Biology ✿ bioenergetics

equation for photosynthesis

carbon dioxide + water → glucose + oxygen

chemical equation for photosynthesis

CO₂ + H₂O → O₂ + C₆ H₁₂ O₆

what type of reaction is photosynthesis?

endothermic as energy is transferred from the environment to the chloroplasts

name 3 factors effecting photosynthesis

• temperature

• light intensity

• carbon dioxide concentration,

how does temperature affect the rate of photosynthesis?

• low temperature → the enzymes work slowly, so the ROP is low

• as temperature increases, ROP also increases

• 40–50°C → enzymes denature at high temperatures

limiting factor

a factor which stops the ROP from increasing

how does light intensity affect the rate of photosynthesis?

• low light intensity → the ROP is low because light energy is insufficient

• as light intensity increases, ROP also increases

• if there isn’t enough of one factor, increasing light intensity wont change the rate

how does carbon dioxide concentration affect the rate of photosynthesis?

• low CO₂ levels → the ROP is low because CO₂ is insufficient to produce glucose

• as light intensity increases, ROP also increases

• if there isn’t enough of one factor, increasing CO₂ levels wont change the rate

how might people in greenhouses maximise the rate of photosynthesis using artificial methods [3]

• use artificial light

• add carbon dioxide in the air

• use heaters

name 4 ways glucose is used

• respiration

• can be converted into starch, fats and oils for storage

• to produce cellulose to strengthen cell wall

• to produce amino acids for protein synthesis

cellular respiration

an exothermic reaction which is continuously occurring in living cells

equation for anaerobic respiration

glucose → lactic acid

equation for anaerobic respiration

glucose + oxygen → carbon dioxide + water

fermentation

anaerobic respiration in yeast cells, using for making alcoholic drinks

equation for fermentation

glucose →  ethanol⁢  +  carbon dioxide

how does the human body react when one is exercising and why?

heart rate, breathing rate and breath volume increases to supply the muscles with more oxygenated blood

what is aerobic respiration, where does it occur and what reaction is it?

• respiration which releases energy using oxygen

• occurs in mitochondria

• exothermic (produces heat)

give 2 differences between anaerobic and aerobic

do not refer to use of oxygen

aerobic respiration happens in cells and produces more energy

anaerobic respiration happens in muscles and produces less energy

what is anaerobic respiration and when does it occur ?

• respiration without oxygen, it provides less energy as glucose isn’t fully oxidised

• occurs during intensive exercises and in cytoplasm

what causes the build up in lactic acid in anaerobic respiration?

the incomplete oxidation of glucose which also creates an oxygen debt

oxygen debt

the amount of extra oxygen the body needs after exercise to react with the lactic acid to remove it from cells

why is lactic acid transported to the liver?

to convert it back into glucose which can either be used for energy again or stored for later

metabolism

the sum of all the reactions in a cell or body

give 4 examples of metabolism reactions

• respiration

• breakdown of proteins to urea

• formation of lipids from glycerol and fatty acids

• conversion of glucose into starch, cellulose or glycogen

give am example of an metabolism reaction in plants

use of glucose/ nitrates to make amino acids

why is there less energy produced in anaerobic respiration?

the oxidation of glucose is incomplete