A2 Biology - Respiration
- Created by: dom
- Created on: 05-01-15 12:00
2 DIFFERENT FORMS OF RESPIRATION
AEROBIC RESPIRATION - REQUIRES O2 AND PRODUCES CO2, WATER AND LOTS OF ATP.
ANAEROBIC RESPIRATION - TAKES PLACE IN ABSENCE OF O2, PRODUCES LACTATE IN ANIMALS OR ETHANOL AND CO2 IN PLANTS - BUT ONLY A SMALL AMOUNT OF ATP
4 STAGES OF RESPIRATION
- GLYCOLYSIS - SPLITTING OF GLUCOSE IN TO TWO 3 CARBON PYRUVATES
- LINK REACTION - COVERSION OF PYRUVATE TO ACETYL COENZYME A
- KREBS CYCLE - INTRO OF ACETYL COENZYME A INTO A CYCLE OF REDOX REACTIONS
- ETC - THE USE OF THE ELECTRONS PRODUCED IN KREBS TO SYNTHESISE ATP WITH WATER
GLYCOLYSIS
INITIAL STAGE IN BOTH AEROBIC AND ANAEROBIC RESPIRATION
OCCURS IN CYTOPLASM OF CELLS
- ACTIVATION OF GLUCOSE BY PHOSPHORYLATION - glucose is unreactive, 2 phosphates must be added - from the hydrolysis of ATP TO ADP to make it more reactive
- SPLITTING OF THE PHOSPHORYLATED GLUCOSE - glucose is split into two 3 carbon molecules known as TP
- OXIDATION OF TP - hydrogen is removed from each TP molecule and transferred to NAD to make NADH.
- PRODUCTION OF ATP - anzyme controlled reactions convert each TP into PYRUVATE - in this process 2 molecules of ATP ARE REGENERATED FROM ADP
ENERGY YIELD FROM GLYCOLYSIS
- 2 MOLECULES OF ATP
- 2 MOLECULES OF NADH
- 2 MOLECULES OF PYRUVATE
LINK REACTION
TAKES PLACE IN MITOCHONDRIA
- PYRUVATES ARE ACTIVLEY TRANSPORTED FROM CYTOPLASM TO MATRIX OF MITOCHONDRIA
- HERE PYRUVATE IS OXIDISED BY REMOVING HYDROGEN
- HYDROGEN IS ACCEPTED BY NAD TO MAKE NADH
- AN ACETYL GROUP IS FORMED
- THE ACETYL GROUP COMBINES WITH COENZYME A TO PRODUCE ACETLY COENZYME A
- CO2 IS PRODUCED FROM EACH PYRUVATE
EQUATION
PYRUVATE + NAD + COA = ACETYL COA + NADH + CO2
KREBS CYCLE
INVOLVES A SERIES OF OXIDATIONA ND REDUCTION REACTIONS
TAKES PLACE IN MATRIX OF THE MITOCHONDRIA
- 2 CARBON ACETYL COENZYME A COMBINES WITH A 4 CARBON COMPOUND (CITRIC ACID) TO MAKE A 6 CARBON COMPOUND
- 6 CARBON MOLECULE LOSES CO2 AND HYDROGEN TO GIVE A 4 CARBON MOLECULE AND ATP IS PRODUCE AS A RESULT OF SUBSTRATE LEVEL PHOSPHORYLATION
- COENZYMES NAD AND FAD COMBINE WITH HYDROGEN TO REDUCE THEM
- THE 4 CARBON COMPUND IS REUSUED IN CYCLE
ENERGY YIELD
- 2 ATP
- 6 NADH
- 2 FADH
IMPORTANCE OF KREBS CYCLE
- BREAKS DOWN MACROMOLECULES INTO SMALLER ONES E.G. PYRUVATE TO CO2
- PRODUCES HYDROGEN ATOMS - CARRIED BY COENZYMES NAD OR FAD TO ETC - LEADS TO PRODUCTION OF ATP
- REGENERATES 4 CARBON COMPOUNT - CITRIC ACID
ELECTRON TRANSPORT CHAIN
MITOCHONDIRA SITE OF ETC
ATTATCHED TO THE CRISTAE - INNER FOLDING MEMBRANE - ARE ENZYMES AND OTHER PROTEINS INVOLVED IN ETC
- NADH AND FADH BRING HYDROGEN ATOMS TO ETC - THEY SPLIT INTO PROTONS AND ELECTRONS
- NADH AND FADH DONATE ELECTRONS OF THE HYDROGEN ATOMS TO FIRST MOLECULE OF ETC
- THIS RELEASES THE PROTONS FROM THE HYROGEN - THEY ARE ACTIVELY TRANSPORTED ACROSS INNER MITOCHONDRIAL MEMEBRANE INTO INTERMEMBRANE SPACE
- THE ELECTRONS MEANWHILE PASS ALONG ETC - SERIES OF REDOX REACIONS - ENERGY LOST IS USED TO FORM ATP FROM ADP
- THE PROTONS THEN DIFFUSE BACK INTO THE MITOCHONDRIAL MATRIX THROUGH PROTEIN CHANNELS CALLED ATP SYNTHASE - CONCENTRATON GRADIENT - CHEMIOSOMOSIS
- THEY JOIN UP WITH THE ELECTRONS AND OXYGEN TO FORM WATER
- OXYGEN IS THE FINAL ELECTRON ACCEPTOR
Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration or photosynthesis
ANAEROBIC RESPIRATION
ONLY GLYCOLYISIS CAN OCCUR IN ABSENCE OF OXYGEN
IN PLANTS - PYRUVATE IS CONVERTED TO ETHANOL AND YEAST
IN ANIMALS - PYRUVATE IS CONVERTED TO LACTIC ACID
ANAEROBIC RESPIRATION - PLANTS
PYRUVATE + REDUCED NAD = ETHANOL + CO2 + NAD
ANAEROBIC RESPIRATION - ANIMALS
PYRUVATE + REDCUED NAD = LACTATE + NAD
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