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Bioenergetics - Coggle Diagram
Bioenergetics
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limiting factors
1) light intensity:
when the light intensity is zero, the rate of photosynthesis is zero.
as you increase the light intensity, the rate of photosynthesis increases. (this is because there is more light energy so the reaction gets faster)
slower reaction means there is not enough light
there comes a point where the rate of photosynthesis will no longer increase
2) carbon dioxide:
as you increase the carbon dioxide level, the rate of photosynthesis increases.
there comes a point where the rate of photosynthesis will no longer increase
3) amount of chlorophyll in the leaf:
leaves that trap less light energy than normal leaves will have a lower rate of photosynthesis.
4) temperature:
as you increase the temperature, the enzymes involved work faster so the rate of photosynthesis increases.
if you keep increasing the temperature the enzymes will denature and the rate of photosynthesis falls
greenhouses:
farmers want to increase the rate of photosynthesis as it increases the yield of crops produced.
greenhouses are lit, heated and extra carbon dioxide is added.
the extra cost has to be justified by the increase in yield.
oil burners are used as they release heat and carbon dioxide at the same time.
respiration
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aerobic respiration:
the sugar glucose is reacted with oxygen gas, this produces carbon dioxide and water. it also releases energy.
glucose + oxygen -----> carbon dioxide + water
|_ energy
releases a large amount of energy because the glucose molecule had been fully oxidised
anaerobic respiration in muscles:
muscle cells need a great deal of energy for contraction, however, under certain conditions the amount of oxygen is limited.
shortage of oxygen/ does not require any oxygen.
glucose ----> lactic acid
|_ energy
glucose is converted to lactic acid.
releases much less energy than aerobic respiration because the oxidation of glucose is incomplete
anaerobic respiration in plant and yeast cells:
the glucose is converted to ethanol and carbon dioxide.
no oxygen is needed for this reaction.
glucose ----> ethanol + carbon dioxide
|_ energy
anaerobic respiration in yeast cells is called fermentation - used to make alcoholic drinks, ethanol is produced by fermentation.
yeast is also used to make bread, uses the carbon dioxide produced by fermentation. this creates bubbles in the dough, causing the bread to rise.
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exercise
during exercise,
the body
needs a great deal of
energy for muscle contraction and the body has to react to the increased demand for energy
aerobic respiration increases as the body needs more energy. the body cells require more oxygen.
to provide the extra oxygen, the breathing rate and breathing volume increase.
the heart rate also increase to pump
the oxygenated blood around the body
when not enough oxygen can be supplied to the muscles, anaerobic respiration takes place in the muscles.
during long periods of exercise the lactic acid causes the muscles to become fatigued, causing them to stop contracting efficiently.
oxygen debt:
where the body has to remove the lactic acid.
the lactic acid is transported out of thee muscles by the blood , then taken to the liver and converted back to glucose in a series of chemical reactions.
reacting with the accumulated lactic acid and removing it from the cells requires oxygen - the oxygen debt is the amount of extra oxygen the body needs after exercise to deal with the accumulated lactic acid
metabolism
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humans don't need to eat
large amounts of protein.
excess proteins are broken down into the chemical urea, this is then excreted by the kidneys
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