Bioenergetics - Photosynthesis 101-107 Flashcards
What is the word and symbol equation for photosynthesis
2 points
1) Carbon dioxide + water –> glucose + oxygen
2) 6CO2 + 6H2O → C6H12O6 + 6O2
what type of reaction is photosynthesis
endothermic, energy is transferred from the environment
where does photosynthesis happen
2 points
1) in chloroplasts
2) they contain pigments like chlorophyll that absorb light
what ways do plants use glucose
5 points
1) respiration
2) making cellulose
3) making amino acids
4) stored as oils or fats
5) stored as starch
how is glucose used for respiration
2 points
1) it transfers energy from glucose
2) which lets the plants convert the rest of the glucose into other useful substances
how is glucose used for making cellulose
glucose is converted into cellulose for making strong plant cell walls
how is glucose used for making amino acids
2 points
1) it’s combined with nitrate ions to make amino acids
2) which is then made into proteins
how is glucose stored as oils or fats
it’s turned into lipids for storing in seeds
how is glucose stored as starch
2 points
1) it’s turned into starch then stored in the roots, stems and leaves ready for use when photosynthesis isn’t happening
2) starch is insoluble which makes it better to store than glucose
what are the limiting factors of photosynthesis
3 points
1) light intensity
2) CO2 concentration
3) temperature
how can chlorophyll also be limiting factor of photosynthesis
3 points
1) the amount can be affected by disease or environmental stress - like a lack of nutrients
2) this causes chloroplasts to be damaged or not make enough chlorophyll
3) this means the rate of photosynthesis is reduced because it can’t absorb as much light
how can light be a limiting factor of photosynthesis
4 points
1) light gives the energy needed
2) as the light level is raised the rate of photosynthesis increases steadily
3) but only up to a certain point, above this it won’t make any difference
4) as it increases the rate won’t increase any more because either the temp or CO2 is now the limiting factor
draw the graph of how the light intensity affects the rate of photosynthesis
pg 102 of bio book
how can CO2 be a limiting factor for photosynthesis
3 points
1) CO2 is one of the raw materials needed for photosynthesis, so too little of it slows the rate down
2) the amount of CO2 will only increase up to a point
3) after this, as the CO2 increases the rate no longer increases, which shows it is not a limiting factor
draw the graph of how CO2 concentration affects the rate of photosynthesis
pg-103 of bio book
how can temperature be a limiting factor for photosynthesis
3 points
1) if the temp is too low, the enzymes needed for photosynthesis work slowly
2) but is the temp is too high, the enzymes will be damages
3) this happens at about 45’c
draw the graph of how temperature affects the rate of photosynthesis
pg-103 of bio book
how can you measure the rate of photosynthesis
6 points
1) a source of white light is placed at a specific distance from some pondweed
2) it’s left to photosynthesise for a set amount of time, as it does the oxygen released will collect in a capillary tube
3) at the end, use the syringe to draw the gas bubble in the tube up by a ruler
4) measure the length of gas bubble, which is proportional to how much O2 is produced
5) repeat this twice with the light source at the same distance and the mean vol of O2 is calculated
6) then repeat the whole experiment with the light at different distances
draw and label the apparatus for measuring the rate of photosynthesis
pg 105 bio book
how can you measure the effect of temp and CO2 on photosynthesis
3 points
1) the same experiment as before
2) but the test tube can be put in a water bath at a set temp or measured amount of sodium hyrdrogencarbonate can be dissolved in water
3) the experiment can then be repeated with different temps of water or concentrations of sodium hydrogencarbonate
what is the inverse square law
light intensity ⍺ 1/distance²
what are ways farmers artificially create ideal conditions for photosynthesis
4 points
1) greenhouses - helps trap suns heat, easier to keep free from pests and diseases
2) artificial light
3) paraffin heater - makes CO2 as a by-product
4) if the conditions are right a decent crop will be harvested which makes more profit
