第十九章碳水化合物-糖 (carbohydrate)(sugar saccharides
第十九章 碳水化合物-----糖 (carbohydrate) (sugar) (saccharides)
在动植物体内大量存在 xCO2+yH2O阻光 叶绿素 Cx(h20)y +xo (chlorophyll) Cx(H2O)y + XO2 一XCO2+yH20+能量 ■通式Cn(H2O)n从结构上看碳水化合物是多羟基醛酮或其 缩聚物。 l单糖:不能水解的多羟基醛酮eg葡萄糖( glucose,果糖 ( monosaccharides)( fructose)核糖( ribose)等。 ■2低聚糖:能水解成两三个或几个分子单糖的碳水化合物 ( oligosaccharides)例如:蔗糖( sucrose,麦芽糖( maltose) 3多糖:水解成10个以上单糖分子的化合物 (polysaccharides)
在动植物体内大量存在: 通式Cm(H2O)n从结构上看碳水化合物是多羟基醛酮或其 缩聚物。 1单糖: 不能水解的多羟基醛酮.eg.葡萄糖(glucose),果糖 (monosaccharides) (fructose),核糖(ribose)等。 2低聚糖: 能水解成两三个或几个分子单糖的碳水化合物 (oligosaccharides) 例如：蔗糖(sucrose),麦芽糖(maltose)。 3多糖： 水解成10个以上单糖分子的化合物 (polysaccharides) (polysaccharides) xCO 2 + yH 2O 阳 光 叶绿素 C x ( H 2O ) y + x O 2 C x (H 2O ) y + xO 2 xCO 2 + yH 2O + 能 量 (chlorophyll)
H, C CH,CH3 H, C CH H CH2 H CO, CH3 C=0 CH、HCH3H FIGURE 22 1 Chlorophyll a. [the structure of chlorophyll a was established largely through the work of H. Fischer(Munich), R willstatter(Munich), and J B Conant(Har- vard). a synthesis of chlorophyll a from simple organic compounds was achieved by r B Woodward(Harvard)in 1960, who won the Nobel Prize in 1965 for his outstanding contri butions to synthetic organic chemistry
Classification of monosaccharides (1)According to the number of carbon atoms present in the molecule triose tetrose pentose hexose 2)According to whether they contain an aldehyde or keto group. aldose ketose ()These two classification are frequently combined for example: C5 aldopentose ketopentose
Classification of Classification of Monosaccharides Monosaccharides: (1)According to the number of carbon atoms present in the (1)According to the number of carbon atoms present in the molecule. molecule. triose tetrose tetrose pentose pentose hexose (2)According to whether they contain an (2)According to whether they contain an aldehyde aldehyde or keto group. group. aldose ketose (3)These two classification are frequently combined. (3)These two classification are frequently combined. for example : C for example : C5 5 aldopentose aldopentose ketopentose ketopentose
CH,OH CH,OH C=0 C=0 CHOH CHOH CHOH (CHOH CHOH CHOH CH2OH、CH2OH CH,OH CH,OH An aldose a ketose An aldotetrose A ketopentose