Biochemistry
Carb. Lecture 2Monosaccharide: • Carbohydrate that can not be hydrolyzed into simple form, they may be sub divided according to the no. of carbon atom into:1- Triose: C3(H2O)3 or C3H6O3 2- Tetrose: C4(H2O)4 or C4H8O43- Pentose: C5(H2O)5 or C5H10O54- Hexose: C6(H2O)6 or C6H12O6The ending OSE means the sugar.
• Monosaccharide can be classified according to the kind of carbonyl group. • It depend whether aldehyde or ketone group is present.We can tell both how many carbon atoms are present and the kind of carbonyl group in a monosaccharide by combining them into one word. For example:1- Aldo hexose: it mean 6 carbon sugar, with aldehyde.2- Keto pentose: it mean 5 carbon sugar, with ketone.
Triose: It is aldotriose, glyceraldehyde or glycerose, or ketotriose, dihydroxyacetone.
CHOH C OH CH2OH Glycer aldehyde Glycerose or aldotriose
CH2OHC = O CH2OH Dihydroxy acetone Keto triose
• Glycerose are the smallest molecule that can be classed as carbohydrate. • They are called (parent sugar) because they are present in every living cell as intermediate product. • Glycerose and dihydroxy acetone sugar are isomers of monosaccharide. ISOMERS: compound have similar carbon atom but different in configuration.2- Tetrose: C4(H2O)4
CHO H C OH H C OH CH2OH(Have no importance)
3- Pentose: C5(H2O)5 The important members of pentose sugar are: ribose, ribulose, arabinose, xylose, lyxose, deoxy ribose.
CHO H C OH H C OH H C OH CH2OH (Ribose)
CHO HO C H H C OH H C OH CH2OH (Arabinose)
CH2OH C = O H C OH H C OH CH2OH (Ribulose)
CHO H C OH HO C H H C OH CH2OH (Xylose)
CHO HO C H HO C H H C OH CH2OH (Lyxose)CHO H C H H C OH H C OH CH2OH (Deoxyribose)
Ribose: it is present in nucleic acid. Ribulose: it is intermediate product in pentose phosphate pathway. Arabinose: present in gum Arabic. Xylose: found in wood gum. Lyxose: present in heart muscle. Deoxy ribose: present in nucleic acid.
4- Hexose: 6C The important isomers of hexose sugar are: Glucose, fructose, galactose and mannose.
CHO H C OH HO C H H C OH H C OH CH2OH (Glucose)
• The source of glucose from:1- Fruit sugar.2- Hydrolysis of starch.3- Cane sugar. 1- Glucose: C6H12O6
• The important of glucose, it is the sugar of the body. The sugar carried by the blood, it is supply the body with the required amount of energy at anytime.• More of half energy of the body provided by oxidation of glucose to CO2 & H2O.• When the value of glucose in blood decrease, headache will occur.• If the value decrease to 40 mg % or lesser, comma take place and the case called hypoglycemia.• When the value of glucose in blood increase to more than 120 mg % the case called hyperglycemia.
• If glucose appear in the urine the case is called diabetes mellitus.• Liver remove glucose from blood by combining many molecule to form glycogen which is stored in liver. • In the mammary gland, glucose is converted to galactose, then a molecule of galactose is combine with a molecule of glucose to form lactose which is milk sugar.• The normal range of glucose in the body is ) 65-100%(. • Glucose, with four asymmetric carbon atoms, can form 16 isomers. • Glucose is the most important carbohydrate in mammalianbiochemistry because nearly all carbohydratein food is converted to glucose for metabolism.