Biomolecules Practice Questions - DPP for JEE

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1. (a)
2. (c)
3. (b)
4. (d) Glucose being an aldose responds to Tollen’s test while fructose,
although a ketose, undergoes rearrangement in presence of basic
medium (provided by Tollen’s reagent) to form glucose, which
then responds to Tollen’s test.
5. (d) Since sucrose is dextrorotatory while hydrolysis product of
sucrose, having equimolar mixture of glucose and fructose, is
laevorotatory. Hence the hydrolysed product of sucrose is known
as invert sugar and the hydrolysis of sucrose is known as inversion.
6. (b) All proteins are not found in L-form but they may be present in
form of D or L.
7. (a) Butter, being a lipid, dissolves in chloroform.
8. (b) Human body can synthesize 10 of the 20 amino acids obtained by
hydrolysis of various proteins
9. (c) Chemically amylose is a long unbranched chain with 200-1000 a-
D-(+ -glucose units held by C1-C4 glycosidic linkage.
10. (a) On the basis of structure of guanine and complementary bases
present in them, we can say that if the sequence of bases in one
strand of DNA is I, then the sequence in the second strand should
be II
A : T : G : C : T : T  : G  : A    I
T : A : C : G : A : A : C : T    II
11. (a) Due to resonance,  ,  C – N bond
acquires some double bond character, hence shorter in length.
12. (c) Proline is an acidic amino acid.
13. (a) Isoelectric point (pH)
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1. (a)
2. (c)
3. (b)
4. (d) Glucose being an aldose responds to Tollen’s test while fructose,
although a ketose, undergoes rearrangement in presence of basic
medium (provided by Tollen’s reagent) to form glucose, which
then responds to Tollen’s test.
5. (d) Since sucrose is dextrorotatory while hydrolysis product of
sucrose, having equimolar mixture of glucose and fructose, is
laevorotatory. Hence the hydrolysed product of sucrose is known
as invert sugar and the hydrolysis of sucrose is known as inversion.
6. (b) All proteins are not found in L-form but they may be present in
form of D or L.
7. (a) Butter, being a lipid, dissolves in chloroform.
8. (b) Human body can synthesize 10 of the 20 amino acids obtained by
hydrolysis of various proteins
9. (c) Chemically amylose is a long unbranched chain with 200-1000 a-
D-(+ -glucose units held by C1-C4 glycosidic linkage.
10. (a) On the basis of structure of guanine and complementary bases
present in them, we can say that if the sequence of bases in one
strand of DNA is I, then the sequence in the second strand should
be II
A : T : G : C : T : T  : G  : A    I
T : A : C : G : A : A : C : T    II
11. (a) Due to resonance,  ,  C – N bond
acquires some double bond character, hence shorter in length.
12. (c) Proline is an acidic amino acid.
13. (a) Isoelectric point (pH)
= 
14. (b)
15. (b)
It is a ß-pyranose hence it is an aldohexose.
16. (d) 2, 4- Dinitroflurobenzene, also known as Sanger's reagent, reacts
with the H
2
N - group of the peptide to from 2, 4- dinitrophenyl
(DNP) derivative of the peptide. The DNP derivative of the
peptide is hydrolysed to give DNP derivative of the single amino
acid
+   
2, 4, Dinitrofluoro benzene
(DNP derivative of polypeptide)
 +  
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1. (a)
2. (c)
3. (b)
4. (d) Glucose being an aldose responds to Tollen’s test while fructose,
although a ketose, undergoes rearrangement in presence of basic
medium (provided by Tollen’s reagent) to form glucose, which
then responds to Tollen’s test.
5. (d) Since sucrose is dextrorotatory while hydrolysis product of
sucrose, having equimolar mixture of glucose and fructose, is
laevorotatory. Hence the hydrolysed product of sucrose is known
as invert sugar and the hydrolysis of sucrose is known as inversion.
6. (b) All proteins are not found in L-form but they may be present in
form of D or L.
7. (a) Butter, being a lipid, dissolves in chloroform.
8. (b) Human body can synthesize 10 of the 20 amino acids obtained by
hydrolysis of various proteins
9. (c) Chemically amylose is a long unbranched chain with 200-1000 a-
D-(+ -glucose units held by C1-C4 glycosidic linkage.
10. (a) On the basis of structure of guanine and complementary bases
present in them, we can say that if the sequence of bases in one
strand of DNA is I, then the sequence in the second strand should
be II
A : T : G : C : T : T  : G  : A    I
T : A : C : G : A : A : C : T    II
11. (a) Due to resonance,  ,  C – N bond
acquires some double bond character, hence shorter in length.
12. (c) Proline is an acidic amino acid.
13. (a) Isoelectric point (pH)
= 
14. (b)
15. (b)
It is a ß-pyranose hence it is an aldohexose.
16. (d) 2, 4- Dinitroflurobenzene, also known as Sanger's reagent, reacts
with the H
2
N - group of the peptide to from 2, 4- dinitrophenyl
(DNP) derivative of the peptide. The DNP derivative of the
peptide is hydrolysed to give DNP derivative of the single amino
acid
+   
2, 4, Dinitrofluoro benzene
(DNP derivative of polypeptide)
 +  
(Amino acid mixture)
17. (d) Zwitter ion contains both +ve and –ve charge. Proton of –COOH
group is transferred to the –NH
2
 group.—NH
3
? +
 group is acidic since
it can donate a proton and —COO
–
 group is basic since it can
accept a proton.
18. (c) Glucose is considered as a typical carbohydrate which contains –
CHO and –OH group.
19. (a) DNA has double stranded a-helical structure
20. (c)
21. (d) The correct structure of thymine is
22. (b) The DNA sequence that codes for a specific protein is called a
Gene and thus every protein in a cell has a corresponding gene.
23. (d) Enzymes are very specific biological catalysts possessing well -
defined active sites.
24. (b) In DNA and RNA heterocyclic base and phosphate ester are at C
1
'
and C
5
' respectively of the sugar molecule.
25. (a)