How do you explain the presence of an aldehydic group in a glucose molecule?
Glucose reacts with hydroxylamine to form a monoxime, and adds one molecule of hydrogen cyanide to give cyanohydrin.
Therefore, it contains a carbonyl group which can be an aldehyde or a ketone. On mild oxidation with bromine water, glucose gives gluconic acid which is a carboxylic acid containing six carbon atoms.
This indicates that carbonyl group present in glucose is an aldehydic group.
Three structures are given below in which two glucose units are linked. Which of these linkages between glucose units are between C1 and C4 and which linkages are between C1 and C6?
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.
Aldopentoses named ribose and 2-deoxyribose are found in nucleic acids.
What is their relative configuration?
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.
When RNA is hydrolysed, there is no relationship among the quantities of different bases obtained. What does this fact suggest about the structure of RNA?
Assertion (A): Vitamin D can be stored in our body.
Reason (R): Vitamin D is fat soluble vitamin.
Which of the following terms are correct about enzyme?
(a) Proteins (b) Dinucleotides
(c) Nucleic acids (d) Biocatalysts
How do you explain the presence of all six carbon atoms in glucose in a straight chain?
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.
Which monosaccharide units are present in starch, cellulose and glycogen and which linkages link these units?
Carbohydrates are essential for life in both plants and animals. Name the carbohydrates that are used as storage molecules in plants and animals, also name the carbohydrate which is present in wood or in the fibre of cotton cloth.
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
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?
How are vitamins classified? Name the vitamin responsible for the coagulation of blood.
Which of the following are purine bases?
(a) Guanine (b) Adenine (c) Thymine (d) Uracil
Sucrose is dextrorotatory but the mixture obtained after hydrolysis is laevorotatory. Explain.
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
Match the following enzyme given in Column I with the reactions they catalyse given in Column II.
Assertion (A): All naturally occurring a-amino acids except glycine are optically active.
Reason (R): Most naturally occurring amino acids have L-configuration.
Structures of glycine and alanine are given below. Show the peptide linkage in glycylalanine.
Assertion (A): In presence of enzyme, substrate molecule can be attacked by the reagent effectively.
Reason (R): Active sites of enzymes hold the substrate molecule in a suitable position.
In disaccharides, if the reducing groups of monosaccharides, i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars. Which of the following disaccharide is a non-reducing sugar?
Optical rotations of some compounds along with their structures are given below which of them have D configuration.
Proteins can be classified into two types on the basis of their molecular shape, i.e., fibrous proteins and globular proteins. Examples of globular proteins are
(a) insulin (b) keratin (c) albumin (d) myosin
Which of the following carbohydrates are branched polymer of glucose?
(a) Amylose (b) Amylopectin (c) Cellulose (d) Glycogen
