Module 5-Respiration Flashcards
(20 cards)
What is ATP used for? General/easy
-movement e.g muscle contraction
-active transport
-endocytosis
-exocytosis
-synthesis of bio molecules
-maintenance of body temp
-dna replication
-cell division
What is the first stag of both aerobic and anaerobic respiration?
Glycolysis
Name the 4 stages of aerobic respiration and where about they take place in the cell?
-glycolysis-cytoplasm
-link reaction-mitochondrial matrix
-krebs cycle-mitochondrial matrix
-oxidative phosphorylation-mitochondrial inner membrane cristae
Describe process of glycolysis
-phosphorylation of glucose to glucose phosphate using 1 molecule of ATP
-phosphorylation of glucose phosphate to hexose bisphosphate using 1 molecule of ATP
-hexose bisphosphate splits into 2 molecules of triose phosphate
-oxidation of triose phosphate produces 2 pyruvates
-net gain is 2 ATP and 2 NADH
Describe the link reaction
-pyruvate made in glycolysis diffuses from the cytoplasm across the mitochondrial membrane and into the matrix of the mitochondria where it is decarboxylated and dehydrogenated to acetate so NADH and CO2 is produced
-acetate then combines with coenzyme A to produce acetylcoenzyme A
-link reaction occurs twice for every glucose molecule as for 1 glucose molecule we have 2 pyruvates being made
-net gain-1 CO2 and 1 NADH
Describe the Krebs cycle
-acetylcoenzyme A reacts with a 4 carbon molecule (oxaloacetate)
-this forms a 6 carbon compound (citrate) which then leases coenzyme A which can be used again in the link reaction
-in a series of redox reactions reduced coenzymes and ATP are produced through substrate level phosphorylation and 2 carbons are released
-this happens twice per glucose molecule
Describe the process of oxidative phosphorylation
-most ATP is made during this stage
-hydrogen atoms have been collected by the coenzymes NAD and FAD are delivered to electron transport chains present in the cristae in the mitochondria membranes
-hydrogen atoms dissociate into H ions and electrons
-the high energy electrons are used in the synthesis of ATP by chemiosmosis
-energy is released during redox reactions as the electrons reduce and oxidise electron carriers as they flow along ETC
-this energy is used to create a proton gradient leading to diffusion of protons through ATP synthase resulting in synthesis of ATP from ADP and Pi
-at the end of ETC the electrons combine with hydrogen ions and oxygen to form water
-oxygen is the final electrons combine with acceptor and electron chain can’t operate unless oxygen is present
Does aerobic respiration fully break down glucose?
Yes
Define chemiosmosis
Movement of ions across a membrane down an electrochemical gradient
Why does fermentation produce less ATP than aerobic respiration?
-organic compounds aren’t fully broken down
Where does anaerobic respiration take place?
In the cytoplasm of the cell only
What are the 2 types of anaerobic respiration
-ethanol fermentation
-lactate fermentation
Describe ethanol fermentation
-only takes lace in plants and yeast
-decarboxylation of pyruvate (produced in glycolysis) by the enzyme pyruvate decarboxylase and converted to ethanal with CO2 as a by product
-ethanal is then reduced to form ethanol by gaining hydrogen from NADH
-this reaction is catalysed by ethanol dehydrogenase
-products-ethanol, oxidised NAD and CO2
-is not a reversible process
Describe the process of lactate fermentation
-takes place in animals and some bacteria
-is common in skeletal muscles when there’s an insufficient oxygen supply during exercise
-pyruvate (produced in glycolysis) gains hydrogen from NADH which is catalysed by lactate dehydrogenase to form lactate
-the oxidised NAD can be reused in glycolysis to ensure more ATP is still synthesised
-lactic acid is converted back to glucose in the liver but oxygen is need to complete this process hence the oxygen debt
-lactate fermentation can occur indefinitely due to the reduced quantity of ATP produced wouldn’t be enough to maintain vital processes for prolonged periods
-accumulation of lactic acids causes a fall in pH which causes proteins denaturing
Define respiratory substrates
-organic molecules that can be used in respiration to produce atp
Give examples of some respiratory substrates
-carbon atoms from lipids are detached to form acetylcoenzyme coenzyme A and are fed directly into the Krebs cycle
-proteins are hydrolysed into amino acids which are delaminated to remove nitrogen before being converted into pyruvate or acetylcoenzyme coenzyme A
How is respiratory quotient calculated?
Volume of CO2produced/oxygen consumed
What substrate has the highest and lowest energy value
Lipids has highest and carbs has lowest
How do you investigate respiration in yeast?
1)use the beaker to set up a water bath at 35degC
2)label 5 test tubes 1-5
3)shake the yeast and glucose mixture
4)add 2cm^3 of yeast and glucose mixture to each tube
5)place all 5 tubes in the water bath and leave them until the contents matches 35degC
6)add 2cm^3 of methylene blue to tube 1 and immediately shake this tube for 10 secs and place this tube back in the bath
7)start stopwatch and record how long it takes the blue colour to disappear
8)repeat this for the other 4 tubes
9)repeat the whole experiment in water baths at different temps 15degc, 25, 45, 55
Why is methylene blue used in the respiration experiment?
-the electrons that are transported down the ETC will be accepted by the methylene blue
-methylene blue is blue in the oxidised state and colourless in its reduced state
-as rate of respiration increases methylene blue will turn colourless more quickly
