Chapter 19

Which of the following statements about enzymes are true? |CBSE 1995] (i) Enzymes lack in nucleophilic groups (ii) Pepsin is proteolytic enryme (iii) Enzymes catalyse chemical reactions by lowering the activation energy (iv) Enzymes are highly specific both in binding chiral substrates and in catalysing their reactions (a) (i) and (ii) (b) (i) and (ii) (c) (i) and (iv) (d) (ii), (iii) and (iv)

The secondary structure of a protein refers to: ICBSE 1995] (a) mainly denatured proteins and structures of prosthetic groups (b) linear sequence of amino acid residues in the polypeptide chain (c) regular folding patterns of continudus portions of the polypeptide chain. (d) three-dimensional structure, specially the bond between amino acid residues that are far apart from each other in polypeptide chain

The function of enzymes in the living system is tos |CBSE 1996] (a) transport oxygen (b) provide immunity (c) catalyse biochemical reactions (d) provide energy

In DNA the complementary bases are : (a) adenine and thymine, guanine and cytosine (b) uracil and adenine, cytosine and guanine (c) adenine and guanine thymine and cytosine (d) adenine and thymine, guanine and uracil

Which of the following is the sweetest sugar? (a) Sucrose (b) Glucose (c) Fructose (d) Maltose

The hormone which controls the processes hike burning of fats, proteins and carbohydrates to liberate energy in the body is : |CBSE 2000\(]\) (a) cortisone (b) thyroxine (c) adrenalin (d) insulin

Glucose molecule reacts with ' \(X\) number of molecules of phenylhydrazine to yield osazone. The value of ' \(X\) is: [CBSE 2000] (a) four (b) one (c) two (d) three

\(\alpha-\mathrm{D}(+)-\) glucose and \(\beta-\mathrm{D}(+)-\) glucose are : [CBSE 2000] (a) anomers (b) epimers (c) enantiomers (d) geometrical isomers

Which of the following is incorrect? ICBSE (a) \(\mathrm{FeCl}_{3}\) is used in detection of phenol (b) Fehling solution is used in detection of glucose (c) Tollen reagent is used in detection of unsaturation (d) \(\mathrm{NaHSO}_{3}\) is used in detection of carbonyl compound

Which one of the following gives positive Fehling's solution test? |CBSE 2001] (a) Sucrose (b) Glucose (c) Fats (d) Protein

Which of the following is correct? (a) Cycloheptane is an aromatic compound (b) Diastase is an enzyme (c) Acetophenone is an ether (d) All of the above

Which is correct statement? |CBSE 2001] (a) Starch is polymer of \(\alpha\)-glucose (b) Amylose is a component of cellulose (c) Proteins are composed of only one type of amino acid (d) In cyclic structure of fructose, there are four carbons and one oxygen atom

Which statement is incorrect about peptide |CBSE 2001| (a) C-N bond length in proteins is longer than usual bond length of \(\mathrm{C}-\mathrm{N}\) bond (b) Spectroscopic analysis show planar structure of - group (c) \(\mathrm{C}-\mathrm{N}\) bond length in proteins is smaller than usual bond length of \(\mathrm{C}-\mathrm{N}\) bond (d) None of above

Enzymes are made up of : (a) edible proteins (b) proteins with specific structure (c) nitrogen containing carbohydrates (d) carbohydrates

Glycolysis is: (a) oxidation of glucose to pyruvate (b) conversion of glucose to haeme (c) oxidation of glucose to glutamate (d) conversion of pyruvate to citrate

Phospholipids are esters of glycerol with: \(\quad\) [CBSE 2003] (a) one carboxylic acid residue and two phosphate groups (b) three phosphate groups (c) three carboxylic acid residues (d) two carboxylic acid residues and one phosphate group

The enzyme which hydrolyses triglycerides to fatty acids and glycerol is called: |CBSE.2004| (a) maltase (b) lipase (c) zymase (d) pepsin

The correct statement in respect of protein haemoglobin is that it : |CBSE 2004] (a) functions as a catalyst for biological reactions (b) maintains blood sugar level (c) act as an oxygen carrier in the blood (d) forms antibodies and offers resistance to diseases

The helical structure of protein is stabilised by : |CBSE.2004| (a) dipeptide bonds (b) hydrogen bonds (c) ether bonds (d) peptide bonds

A sequence of how many nucleotides in messenger RNA makes a codon for an amino acid? |CBSE 2004] (a) Three (b) Four (c) One (d) Two

The hormone that helps in the conversion of glucose to glycogen is : [CBSE 2004] (a) cortisone (b) bile acids (c) adrenalin (d) insulin

Which functional group participates in disulphide bond formation in proteins? |CBSE 2005] (a) Thiolacetone (b) Thiol (b) Thioether (d) Thioester

\(\alpha\)-D-glucose and \(\beta-D\)-glucose have a specific rotation of \(+112^{\circ}\) and \(+19^{\circ}\) respectively. In aqueous solution the rotation becomes \(+52^{\circ} .\) This is known as: [AFMC 1996] (a) racemisation (b) mutarotation (c) inversion (d) enolisation

The type of vitamins we require daily are: (a) water soluble (b) alcohol soluble (c) fat soluble (d) all of these

The hydrolysis of sugar to glucose and fructose is catalysed by: [AFMC 1998] (a) zymase (b) invertase (c) diastase (d) maltase

Insulin is secreted by: (a) stomach (b) intestine (c) pancreas (d) brain

Glucose \(+\) Tollen's reagent \(\rightarrow\) silver mirror. The above process shows: (a) presence of - COOH group (b) presence of keto group (c) presence of -CHO group (d) presence of \(-\mathrm{CONH}_{2}\) group

Sucrose on treatment with \(\mathrm{HCl}\) produces: (a) glucose (b) fructose (c) both (a) and (b) (d) laevulinic acid

Enzymes are: \(\quad\) [AFMC 2001] (a) moulds (b) inorganic compound (c) proteins (d) micro-organism

Soaps are classified as: (a) carbohydrates (b) salts of fatty acids (c) ethers (d) alcohols

The type of linkage present in protein molecule is: (a) ether linkage (b) peptide linkage (c) stycosidic linkage (d) ester linkage

The base not present in DNA is: (a) uracil (b) guanine (c) adenine (d) cytosine

The group present in wax is: (a) acid group (b) ester group (c) alcohol group (d) ether group

The sugar present in milk is : (a) glucosee (b) lactose (c) maltose (d) sucrose

Monosaccharides are defined as: (a) aldehydes (b) ketones (c) starch (d) non-hydrolysing sugars

The water soluble vitamin is: (a) vitamin B (b) vitamin \(\mathrm{A}\) (c) vitamin \(\mathrm{K}\) (d) vitamin \(\mathrm{E}\)

An organic compound responds to Molisch test. It gives a blue colour with iodine. The compound is : (a) glucose (b) fructose (c) starch (d) tartaric acid

\alpha-D-glucose and \(\beta\)-D-glucose differ from each other due to \mathrm{\\{} ~ d i f f e r e n c e ~ i n ~ c a r b o n ~ a t o m ~ w i t h ~ r e s p e c t ~ t o ~ i t s ~ : ~ (a) structure (b) conformation (c) configuration (d) none of these

The deficiency of iodine in diet causes : (a) rickets (b) nightblindness (c) beri-beri (d) goitre

Chemically ascorbic acid is: (a) vitamin \(\mathrm{B}\) (b) vitamin \(\mathrm{C}\) (c) vitamin \(\mathrm{E}\) (d) vitamin \(\mathrm{B}_{6}\)

Starch is converted into maltose by : (a) invertase (b) amylase (c) diastase (d) zymase

The general molecular formula for disaccharide is : (a) \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\) (b) \(\mathrm{C}_{10} \mathrm{H}_{20} \mathrm{O}_{10^{+}}\) (c) \(\mathrm{C}_{12} \mathrm{H}_{20} \mathrm{O}_{10}\) (d) \(\mathrm{C}_{12} \mathrm{H}_{2} \mathrm{O}_{10}\)

Deficiency of vitamin-D causes: (a) night blindness (b) rickets (c) scurvy (d) loss of appetite

Sucrose on treatment with conc. HCl produces: (a) glucose (b) fructose (c) both (a) and (b) (d) laevulinic acid

Enzymes having two sites are: \(\quad\) IAIIMS 2002] (a) conjugate enzyme (b) apoenzyme (c) holoenzyme (d) allosteric enzyme

Among the following, the achiral amino acid is: (a) 2 -ethylalanine (b) 2-methylglycine (c) 2-hydroxymethyl serine (d) tryptophen

The nucleic acid base having two possible binding sites is: [AIIMS 2004] (a) thymine (b) cytosine (c) guanine (d) all of these

Which of the following statements is true for protein synthesis (translation)? |AIIMS 2005] (a) Amino acids are directly recognised by m-RNA (b) The third base of the codon is less specific (c) Only one codon codes for an amino acid (d) Every \(t\)-RNA molecule has more than one amino acid attachment

Conversion of starch into maltose takes place by the enzyme: |BHU 1999] (a) invertase (b) maltase (c) diastase (d) zymase

Which one of the following is a conjugated protein? (a) Phosphoprotein (b) Glycoprotein (c) Chromoprotein (d) All of these