p1 topic 4 - bioenergetics

what is respiration

the process of transferring energy from glucose which goes in every cell

is respiration exothermic or endothermic

exothermic as it transfers energy to the environment

what does respiration transfer energy for

build up larger molecules from smaller ones, allow animal muscles to contract, keeps mammals and birds body temperature steady in cooler surroundings

what is metabolism

sum of all the chemical reactions in an organism

what happens to small glucose molecules

join together in reactions to form starch, glycogen, and celluose

what are lipid molecules made from

one molecule of glycerol and three fatty acids

what does glucose make

combines with nitrate ions to make amino acids which are then made into proteins

what happens to excess protein

broken down in a reaction to produce urea which is excreted in urine

what is aerobic respiration

respiration needing oxygen to transfer energy from glucose

where do most of the reactions happen in aerobic respiration

mitochondria

word equation for aerobic respiration

glucose + oxygen to carbon dioxide + water

symbol equation for aerobic respiration

C6H12O6 + 6O2 to 6CO2 + 6H2O

what is anaerobic respiration

when the body cannot supply enough oxygen to the muscles, it is the incomplete breakdown of glucose making lactic acid

word equation for anaerobic respiration

glucose to oxygen

what happens to energy in anaerobic respiration

does not transfer nearly as much energy as the glucose is not fully oxidised

what do plant and yeast cells produce instead of lactic acid

ethanol and carbon dioxide

word equation for anaerobic respiration in plant and yeast cells

glucose to ethanol and carbon dioxide

what is anaerobic respiration in yeast cells called

fermentation

process of photosynthesis

uses energy to change carbon dioxide and water into glucose and oxygen

where does photosynthesis take place

chloroplasts in green plant cells and contain pigments like chlorophyll and absorb light

is photosynthesis is endothermic or exothermic

endothermic as energy is transferred from the environment in the process

word equation for photosynthesis

carbon dioxide + water to glucose + oxygen

symbol equation for photosynthesis

6CO2 + 6H2O to C6H12O6 + 6O2

how do plants use glucose to respire

transfers energy which enables the plants to convert the rest of the glucose into various other useful substances

how do plants use glucose to make cellulose

glucose is converted into cellulose for strong cell walls

how do plants use glucose to make amino acids

glucose is combined nitrate ions to make amino acids which are then made into proteins

how do plants use glucose for storing fats or oils

glucose is turned into lipids for storing in seeds

how do plants use glucose for storing starch

glucose is turned into starch and stored in roots, stems and leaves. starch is insoluble so it is better for storing glucose as it would not swell

what is the rate of photosynthesis affected by

intensity of light, concentration of co2 and temperature

how does the amount of chlorophyll reduce photosynthesis

chlorophyll can be affected by disease, environmental stress, lack of nutrients. light cannot be absorbed as much as there is not enough chlorophyll

what will happen to the rate of photosynthesis as light level is raised

increases steadily up to a certain point

why will the photosynthesis rate no longer increase after a certain point

either the temperature or co2 level will be the limiting factor

why can too little carbon dioxide slow the rate of photosynthesis down

as the carbon dioxide increases the light and temperature needs to also which shows co2 is not the limiting factor

what happens when the temperature is too hot for photosynthesis

the enzymes needed for photosynthesis and other reactions will be damaged

what happens when the temperature is too cold for photosynthesis

the enzymes needed for photosynthesis will work more slowly

what is oxygen debt

the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells

what happens to the blood that enters the muscles

transports the lactic acid back to the liver where it is converted back into glucose