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biology unit 4 bioenergetics. - Coggle Diagram
biology unit 4 bioenergetics.
carbon dioxide + water --> glucose + oxygen
6CO2 + 6H2O --> C6H12O6 + 6O2
endothermic - takes heat in. Sunlight taken in by chlorophyll in chloroplasts.
factors affecting photosynthesis.
temperature - as temp rises so does the rate of photosynthesis = more energy for reaction. as temp approaches 45oC photosynthesis drops to 0 because enzymes controlling have denatured due to active site shape becoming distorted.
carbon dioxide conc. - as co2 increases so does rate of photosynthesis. after a certain point to the increase has no further effect as it is no longer the limiting factor.
light intensity - as light intensity increases so does rate of photosynthesis as more energy provided. after a certain point it has no effect as it is no longer the limiting factor.
chlorophyll concentration - not vary in short term but change if plants are grown in soil without enough minerals to make chlorophyll.
required practical - light intensity on rate of photosynthesis.
observing oxygen output from a piece of pondweed.
place a peice of pondweed in a beaker and shine a light at it using a lamp at a specific distance away.
record the number of bubbles of as coming out of the ponweed in one minute.
repeat this with the lamp at different distances from the pondweed.
independent variable - light intensity/the distance from the light. Dependant variable - number of bubbles in one minute. Control variables - piece of pondweed, the temperature, conc of carbon dioxide.
when light intensity studied, doubling the distance between the lamp and the pondweed will reduce the light intensity by a quarter. This is called inverse square law.
glucose produced in photosynthesis is used in.
used in respiration to provide energy.
insoluble starch - stored in stem leaves or roots.
fats and oils - stored. e.g in seeds.
cellulose - strengthen cell walls.
with nitrate ions from soil, proteins are made which are used for growth and for enzymes.
fructose.
respiration
exothermic reaction. releases energy from glucose molecule used in: chemical reactions to build larger molecules, for movement, to keep warm.
aerobic respiration
glucose + oxygen --> carbon dioxide + water.
C6H12O6 + 6O2 --> 6CO2 + 6H2O
anaerobic respiration
glucose not completely broken down. much less energy than aerobic respiration.
glucose --> lactic acid = in Animals.
glucose --> ethanol + carbon dioxide in plants, yeast and alchohol.
in yeast cells it is called fermentation. Used in manufacture of bread and alcoholic drinks.
exercise and respiration.
rate of respiration increase. heart rate, breathing rate and breath volume increase to supply muscles with more oxygen and glucose for the increase in anaerobic respiration.
build up of lactic acid creates an oxygen debt. lactic acid causes muscles to hurt and stops them contracting efficiently. is poisonous so needs to be removed.
blood flowing through muscles transports the lactic acid to liver where it is broken down. the oxygen debt is the amount of extra oxygen the body needs to react with the lactic acid and remove it from the cells.
metabolism
sum of all the chemical reactions in a cell or in the body.
controlled by enzymes and need a transfer on energy. transferred through respiration and used to make new molecules including:
the conversion of glucose to starch, glycogen and cellulose.
formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids.
use of glucose and nitrate ions to form amino acids which are used to synthesise proteins.
the breakdown of excess proteins into urea for excretion.