Respiration- BP Flashcards
What is respiration?
releasing energy from glucose to make ATP
ATP will provide energy for life processes
occurs in all living organisms
ATP can be made by substrate-level phosphorylation (glycolysis & krebs cycle) and oxidative phosphorylation (electron transport chain)
2 types of respiration?
- aerobic respiration (with oxygen)
- anaerobic respiration (without oxygen)
what is glycolysis?
uses glucose to produce 2x pyruvate, 2x ATP, 2x reduced NAD
pyruvate enters link reaction
ATP made by substrate-level phosphorylation
reduced NAD used in ETC
link reaction?
uses pyruvate to produce acetyl coenzyme A, reduced NAD, CO2
pyruvate + coenzyme A + NAD = acetyl coenzyme A + reduced NAD + CO2
acetyl coenzyme A used in krebs cycle
reduced NAD used in ETC
CO2 given off as waste
krebs cycle?
- acetyl coenzyme A joins with oxaloacetate to form citrate
- coenzyme A goes back to link reaction to be reused
- citrate loses co2 and hydrogen
- hydrogen reduces NAD
- 5c compound formed
- 5c molecule converted into 4c molecule
- decarboxylation + dehydrogenation occur
- 1 reduced FAD and 2 reduced NAD
- ATP produced
- 4c oxaloacetate joins with acetyl coenzyme A and the cycle starts again
electron transport chain?
- reduced NAD and reduced FAD release the hydrogen atom (H+/e-) they are carrying
- the H+ build up in the matrix of the mitochondria
- the e- enter the ETC
- the electron (e-) moves along the chain releasing energy
- this pumps the protons (H+) from the matrix into the intermembrane space
- the H+ build up in the intermembrane space, then diffuse back into the matrix via a transport protein carrying ATP Synthase enzyme
- this leads to the production of ATP = oxidative phosphorylation
- oxygen is used as a final electron acceptor and proton acceptor
- it removes the electron from the end of the ETC, so the ETC can continue
- it removes the proton from the matrix, hence maintaining concentration gradient
- it becomes water
Describe anaerobic respiration?
no oxygen present, so no final electron acceptor and proton acceptor
ETC stops
Krebs Cycle and Link Reaction also stop as NAD and FAD are not reformed in ETC
Glycolysis can continue as it reforms its own NAD
so Anaerobic Respiration only relies on Glycolysis (making 2x ATP by substrate-level phosphorylation
NAD is reformed from the reduced NAD made in glycolysis
the reduced NAD donates its hydrogen atom (H+/e-) to pyruvate to reform NAD
in animals the pyruvate becomes lactate (lactic acid)
in plants/yeast the pyruvate becomes ethanol and CO2
How to measure rate of respiration?
measure amount of O2 used or measure amount of CO2 produced, in a certain time
one method = respirometer
How does a respirometer work?
measures amount of gas exchange taking place between organism and the air in a test tube
the test tube is connected to a manometer (a U-shaped tube that contains a coloured liquid)
if the organism takes in more gas then it gives out (more O2 in), the amount of air in the test tube decreases, therefore there will be less pressure on the coloured liquid in the manometer, therefore the coloured liquid will move towards the test tube
if the organism gives out more air than it takes in (more CO2 out), the amount of air in the test tube increases, therefore there will be more pressure on the coloured liquid in the manometer, therefore the coloured liquid will move away from the test tube
the amount/volume by which the coloured liquid moves represents the volume of gas taken in or given out
why does converting pyruvate to lactate allow the continued production of ATP by anaerobic respiration?
- produces NAD
- NAD used in glycolysis
Glycolysis process using fats?
- hydrolysed to glycerol + fatty acid
- glycerol is phosphorylated
- converted into TP
- TP converted to pyruvate
- then enters the link reaction and then Krebs
- fatty acids converted to 2C fragments then to acetyl coenzyme A
- this then also joins the Krebs cycle
glycolysis process using carbohydrates?
- glucose is phosphorylated (phosphate is added)
- this lowers the activation energy of glucose
- glucose converted into TP
- hydrogen removed from each TP
- hydrogen transferred to NAD
- reduced NAD is formed
- TP converted into pyruvate
- ATP is produced
