photosynthesis and respiration Flashcards
equation for photosynthesis
6CO2 + 6H20 —–> C6H1202 + 602
processs of photosynthesis
energy is transferred from the environment to the chloroplast by light
the energy is then converted into CO2 from the air plus water from the soil glucose and oxygen
what type of reaction is photosynthesis
endothermic
how are leaves adapted for photosynthesis
- broad leaves giving them a big surface area for light
- thin so diffusion distances for gases are short
- contain chlorolphyll in the chlorolplast
what does photosynthesis use energy for
to change carbon dioxide and water into oxygen and glucose
where does photosynthesis take place
in the chloroplasts
how do plants use glucose
- for respiration
- to store as oils or fats
- store as starch
- making cellulose
- making amino acids
how does plants use glucose for respiration
it transfers energy to glucose enabling it to the covert the rest of the glucose into various other useful substances
why is glucose converted into celluose
glucose is converted into cellulose for making strong plant cell walls
how does glucose make amino acids
the glucose is combined with nitrate ions to make amino acids which are then made into proteins
why is glucose stored as fats and oils and how
glucose is turned into lipids for storing seeds
why is glucose turned into starch
- glucose is turned into starch and stored in roots, stems or leaves, ready for use when photosynthesis is not happening. Starch is insoluble making it much better for staring than glucose as a cell with lots of glucose would draw loads of water and swell
what limiting factors affect the rate of photosynthesis
- light intensity
- concentration of CO2
- chlorophyll
- temperature
what is a limiting factor
a factor that stops a rate of rection from going any faster
in what conditions do the limiting factors effect photosynthesis
- at night light is the limiting factor
- in winter its temperature
- in warm bright conditions its CO2 concentration
how can the amount of chlorophyll be a limiting factor of photosynthesis
-the amount of chlorophyll in a plant can be affected by a disease or environmental stress, which can cause chloroplasts to become damaged or unable to make enough chlorophyll, this means that the rate of photosynthesis is reduced as they can’t absorb as much light
how does light intensity affect the rate of photosynthesis
- as the light intensity increases the rate of photosynthesis increases at a constant rate, however, it only increases to a certain point (hence why the graph levels off) as beyond that point an increase in light intensity will no longer have an effect, so the rate would not increase. this is because CO2 and temperature are limiting factors so they would need to be increased for the rate to increase and light is not longer the limiting factor
how can you change the light intensity in a lab to see the effect of photosynthesis
by moving a lamp closer or further away from your plant or you could use a light meter which will help you plot a graph much more easier
what does light do to photosynthesis
it provides the energy needed for photosynthesis
how does light intensity affect the rate of photosynthesis
- as the light increases, the rate of photosynthesis increases at a constant rate, however, it only increases to a certain point (hence why the graph levels off) as beyond that point an increase in CO2 concentration will no longer have an effect, so the rate would not increase. this is because light intensity and temperature are limiting factors so they would need to be increased for the rate to increase and CO2 is no longer the limiting factor
how does CO2 contribute to photosynthesis
its one of the raw material needed for photosynthesis
how does temperature affect the rate of photosynthesis
- if the temperature is too low the enzymes needed for photosynthesis will wotk more slowly at low temperature
- if the temperature is too hot the enzymes it needs for photosynthesis will denature
what temperature does photosynthesis happen at
45 degrees
what does oxygen production show
the rate of photosynthesis
REQUIRED PRACTICAL photosynthesis
1) place a boiling tube 10cm away from an LED light source, an LED light is used as these do not release very much heat as too much heat would change the temp of the experiment, if we did use a normal light bulb then we would have to place a beaker of water in between the light and the BT so it would absorb the heat produced by it
2) fill the boiling tube with sodium hydrogen carbonate solution, the sodium hydrogen carbonate solution releases CO2, which is needed for photosynthesis
3) place pondweed into the BT with the cut end at the top
4) leave the pondweed for 5 minutes so it can acclimatise to the condition in the boiling tube
5) bubbles of gas should then be produced from the cut end of the pondweed , this gas is oxygen which is produced by photosynthesis
REQUIRED PRACTICAL photosynthesis
1) place a boiling tube 10cm away from an LED light source, an LED light is used as these do not release very much heat as too much heat would change the temp of the experiment, if we did use a normal light bulb then we would have to place a beaker of water in between the light and the BT so it would absorb the heat produced by it
2) fill the boiling tube with sodium hydrogen carbonate solution, the sodium hydrogen carbonate solution releases CO2, which is needed for photosynthesis
3) place pondweed into the BT with the cut end at the top
5) leave the pondweed for 5 minutes so it can acclimatise to the condition in the boiling tube
6) bubbles of gas should then be produced from the cut end of the pondweed, this gas is oxygen which is produced by photosynthesis
7) start a stopwatch and count the number of bubbles produced in 1 minute, repeat this 2 more times and calculate the mean number of bubbles produced in a minute
8) repeat the experiment at 20 cm then 30 then 40 cm
ANOMALIES OF REQUIRED PRACTICAL
- the number of bubbles can be too fast to count accurately
- the bubbles are not always the same size
how can we improve the REQUIRED PRACTICAL
- by measuring the volume of oxygen produced instead of counting the bubbles by placing the pondweed under a funnel and catching the bubbles in a measuring cylinder then use the measuring cylinder to measure the volume of oxygen produced
whats the inverse square law
that if you half the distance the light intensity will be four times greater ( so if you third the distance the light intensity would be 9 times greater or if you double the distance the light intensity would be 4x smaller )
how do we work out the light intensity
1/ distance squared
what is the most common way to artificially create the most ideal conditions for plants
- to grow them in greenhouses
- artificial light
- increases levels of carbon dioxide
what do greenhouses do and how does it help farming
- help trap the suns heat and make sure that the temperature does not become limiting - in winter a farmer or gardener might use a heater as well to keep the temperature at an ideal level - in summer they might use shade and ventilation to cool things down
- keeping plants enclosed in a greenhouse makes it easier to keep them free from pests and disease, the farmers can add fertiliser to the soil to provide minerals needed for healthy growth
how can artificial light help with farming
- light is needed for photosynthesis so commercial farmers use artificial light after the sun goes down to give their plants more quality photosynthesis time
how can farmers control levels of CO2
farmers can increase the level of carbon dioxide in a greenhouse by using paraffin heaters, as the heater burns it produces CO2 as a by-product and heats the greenhouse
disadvantages of the most common way to artificially create the most ideal conditions for plants
- its expenisve
- Risk of antibiotic resistance
advantages of the most common way to artificially create the most ideal conditions for plants
- the plants will grow much faster at ideal conditions
- a decent crop can be harvester more often which can then be sold
- higher yield
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what does respiration do
transfers the energy that the cell needs for all living processes
what is respiration
the process of transferring energy from glucose which goes on every cell
what type of reaction is respiration
exothermic
how do organisms use respiration
- to build up large molecules from smaller ones
- to allow muscles to contract and relax
- to keep body temperature steady in colder conditions in mammals
what is metabolism
the sum of all of the reactions that happen in a cell or the body
what are chemical reactions controlled by
enzymes
examples where large molecules are made from smaller ones
- lots of small glucose molecules are joined together in reactions to form starch, glycogen and cellulose
- lipid molecules are made from one molecule of glycerol and three fatty acids
- glucose is combined with nitrate ions to make amino acids which are then made into proteins
examples where larger molecules are broken down into smaller ones
- glucose is broken down in respiration, respiration transfers energy to power all the reactions in the body that make molecules
- excess protein is broken down in a reaction to produce urea, urea is then excreted in urine
what is aerobic respiration
respiration using oxygen
what is the most efficient way to transfer energy from glucose
aerobic respiration
where does aerobic respiration take place
in the mitochondria
symbol equation for aerobic respiration
C6H10O6 + 6O2 —-> 6CO2 + 6H20
word equation for aerobic respiration
glucose + oxygen —–> carbon dioxide + water
what is anaerobic respiration
its the incomplete breakdown of glucose, making lactic acid
word equation for anaerobic respiration
glucose —–> lactic acid
why doesnt anaerobic respiration transfer as much energy as aerobic respiration
as the glucose does not fully oxidise so anaerobic respiration is only useful in emergencies
word equation for fermentation
glucose ——> ethanol + carbon dioxide
what us anaerobic respiration called in yeast cells
fermentation
advantages of fermentation
- in the food and drink industry fermentation by yeast provides great value as its used to make bread and alcoholic drinks
- in bread making its the carbon dioxide in the fermentation process that makes the bread rise
- in beer and wine making its the fermentation process that produces alcohol
what happens to your muscles during exercise
- your muscles need more energy from respiration to contract as some of your muscles are contracting more frequently than normal so your rate of respiration increases to provide more energy to your muscles
responses to exercise
- breathing rate and breath volume increase to get more oxygen into the blood
- your heart rate increases to get the oxygenated blood around body faster, this removes CO2 more quickly at the same time
what happens when you do really vigorous exercise
- your body cant supply oxygen to your muscles quick enough so they start respiring anaerobically, this is not the best way to transfer energy from glucose as lactic acid builds up in the muscle which can get painful
- it can also cause muscle fatigue and this is where the muscles get tired and stop contracting efficiently
what is oxygen debt
the amount of extra oxygen needed to react with lactic acid in muscles and remove it from cells
what does oxygen and lactic acid make
CO2 + H2O
what happens to your body when theres high levels of lactic acid
- oxygen debt occurs so your pulse and breathing rate stays high to repay the oxygen your muscles didnt get in time as your lungs, heart and blood couldnt keep up with the demands earlier on, so even after you stop exercising your breathing rate i high to get more oxygen in the blood
except oxygen debt how else does your body cope with high levels of lactic acid
the blood that enters your muscles transports the lactic acid to the liver and in the liver the lactic acid is converted back into glucose
how can you investigate effect if exercise on the body
- you can measure the breathing rate by counting breaths, heart rate and by taking the pulse
- your pulse rate will increase the more intense the exercise is as your body needs to get more oxygen to the muscles and take more C02 away from the muscles
how to reduce random errors when investigating the effect of exercise on the body
do it as a group and plot the average pulse for each exercise
Give two uses of the energy released in respiration.
- movement / muscle
contraction - keeping warm
Water is taken in by the roots, transported up the plant and lost from the leaves.
Which scientific term describes this movement of water?
transpiration stream
why is photosynthesis an endothermic reaction
more energy needs to be taken in from the environment
to break bonds between the atoms in carbon dioxide and water together
than is released when new bonds form in glucose and oxygen
what does metabolism include
- conversion of glucose to starch, glycogen and cellulose
- the formation of lipid molecules from a molecule of glycerol and three
molecules of fatty acids - the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins
- respiration
how can carbon from the atmosphere become part of a starch molecule inside a leaf
carbon atom in carbon dioxide
diffuses through stomata
into air spaces in leaf
into chloroplasts
joins / bonds with water / hydrogen and oxygen
to make glucose
glucose is converted to starch (for storage)
