bioenergetics Flashcards
photosynthesis
- process by which plants make glucose from sunlight
- endothermic reaction in which energy transferred from the environment to the chloroplasts by light
photosynthesis word equation
carbon dioxide + water (light) -> glucose + oxygen
photosynthesis balanced equation
6CO2 + 6H2O -> C6H12O6 + 6O2
effect of temp on photosynthesis
- increase temp = increase in rate of photosynthesis
- temp is controlled by enzymes
- trend continues up to a certain temp until enzymes begin to denature and rate of reaction decreases again
effect of light intensity on photosynthesis
- higher light intensity = faster rate of reaction
effect of carbon dioxide concentration on photosynthesis
- carbon dioxide concentration increases = rate of reaction increases
effect of amount of chlorophyll on photosynthesis
- chlorophyll levels reduce through magnesium deficiency = rate of reaction to decrease
limiting factor
an environmental condition, which, in low levels, restrict any increase in the rate of photosynthesis despite increases in other factors, the rate of photosynthesis will not increase any more
knowledge on limiting factors can…
help farmers enhance the conditions in greenhouses for a greater rate of photosynthesis
inverse proportion
describes a relationship between two factors which involves one increasing whilst one decreasing
inverse square law
as the distance between the light source and the plant increases, light intensity decreases
uses of glucose from respiration
- for respiration
- converted into insoluble starch for storage
- to produce fat or oil for storage (in seeds)
- to produce cellulose to strengthen cell walls
- combined with nitrates (absorbed from soil) to form amino acids which produce proteins
respiration
process of transferring energy from glucose so living processes can occur
- all living things and cells respire
respiration is exothermic
energy is transferred to the environment
aerobic respirationn
- uses oxygen
- yields most energy
- most of the reactions that make up aerobic respiration occur in mitochondria
- opposite equation to photosynthesis
anaerobic respiration
- occurs when there is not enough oxygen
- does not yield as much energy
- only used as a last resort e.g a spring where it is hard to breathe in enough oxygen
- oxidation of glucose is incomplete
anaerobic respiration in animals
glucose -> lactic acid
anaerobic respiration in plant and yeast cells
- fermentation
- glucose -> ethanol + carbon dioxide
- used to make bread and alcoholic drinks
more exercise = …
more energy for muscles to contract = respiration has to occur faster = more oxygen supplied to cells
more oxygen can be supplied by…
- heart rate increasing
- breathing rate increasing
- breath volume increasing
not enough oxygen supplied during vigorous exercise = …
- anaerobic respiration taking place
lactic acid is a byproduct of anaerobic respiration and…
it builds up creating an oxygen debt (oxygen needed to break down lactic acid)
oxygen debt
amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells
oxygen debt results in…
muscles tiring and not contracting properly
blood flowing though the muscles transport the lactic acid to the…
liver where it is converted back to glucose
metabolism
sum of all the reactions in a cell or the body
energy transferred in the cells by respiration is used in…
the processes of metabolism to make new molecules (processes controlled by enzymes)
examples of metabolic reactions
- glucose molecules converted to starch glycogen and cellulose by being joined together
- reactions in respiration
- urea forming from the breakdown of proteins and excretion
- glucose and nitrate ions forming amino acids
