Bioenergetics - Photosynthesis and respiration Flashcards
photosynthesis word equation
carbon dioxide + water —> glucose + oxygen
photosynthesis symbol equation
6CO2 + 6H20 -> C6H12O6 + 6O2
what kind of reaction is photosynthesis
endothermic, because energy is absorbed from the environment
where does photosynthesis take place
in the chloroplasts in the leaves
5 ways plants use glucose
- used to release energy in respiration
- converted into insoluble starch for storage (can be converted back into starch when needed)
- used to produce fat or oil for storage
- used to produce cellulose, which strengthens the cell wall
- used to produce amino acids for protein synthesis (and nitrate ions)
what are the 4 factors that affect the rate of photosynthesis
- concentration of CO2
- temperature
- light intensity
- amount of chlorophyll
what happens if a plant gets too hot
the enzymes needed for photosynthesis will become denatured and will no longer work
why do greenhouses have the ideal conditions for photosynthesis
because they help trap the suns heat, making sure that temperature doesn’t become a limiting factor, but during the heat they might use shades and ventilation
- they supply artificial light when the sun goes down
- farmers and gardeners can also increase the CO2 concentration by using a paraffin heater to heat the greenhouse (as paraffin burns,it makes CO2 as a by product)
advantages of greenhouses
- keeps plants free from pests and diseases
- farmers can keep the conditions just right for photosynthesis
why is respiration so important
it transfers the energy that the cell needs to do just about anything, anf it is used for all living processes
what kind of reaction is respiration
exothermic, as it transfers energy tp the environment
examples of how organisms use energy transferred by respiration
- to build up larger molecules from smaller ones, like proteins from amino acids
- in animals, used to contract muscles so they can move about
- in mammals and birds, to keep warm in colder surroundings
what is metabolism
the sum of all the reactions in a cell or the body
examples of when smaller molecules are used to make bigger ones
- lots of glucose molecules join together to form starch, glycogen and cellulose
- lipid molecules made from one molecule of glycogen and 3 fatty acids
- glucose is combined with nitrate ions to make amino acids, which are then made into proteins
examples of when larger molecules are broken down into smaller ones
- glucose is broken down during respiration
- excess protein is broken down in a reaction to produce urea, which is then excreted in urine
what is aerobic respiration
respiration using oxygen
equation for aerobic respiration
glucose + oxygen —> carbon dioxide + water
what is anaerobic respiration
respiration without oxygen
what is the difference in energy between aerobic and anaerobic respiration
As the oxidation of glucose is incomplete in anaerobic respiration much
less energy is transferred than in aerobic respiration.
word equation for anaerobic respiration in muscle cells
glucose —> lactic acid
when will the body start doing anaerobic respiration
when you do vigorous exercise and your body can’t supply enough oxygen to your muscles
difference between anaerobic respiration in plants and yeast compared to in animals
they produce ethanol and carbon dioxide rather than lactic acid
what is the word equation for anaerobic respiration in yeast and plant cells
glucose —> ethanol + carbon dioxide
what is the process of anaerobic respiration in yeast called
fermentation
uses of fermentation
- beer and wine making
- bread making, the carbon dioxide from fermentation makes bread rise
what happens to the body as you exercise more
- aerobic respiration increases, meaning that the body cells require more oxygen
- your breathing rate and volume increases to get more oxygen into the blood, then your heart rate increases to get the oxygenated blood around the body faster, removing CO2 quicker
what happens to the body once you start doing really vigorous exercise
your body cannot supply oxygen to your muscles quick enough, so they start respiring anaerobically,
lactic acid builds up in the muscles because of the incomplete oxidation of glucose,
at this point the body has to remove the lactic acid from the muscles, this creates oxygen debt
what is muscle fatigue
when the muscles get tired and stop contracting efficiently
what is oxygen debt
the amount of extra oxygen your body needs to react with lactic acid to remove it fromcells
how can lactic acid be removed from cells
- the lactic acid is transported out of muscles by the blood
- its then taken to the liver and converted back into glucose
what does chlorophyll do
absorbs light energy
what effect does light intensity have on the rate of photosynthesis
- when light intensity is zero, the rate of photosynthesis is zero, plants need light to carry it out
- as we increase the light intensity, the rate of photosynthesis increases, because the plant has more light energy to carry out the photosynthesis, so the reaction gets faster
- if we keep increasing the light intensity, there comes a point where the rate of photosynthesis no longer increases
- at this point, light intensity is no longer the limiting factor
why do farmers want to increase the rate of photosynthesis
it will increase the yield of the crops they produce
disadvantages of greenhouses
- expensive
- some gardeners use oil burners as these release heat and carbon dioxide at the same time
what is energy used for
- movement
- to keep warm
- for chemical reactions to build larger molecules
why is the carbon dioxide produced from fermentation useful when making bread
it creates bubbles in the dough, causing it to rise
