Bioenergetics Flashcards
what is photosynthesis
the process by which plants make glucose from sunlight. it is an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light.
word equation for photosynthesis
light
carbon dioxide + water —> glucose + oxygen
what is the chemical symbol for glucose
C. H. O
6. 12. 6
how does temperature effect photosynthesis
-increase in temp, photosynthesis increases
- trend continues until enzymes denature and rate of reaction decreases as the reaction is controlled by enzymes
how does light intensity affect photosynthesis
-the higher the light intensity, the faster the rate of the reaction
how does carbon dioxide concentration affect photosynthesis
-carbon dioxide needed to make glucose
-as concentration increases, rate of reaction increases
how does the amount of chlorophyll affect rate of photosynthesis
-converts light energy to food for the plant so it is essential
-if chlorophyll levels are reduced the rate of photosynthesis decreases
what is a limiting factor
an environmental condition which in low levels restricts any increase in the rate of photosynthesis
how does a limiting factor affect the rate of photosynthesis
despite increases in other factors the rate of photosynthesis will not increase any more
how can you see a limiting factor on a graph
the curve levelling off
what does a graph with once limiting factor look like
if it has one line which levels off
factor on the horizontal axis and rate of photosynthesis on vertical axis
what does a graph with two limiting factors look like?
two lines
the investigation involves increasing the factor on the horizontal axis and is carried out at two different other environmental conditions
what is light intensity measured in
lux
how do farmers use knowledge of limiting factors
to enhance the conditions in the greenhouse for a greater rate of photosynthesis
this will increase growth leading to increased profits
what is inverse proportion
describes a relationship between two factors which involves one increasing whilst one is decreasing
what is the inverse square law
light intensity { 1/distance^2
how is glucose used from photosynthesis
respiration
converted into soluble starch for storage (roots stems leaves)
produce fat or oil for storage (in seeds)
produce cellulose to strengthen cell walls
combined with nitrates from soil to form amino acids which produce proteins
what is respiration
the process of transferring energy from glucose so living processes can occur
what kind of reaction is respiration
exothermic
how does aerobic respiration work
this uses oxygen
it yields the most energy
most of the reactions that make up aerobic respiration occur in the mitochondria
how does anaerobic respiration work
occurs when there is not enough oxygen
it does not yield as much energy as aerobic respiration
it is only used as a last resort
the oxidation of glucose is incomplete
why is more energy needed in exercise
for muscles to contract for respiration to occur faster therefore more oxygen needs to be supplied to cells and more co2 removed
how is more energy provided during exercise
heart rate increasing
breathing rate increasing
breath volume increasing
when does anaerobic respiration occur
if there is not enough oxygen being supplied eg vigorous exercise
why does anaerobic respiration build up creating an oxygen debt
lactic acid is a byproduct of this reaction and oxygen is needed to break lactic acid down
what is oxygen debt
the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells
what does oxygen debt result in
muscles tiring and not contracting properly
how is lactic acid transported
blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose
what is metabolism
the sum of all the reactions in a cell or the body,
how are new molecules made
the energy transferred in the cells by respiration is used in the processes of metabolism to make new molecules
how are the processes of using metabolism to make new molecules controlled
these processes are controlled by enzymes
examples of metabolic reactions
-glucose molecules being converted to starch, glycogen and cellulose by being joined together
-a glycerol molecule and three molecules of fatty acids forming a lipid molecule
-glucose and nitrate ions forming amino acids which are used to form proteins
-the reactions in respiration
-urea forming the breakdown of proteins for excretion
