Kev faib cov carbohydrate - Monosaccharides, Cov Khoom Siv Tsis Pub Khoom thiab Polysaccharides

Carbohydrates (qab zib, saccharides) - cov tshuaj organic uas muaj cov pab pawg carbonyl thiab ntau pawg hydroxyl. Lub npe ntawm cov chav kawm ntawm cov sib txuas los ntawm cov lus "carbon hydrates", nws tau xub thov los ntawm C. Schmidt hauv 1844. Cov tsos ntawm lub npe no yog vim qhov tseeb tias thawj ntawm cov carbohydrates paub hauv kev tshawb fawb tau piav qhia los ntawm cov khoom noj tag nrho C_x(H₂O)_ythawm xyoo raug sib txuas ntawm carbon thiab dej.

Cov carbohydrates yog qhov muaj txiaj ntsig ntawm lub hlwb thiab cov nqaij ntawm txhua yam muaj sia ntawm cov nroj tsuag thiab tsiaj hauv ntiaj teb, ua kom (los ntawm qhov hnyav) feem ntau ntawm cov organic hauv ntiaj teb. Qhov ntawm carbohydrates rau txhua qhov muaj sia nyob yog cov txheej txheem photosynthesis nqa los ntawm cov nroj tsuag.

Carbohydrates tau muab faib ua ke monosaccharides, oligosaccharides thiab polysaccharides.i

Monosaccharides (cov carbohydrates yooj yim) yog cov neeg sawv cev yooj yim tshaj plaws ntawm cov carbohydrates thiab tsis zom rau hauv cov khoom sib xyaws yooj yim thaum hydrolysis. Monosaccharides yog qhov ceev tshaj plaws thiab qhov zoo tshaj plaws ntawm lub zog rau cov txheej txheem tshwm sim hauv lub cell. Monosaccharides yog tam sim ntawd oxidized rau carbon dioxide thiab dej, thaum cov protein thiab cov rog tau oxidized rau cov khoom qub los ntawm cov txheej txheem ntawm cov kev sib xyaw theem nrab. Monosaccharides muaj lub qab qab thiab yog li lawv hu ua "suab thaj".

Oligosaccharides - ntau cov tebchaw tsim los ntawm ob peb (ntawm 2 txog 10) monosaccharide seem. Kev tsis ncaj ncees (oligosaccharides), zoo li monosaccharides, muaj lub qab qab thiab yog li lawv hu ua "suab thaj".

Polysaccharides - siab molecular phaus sib txuas - polymers tsim los ntawm cov coob ntawm monosaccharides. Lawv tau faib ua haujlwm zom tau (hmoov txhuv nplej siab, glycogen) thiab tsis zom mov (kev noj haus fiber ntau - fiber, hemicellulose, pectin tshuaj) nyob rau hauv lub plab zom mov. Polysaccharides tsis muaj qab zib rau.

Monosaccharides tau cais raws li ob yam ntxwv:
• qhov xwm ntawm cov pab pawg carbonyl,
• Cov saw carbon ntev.

Monosaccharides uas muaj cov aldehyde pawg hu ua aldoses, ketone pawg (feem ntau nyob hauv txoj hauj lwm 2) - hwj kais (ntawv kawg -ceev tus yam ntxwv rau lub npe ntawm txhua lub monosaccharides: qabzib, galactose, fructose). Cov qauv ntawm aldoses thiab ketosis feem ntau tuaj yeem sawv cev raws li hauv qab no.

Ua raws li qhov ntev ntawm cov pa roj carbon foob (3-10 atoms), monosaccharides tau muab faib ua trioses, tetrose, pentoses, hexoses, heptoses, etc. Pentoses thiab hexoses feem ntau muaj.

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Kev faib tawm

Tag nrho cov carbohydrates yog muaj li ntawm "units", uas yog saccharides. Raws li lawv lub peev xwm rau hydrolyze rau hauv monomers, carbohydrates tau muab faib ua ob pawg: yooj yim thiab ntau. Carbohydrates uas muaj ib chav hu ua monosaccharides, ob chav yog disaccharides, ob mus rau kaum chav yog oligosaccharides, thiab ntau tshaj kaum yog polysaccharides. Monosaccharides nce sai sai rau cov piam thaj hauv ntshav thiab muaj qhov siab glycemic siab, yog li lawv tseem hu ua sai carbohydrates. Lawv tau yooj yim soluble hauv dej thiab sib tov hauv cov nroj tsuag ntsuab. Carbohydrates muaj 3 lossis ntau dua ib pawg hu ua complex. Cov zaub mov muaj nplua nuj nyob hauv cov khoom noj carbohydrates maj mam nce qabzib thiab muaj glycemic qis, uas yog vim li cas lawv tseem hu ua kev ua kom muaj carbohydrates qeeb. Cov carbohydrates nyuaj yog cov khoom lag luam polycondensation ntawm cov suab thaj yooj yim (monosaccharides) thiab, tsis zoo li cov khoom yooj yim, tuaj yeem hloov mus rau hauv cov monomers thaum lub sijhawm ua kua dej tsis txaus los ua ntau pua thiab ntau txhiab tus monosaccharide lwg me me.

Lub ntsej muag lub nplhaib cov qauv

Thaum cov kua nplaum tsim cov nplhaib ua rau lub cim xeeb, muaj 50 feem pua ​​ntawm cov thawj cov pa roj carbon muaj hydroxyl pawg hauv qab dav hlau ntawm lub nplhaib.

Cov piam thaj suab thaj yuav muaj ob qhov chaw sib txawv ntawm cov pab pawg hydroxyl (-OH) nyob ib ncig ntawm cov pa roj carbon anomeric (carbon No. 1, uas ua rau cov txheej txheem asymmetric hauv cov txheej txheem ntawm lub nplhaib tsim, lub tso suab tso zis nruab nrab).

Yog tias pawg hydroxyl qis dua carbon 1 hauv cov piam thaj, tom qab ntawd lawv hais tias nws nyob hauv qhov chaw alpha (α) thiab yog tias nws yog tshaj lub dav hlau, lawv hais tias nws nyob hauv qhov chaw beta (β) .

Lwm lub tebchaw

Lwm lub monosaccharide tebchaw muaj nyob. Lawv tuaj yeem yog ntuj thiab semi-dag.

Galactose belongs rau ntuj. Nws kuj tseem pom hauv cov khoom noj, tab sis tsis tshwm sim hauv nws daim ntawv ntshiab. Galactose yog los ntawm hydrolysis ntawm lactose. Nws lub hauv paus tseem ceeb yog mis nyuj.

Lwm yam monosaccharides ntuj yog ribose, deoxyribose thiab mannose.

Tseem muaj ntau yam ntawm cov carbohydrates, rau qhov uas siv thev naus laus zis.

Cov tshuaj no kuj tseem muaj nyob hauv cov zaub mov thiab nkag mus rau hauv tib neeg lub cev:

Ib qho ntawm cov sib txuas sib txawv nws cov yam ntxwv thiab ua haujlwm.

Kev sib cais thiab kev siv

Hom tom ntej no ntawm cov nplawm carbohydrate yog kev cuam tshuam. Lawv suav hais tias yog cov tshuaj sib txawv. Raws li qhov tshwm sim ntawm hydrolysis, ob lub monosaccharide lwg me me tau tsim los ntawm lawv.

Hom carbohydrate no muaj cov yam ntxwv hauv qab no:

• hardness
• solubility hauv dej
• solubility tsis zoo nyob rau hauv cov cawv ntau,
• qab zib saj
• xim - los ntawm dawb mus rau xim av.

Lub zog tseem ceeb ntawm cov tshuaj tsis haum yog cov kua dej tsis haum (glycosidic bonds tau tawg thiab monosaccharides raug tsim) thiab hws (polysaccharides yog tsim).

Nws muaj 2 hom ntawm cov tebchaw:

1. Rov Kho DuaCov. Lawv qhov tshwj xeeb yog qhov muaj cov pub dawb semi-acetal hydroxyl pawg. Vim nws, xws li cov tshuaj muaj txo cov khoom. Pab pawg ntawm carbohydrates no suav nrog cellobiose, maltose thiab lactose.
2. Tsis khoCov. Cov tebchaw no tsis muaj qhov ua tau, vim tias lawv tsis muaj ib nrab-acetal hydroxyl pawg. Cov tshuaj uas nrov tshaj plaws ntawm hom no yog sucrose thiab trehalose.

Cov tebchaw no muaj thoob plaws qhov. Lawv tuaj yeem pom ob qho tib si hauv daim ntawv pub dawb thiab yog ib feem ntawm lwm cov tebchaw. Kev ua kom tsis haum yog lub hauv paus ntawm lub zog, txij li cov kua nplaum tsim los ntawm lawv thaum lub sij hawm hydrolysis.

Lactose yog qhov tseem ceeb heev rau menyuam yaus, vim nws yog qhov khoom tseem ceeb ntawm menyuam yaus cov khoom noj. Lwm txoj haujlwm ntawm cov carbohydrates ntawm hom no yog cov txheej txheem, txij li lawv yog ib feem ntawm cov cellulose, uas tsim nyog rau kev tsim cov nroj tsuag hlwb.

Cov yam ntxwv thiab cov yam ntxwv ntawm polysaccharides

Lwm hom carbohydrates yog polysaccharides. Nov yog hom kev sib txuas uas nyuaj tshaj plaws. Lawv muaj ntau ntawm cov monosaccharides (lawv lub ntsiab tseem ceeb yog cov piam thaj). Hauv txoj hnyuv plab, polysaccharides tsis yaim - lawv qhov kev tawm mus yog qhov coj los ua ntej.

Cov yam ntxwv ntawm cov tshuaj muaj raws li nram no:

• insolubility (lossis solubility tsis zoo) hauv dej,
• xim daj (lossis tsis muaj xim)
• lawv tsis muaj ntxhiab tsw
• yuav luag txhua tus ntawm lawv yog cov tsis qab (qee qhov muaj lub tsw qab).

Cov cuab yeej siv tshuaj lom neeg ntawm cov tshuaj muaj xws li hydrolysis, uas tau ua los ntawm kev cuam tshuam ntawm catalysts. Qhov tshwm sim ntawm kev tawm tsam yog qhov kev rhuav tshem ntawm qhov sib txuas rau hauv cov txheej txheem yam ntxwv - monosaccharides.

Lwm cov cuab yeej yog qhov tsim ntawm kev tsim khoom. Polysaccharides tuaj yeem siv nrog cov kua qaub.

Cov khoom tsim nyob rau hauv cov txheej txheem no muaj ntau haiv neeg heev. Cov no yog cov acetates, sulfates, esters, phosphates, thiab lwm yam.

Kev kawm video rau cov haujlwm thiab kev faib tawm ntawm carbohydrates:

Cov tshuaj yeeb dej caw no tseem ceeb rau kev ua haujlwm ntawm tag nrho cov kab mob thiab lub hlwb ntawm tus kheej. Lawv muab lub cev nrog lub zog, koom nrog kev tsim ntawm cov hlwb, tiv thaiv cov kabmob hauv nruab nrog los ntawm kev puas tsuaj thiab cuam tshuam tsis zoo. Lawv kuj ua lub luag haujlwm ntawm kev khaws cov khoom uas cov tsiaj thiab nroj tsuag xav tau thaum muaj lub sijhawm nyuaj.

Oligosaccharides

Oligosaccharides yog cov suab thaj muaj ob lossis peb hom suab thaj yooj yim sib raug zoo ua ke los ntawm covalent bonds hu ua glycoside.

Glycoside daim ntawv cog lus tuaj yeem yog alpha lossis beta.

Piv txwv ntawm cov kev tsis ncaj ncees tseem ceeb tshaj plaws,

1) Maltose (maltose) - muaj ob lub lwg me α-piam thaj tuav ua ke 1-4-glycosidic daim ntawv cog lusCov. Maltose tuaj yeem pom hauv cov nplej uas tau siv rau hauv cov npias ntau lawm.
2) Sucrose - muaj - ntshav qabzib thiab - fructose nrog 1-2 - glycosidic daim ntawv cog lus nruab nrab ntawm lawv. Ib qho piv txwv ntawm sucrose yog piam thaj.
3) Lactose (lactose) - muaj - ntshav qabzib thiab - galactoseCov. Lactose feem ntau pom muaj hauv mis.

Polysaccharides

Cov tshuaj polysaccharides yog cov monosaccharide polymers uas muaj los ntawm ob peb puas mus rau ntau txhiab monosaccharide subunitstuav ua ke los ntawm glycosidic bonds.

Qee qhov polysaccharides yog suav nrog cov saw ncaj thiab qee qhov yog txiav. Cov piv txwv tseem ceeb ntawm polysaccharides yog hmoov txhuv nplej siab, glycogen, cellulose thiab chitin.

Hmoov txhuv nplej siab (hmoov txhuv nplej siab) yog ib hom qab zib uas muab los ntawm cov nroj tsuag thiab muaj amyloses thiab amylopectin uas yog cov kua nplaum pleev polymers.

Cov hmoov txhuv nplej siab muaj cov kua nplaum monomers, uas txuas nrog los ntawm α 1-4 lossis 1-6 cov kua roj glycosidic. Cov lej 1-4 thiab 1-6 yog hais txog tus lej ntawm cov pa roj carbon atom hauv cov monomers uas lawv tau txuas nrog.

Amylose yog cov hmoov txhuv nplej siab tsim los ntawm kev sib txuas ua ke tsis muaj qabzib cov kua nplaum (tsuas yog α 1-4 daim ntawv cog lus), thaum amylopectin yog pob txha qhuav (α 1-6 bonds ntawm cov ceg taw tes).

Glycogen (glycogen) yog ib daim ntawv ntawm cov piam thaj hauv tib neeg thiab lwm lub pob txha caj qaum thiab muaj cov piam thaj hauv monomers.

Cellulose Nws yog cov qauv polysaccharide tseem ceeb ntawm txhua cov nroj tsuag thiab yog cov khoom tseem ceeb hauv cov xovtooj ntawm tes.

Cellulose yog unbroken gluc-glucose polymer uas tau sib koom ua ke los ntawm 1-4 glycosidic bonds.

Txhua txhua cov kua nplaum hauv qab thib ob hauv cellulose yog tig rov qab thiab cov monomers tau nruj nreem ntim rau hauv cov xov polymer ntev. Qhov no muab cov cellulose nws rigidity thiab high tensile lub zog, uas yog li tseem ceeb rau cov nroj tsuag hlwb.

Txawm hais tias daim ntawv cog lus hauv cellulose tsis tuaj yeem raug rhuav tshem los ntawm tib neeg cov zom cov hlab ntsha, tshuaj tua kab mob xws li nyuj, koalas, buffalos thiab nees muaj peev xwm zom cov khoom cog muaj fiber ntau thiab siv nws ua khoom noj los siv kev siv tshwj xeeb hauv lawv lub plab.

Cov cellulose-zoo li polymer muaj nyob rau hauv lub qhov txhav ntawm cov kab, kab hauv plab.

Qhov polymer no yog lub npe hu ua chitin uas yog ib qho polysaccharide uas muaj nitrogen. Nws muaj cov ntu rov ua ntawm N-acetyl-β-d-glucosamine (hloov kho suab thaj).

Chitin tseem yog ib qho tseem ceeb ntawm cov xovtooj ntawm fungal. Cov nceb yog cov tsis yog tsiaj los yog nroj tsuag thiab tsim sub-lub nceeg vaj hauv lub nceeg vaj ntawm eukaryotes.

Cov khoom noj carbohydrates, lawv cov qauv thiab kev ua haujlwm.