Ua tiav oxidation ntawm qabzib. Glucose oxidation cov tshuaj tiv thaiv

2024 Tus sau: Angel Austin | [email protected]. Kawg hloov kho: 2023-12-17 05:28

Nyob hauv kab lus no, peb yuav saib seb cov piam thaj li cas oxidized. Carbohydrates yog cov tebchaw ntawm polyhydroxycarbonyl hom, nrog rau lawv cov derivatives. Cov yam ntxwv yam ntxwv yog muaj cov aldehyde lossis ketone pawg thiab tsawg kawg yog ob pawg hydroxyl.

Raws li lawv cov qauv, carbohydrates tau muab faib ua monosaccharides, polysaccharides, oligosaccharides.

Monosaccharides

Monosaccharides yog cov carbohydrates yooj yim tshaj plaws uas tsis tuaj yeem hydrolyzed. Nyob ntawm seb pawg twg muaj nyob rau hauv cov muaj pes tsawg leeg - aldehyde lossis ketone, aldoses raug cais tawm (cov no suav nrog galactose, qabzib, ribose) thiab ketoses (ribulose, fructose).

Oligosaccharides

Oligosaccharides yog carbohydrates uas muaj nyob rau hauv lawv cov muaj pes tsawg leeg los ntawm ob mus rau kaum seem ntawm monosaccharide keeb kwm, txuas nrog glycosidic bonds. Raws li tus naj npawb ntawm monosaccharide residues, disaccharides, trisaccharides, thiab lwm yam yog txawv. Dab tsi yog tsim thaum qabzib oxidized? Qhov no yuav tham tom qab.

YPolysaccharides

YPolysaccharidesyog carbohydrates uas muaj ntau tshaj kaum monosaccharide residues interconnected los ntawm glycosidic bonds. Yog hais tias muaj pes tsawg leeg ntawm polysaccharide muaj tib cov monosaccharide residues, ces nws yog hu ua homopolysaccharide (piv txwv li, hmoov txhuv nplej siab). Yog tias cov residue sib txawv, ces nrog heteropolysaccharide (piv txwv li, heparin).

Dab tsi yog qhov tseem ceeb ntawm cov piam thaj oxidation?

Kev ua haujlwm ntawm carbohydrates hauv tib neeg lub cev

Carbohydrates ua cov haujlwm tseem ceeb hauv qab no:

1. Zog. Cov haujlwm tseem ceeb tshaj plaws ntawm carbohydrates, vim lawv ua haujlwm tseem ceeb ntawm lub zog hauv lub cev. Raws li qhov tshwm sim ntawm lawv cov oxidation, ntau tshaj ib nrab ntawm lub zog xav tau ntawm ib tug neeg txaus siab. Raws li qhov tshwm sim ntawm oxidation ntawm ib gram ntawm carbohydrates, 16.9 kJ raug tso tawm.
2. Reserve. Glycogen thiab hmoov txhuv nplej siab yog ib daim ntawv ntawm kev khaws cia.
3. Structural. Cellulose thiab qee qhov sib txuas ntawm polysaccharide ua lub hauv paus muaj zog hauv cov nroj tsuag. Tsis tas li ntawd, lawv, ua ke nrog lipids thiab proteins, yog ib feem ntawm tag nrho cov cell biomembranes.
4. Tiv thaiv. Acid heteropolysaccharides ua lub luag haujlwm ntawm cov roj ntsha roj ntsha. Lawv txoj kab ntawm cov pob qij txha uas kov thiab rub tawm ib leeg, cov mucous ntawm lub qhov ntswg, lub plab zom mov.
5. Anticoagulant. Ib qho carbohydrate xws li heparin muaj cov khoom tseem ceeb lom neeg, uas yog, nws tiv thaiv cov ntshav txhaws.
6. Carbohydrates yog ib qhov chaw ntawm carbon tsim nyog rau synthesis ntawm proteins, lipids thiab nucleic acids.

Rau lub cev, lub hauv paus tseem ceeb ntawm cov carbohydrates yog cov zaub mov carbohydrates - sucrose, starch, qabzib, lactose). Glucose tuaj yeem ua ke hauv lub cev nws tus kheej los ntawm cov amino acids, glycerol, lactate thiab pyruvate (gluconeogenesis).

YGlycolysis

Glycolysis yog ib qho ntawm peb hom ua tau ntawm cov txheej txheem oxidation qabzib. Hauv cov txheej txheem no, lub zog raug tso tawm, uas tom qab ntawd khaws cia hauv ATP thiab NADH. Ib qho ntawm nws cov molecules tawg ua ob lub molecules ntawm pyruvate.

Cov txheej txheem ntawm glycolysis tshwm sim nyob rau hauv kev ua ntawm ntau yam enzymatic tshuaj, uas yog, catalysts ntawm ib tug kab mob lom. Qhov tseem ceeb tshaj plaws oxidizing tus neeg sawv cev yog cov pa oxygen, tab sis nws tsim nyog sau cia tias cov txheej txheem ntawm glycolysis tuaj yeem ua tiav thaum tsis muaj oxygen. Hom glycolysis no hu ua anaerobic.

Anaerobic hom glycolysis yog txheej txheem qib ntawm cov piam thaj oxidation. Nrog rau qhov no glycolysis, qabzib oxidation tsis tshwm sim tag nrho. Yog li, thaum lub sij hawm oxidation ntawm qabzib, tsuas yog ib tug molecule ntawm pyruvate yog tsim. Hais txog cov txiaj ntsig ntawm lub zog, anaerobic glycolysis tsis muaj txiaj ntsig zoo dua li aerobic. Txawm li cas los xij, yog tias oxygen nkag mus rau hauv lub cell, ces anaerobic glycolysis tuaj yeem hloov mus rau hauv aerobic, uas yog qhov ua tiav oxidation ntawm qabzib.

Y

Mechanism ntawm glycolysis

Glycolysis zom rau 6-carbon qabzib rau hauv ob lub molecules ntawm peb-carbon pyruvate. Tag nrho cov txheej txheem tau muab faib ua tsib theem kev npaj thiab tsib ntxiv, thaum lub sijhawm ATP khaws ciazog.

Yog li, glycolysis tshwm sim hauv ob theem, txhua qhov muab faib ua tsib theem.

theem 1 ntawm cov piam thaj oxidation cov tshuaj tiv thaiv

• thawj theem. Thawj kauj ruam yog glucose phosphorylation. Saccharide activation tshwm sim los ntawm phosphorylation ntawm lub thib rau carbon atom.
• theem thib ob. Muaj cov txheej txheem ntawm isomerization ntawm qabzib-6-phosphate. Nyob rau theem no, cov piam thaj hloov mus rau fructose-6-phosphate los ntawm catalytic phosphoglucoisomerase.
• thib peb. Phosphorylation ntawm fructose-6-phosphate. Nyob rau theem no, kev tsim ntawm fructose-1,6-diphosphate (tseem hu ua aldolase) tshwm sim nyob rau hauv kev cuam tshuam ntawm phosphofructokinase-1. Nws koom nrog nrog rau pawg phosphoryl los ntawm adenosine triphosphoric acid mus rau fructose molecule.
• theem plaub. Nyob rau theem no, cleavage ntawm aldolase tshwm sim. Yog li ntawd, ob lub triose phosphate molecules yog tsim, tshwj xeeb tshaj yog ketoses thiab eldoses.
• theem tsib. Isomerization ntawm triose phosphates. Nyob rau theem no, glyceraldehyde-3-phosphate raug xa mus rau theem tom ntej ntawm kev puas tsuaj ntawm cov piam thaj. Hauv qhov no, kev hloov pauv ntawm dihydroxyacetone phosphate mus rau hauv daim ntawv ntawm glyceraldehyde-3-phosphate tshwm sim. Qhov kev hloov pauv no yog ua raws li kev ua ntawm enzymes.
• The sixth stage. Cov txheej txheem ntawm oxidation ntawm glyceraldehyde-3-phosphate. Nyob rau theem no, cov molecule yog oxidized thiab ces phosphorylated rau diphosphoglycerate-1, 3.
• 7th theem. Cov kauj ruam no suav nrog kev hloov pauv ntawm pawg phosphate los ntawm 1,3-diphosphoglycerate rau ADP. Qhov kawg tshwm sim ntawm cov kauj ruam no yog 3-phosphoglyceratethiab ATP.

theem 2 - ua tiav oxidation ntawm qabzib

• the yim yim. Nyob rau theem no, kev hloov pauv ntawm 3-phosphoglycerate mus rau 2-phosphoglycerate yog nqa tawm. Txoj kev hloov pauv yog ua raws li kev ua ntawm ib qho enzyme xws li phosphoglycerate mutase. Cov tshuaj tiv thaiv ntawm cov piam thaj oxidation ua haujlwm nrog rau qhov yuav tsum muaj ntawm magnesium (Mg).
• cuaj theem. Nyob rau theem no, lub cev qhuav dej ntawm 2-phosphoglycerate tshwm sim.
• theem kaum. Muaj kev hloov pauv ntawm phosphates tau los ntawm cov kauj ruam dhau los rau hauv PEP thiab ADP. Phosphoenulpyrovate hloov mus rau ADP. Cov tshuaj tiv thaiv zoo li no tuaj yeem ua rau muaj magnesium (Mg) thiab potassium (K) ions.

Raws li kev mob aerobic, tag nrho cov txheej txheem los rau CO₂ and H₂O. Qhov sib npaug rau cov piam thaj oxidation zoo li no:

S₆N₁₂O₆+ 6O₂ → 6CO₂+ 6H₂O + 2880 kJ/mol.

Yog li, tsis muaj NADH nyob rau hauv lub cell thaum tsim lactate los ntawm qabzib. Qhov no txhais tau hais tias cov txheej txheem zoo li no yog anaerobic, thiab nws tuaj yeem ua tiav thaum tsis muaj oxygen. Nws yog cov pa oxygen uas yog tus txais hluav taws xob zaum kawg uas tau xa los ntawm NADH mus rau txoj hlab pa.

Nyob rau hauv tus txheej txheem ntawm kev xam lub zog tshuav ntawm cov tshuaj tiv thaiv glycolytic, nws yuav tsum raug coj mus rau hauv tus account tias txhua kauj ruam ntawm theem thib ob rov ua dua ob zaug. Los ntawm qhov no peb tuaj yeem xaus tias ob lub ATP molecules tau siv nyob rau hauv thawj theem, thiab 4 ATP molecules yog tsim nyob rau theem thib ob los ntawm phosphorylation.hom substrate. Qhov no txhais tau hais tias los ntawm oxidation ntawm txhua cov piam thaj molecule, lub cell accumulates ob ATP molecules.

Peb saib oxidation ntawm qabzib los ntawm oxygen.

Anaerobic qabzib oxidation txoj kev

Aerobic oxidation yog cov txheej txheem oxidation uas lub zog tawm thiab ua rau muaj cov pa oxygen, uas ua raws li qhov kawg lees txais ntawm hydrogen hauv cov kab ua pa. Tus pub ntawm hydrogen molecules yog qhov txo qis ntawm coenzymes (FADH2, NADH, NADPH), uas yog tsim thaum lub sij hawm nruab nrab cov tshuaj tiv thaiv ntawm substrate oxidation.

Cov txheej txheem aerobic dichotomous hom qabzib oxidation yog txoj hauv kev tseem ceeb ntawm cov piam thaj catabolism hauv tib neeg lub cev. Hom glycolysis no tuaj yeem nqa tawm hauv txhua cov ntaub so ntswg thiab cov kabmob ntawm tib neeg lub cev. Qhov tshwm sim ntawm cov tshuaj tiv thaiv no yog kev sib cais ntawm cov piam thaj molecule rau hauv dej thiab carbon dioxide. Tom qab ntawd lub zog tso tawm yuav muab cia rau hauv ATP. Cov txheej txheem no tuaj yeem muab faib ua peb theem:

1. Tus txheej txheem ntawm hloov cov piam thaj molecule rau hauv ib khub pyruvic acid molecules. Cov tshuaj tiv thaiv tshwm sim hauv cov cell cytoplasm thiab yog ib txoj hauv kev tshwj xeeb rau kev ua kom qabzib.
2. Cov txheej txheem ntawm kev tsim ntawm acetyl-CoA los ntawm oxidative decarboxylation ntawm pyruvic acid. Cov tshuaj tiv thaiv no tshwm sim hauv cellular mitochondria.
3. Cov txheej txheem ntawm oxidation ntawm acetyl-CoA nyob rau hauv lub voj voog Krebs. Cov tshuaj tiv thaiv tshwm sim hauv cellular mitochondria.

Nyob rau txhua theem ntawm cov txheej txheem no,txo cov ntaub ntawv ntawm coenzymes oxidized los ntawm enzyme complexes ntawm cov kab mob ua pa. Yog li ntawd, ATP yog tsim thaum qabzib yog oxidized.

Y

Kev tsim cov coenzymes

Coenzymes, uas tau tsim nyob rau theem thib ob thiab thib peb ntawm aerobic glycolysis, yuav raug oxidized ncaj qha rau hauv mitochondria ntawm cov hlwb. Ua ke nrog qhov no, NADH, uas tau tsim nyob rau hauv lub cell cytoplasm thaum lub sij hawm cov tshuaj tiv thaiv ntawm thawj theem ntawm aerobic glycolysis, tsis muaj peev xwm nkag mus rau hauv lub mitochondrial daim nyias nyias. Hydrogen yog kis los ntawm cytoplasmic NADH mus rau cellular mitochondria ntawm shuttle cycles. Ntawm cov voj voog no, qhov tseem ceeb tuaj yeem paub qhov txawv - malate-aspartate.

Tom qab ntawd, nrog kev pab ntawm cytoplasmic NADH, oxaloacetate txo qis rau malate, uas, dhau los, nkag mus rau hauv cellular mitochondria thiab tom qab ntawd oxidized kom txo mitochondrial NAD. Oxaloacetate rov qab mus rau lub cell cytoplasm li aspartate.

Hloov cov ntawv ntawm glycolysis

Glycolysis kuj tseem tuaj yeem nrog kev tso tawm ntawm 1, 3 thiab 2, 3-biphosphoglycerates. Nyob rau tib lub sijhawm, 2,3-biphosphoglycerate nyob rau hauv kev cuam tshuam ntawm cov khoom siv roj ntsha tuaj yeem rov qab mus rau cov txheej txheem glycolysis, thiab tom qab ntawd hloov nws daim ntawv mus rau 3-phosphoglycerate. Cov enzymes no ua haujlwm ntau yam. Piv txwv li, 2, 3-biphosphoglycerate, pom nyob rau hauv hemoglobin, txhawb kev hloov cov pa oxygen mus rau cov ntaub so ntswg, thaum pab txhawb kev sib cais thiab txo qis hauv kev sib raug zoo ntawm cov pa oxygen thiab cov qe ntshav liab.

Zoo kawg

Ntau tus kab mob tuaj yeem hloov daim ntawv glycolysis ntawm nws ntau theem. Hauv qhov no, nws muaj peev xwm txo tau lawv tus lej tag nrho lossis hloov kho cov theem no raws li qhov tshwm sim ntawm ntau yam enzymatic tebchaw. Qee cov anaerobes muaj peev xwm decompose carbohydrates nyob rau hauv lwm txoj kev. Feem ntau cov thermophiles tsuas muaj ob lub glycolytic enzymes, tshwj xeeb tshaj yog enolase thiab pyruvate kinase.

Peb saib seb cov piam thaj li cas hauv lub cev oxidized.