 is in muscles because it is a product of aerobic respiration)
-do as a group and plot the average
5 chemical reactions involved in metabolism
-conversion of glucose to starch/glycogen/cellulose
-formation of lipid molecules from 1 glycerol + 3 fatty acids
-glucose and nitrate ions form amino acids which synthesise protiens
-respiration
-breakdown of excess protein to form urea for excretion
metabolism is..
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energy released by respiration is used by…..
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-the chemical reactions that occur in our bodies are controlled by…
the sum of all the reactions in a cell/ the body
-energy released by respiration is used by enzymes to synthesise new molecules in the cell
-enzymes
why is glucose important x2
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how is glucose used in only plants-x3
these are included in metabolism
-starting point for many new chemicals
-energy released from glucose in respiration
-glucose molecules converted into starch- a storage form of glucose
-glycose reacts w/ nitrate ions to form amino acids-
amino acids used to synthesis protiens
-glucose converted into cellulose-
how is glucose used in only animals x1
-other reactions involved in metabolism x3
glucose converted into Glycogen- storage form glucose
*1 molecule of glycerol reacted w/ 3 molecules of fatty acids to form a lipid molecules- found in cell membrane
*excess protiens broken down into urea which is excreted in urine by kidneys
*glucose broken down in respiration to transfer energy
