Fig. 8-CO, p. 171
Fig. 8-CO, p. 171
Eiwitten aminozuren CO2
Vetten glycerol, vetzuren ATPpolysacchariden monosacchariden H2O
Hoofdstuk Hoofdstuk IVIVDe Cellulaire RespiratieDe Cellulaire Respiratie
De synthese van ATP door afbraak van moleculenDe synthese van ATP door afbraak van moleculen
Aerobe respiratie: afbraak voedingsmoleculen tot COAerobe respiratie: afbraak voedingsmoleculen tot CO22 en en HH22O met produktie van ATP en O met produktie van ATP en met verbruik van met verbruik van zuurstofzuurstof (sommige prokaryoten, protisten, eukaryoten).(sommige prokaryoten, protisten, eukaryoten).
Anaerobe respiratie: idem maar Anaerobe respiratie: idem maar in afwezigheid van in afwezigheid van zuurstofzuurstof (sommige prokaryoten).(sommige prokaryoten).
Fermentatie: afbraak voedingsmoleculen Fermentatie: afbraak voedingsmoleculen zonder zonder elektronentransportketenelektronentransportketen met produktie van ATPmet produktie van ATP(sommige prokaryoten en fungi). (sommige prokaryoten en fungi).
p. 172
De aerobe respiratie
Glucose + 6 HGlucose + 6 H22O + 6 OO + 6 O22 →→→→→→→→ 6 CO6 CO22 + 12 H+ 12 H22O + O + EnergieEnergie
Fig. 8-1, p. 172
Vier stappen Vier stappen in de in de aaëërobe respiratierobe respiratie
1.1. GlycolyseGlycolyse: Glucose : Glucose →→→→→→→→ pyruvaat pyruvaat (ATP, NADH)(ATP, NADH)2.2. Vorming Vorming vanvan acetyl acetyl CoACoA + CO+ CO2 2 (NADH)(NADH)3.3. CitroenzuurcyclusCitroenzuurcyclus: CO: CO22, ATP, NADH en FADH, ATP, NADH en FADH22
4.4. ElektronentransportElektronentransport : NADH en FADH: NADH en FADH22 →→→→→→→→ ATPATP
Fig. 8-4a, p. 176
Energy investment phase and splitting of glucose
Two ATPs invested per glucose
GlucoseGlycolysis begins with preparation reaction in which glucose receives phosphate group from ATP molecule. ATP serves as source of both phosphate and energy needed to attach phosphate to glucose molecule. (Once ATP is spent, it becomes ADP and joins ADPpool of cell until turned into ATP again.) Phosphorylated glucose is known as glucose-6-phosphate. (Note phosphate attached to its carbon atom 6.) Phosphorylation of glucose makes it more chemically reactive.
ATP
ADP
Glucose-6-phosphate
Hexokinase
Phosphoglucoisomerase
1
Fig. 8-4a, p. 176
Glucose-6-phosphate undergoes another preparation reaction, rearrangement of its hydrogen and oxygen atoms. In this reaction glucose-6-phosphate is converted to its isomer, fructose-6-phosphate.
Next, another ATP donates phosphate to molecule, forming fructose-1,6-bisphosphate. So far, two ATP molecules have been invested in process without any being produced. Phosphate groups are now bound at carbons 1 and 6, and molecule is ready to be split.
Fructose-1,6-bisphosphate is then split into two 3-carbon sugars, glyceraldehyde-3- phosphate (G3P) and dihydroxyacetone phosphate.
Dihydroxyacetone phosphate is enzymatically converted to its isomer, glyceraldehyde-3-phosphate, for further metabolism in glycolysis.
Fructose-6-phosphate
PhosphofructokinaseATP
ADP
Fructose-1,6-bisphosphate
Aldolase
Isomerase
Dihydroxyacetonephosphate
Glyceraldehyde-3-phosphate (G3P)
2
3
4
5
Glucose + 2 ATP 2 glyceraldehyde 3-fosfaat + 2 ADP
Fig. 8-4b, p. 177
Energy capture phaseFour ATPs and two NADH produced per
glucose
Two glyceraldehyde-3-phosphate (G3P)from bottom of previous page
2 NAD+
2 NADH
Glyceraldehyde-3-phosphate dehydrogenase
Phosphoglycerokinase
Two 1,3-bisphosphoglycerate
2 ADP
2 ATP
Each glyceraldehyde-3-phosphate undergoes dehydrogenationwith NAD+ as hydrogen acceptor. Productof this very exergonic reaction is phosphoglycerate,which reacts with inorganic phosphate present incytosol to yield 1,3-bisphosphoglycerate.
One of phosphates of 1,3-bisphosphoglycerate reactswith ADP to form ATP. This transfer of phosphate fromphosphorylated intermediate to ATP is referred to assubstrate-level phosphorylation.
Two 3-phosphoglycerate
Phosphoglyceromutase
6
7
Fig. 8-4b, p. 177
Two 2-phosphoglycerate
Enolase
Pyruvate kinase
Two pyruvate
2 H2O
Two phosphoenolpyruvate2 ADP
2 ATP
3-phosphoglycerate is rearranged to 2-phosphoglycerateby enzymatic shift of position of phosphate group.This is a preparation reaction.
Next, molecule of water is removed, which results information of double bond. The product, phosphoenolpyruvate (PEP), has phosphate group attached by an unstable bond (wavy line).
Each of two PEP molecules transfers its phosphate groupto ADP to yield ATP and pyruvate. This is substrate-levelphosphorylation reaction.
8
9
10
2 glyceraldehyde 3-fosfaat + 2 NAD+ + 4 ADP 2 pyruvaat + 2 NADH + 4 ATP
2 pyruvaat + 2 NAD+ + 2 CoA 2 acetyl CoA + 2 NADH + 2 CO2
Vitamine Vitamine B5B5
Per glucose Per glucose zijn er twee zijn er twee KrebsKrebs--cyclicycli nodignodig: : dit leidt dit leidt tot 4 COtot 4 CO22, 6 NADH, 2 FADH, 6 NADH, 2 FADH22 en 2 ATPen 2 ATP
Per glucosePer glucosebijbij acetylacetyl CoA vormingCoA vorming : 2 CO: 2 CO22 en 2 en 2 NADHNADH
Per Per glycolyseglycolyse((dusdus per glucose): 2 ATP en 2 NADHper glucose): 2 ATP en 2 NADH
Volledige cyclusVolledige cyclus, per glucose:, per glucose:
4 4 ATPATP’’ ss, 10 , 10 NADHNADH ’’ ss, 2 FADH, 2 FADH22’’ s en 6 COs en 6 CO22’’ ss
Oxidatieve fosforylatie
p. 182Symphocarpus foetidus
Chemische verbranding Chemische verbranding van glucose van glucose →→→→→→→→ 2870 2870 kJoulekJoule/mol/mol
VrijeVrije energieenergievan de van de fosfaatbindingfosfaatbinding in ATP in ATP →→→→→→→→ 31,8 31,8 kJoulekJoule/mol/mol
36 ATP 36 ATP →→→→→→→→ 1146 1146 kJoulekJoule/mol/mol
1146/2870 1146/2870 →→→→→→→→ 40% 40% rendement rendement (+(+warmtewarmte))
Deaminatie Deaminatie van van aminozurenaminozurenAlanineAlanine →→→→→→→→ pyruvaatpyruvaatGlutaminezuur Glutaminezuur →→→→→→→→ αααααααα--ketoglutaarzuurketoglutaarzuurAsparaginezuur Asparaginezuur →→→→→→→→ oxaloacetaatoxaloacetaat
Ook regulatie Ook regulatie van:van:
HexokinaseHexokinase: : inhibitie inhibitie door glucosedoor glucose--6 6 fosfaatfosfaat
Pyruvaat kinasePyruvaat kinase: : inhibitie inhibitie door ATPdoor ATP
Pyruvaat dehydrogenasePyruvaat dehydrogenase
Drie enzymen Drie enzymen van de van de citroenzuurcitroenzuur--cycluscyclus
ADPADP
AnaAnaëërobe respiratie robe respiratie en en fermentatiefermentatie
AnaAnaëërobe respiratierobe respiratie: : alternatieve elektronenacceptorenalternatieve elektronenacceptorenSOSO44
22--, NO, NO33--, Fe, Fe3+3+, CO, CO22 →→→→→→→→ HH22S, NOS, NO22
--, N, N22, Fe, Fe2+2+, CH, CH44
FermentatieFermentatie: : anaanaëëroob proces zonder elektronentransportroob proces zonder elektronentransportRegeneratieRegeneratievan NADvan NAD++ door door reductie reductie van van organische organische moleculenmoleculen
Red-eared Slider (Trachemys scripta elegans).
Credit: © Cleve Hickman Jr./Visuals Unlimited 304559