CHAPTER 22 CARBOHYDRATES 22.1 NTRODUCTION 21.1A CLASSIFICATION OF CARBOHYDRATES Carbodydrares: polyhydroxy aldehydes and ketones or substances that hydrolyze to yield polyhydroxy aldehydes and ketones Monosaccharides: simple carbohydrates cannot be hydrolyzed into smaller simpler carbohydrates
CHAPTER 22 CARBOHYDRATES 22.1 INTRODUCTION 21.1A CLASSIFICATION OF CARBOHYDRATES Carbodydrares: polyhydroxy aldehydes and ketones or substances that hydrolyze to yield polyhydroxy aldehydes and ketones. Monosaccharides: simple carbohydrates cannot be hydrolyzed into smaller simpler carbohydrates
Disaccharides: on a molecular basis. carbohydrates that undergo hydrolysis to produce only two molecules of monosaccharide Trisaccharides: those carbohydrates that yield three molecules of monosaccharide Polysaccharide: carbohydrates that yield a large number of molecules of monosaccharide(>10) Disaccharides Trisaccharides and polysaccharide are easily Hydrolysis to monosaccharide
Disaccharides: on a molecular basis, carbohydrates that undergo hydrolysis to produce only two molecules of monosaccharide. Trisaccharides: those carbohydrates that yield three molecules of monosaccharide. Polysaccharide: carbohydrates that yield a large number of molecules of monosaccharide (﹥10). Disaccharides Trisaccharides and Polysaccharide are easily Hydrolysis to monosaccharide
Carbohydrares are the most abundant organic constitutes of plants We encounter carbohydrates at almost every turn of our daily life 211B PHOTOSYNTHESIS AND CARBOHYDRATE METABOLESM Carbohydrates are synthesized in green plants by photosynthesis Xco2 yH2O+ solar energy Cy(H2Ov + xO2 Carbohydrate (碳水化合物)
Carbohydrares are the most abundant organic constitutes of plants. We encounter carbohydrates at almost every turn of our daily life. 21.1B PHOTOSYNTHESIS AND CARBOHYDRATE METABOLESM Carbohydrates are synthesized in green plants by photosynthesis: χCO2 + yH2 O + solar energy Cχ (H2 O) y + O2 χ Carbohydrate (碳水化合物）
Carbohydrates can be released energy when animals or plants metabolize them to carbon dioxide and water Cy(H2O)v XOz Xco2+ yH20+ energy Much of the energy is conserved in ATP. Plants and animals can use the energy of aTp to carry out all of their energy-requiring process When the energy in ATP is used, a coupled reaction takes place in which ATP is hydrolyzed ATP +Ho -energy ADp +p
C χCO2 + yH2 O + energy χ (H2 O) y + O2 χ Much of the energy is conserved in ATP. Plants and animals can use the energy of ATP to carry out all of their energy-requiring process. When the energy in ATP is used, a coupled reaction takes place in which ATP is hydrolyzed: ATP + H2 O -energy ADP + Pi Carbohydrates can be released energy when animals or plants metabolize them to carbon dioxide and water
22.2 MONOSACCHARIDES 22.2A CLASSIFICATION OF MONOSACCHARIDES Monosaccharides are classified according to The number of carbon atoms present in the molecular (2)whether they contain an aldehyde or keto group three carbon atoms- triose(丙糖) four carbon atoms— tetrose(四糖) five carbon atoms→- pentose(戊糖) six carbon atoms— hexose(己醣)
22.2A CLASSIFICATION OF MONOSACCHARIDES 22.2 MONOSACCHARIDES Monosaccharides are classified according to: (1) The number of carbon atoms present in the molecular. (2) whether they contain an aldehyde or keto group. three carbon atoms four carbon atoms five carbon atoms six carbon atoms triose tetrose pentose hexose (丙糖) (四糖) (戊糖) (己醣)
These two classification are frequently combined. For example C4 aldose→- aldotetr (丁醛糖) Cs ketose ketopentose (戊酮糖) CH,OH CH,OH CH CH C=0 CHOH CHOH (CHOh)n (CHOH)n CHOH CHOH CH,OH CH,OH CH,OH CH,OH An aldose a ketose aldotetrose ketopentose (醛醣) (酮糖) (丁醛糖) (戊酮糖)
These two classification are frequently combined. For example: C4 aldose aldotetrose (丁醛糖） C5 ketose ketopentose (戊酮糖） O CH CHOH CHOH CH2OH O CH (CHOH)n CH2 OH CH2 OH C (CHOH)n O CH2 OH CH2 OH C O CHOH CHOH CH2 OH An aldose (醛醣) A ketose (酮糖） aldotetrose (丁醛糖） ketopentose (戊酮糖）
22.2B D ANDL DESIGNATIONS OF MONOSACCHARIDES Glyceraldehyde exists two enantiomeric forms which have the absolute configurations H C—H HDC-OH lOrCH CH,OH CH,OH (+)-Glyceraldehyde ()-Glyceraldehyde (+)-甘油醛 ()+甘油醛 (+)-Glyceral dehyde should be designated(R)-(+)-Glyceraldehyde and(-)-Glyceraldehyde should be designated(S)-(-Glyceraldehyde (section 5.5)
22.2B D AND L DESIGNATIONS OF MONOSACCHARIDES Glyceraldehyde exists two enantiomeric forms which have the absolute configurations: O C C CH2OH H OH H O C C CH2 OH HO H H (+)-Glyceraldehyde (+)-甘油醛 (-)-Glyceraldehyde (-)-甘油醛 (+)-Glyceraldehyde should be designated (R)-(+)- Glyceraldehyde and (-)-Glyceraldehyde should be designated (S)-(-)- Glyceraldehyde (section 5.5)
Other system designated (+)-Glyceraldehyde as D-(+)-Glyceraldehyde and (-)-Glyceral dehyde as L-(-)-Glyceraldehyde I CH,OH I CHO O 2* CHOH 3* CHOH 3*CHOH 4* CHOH HDC-OH HOrC-H 5 CH,OH Highest number sterocenter CH,OH D-aldopentose L-ketohexose (D-戊醛糖) (L-已酮糖) D and l designations are not necessarily related to the optical rotations of the sugars to which they are applied
Other system designated (+)-Glyceraldehyde as D-(+)- Glyceraldehyde and (-)-Glyceraldehyde as L-(-)-Glyceraldehyde. CHO CHOH CHOH C CH2 OH C CHOH CHOH C CH2OH H OH HO H * * * * O CH2OH Highest number sterocenter 1 2 3 4 5 1 2 3 4 D-aldopentose (D-戊醛糖） L-ketohexose (L-己酮糖） D and L designations are not necessarily related to the optical rotations of the sugars to which they are applied
22.2C ATRUCTURAL FORMULAS FOR MONOSACCHARIDES Fisher projection formula: horizontal lines project out towards the reader and vertical lines project behind the plane of the page CHO H人OH CHO CHO H OH HOH HCOH 0-TH HOH≡三 HOtCH H OH HeCOH H OH HOOH HDCKOH CH,OH CH,OH CHOH Fisher projection Cirele-and-line Wedge-line-dashed formula formula wedge formula 3
22.2C ATRUCTURAL FORMULAS FOR MONOSACCHARIDES Fisher projection formula: horizontal lines project out towards the reader and vertical lines project behind the plane of the page. CHO H OH HO H H OH H OH CH2OH CHO H C OH C C HO H C H OH H OH CH2 OH CHO HO H H OH H OH H OH CH2OH Fisher projection formula Cirele-and-line formula Wedge-line-dashed wedge formula 1 2 3
CHOH CHOH O、OH H OH H OH H OH OH H H H Haworth formulas 5 OH OH H2C HC HO HO HO OH OH OH OH a-D-(+)-Glucopyranose B-D-(+)-Glucopyranose (α-D-(+)-吡喃(型)葡萄糖) (βD-(+)-吡喃(型)葡萄糖) Open-chair structure(1, 2, or 3)exists equilibrium with two cyclic forms 4 and 5 or 6 and 7
Open –chair structure (1, 2, or 3) exists equilibrium with two cyclic forms 4 and 5 or 6 and 7. H O OH H OH H H OH OH CH2OH H H O OH OH H H H OH OH CH2OH H 4 5 6 7 Haworth formulas + + O HO HO H2C OH OH OH O HO HO H2 C OH OH OH α-D-(+)-Glucopyranose (α-D-(+)-吡喃(型)葡萄糖) β-D-(+)-Glucopyranose (β-D-(+)-吡喃(型)葡萄糖)