Chapter 31

Consider the following statements about proteins: 1\. all natural amino acids which are constituents of proteins are \(\alpha\)-amino acids 2\. \(\alpha\)-amino acids are all optically active and have the L-configuration 3\. an especially favourable conformation for the peptide linkage in proteins is the \(\alpha\)-helix arrangement. 4\. \(\alpha\)-amino acids are connected by ester linkages of these statements (a) 1 and 3 are correct (b) 1 and 2 are correct (c) 2 and 3 are correct (d) 2,3 and 4 are correct

Consider the following statements: (1) monosaccharides are optically active polyhydroxy carbonyl compounds (2) fructose does not reduce Fehling's solutio because it is a ketose (3) \(\alpha-\mathrm{D}(+)\)-glucose and \(\beta-\mathrm{D}(+)\)-glucose are anomers (4) D-glucose and D-mannose are C-2 epimers Which of the following statements are correct? (a) 1,2 and 3 (b) 1,3 and 4 (c) 1,2 and 4 (d) 2,3 and 4

Which of the following is true? (i) sucrose is a non reducing agent (ii) glucose is oxidized by bromine water (iii) glucose rotates plane polarized light in clockwise direction (iv) fructose is oxidized by bromine water Select the correct answer during the coded given below (a) (i), (ii), (iii) (b) (i), (ii) only (c) (ii), (iii) only (d) (i) (iv) only

Consider the following statements about amino acids: (1) nitrous acid liberates nitrous oxide from amino acids (2) an important sensitive test for the detection of amino acids is the ninhydrin colour test (3) glycine is the only amino acid which does not possess a chiral centre. (4) all the natural amino acids that occur as constituents of proteins belong to the L-series Which of these statements are correct? (a) 1,2 and 3 (b) 1,2 and 4 (c) 2,3 and 4 (d) 2 and 3 only

Which statements are correct about peptide bond? (1) \(-\) CONH- group is planar (2) C-N bond length in protein is longer than usual bond length of C-N bond (3) C-N bond length in protein is smaller than usual bond length of C-N bond (a) 2 and 3 (b) 1 and 2 (c) 2 only (d) 1 and 3

Which are incorrect statements? (a) amylose is a component of cellulose (b) starch is a polymer of \(\alpha\) - glucose (c) proteins are compounds of only one type of amino acids (d) in cyclic structure of fructose, there are four carbon atoms and one oxygen atom. (a) 1,2 and 4 (b) 1,3 and 4 (c) 1,2 and 3 (d) 2,3 and 4

Consider the following statements about carbohydrates: 1\. Bromine water can be used to differentiate an aldose from a ketose 2\. All monosaccharides, whether aldose or ketose, are reducing sugars 3\. Osazone formation destroys the configuration about C-2 of an aldose, but does not affect the configuration of the rest of the molecule 4\. A pair of diastereomeric aldoses which differ only in configuration about \(\mathrm{C}-2\) is termed as pair of anomers Which of the above statements are correct? (a) 1 and 4 (b) 2 and 4 (c) 1,2 and 3 (d) 2,3 and 4

Consider the following sequence of reactions. Glucose \(\frac{\mathrm{PhNHNH}_{2} \text { (exoess) }}-(\mathrm{X}) \stackrel{\mathrm{H}_{3} \mathrm{O}^{+}, \Delta}{\longrightarrow}\) (Y) \(\stackrel{\mathrm{Zn} / \mathrm{AcOH}}{\longrightarrow}\) Here, the product ( \(Z\) ) is (a) fructose (b) mannose (c) arabinose (d) Sorbitol

An aldose is oxidized separately by \(\mathrm{Br}_{2} / \mathrm{H}_{2} \mathrm{O}\) (condition-A) and by \(\mathrm{HNO}_{3}\) (condition-B). Which of the following is the correct combination of the products formed? (a) condition-A gives aldaric acid while condition-B yields a mixture of aldonic and aldaric acids (b) condition-A gives aldonic acid while condition-B yields a mixture of aldonic and aldaric acids (c) condition-A gives aldaric acid while condition-B yields aldonic acid (d) condition-A gives aldonic acid while condition-B yields aldaric acid

Which of the following give the same osazone on treatment with phenyl hydrazine? (a) Glucose (b) Galactose (c) Fructose (d) Mannose

If \(\mathrm{C}-5\) carbon of \(\mathrm{D}-\) glucose is inverted the new compound is related to the parent compound as (a) Enantiomer (b) Epimer (c) Anomer (d) diastereomer

Which of the following statements are correct? (a) All monosaccharides whether aldose or ketose act as reducing sugars. (b) Bromine water can be used to differentiate between aldoses and ketoses. (c) A pair of diastereomeric aldoses which differ only in configuration about \(\mathrm{C}_{2}\) is termed as a pair of anomers. (d) Osazone formation destroys the configuration about \(\mathrm{C}_{2}\) of an aldose but does not affect the configuration of the rest of the molecule.

The characteristics of glycosidic linkage is/ are (a) ether linkage of sugar (b) it is hydrolysed by acid (c) it is hydrolysed by alkali (d) it is also hydrolysed by specific enzyme

Which of the following statement(s) is/are correct? (a) The smallest aldose to form a cyclic hemi- acetal must have 4 carbon atoms. (b) D- glucose and D- fructose can be differentiated using Benedict's solution (c) When D- galactose is oxidised by \(\mathrm{HNO}_{3}\), it gives a meso isomer. (d) Aldoses react with Fehling's solution and \(\mathrm{PhNHNH}_{2}\) but not with \(\mathrm{NaHSO}_{3}\).

Primary structure of protein involves (a) Vander Waal's interaction (b) Hydrogen bonds (c) Peptide bonds (d) Disulphide bonds

Which of the following has a glucosidic linkage? (a) Amylose (b) Sucorse (c) Maltose (d) Galactose

Which of the following statements is/are correct (a) The \(\mathrm{C}_{1}\) carbon atom in aldoses and \(\mathrm{C}_{2}\) carbon atom in ketoses around which the configuration of epimers differ are called glycosidic carbon (b) All monosacchorides and disaccharides are reducing sugars. (c) All reducing carbonhydrates undergo mutarotation in aqueous solutions. (d) Glucose and fructose give the same osazone.

Which of the following Aminoacids can be used in the prepration of dipeptide? (a) CC(N)C(=O)O (b) \(\mathrm{H}_{2} \mathrm{~N}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{COOH}\) (c) CC(N)CC(=O)O (d) NCC(=O)O

The following amino acid has characteristic pKa values \(\mathrm{H}_{3} \mathrm{~N}^{\oplus}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}-\mathrm{COOH}\) (3) [C-] \(\mathrm{NH}_{3}\) (2) \(\mathrm{pK}_{\mathrm{a}(1)}=2.18 ; \mathrm{pK}_{a(2)}=8.95\) and \(\mathrm{pK}_{\mathrm{a}(3)}=10.79\) The isoelectric point pI of the above amino acid is (a) \(5.56\) (b) \(9.87\) (c) \(11.13\) (d) \(12.97\)

What is the structure of the a bove amino acid in a solution of \(\mathrm{pH}=9.87 ?\) (a) NCCCCC(CO)C(=O)O \(\oplus\) (b) CC(CCCCN)C(=O)O \(\oplus\) (c) NCCCCC(N)C(=O)[O-] - (d) NCCCCC(N)C(=O)[O-]

Which of the following cannot be oxidized by bromine water? (a) D- glycerladehyde (b) D- arabinose (c) L- fructose (d) L- glucose

Fructose on oxidation with conc. \(\mathrm{HNO}_{3}\) gives (a) Tartaric acid (b) Saccharic acid (c) Glycolic acid (d) Both (a) and (c)

Match the following: List I List II 1\. Nucleic acid A I D.N.A. B 2\. Uracil \(\quad\) B Hormones 3\. Thymine C I Polynucleotides D R \(\begin{array}{lll}\text { 4. Double helix structure } & \text { D R.N.A }\end{array}\) The correct matching is 1 2 3 4 (a) \(\mathrm{C}\) D \(\mathrm{A}\) A (b) C A \(\mathrm{A}\) D a \(B\) (c) C t. \(\mathrm{D}\) A (d) \(\mathrm{C}\) \(\mathrm{B}\) D C

Match the following Column-I Column-II (a) Glycine (p) Forms chloroacetic acid with NOCl (b) Lysine (q) Neutral (c) Proline (r) Optically inactive (d) Glutamic acid (s) Basic (t) Isoelectric point

Match the following \begin{tabular}{ll} \hline Column-I & Column-II \\ \hline (a) Glucose & (p) Tollen's reagent \\ (b) Acetaldehyde & (q) Bromine water \\ (c) Sucrose & (r) Phenyl hydrazine \\ (d) Maltose & (s) Disaccharide \\ & (t) Ammonia \end{tabular}

Match the following \begin{tabular}{ll} \hline Column-I & Column-II \\ \hline (a) Glucose & (p) Reduces Fehling's \\ solution \\ (b) Fructose & (q) Exhibits mutarotation \\ in mild alkaline \\ medium. \\ (c) Mannose & (r) Produces tetra acetate \\ derivative on treatment \\ with acetic anhydride \\ and pyridine. \\ (d) A-methyl & (s) Get oxidized by \(\mathrm{Br}_{2} /\) \\ glucopyranoside & \(\mathrm{H}_{2} \mathrm{O}\) \\ & (t) With \(\mathrm{NaBH}_{4}\) gives mai- \\ tol and sorbitol \end{tabular}

Number of anomers formed when glucose forms its ring structure is

The number of dipeptides possible with three different amino acids combined are

An amino acid has one amino group and one acidic group. If its pKa values are 5 and 3, what will be its isoelectric point?

The number of monosaccharide molecules formed during hydrolysis from one mole of raffinose is

RNA contains (a) ribose sugar and thymine (b) ribose sugar and uracil (c) deoxyribose sugar and uracil (d) deoxyribose sugar and thymine

The reason for double helical structure of DNA is operation of [2003] (a) van der waals forces (b) hydrogen bonding (c) dipole-dipole moment (d) electrostatic attractions

Complete hydrolysis of cellulose gives (a) D-fructose (b) D-glucose (c) D-ribose (d) L-glucose

Insulin production and its action in human body is responsible for the level of diabetes. This compound belongs to which of the following categories? [2004] (a) an enzyme (b) an antibiotic (c) a hormone (d) a co- enzyme

The term anomers of glucose refers to [2006] (a) isomers of glucose that differ in configurations at carbons one and four (C-1 and C-4) (b) a mixture of (d)-glucose and (L)-glucose (c) enantiomers of glucose (d) isomers of glucose that differ in configuration at carbon one (C-1)

The pyrimidine bases present in DNA are (a) cytosine and adenine (b) cytosine and guanine (c) cytosine and thymine (d) cytosine and uracil

\(\alpha-\mathrm{D}-(+)\)-glucose and \(\beta-\mathrm{D}-(+)\)-glucose are (a) Conformers (b) Epimers (c) Anomers (d) Enantiomers

The two functional groups present in a typical carbohydrate are: [2009] (a) \(-\mathrm{CHO}\) and \(-\mathrm{COOH}\) (b) \(>\mathrm{C}=\mathrm{O}\) and \(-\mathrm{OH}\) (c) \(-\mathrm{OH}\) and \(-\mathrm{CHO}\) (d) \(-\mathrm{OH}\) and \(-\mathrm{COOH}\)

The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA? [2011] (a) \(2^{\text {nd }}\) (b) \(3^{\text {rd }}\) (c) \(4^{\text {th }}\) (d) \(1^{\text {st }}\)

Which of the following compounds can be detected by Molisch's test? (a) Amines (b) Sugars (c) Nitro compounds (d) Primary alcohols

Which one of the following statements is correct? \([2012]\) (a) All amino acids except glycine are optically active (b) All amino acids are optically active (c) All amino acids except lysine are optically active (d) All amino acids except glutamic acid are optically acitve

Synthesis of each molecule of glucose in photosynthesis involves: (a) 8 molecules of ATP (b) 6 molecules of ATP (c) 18 molecules of ATP (d) 10 molecules of ATP

Which one of the following bases is not present in DNA ? (a) Cytosine (b) Thymine (c) Quinoline (d) Adenine

Which of the vitamins given below is water soluble? [2015] (a) Vitamin \(\mathrm{C}\) (b) Vitamin D (c) Vitamin \(\mathrm{E}\) (d) Vitamin \(\mathrm{K}\)

Thiol Group is present in? (a) Cystine (b) Cysteine (c) Cytosine (d) Methionine