respiration a level biology sutton girls grammar school

RespirationRespirationA level Biology

Sutton Girls Grammar school

RespirationRespirationWhen oxygen is available, aerobic respiration can take placeAerobic respiration has 4 stages:

•Glycolysis•The link reaction•The Krebs’ cycle•Oxidative phosphorylation

When there is no oxygen available, anaerobic respiration takes place

GlycolysisGlycolysis GlucoseGlucose

Glucose is the substrate

GlycolysisGlycolysis GlucoseGlucoseATP

Glucose is phosphorylated


Glucose 6 PGlucose 6 PForming G6P


Glucose 6 PGlucose 6 PATP

G6P is phosphorylated



Fructose 1,6 PFructose 1,6 P

Forming F1,6P




3-C sugar3-C sugar 3-C sugar3-C sugar

F1,6P splits to form two 3 carbon sugars





PyruvatePyruvate PyruvatePyruvate

These are converted to pyruvate






2ATP 2ATP

Giving out 2 ATP…






2ATP 2ATP

2H 2H

… and 2H+ each






2ATP 2ATP

2H 2H

Net yield then is:2ATP2x (2H+)

Glycolysis occurs in the cytoplasm.

The link reactionThe link reactionPyruvate is converted to acetyl coenzyme A

PyruvatePyruvate

Acetyl coenzyme AAcetyl coenzyme A

The link reactionThe link reactionGiving out 2H+ …

PyruvatePyruvate


2H

The link reactionThe link reaction… and CO2

PyruvatePyruvate


2H CO2

The link reactionThe link reactionThis occurs inside the mitochondria.

PyruvatePyruvate


2H CO2

The link reactionThe link reactionNet yield then is:

2x 2H+

2 CO2 PyruvatePyruvate


2H CO2

The Krebs’ cycleThe Krebs’ cycleIn the matrix of the mitochondrion:


The Krebs’ cycleThe Krebs’ cycleAcetyl CoA combines with a 4C acid…


Four carbon acidFour carbon acid

The Krebs’ cycleThe Krebs’ cycle… forming the 6 carbon compound citrate:


Citrate (6C)Citrate (6C)Four carbon acidFour carbon acid

The Krebs’ cycleThe Krebs’ cycleThe citrate is decarboxylated to a 5C acid:



Five carbon acidFive carbon acid

The Krebs’ cycleThe Krebs’ cycle… releasing CO2…


CO2



The Krebs’ cycleThe Krebs’ cycle… and 2H+


2H

CO2



The Krebs’ cycleThe Krebs’ cycleThe 5C acid is decarboxylated - reforming the 4C acid:


2H

CO2



The Krebs’ cycleThe Krebs’ cycleReleasing another CO2


2H

CO2


Five carbon acidFive carbon acidCO2

The Krebs’ cycleThe Krebs’ cycle… three 2H+


2H

CO2



2H

2H2H

The Krebs’ cycleThe Krebs’ cycle… and an ATP


2H

CO2



2H

2H2H

ATP

The Krebs’ cycleThe Krebs’ cycle Net yield:

2ATP4CO2

8x 2H+Acetyl coenzyme AAcetyl coenzyme A

2H

CO2



2H

2H2H

ATP

Oxidative phosphorylationOxidative phosphorylation

The 2H+ reduces NAD to NADH+ + H+

2H

NADNAD

FADFAD

carriercarrier

carriercarrier


The 2H+ reduces NAD to NADH+ + H+

2H

NADHNADHHH

FADFAD

carriercarrier

carriercarrier


FAD is then reduced…

2H

NADNAD

FADHFADHHH

carriercarrier

carriercarrier


… generating ATP

2H

ATP

NADNAD

FADHFADHHH

carriercarrier

carriercarrier


Two more carriers are reduced…

2H

ATP

NADNAD

FADFAD

carriercarrier

carriercarrier


… generating more ATP.

2H

ATP

NADNAD

FADFAD

carriercarrier

carriercarrier

ATP

ATP


The 2H+ is then passed onto O2

2H

2H

O2

ATP

NADNAD

FADFAD

carriercarrier

carriercarrier

ATP

ATP


Which forms water.

2H

H2O

2H

O2

ATP

NADNAD

FADFAD

carriercarrier

carriercarrier

ATP

ATP

Oxidative phosphorylationOxidative phosphorylationThis occurs across the inner membrane of the mitochondria – ATP synthesised using the stalked particles.

2H

H2O

2H

O2

ATP

NADNAD

FADFAD

carriercarrier

carriercarrier

ATP

ATP


Some of the 2H+ reduces FAD

2H

H2O

2H

O2

NADNAD

FADFAD

carriercarrier

carriercarrier


So only produces 2ATP.

2H

H2O

2H

O2

NADNAD

FADFAD

carriercarrier

carriercarrier

ATP

ATP

SummarySummaryGlycolysis

6 H2O

2(2H+)

6 O2

2 ATPGlucoseGlucose

Link reaction

Krebs’ cycle

2 CO2

4 CO2

2(2H+)

2(2H+)

2 ATP

4 ATP

6 ATP

4 ATP

18 ATP6(2H+)

Anaerobic respirationAnaerobic respirationIn the absence of oxygen anaerobic respiration takes place

GlucoseGlucose

Anaerobic respirationAnaerobic respirationGlucose is phosphorylated to two 3-C sugars

2ATP


GlucoseGlucose

Anaerobic respirationAnaerobic respirationThese are then converted to pyruvate, generating ATP & 2H+

2(2H+)

2 ATP


2ATP

3-C sugar3-C sugar 3-C sugar3-C sugar2 ATP

2(2H+)

GlucoseGlucose

Anaerobic respirationAnaerobic respirationIn yeast the pyruvate is decarboxylated to ethanal:

2(2H+)

2 ATP

CO2


2ATP


CO2

2 ATP

2(2H+)

GlucoseGlucose

EthanalEthanal EthanalEthanal

Anaerobic respirationAnaerobic respiration… and then converted to ethanol – using the 2H+ from the previous stage.

2(2H+)

2 ATP

CO2


2ATP


CO2

2 ATP

2(2H+)

EthanolEthanol EthanolEthanol

GlucoseGlucose


Anaerobic respirationAnaerobic respirationNet production is:2ATP 2CO2 2 ethanol

2(2H+)

2 ATP

CO2


2ATP


CO2

2 ATP

2(2H+)

EthanolEthanol EthanolEthanol

GlucoseGlucose


Anaerobic respirationAnaerobic respirationIn animals, the pyruvate is converted to lactate:

2(2H+)

2 ATP


2ATP


2(2H+)

LactateLactate LactateLactate

GlucoseGlucose

Anaerobic respirationAnaerobic respiration… using the 2H+ again:

2(2H+)

2 ATP


2ATP


2(2H+)


GlucoseGlucose

Anaerobic respirationAnaerobic respirationNet production is:2ATP2 lactate

2(2H+)

2 ATP


2ATP


2(2H+)


GlucoseGlucose

respiration a level biology sutton girls grammar school

Documents