2024 Tus sau: Elizabeth Oswald | [email protected]. Kawg hloov kho: 2024-01-13 00:07
Epimers yog diastereomers uas muaj ntau tshaj ib lub chaw chiral tab sis txawv ntawm ib leeg hauv kev teeb tsa tiav ntawm ib qho chaw chiral nkaus xwb. YGlucose thiab fructose tsis yog epimers.
Dab tsi yog ob lub epimers ntawm qabzib?
Epimers. Ob lub suab thaj sib txawv hauv kev teeb tsa ntawm ib qho asymmetric carbon atom hu ua epimers. Glucose thiab mannose yog C2 epimers, ribose thiab xylose yog C3 epimers, thiab gulose thiab galactose kuj yog C3 epimers (Daim duab 3). d-Arabinose thiab l-xylose yog C4 epimers, thiab yog li yog d-glucose thiab d-galactose.
Y Dab tsi yog qhov epimers ntawm fructose?
Fructose muaj nyob hauv cov khoom noj xws li fructose dawb (xws li txiv hmab txiv ntoo, zib ntab, lossis cov txiv hmab txiv ntoo siab fructose) lossis fructose khi rau qabzib (sucrose) [4]. Allulose, c-3 epimer ntawm fructose, yog cov qab zib tsawg-calorie (~0.4 kcal / g) pom ib txwm muaj me me hauv cov txiv hmab txiv ntoo qhuav, qab zib xim av, thiab maple phoov [5].
Yuav ua li cas yog hom isomerism ntawm qabzib thiab fructose?
Yog li, qabzib thiab fructose muaj tib lub qauv molecular nrog cov pab pawg ua haujlwm sib txawv thiab yog li nws ua piv txwv ntawm kev ua haujlwm isomerism. Yog li, peb tuaj yeem hais tias qabzib thiab fructose yog functional isomers..
YPuas yog fructose thiab mannose epimers?
Lawv yog hom tshwj xeeb ntawm stereoisomers uas muaj ntau lub stereocenters tab sis txawv ntawm ib leeg los ntawm kev teeb tsa ntawm ib qho ntawm stereogenicchaw. Nyob rau hauv rooj plaub ntawm cov piam thaj thiab mannose, lawv txawv ntawm ib leeg los ntawm kev teeb tsa ntawm C-2 atom. Thiab yog li ntawd, lawv yog epimers.
Pom zoo:
Anomers puas yog epimers?
Anomers yog cyclic monosaccharides lossis glycosides uas yog epimers, sib txawv ntawm ib leeg hauv kev teeb tsa ntawm C-1 yog tias lawv yog aldoses lossis hauv kev teeb tsa ntawm C-2 yog tias lawv yog ketoses. Cov pa roj carbon epimeric hauv anomers hu ua anomeric carbon lossis anomeric center.
Puas yog hmoov txhuv nplej zom rau qabzib?
Starch yog zom rau cov piam thaj hauv ob kauj ruam yooj yim: Amylase cleaves tsuas yog sab hauv alpha (1-4) glycosidic bonds, yog li txo cov hmoov txhuv nplej siab rau peb qhov sib txawv oligosaccharides: m altose (disaccharide), m altotriose (trisaccharide), thiab ib pawg ntawm alpha-limit dextrins uas muaj ceg ntsiab lus los ntawm amylopectin.
Puas yog qabzib tsuas yog molecule uas tuaj yeem catabolized?
Puas yog cov piam thaj tib yam uas tuaj yeem ua rau catabolized thaum lub sijhawm ua pa ntawm tes? Glucose yog lub ntsiab molecule rau kev ua pa cellular respiration (los ntawm glycolysis thiab ces kreb lub voj voog) muab ATP. Lwm cov molecules suav nrog cov khoom ntawm glycolysis thiab kreb lub voj voog tshwj xeeb tshaj yog acetyl-coenzyme A (acetyl CoA).
Puas yog txhua tus anomers epimers?
Anomers yog cyclic monosaccharides lossis glycosides uas yog epimers, sib txawv ntawm ib leeg hauv kev teeb tsa ntawm C-1 yog tias lawv yog aldoses lossis hauv kev teeb tsa ntawm C-2 yog tias lawv yog ketoses. Cov pa roj carbon epimeric hauv anomers hu ua anomeric carbon lossis anomeric center.
Dab tsi disaccharide yog tsim los ntawm qabzib thiab fructose?
Sucrose, qhov tshwm sim dav dav pom nyob hauv ntau cov nroj tsuag (cane qab zib thiab beet qab zib), muaj cov piam thaj thiab fructose moieties txuas ua ke los ntawm C1 ntawm qabzib thiab C2 ntawm fructose. Sucrose tsis yog qhov txo qis qab zib thiab tsis mutarotate.
