Activation energy for the acid catalysed hydrolysis of sucrose is 6.22 kJ mol-1, while hydrolysis is catalysed by the enzyme sucrase. Explain.
Enzymes are biocatalysts. They reduce the magnitude of activation energy by providing alternative path. In the hydrolysis of sucrose, the enzyme sucrase reduces the activation energy from 6.22 kJ mol-1 to 2.15 kJ mol-1. As a result, enzyme catalysed reactions occur at a much faster rate than the ordinary chemicdl reactions using conventional catalysts.
The letters ' D ' or ' L' before the name of a stereoisomer of a compound indicate the correlation of configuration of that particular stereoisomer.
This refers to their relation with one of the isomers of glyceraldehydes. Predict whether the following compound has ‘D' or ‘L' configuration.
In nucleoside a base is attached at 1′ position of sugar moiety. Nucleotide is formed by linking of phosphoric acid unit to the sugar unit of nucleoside. At which position of sugar unit is the phosphoric acid linked in a nucleoside to give a nucleotide?
Match the following enzyme given in Column I with the reactions they catalyse given in Column II.
Name the sugar present in milk. How many monosaccharide units are present in it? What are such oligosaccharides called?
Which monosaccharide units are present in starch, cellulose and glycogen and which linkages link these units?
Assertion (A): Deoxyribose, C5H10O4 is not a carbohydrate.
Reason (R): Carbohydrates are hydrates of carbon so compounds which follow Cx(H2O)y formula are carbohydrates.
In fibrous proteins, polypeptide chains are held together by
(a) van der Waals forces (b) disulphide linkage
(c) electrostatic forces of attraction (d) hydrogen bonds
Activation energy for the acid catalysed hydrolysis of sucrose is 6.22 kJ mol-1, while hydrolysis is catalysed by the enzyme sucrase. Explain.
Carbohydrates are classified on the basis of their behaviour on hydrolysis and also as reducing or non-reducing sugar. Sucrose is a .
(a) monosaccharide (b) disaccharide
(c) reducing sugar (d) non-reducing sugar
Monosaccharides contain carbonyl group hence are classified, as aldose or ketose. The number of carbon atoms present in the monosaccharide molecule are also considered for classification. In which class of monosaccharide will you place fructose?
Some enzymes are named after the reaction, where they are used. What name is given to the class of enzymes which catalyse the oxidation of one substrate with simultaneous reduction of another substrate?
Protein found in a biological system with a unique three dimensional structure and biological activity is called a native protein. When a protein in its native form, is subjected to a physical change like change in temperature or a chemical change like, change in pH, denaturation of protein takes place. Explain the cause.
Which of the following monosaccharides are present as five membered cyclic structure (foranose structure)?
(a) Ribose (b) Glucose (c) Fructose (d) Galactose
Aldopentoses named ribose and 2-deoxyribose are found in nucleic acids.
What is their relative configuration?
α-Helix is a secondary structure of proteins formed by twisting of polypeptide chain into right handed screw like structures. Which type of interactions are responsible for making the a-helix structure stable?
Assertion (A): Vitamin D can be stored in our body.
Reason (R): Vitamin D is fat soluble vitamin.
Assertion (A): Glycine must’be taken through diet.
Reason (R): It is an essential amino acid.
How are vitamins classified? Name the vitamin responsible for the coagulation of blood.
Assertion (A): β-glycosidic linkage is present in maltose.
Reason (R): Maltose is composed of two glucose units in which C-l of one glucose unit is linked to C-4 of another glucose unit.
Classify the following into monosaccharides and disaccharides. Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose.
Optical rotations of some compounds along with their structures are given below which of them have D configuration.
Which of the following carbohydrates are branched polymer of glucose?
(a) Amylose (b) Amylopectin (c) Cellulose (d) Glycogen
Glucose or sucrose are soluble in water but cyclohexane and benzene (simple six membred ring compounds) are insoluble in water Explain.
Structure of a disaccharide formed by glucose and fructose is given below. Identify anomeric carbon atoms in monosaccharide units.
Sucrose is dextrorotatory but the mixture obtained after hydrolysis is laevorotatory. Explain.