10 Biomolecules

Chapter
Topic-1: Carbohydrates

(a) Formation of pentaacetate of glucose with acetic

1 Multiple Choice Ouestions
anhydride.
1. When D-glucose reacts with HI, it forms (b) formation of addition product with 2,4 DNP reagent.
ab [AlIndia 2023, Set-, K) (c) Silver mirror fomation with Tollen's reagent.
(a) Gluconic acid (b) n-hexane (d) existence of alpha and beta forms of glucose.
(c) Saccharic acid (d) lodohexane 7. Which one of the following statement is correct about
2. Which of the following statements is not true about sucrose: |CBSE Sample 2021-22, Term-1, KI
glucose? (Delhi2023, Set-1, K| (a) It can reduce tollen's reagent however cannot reduce
(a) It is an aldohexose fehling's reagent
(b) On heating with HI it forms n-hexane (b) It undergoes mutarotation like glucose and fructose
(c) It is present in pyranose form (c) It undergoes inversion in the configuration on
(d) It gives 2, 4 DNP test hydrolysis
3. Hydrolysis of sucrose is called |Delhi2023 Set-1, K (d) It is lacvorotatory in nature
(a) inversion (b) hydration 8. In the following reaction, identify Aand B:
(c) esterification (d) saponification JAIlIndia 2021-22, Term-1, U|
4. Which of the following sugar is known as dextrose? CH,0, Acetic anhydride ’A
|AIl India 2022, Term-1, K| Conc.nitric acid
(a) Glucose (b) Fructose B

(c) Ribose (d) Sucrose

(a) A-C0OH -(CH), -COOH, B=OHC
5. Glucose on reaction with Br, water gives : (CHOCOCH),- CH,0C0CH,
JAll India 2022, Term-1, K) (b) A=COOH-(CH,),-CHO,B=OHC
(a) Saccharic acid (b) Hexanoic acid (CHOCOCH), - CH,0C0CH,
c) Gluconic acid (d) Salicyclic acid (c) A=OHC - (CHOCOCH,),- CH,0COCH,
6. Which one of the following reactions is not explained by B= COOH-(CH,),-CHO
the open chain structure of glucose: (0) A=OHC -(CHOCOCH),-CH,0COCH,,
|CBSE Sample 2021-22, Term-I, K) B=COOH-(CH,),-COOH
 202 Blomolecules
203
9
Which one of the following reactions is not
the open chainStructure of glucose:
explained by 13. Dissachrides that are reducing in nature are: Chemistry Short Answer Questions (2 or 3 Marks) 24. Give the
reaction of glucose with acetic anhydride.
(CBSE Sample 2020-21, IRi Presence of which group is confimed by this reaction?
|CBSE Sample 2021-22, U) (a) sucrose and lactose
When sucrose is hydrolysed the optical rotation values
(a) Formation of pentaacetate of glucose with acetic 21. |Delhi 2023, Set-1, K|
(b) sucrose and maltose are measured using a polarimeter and are given in the 25. Account for the following: |CBSE Sample 2022-23, U|
anhydride. following table: |CBSE Sample 2023-24, Ap|
(b) formation of (c) lactose and maltose (a) There are 5 OH groups in glucose
addition product with 2,4 DNP reagent. S.No. Time (hours) Specifie Rotation
(c) Silver (d) sucrose, lactose and maltose (b) Glucose is a reducing sugar
mirror formation with Tollen's 1 0 +66,5°
(d) existence of alpha reagent.
and beta forms of 2 -39,9° 26. What happens when D-glucose is treated with the
10. Which of the
following is a
glucose. 2 Assertion Reasonvo Statement 1ype
Questions following reagents (CBSE Sample 2022-23,U|
polysaccharide?
|CBSE Sample 2021-22, K] Given below are two
! (a) Account for the two specific rotation values.
(a) Bromine water
(a) glucose statements labelled as Assertion (AY (b) What is the specific name given to sucrose based on
(b) maltose and Reason (R). Select the most the above observation. (b) HNO,
(c) glycogen
(d) lactose
appropriate answer from the
11. options given below: (c) One of the products formed during the hydrolysis of 27. Give the plausible explanation for the following:
Which one of the
following statement is correct about (a) Both (A) and (R)
are true and (R) is the sucrose is aglucose, that reacts with hydroxylamine JAIl India 2020, U|
sucrose: correos
(a) It can
[CBSE Sample 2021-22, U explanation of (A).
to give compound A. ldentify compound A. (a) Glucose doesn't give 2,4-DNP test.
reduce tollen's reagent (b) Both (A) and
however cannot reduce (R) are true, but (R) 1s (b) The two strands in DNA are not identical but are
fehling's reagent explanation of (A).
not the correct 12. Give the reaction ofheating glucose with hydroxylamine.
(b) It
undergoes mutarotation like glucose and Presence of which group is confirmed by this reaction? complementary.
(c) (A) is true, but (R) is false.
(c) It
undergoes inversion in the fructose (d) (A) is false, but (R) is true.
|Delhi 2023 Set-II, K (c) Starch and cellulose both contain glucose unit as

hydrolysis configuration on 14. Assertion (A) :Sucrose is a

23. Give the reaction of glucose with hydrogen cyanide. monomer, yet they are structurally different.
(d) It is
laevorotatory in nature
non-reducing sugar, Presence of which group is confirmed by this reaction?
2. In the JAll India 2020, Ki |Delhi 2023 Set-II, K|
following reaction, identify A and B: Reason (R) :Sucrose has
glycosidic linkage.
JCBSE Sample 2021-22, U| Very Short Answer
C,H,,0, Acetic anhydrnde,A Questions (1 Mark) Topic-2: Proteins, Enzymes
15. What type of
Conc.nitric ac1d linkage is present in
B polysaccharides? Multiple Choice Questions
3 Amino acids which cannot be synthesized in the body

(a) A=COOH-(CH,),-COOH, B-OHC-{CHOCOCH), 16. What is the

basic |Delhi 2020, K) and must be obtained through diet are known as
and fructose?
structural difference between glucose 1. Protein are polymers of [AlIndia 2023 Set-1, K| JAlI India 2022, Term-1, K|
-CH,0C0CH, 17. Write the |Delhi 2019, K) (a) Nucleic acids (a) Acidic amino acids
(b) A
COOH - (CH,)4 CHO, B = OHC
products obtained after hydrolysis of lactose. (b) Amino acids (b) Essential amino acids

(CHOCOCH,(CHOCOCH,
(c) A= OHC - ),-CH,0COCH,), CH,0C0CH,, - B=
18. What are the products of |Delhi 2019, K|
hydrolysis of sucrose?
(c) Monosaccharides

(d) Amines
(c) Basic amino acids
(d) Non-essential amino acids

(d)
COOH-(CH,), -CHO
A= OHC -
19
Which of the two
JAI India 2014, K) 2. B-pleated sheet structue in proteins refers to 4. Complete the following analogy:
components of starch is water soluble ? JAJI India 2022, Term-1, K|
COOH - (CH,),(CHOCOCH,), CH,0C0CH, B =
- |Delhi 2023 Set-III, K
Curdling of milk : A : a-helix :B
-COOH 20. What are the |Delhi 2014, K| (a) primary structure
products of hydrolysis of sucrose? (b) secondary structure (a) A: Primary structure B: Secondary structure

[AIl India 2013, K] (b) A:Denatured protein B:Primary structure

(c) tertiary structure
(d) quaternary structure (c) A:Secondary structure B: Denatured protein
(d) A: Denatured protein B: Secondary structure
 204

Which of the following sttement is corect

ICBSE Sample 2821-22, Term-I.
10. Asertion (A): Proteins are polymers of o
connected by s peptide bond.
Cheminostraciyds
(Delhl 2023amiSet-4,
Biomolecules
17, (a) Write the product when Ducone react with conc 18, Define the following terms as related to proteins:
205

a Fhe pteis a generslly solahle in water HNO, (Delhi 2019, (3 6) Peptide Sinkage
Reason (R): Atetrapeptide Contains 4
b) Albumin is an eample of fheosproteins linked by 4peptide bonds Amino acids (b) Amino acids show amphoteric behaviour. Why? G) Primary structure
(c) In 6heos peoteins, the structure s stbilised by 11. Assertion (Aj: Proteins are found to have (cy Write one difference between -helix and B-pleated (ii1) Denaturation
two
hydrogen bond and disutphide honds
(d pll does not afect the primary
types of sccondary structures viz
plested sheet structure.
alpha- helix anddifferent
beta
structures of proteins. SAl Sndia 2014, /K|
structure of protein
6 Which of he following statenent is corect Reason (R): The sccondary structure of
ICBSE Sample 2021-22, stabilized by hydrogen bonding. proteins is Topic-3: Vitamins, Nucleic Acids, Hormones
(a) Fihrous peoteins are generally soluble in water
ICBSE Sample 2022-23, U
b) Albumin is an eanple of fihrous (c) nucleotides
proteins Short Answer Ouestions (2 or 3 Marks) Multiple Choice Duestons
c) In fihrous proteins, the structure is stabilised by (d) glucose
ydrogen bonds and disulphide bonds 12. Define the following terms with a 1. The vitamins which can be stored in our body are:
(d) pli does not afflect the primary cach:
suitable cxample in (CBSE Sample 2023-24, K 2 Assertion Reason/Two Statement Type Ouestions
structure of proein
7. Curding of milkis an example of (a) Polysaccharides
(|Delhi 2020, RI (a) Vitamin A, B, Dand E Given below are two statements labelled as Assertion (A)
ICBSE Sample 2020-21. K (b) Denatured protein (b) Vitamin A, C, Dand K and Reason (R). Select the most appropriate answer from the
(a) breaking of peptide linkage )0h
(c) Fibrous protcin (C) Vitamin A, B,Cand options given below:
(b) bydrolysis of lactose
13. Differentiate between following (d) Vitamin A, D, E and K (a) Both (A) and (R) are true and (R) is the correct
(c) breaking of protein into amino acids [Delhi 2020, Set-1|
) Amylose and Amylopcctin 2 Nucleosides are composcd of explanation of (A).
(d) denauration of proetin
(i1) Globular protein and Fibrous protein |AIl India 2022, Term-L. KI (b) Both (A) and (R) are true, but (R) is not the correct
Amino acids are |Delhi 2020, Set-|
(i) Nucleotide and Nucleoside (a) a pentose sugar and phosphoric acid explanation of (A).
(a) acidsc (b) basiC
14. a (b) a nitrogenous base and phosphoric acid (c) (A)is true, but (R) is false.
(c) amphoteric (d) neutral Differentiate between the following: |Delhi 2019, RI
) c) a nitrogenous base and a pentose sugar (d) (A) is false, but (R) is true.
Amylose and Amylopectin
Assertion Reason/Two Statement Type Questions () Peptide linkage and Glycosidic (d) a nitrogenous base, a pentose sugar and phosphoric Assertion (A):Vitamin Ccannot be stored in our body.
linkage
Given bclow are two statements labelled as (ii) Fibrous proteins and Globular Reason (R) :Vitamin Cis fat soluble and is excreted
Assertion (A) protcins 3, The he uhid from the body in urine.
and Reason (k). Select the most
appropriate answer from the 15, Write chemical reactions to show that open which is present in DNA but not in RNA, is [Delhi 2023, K]
options given below structurc of ull ddady All India 2022, Term-1, K| 6 Assertion (A): The backbone of DNA and RNA
(a)
D-glucose contains the following: |Delhi 2019, K|
Both (A) and (R) are true and (R) is (a) Cytosine molecules is a chain consisting of heterocyclic base,
the correct i) Straight chain
explanation of (A) (b) Guaninc pentose sugar nd phosphate group. (Delhi 2023 Set-3, U|
(b) Both (A) and (R)are truc, but (i) Five alcohol groups
(R) is not the corrcct c) Adenine Reason (R): Nucleotides and nucleosides mainly differ
explanation of (A) (i) Aldehyde as carbonyl group from cach other in presence of phosphate group.
a (d) Thymine 1
(c) A)is true, but (R) is false. 16. Define the following with an example of each : 7. Assertion: The two strands of DNAare complementary
4. Nucleic acids are polymero f a b
(d) (A) is false, but (R) is true. to cach other (CBSE Sample 2020-21, U|
|AIl India 2018,K| bus al d o AIl India 2022, Term-1. KI
9.
Asertion (Ay: Enzymes are very specific for a (a) Polysaccharides I(a) amino acids Reason: The hydrogen bonds are formed between
reaction and for a particular substrate. particular
(b) Denatured protein (b) nucleosides specific pairs of bases.
Reason (Ry: Enzymes are
biocatalysts, (c) Essential amino acids
(CBSE Sample 2023-24, |
 206 Biomolecules

Matching Based Questions

(b) Amino acids behave like salts.

Water soluble vitamins must be

Chemistry 19. i)
Deficiency of which vitamin causes night blindless?
207
scientists-notably, Phoebus Levene and Erwin Chargaff
(c)
taken |Delhi 2014, K| -carried out a series of research efforts that
8 Match the following |CBSE Sample 2021-22, K] diet. regularly in i) Name the base that is found in nucleotide of RNA additional details about the DNA molecule,
revealed
(d) The two strands in DNA are including
()Amino acids (A) Protein other.
complimentaryyto cach only. [Delhi 2014, K| its primary chemical
components and the ways in which
i) Glucose on reaction with HI gives n-hexane, What they joined with one another. Without the
() Thymine (B) Nucleic acid What is the scientific
14. (a) difference between
(m)Insulin (C) DNA native protein and
does it suggest about the structure of glucose ? foundation provided by these pioneers, Watson and
denatured protein?
(iv) Phosphodiester linkage (D) Zwitter ion JAII India2019, K |Delhi 2014, K| Crick may never have reached their
(v) Uracil Which one ofthe following is a groundbreaking
disaccharide Case Based Questions conclusion of 1953: that the DNA molecule exists in the
Which of the following is the best matched options? Glucose, Lactose, Amylose, Fructose form of a three-dimensional double helix.
(a) ()-A: (v) - D; (m) -C: (iv) - B (c) Wite the name of the vitamin 0Carbohydrates are optically active polyhydroxy aldehyde
coagulation of blood.
responsible for the Chargaff, an
Austrian biochemist, as his first step in
(b) )-D; () - C: (ii) - A: (iv) -B and ketones. They are also called saccharides. AIl these this DNA research, set out to see whether there
were
(c) (i)-D. (v) - D: (ii) -A: (iv) - B 15. (i) Write the structural difference carbohydrates which reduce. Fehling's solution and
(d) i)-A: (i) -C: (i) - D: (iv)- B cellulose.
between starch and Tollen's reagent are referred to as reducing sugar. Glucose,
any differences in DNAamong different species. After
developing a new paper chromatography method for
(ii) What type of linkage is present in nucleic the most important source of energy for mammals
4 acide 2 separating and identifying small amounts of organic
Very Short Answer Questions (1 Mark) is obtained by the hydrolysis of starch. Vitamins are
(iii) Give one example each for fibrous material, Chargaff reached two major conclusions:
9
globular protein.
protein and necessary food factors required in the diet. Proteins are the
What are three types of RNA molecules which perform |AIl India 2016, K| |CBSE Sample 2022-23, A|
different functions? 16. (i) Write the name of two polymers of amino acids and perform various structural
[Delhi 2013, K| mnonosaccharides (i) the nucleotide composition of DNA varies among
on hydrolysis of lactose sugar. obtained and dynamic functions in the organisms. Deficiency of
5 Short Answer Questions (2 or 3 Marks)
ii) Why Vitamin C cannot be stored in our body ?
[Delhi 2016, K| vitamins leads to many diseases.
species.
(i1) Almost all DNA, no matter what
10. (a) DNA fingerprinting is used to determine paternity 2Answer the following: organism or tissue
JAIIIndia 2023, Set-1, K| type it comes from maintains certain properties,
of an individual. Which property of DNA helps in (i) What is the
[Delhi 2015, K| (a) The penta-acetate of glucose does not react with even as its composition varies. In particular, the
the procedure?
difference between a nucleoside and
[CBSE Sample 2023-24, U| nucleotide ?
Hydroxylamine. What does it indicate? amount of adenine (A) is similar to the amount
(b) What structural change will occur when a native 17, (i) Write the product
[Delhi 2015, K| (b) Why cannot vitamin C be stored in our body? of thymine (T), and the amount of guanine (G)
protein is subjected to change in pH? obtained when D-glucose reacts (c) Define the following as related to proteins. approximates the amount of cytosine (C). In other
with H,N -OH. JAII India 2015, K
11. What are nucleic acids? Why two strands in DNA are not ) Peptide linkage JAIl India 2023, Set-1, K) words, the total amount of purines (A + G) and the
(ii) Amino acids show amphoteric behaviour. Why
identical but are complementary? (ii) Denaturation total amount of pyrimidines (C+ T) are usually
|AII India 2023, Set-I, K| [Delhi 2015, K] OR nearly equal. This conclusion is now known as
(iii)) Why cannot vitamin C be stored in our body?
12. (a) What is the difference between a nucleoside and (c) Define the following as related to carbohydrates: "Chargaff's rule."
nucelotide? JAl India 2023 Set-II, K| |Delhi 2015, K| ba 0) Anomers |AIl India 2023, Set-I, K|
Chargaffs rule is not obeyed in some viruses. These
(b) What products would be formed when a nucleotide 18. (i) Which one of the following is a disaccharide: Starch. either have single- stranded DNA or RNA as their
t (i) Glycoside linkage
from DNA containing thymine is hydrolysed? Maltose, Fructose, Glucose ? [Delhi 2015, K| genctic material. Answer the following questions:
21. Strengthening the Foundation: Chargaff Formulates His
13. Give reasons for any 3 of the following observations: (ii) What is the difference between fibrous protein and bsRules" (a) Asegment of DN Ahas 100 adenine and 150 cytosine
globular protein ? bases. What is the total number of nucleotides
[Delhi2023, Set-1, U| |Delhi 2015, K| Many people believe that James Watson and Francis
(a) (iii) Wríte the name of vitamín whose deficiency causes present in this segment of DNA?
Penta-acetate of glucose does not react with Crick díscovered DNA in the 1950s. In reality, this is
hydroxylamine. (b) A sample of hair and blood was found at two
bone deformities in children. |Delhi 2015, K| not the case. Rather, DNA was first identified in the
sites. Scientists claim that the samples belong to
late 1860s by Swiss chemist Friedrich Miescher. Then.
same species. How did the scientists arrive at this
in the decades following Miescher's discovery, other
conclusion?
 208
Biomolecules
(C) The sample ofa vins was tested and it was
contain 2096 adenine. 20% thvmine, 20 %
and the rest cytosine. Is the
found to
guanine
canteen contractor to replace the
some proteins and vitamins rich food Chemistry
bakery products
ike fruits, with
209

virs (a) DNA- double belix (b)

(c) RNA? What do v¡u infer
OR
genetic material of this
DNA-single helix
from this data?
sprouts ete

and students
The decision was
welcomed by the parents
Affer reading the above passage, answer |Dtheelhi 2017,
salads.
Solutions
How can Chargaff's rule be used to
infer that the genetic
material of an organism is double- helix or
single- helix?
questions :
() What are thee values (at least fol owing
two) displayed by
Topic-l: Carbokydrates
1ek
() A OHC-
(CHOCOCH,)-CH,0COCH,
BCOOH-(CH),-COOH
CHO
(b) n-hexane;
22. After watching a
programme on TV about the
() Which polysaccharide
component of Ritu? 1.
COOH

carbohydrates
CHO
carcinogens (cancer causing agents) potassiumpresence
of iscommonly present in bread ? CH, (CHOH), INO,

and potassiurn iodate in bread bromate (i) Write the two types of (CHOH), , (CH,), CH,0H
(CHO),
and other bakery secondary COOH
Rupali a class XI student decided to
about the adverse effects of
products,
make others aware
proteins.
iv) Give two
structure
of CH,OH
D-Glucose
CH,
n-Hexane
Glucose
CHO
Saccharic acid

these carcinogens in foods. examples of water soluble vitamins 2. (d) The molecular formula of glucose is
(1 Mark)
(CHOH), +S(CH,C),0
She consulted the school 24. Shanti, a CH,,0, and it
principal and domestic helper of Mrs. Anuradha, fuin,
instruct the canteen contractor to stop requested him to contains an aldehydic (-CHO) functional group. Acetie anhydride
while mopping the floor. Mrs. Thus, it is an aldohexose.
selling sandwiches Anuradha CH,OH
pizzas, burgers and other bakery
The principal took an products to the students. took her to the nearby hospital where
to be severely
eshe
was immediately On prolonged heating with HI, it
forms n-Hexane
Glueose

the canteen
immediate action and instructed
contractor to replace the bakery products rich diet and
'anaemic. The doctor prescribed an irondiagnosed suggesting a straight chain form.
It exists in a
CHO

(CHOCOCH), +SCH,CoOH
with some protein and multivitamins supplement to her. Mr six-nmembered pyranose ring fornm.
vitamin rich food like fruits, Anuradha supported her Due to the cyclic structure, it does not
After a month, Shanti wasfinancially get the medicines
to give 2, 4-DNP
salads, sprouts, etc. The decision was test. Bbok eu CH,0-C-CH,
parents and the students. welcomed by the diagnosed to be nomal. ete Therefore, option (d) is correct. (Mark)
Glucose penta acetate
(1 Mark)
JAII India 2017, A) JAIl India 2013, K1 3. (a) Hydrolysis of sucrose to give 9 (d) Glucose is found to exist in two different crystalline
After reading the above
passage, answer the following After reading the above
passage, answer the following D- () - glucose and D -( equimolar mixture of
- fructose is called t forms which are named as t and Bwhich can not be
question:
questions inversion. It is because it brings about a explained by open chain structure of glucose.
the sign of rotation, from dextro (t) to change
in
(a) What are the (i) What values are
values (atleast two) dispalyed by displayed by Mrs. Anuradha? laevo () and (1 Mark)
Rupali? the product is named as invert sugar. 10. (c) Glycogen (It is a
(i) Name the polymer of glucose) (1 Mark)
(b) Which
vitamin whose deficiency causes CHyO11+ H,0CGH0,+CçHi20% 11. (c) It undergoes
inversion in the
polysaccharide component of carbohydrates 'pernicious anaemia". Sucrose
D-(+)-Glucose D--Pructose hydrolysis. configuration on
is commonly present in bread? (iii) Give an example of a (1Mark)
12. (d) A- OHC-
(c) Write the two 25. After
water soluble vitamin. 4. (a) Glucose is a carbohydrate and act as a
(1Mark) (CHOCOCH), -CH,0COCH,
B= COOH-(CH,),-COOH
type of secondary watching a programme on TV
structures of reducingciosheliCHO
sugar. It is also known as dextrose as it rotates the
proteins. effects of junk food and soft drinks about the adverse
on the health of plane polarised light to the right.
COOH
(d) Give two
examples of water soluble vitamins school children, Sonali, a student of (1Mark) (CHOH),HNO,
23. After watching a Class XII, discussed CHO COOH (CHOH),
programme on TV about the presence the issue with the school CH,OH COOH
of principal. Principal immediately 5. (c) (CHOH), +[0]- Br,/water
’ (CHOH)A5 Glucose Saccharic acid
carcinogens(cancer causing agents) Potassium
bromate and Potassium iodate in
instructed the canteen contractor to replace the
fast food
CHO

bread and other bakery with the fibre and vitamins rich CH,0H
products, Ritu a class XIl student food like sprouts, salad,
at CH,OH
Gluconic (CHOH), + 5(CH,CH),0
decided to aware others fruits etc. This decision was Glucose
Acetic anhydride
about the adverse effects of the students. After
welcomed by the parents and acid

these carcinogens in foods. reading the (1 Mark) CH,OH

She consulted the above passage, answer the 6. (d) Glucose is found to exist in two different Glucose
school principal and following questions:Ales crystalline
instruct canteen contractor to stop requested him to (a) What
values are expressed by Sonali and
[Delhi 2013, K] forms which are named as a and ß which can not be
explained by open chain structure of glucose.
CHO

pizza, burgers and other selling sandwiches, the (CHOCOCH), +SCH,COOH

bakery Principal of the school?
Principal took an immediate products the students.
to
p (b) Give two (c) It undergoes inversion in the
(1 Mark)
action and instructed the examples of configuration on
CH,0- C-CH,
water-soluble vitamins. hydrolysis. (1 Mark) Glucose penta acetate
(1 Mark)
 210 Biomolecules
13.

14.
(c)
(b) Sucrose is a non-reducing sugar because the
(1 Mark) 16. Glucose:
It is a aldohexose and contains
Chemistry
aldehyde
24
Clucose reacts with acetic anhydride and undergoes
acetylation and gives pentaacetate, CHO COOH
(b) [CHOH), Oxidation (CHOH), Odtn (CHOH),
COOH
211

two monosaccharide units are held together by a

glycosidic linkage between C, of a-glucose and C,
of B-fructose. The reducing groups are involved in
group.
Fructose: functional
AMark)
CHO

CHOH),
Acetic anhydride
CHO

e, (CH-0-C-CH,), CH,OH COOH CH,OH

It is a ketohexose contains ketone functional Saccharic acid Gluconic acid
glycosidic bond formation. CH,0H
15. Glycosidic linkage is present in
(1 Mark)
group.
A Mark) CH,-0-C-CH, 27. (a) Aldehyde group is not free in glucose, it is involved
(1 mark)
polysaccharides.
(1 Mark) (1Mark) in the formation of cyclic structure in glucose. Thus,
17
The formation of pentaacetate confirms the presence it does not react with 2, 4-dinitrophenylhydrazine.
Topper's Answer of five -OH groups. (1 Mark) (1 Mark)
(b) The two strands in DNA are held topether by hydrogen
25. (a) Acetylation of glucose with acetic anhydride gives bonds between specific pair of bases (cytosine with
clucose pentaacctate which confirms the presence of
guanine and adenine with thymine). Thus, the two
five-OH groups, Since it exists as astable compound,
no five-OH groups should be attached to different carbon strands are complementary to cach other. (IMark)
(c) Starch contains G-D-glucose, while cellulose contains
atoms. (1Mark)
CHO p-D-glucose as their monomers. (1Mark)
CHO
euOHL. Actic anbydrde, (CH-0CH.L Tople-2: Proteins, Enzymes
s-Dgatactogyranae pagpyYansIe
CH,OH CH,-0C CH, 1. (b) All proteins are polymers of a-amino acids.
(I Mark)
The products of hydrolysis of lactose are B-D-glucose and ß-D-galactose. (b) Glucose reduces Fehlings reagent
(1 Mark) 2. (b) ß-pleated sheet structure and o-Helix in proteins
H
refers to secondary structure. These structures arise
18. The products ofhydrolysis of sucrose are: (c) Glucose
D-glucose and (1 Marlk) due to the regular folding of the backbone of the
D-fructose (½+ ½= IMark) CH=N OH H-COH polypeptide chain due to hydrogen bonding between
19. Amylose is water soluble component of
starch which
constitute about 15-20%. (1 Mark)
(CHOH), HO CH +2Cu+ 21H,0 -C-and- NH-groups of thepeptide bond,
20 Glucose and fructose. CH,OH HCOH (1 Mark)
22. Glucose reacts with hydroxylamine to form an oxime H-COH 3. (b) Theamino acids which are not synthesized in our body
CpH201 +H,0 CoHyp06+CoHj20% and obtained through diet are essential amino acids.
Glucose Fructose This reaction confirms the presence of a carbonyl group
CH,OH For example: histidine, lysine, leucine etc. (1 Mark)
(1 Mark)
21. (a) Thereactant Sucrose is dextrorotatory. On hydrolysis
o-o)in glucose. (1 Mark) HO 4, (d) A:Denatured protein
CHO CH = N-OH B: Secondary protein
it give glucose dextrorotatory and fructose which is
NH, OH HCOH Curdling of milk is due to denaturation of proteins.
leavoroatatory. The specific rotation of fructose is
higher than glucose
(CHOH), (CHOH), d-helix is an clement of secondary structure in
HOC-H +Cu,0 +4H
Sucrose is dextrorotatory but after hydrolysis gives CH,OH CH,OH (1 Mark)
which the amino acid chain is arranged in a spiral.
(1 Mark)
HCOH
dextrorotatory glucose and laevorotatory fructose. 23. Glucose reacts with hydrogen cyanide to give
5 (d) pH does not affect the primary structure of protein
Since the laevorotation of fructose (-92.4°) is more cyanohydrin. This reaction confirms the presence of a HCOH while pH affects the tertiary structure. (1Mark)
than dextrorotation of glucose (+ 52.5°), the mixture carbonyl group (C- 0) in glucose. (1 Mark)
CH,OH (1 mark)
6. (d) pH does not affect the primary structure of protein
is laevorotatory. (1 Mark) (1 Mark)
CHO COOH while pH affects the tertiary structure.
(b) Invert sugar, The hydrolysis of sucrose brings about CHO CN
CH 7 (1Mark)
(CHOH, Br, water yfCHOH),
(d)
a change in the sign of rotation, from dextro (+) to 26. (a) (1 mark)
laevo (-) and the product is named as invert sugar. (CHOH), HCN (CHOH), CH,OH
8.
Topper's Answer
(1Mark)
CH,OH Gluconic acid
CH,OH CH,OH (1 Mark)

(1 Mark)
 213
212 Biomolecules
one
WhenOH group of hemiacetal carbon of
Chemistry
9
(b) Both A and R are true and
R is not the corect oIobn helix get uncoiled and protein Amylose and|Amylopectin monosaccharide is condensed withOH group of
Cxplanation of A. (1 Mark) loses its biologi 14. ) lmnlose: It is a linear polymer of a-D glucose
another, glycosidic bond is formed, which
links two
10. (c) All proteins are polymers of lHc activity. This form is called
Example: Coagulation of egg white on boiline
logical
'denatured having approximately 200-1000
a-D-glucose (1 Mark)
10 a-amino acids. A
tetrapeptide contains four amino acids linked by
protein' units. C-l of one a-D glucose is
C-4
attached to monosacharide together.
three peptide bonds. bond. It is (ii)
11. (b) Both A and R are true (1 Mark) (1 Mark) of another a-D glucose with glycosidic Fibrous Proteins Globular Proteins
Note starch
but R is not the correct water soluble and it forms 15-20% part of In these proteins
explanation of A. I,. () Proteins which (i)
12. (a) (1Mark) Denaturation destroys secondary and I and give blue colour with poly-peptides
Polysaccharides: Carbohydrates which yield a tertiary are made up of
large number of monosaccharide units on
hydrolysis
are called polysaccharides. Example: Starch
protein, but primary structure remaing intan
(c) Fibrous protein: When the
structures of Amlopectin: It is a branched chain polymer of a-D
glucose which is constituted by hundreds of small
linear, thread like
moleculesarecalled
attain spherical
shape and poly
(1 Mark) l1 run parallel and are held together by polypeptide chains chain having 20-30 a-D glucose unit. In it small fibrous protein. peptides are

structuhydr
re isogen
C-1e
(b) Denatured protein: When a protein is subjected
disulphide bonds,then fibre like and chain are formed by glycosidic bonds between In these molecules, held together
tophysical change like change in pH, the hydrogen
bonds are disturbed. Due to this, globules unfold and
Such type of proteins are called formed.
'fibrous proteins and C-4. These chain are joined by C C, bonds. poly-peptide chains
are held together
with relatively
weaker-H
Example: Keratin This fraction does not give blue colour with I, bonds,
13. (1 Mark) (1 Mark)
with H bonds.
They are soluble
linkange They are insoluble (iü)
() Peptide linkage and Glycosidic
(ii)
Topper's Answer in water but soluble inwater, alkalies,
The bond conecting two or more similar or different in strong acid and saltsolutions and
amino acid in protein is commonly called peptide bases.
acid solutions.
bond or peptide linkage. In the formation of peptide Example: Keratin, Example:
bond-NH, group of one amino acid is condensed Myosin Globulin, Pepsin
with -COOH of adjacent amino acid to form (1 Mark)
CONH linkage.
B)comess q inea chain
15
Topper's Answer

Globuas ecm
OR

.
n-hexane)
) E knatim, mgesin
(w) Nucoeta Nuctocide
Phasptor
hhen e pheshenus cothound ) Kolen the nianehw base
me attacched to 5 foutin

-mucleoti des thaouh

-dewton kintaa plroyte and thenfm fotyollLacidan
 214
215

21

9.
Chemisoy Biomolecules

CHO OH
acids exist as zwitter jon form and can react with
acids as well bases. (1 Mark)

HCN (c) a-Helix: The polypeptide chains twist into a right

(CHOH), CHOH). handed screw with -NH group of amino acid
CH,OH CH,OH bydrogen bonded withCOgroup of an adjacent
Glacose cyanohydrin
1 nacthing turn of the helix.
(1 Mark)
Thiajanont'anpeniaoatake Bpleated: The polypeptide chains stretch to
16. (a) Polysaccharides : These
carbohydrates yield a large
maximum extension and lay side by side in a zig-zag
number of monosaccharide units on hydrolysis.
For ex :starch, cellulose, gums (any one) manner to form a flat sheet. Each chain is held to two
(1 Mark) neighbouring chains by hydrogen bond (1 Mark)
native
(b) Denatured protein : When a protein in its change
fom is subjected to a physical change like 18. (a) Peptide linkage: A peptide bond is an amide
D-Gucas
in temperature or chemical change like change in linkage formed between- COOH group of one
pH, the H-bonds break, globules unfold, the helix
gets uncoiled and the protein loses its biological a-amino acid and NH, group of other a-amino acid
activity. This is denatured protein. by loss ofa water molecule. For example:
For ex coagulation of egg white on boiling,
curdling of milk (any one) (1 Mark)
H,N - CH,-C - OH +H-E-ÇH-COOH
Note
H CH,
Food, especially meat is cooked in order to denature the
proteins within and make them easier to digest. CH,
Dydised (c) Essential amino acids : These amino acids cannot ’H,N-CH,C-NHCH-COOH
be synthesised in the body and must be obtained Peptide
bond
through diet.
() (1Mark) (1Mark)
Glucose on heating with HI and red For ex :Valine, leucine, lysine
(b) Primary structure: Each polypeptide chain of
100C, it forms
of straight n-hexane. This provesphosphorous
chain of six carbon
at
the presence CHO
Note
Thenineessentialamino acidsarehistidine, isoleucine,leucine,
proteins has a large number of a-amino acids which
are linked to one another in a specific manner. The
CHO atom in glucose. ysin, methionine. phenylalanine, threonine, tryptophan and
(CHOH)4+5 CH;C0CI ZnCl,
valine. specific sequence in which various a-amino acids
(CHOH), H. Red P CH-OH acetylchlonde 17. (a) When glucose reacts with conc HNO,, saccharic
present in a protein are linked to one another
is

CH,OH called its primary structure. Any change in sequence

acid is formed.
CHO of a-amino acids creates a different protein.
CHO COOH

(1)
CH-CH-CH-n-hexancCH-CH-CH,
Glucose forms pentaacetyl (1 Mark)
(CHOCOCH), +5HCI
CH0COCH
Glucoseppentaacetate
(CHOH),
CH,0H
glucose
Conc.
HNO,
(CHOH),
CoOH
saccharic acid
(c) Denaturation: When a protein in its native
(IMark)
form

is subjected to physical changes such as change in

temperature, pH, etc., H-bonds are broken. Due to
derivatives
chloride and acid anhydride in the with acid (1Mark) (1 Mark)
(1) Glucose reacts cleavage ofH-bonds, unfolding of protein molecule
anhydrous zinc chloride. It proves that onepresence of withhydrogen (b) Amino acids show amphoteric behaviour in zwitter
of glucose
contains five OH molecule cyanohydrin. This reaction provescyanide to form,
the presence of ionic form as they react both with acids and bases.
occurs and the protein loses its biological activity.
This loss ofbiological activity is called denaturation.
groups. carbonyl group. Due to presence of both acidic (carboxyl group) (1 Mark)
and basic (amino group)in same molecule, amino
 216

SNote
Denaaration efproteis ivoves the disruption of both
9 The three
functions aretypes of RNA which perform
(i)
Chemidifferens
stry Biomolecules
H These vitamins include vitamin Band C.
217

seconuar and tertiaryy strctures Denatteration reactions

(1)
Transfer RNA or tRNA. beoaHO- H,C Base
(iii) Ribosomal RNA or rRNA. (1 Mark)
are not eet strong o break the pepide bonds therefore
primar sructhure of proteinS remain întact Denaturation
pirocese disrat the normaf alpha-helixr and beta sheets in Messenger RNA or mRNA.
10. (a) Replication (d) The two strands in DNA are complimentary to
roteie and ucois thet into random shap
A
(1 Mark) H/
sequence
person
of
and is thebases on DNA is unique for a
i H3
,/H cach other because the purines and pyrimidines of
from genetic
Topic-3: Vitamins, Nucleic Acids, Hormones the material transferred to
individual
determination of the parent
paternity. which helps in the OH
one strand bond to their counterparts in the second
(b) During OH strand according to the rule A ’T and G ’C
1. (d) Vitamin A. D, E and K.
These are fat soluble structures denaturation
are secondary and
(1 Mark) (a) Nucleoside
Vitamins remains intact. destroyed but the primary tertiary through Hydrogen bonds. (1 Mark)
(1structure
(1 Mark 11.
2. c)
Nucleosides are composed of a nitrogenous base, Nucleic
are one ofAcids, the long chain Mark) 14. (a) Proteins which are found in a biological system
nucleus
the
of the components of polymeric biomolecules. 0-P-o-H.c Base with unique 3D-structure and biological activity
3. (d)
and a pentose sugar.
The bases which are
(1 Mark) the genetic
cell. These are chromosome present
for
in the
is known asinformation. The responsibleof transmitting 4' 1 are called native proteins. When a native protein is
present in RNA are adenine.
uracil. guanine and cytosine. nucleotide.
The two strands monomer the biopolymer H H
subjected to physical and chemical change, it loses
in DNA are (1 Mark) 2/H
4. (c) Nucleic acids are
biological
(1Mark) other because the H-bonds formcomplementary to each its biological activity and are called as denatured
are polymers of
repeating macromolecules
which sof bases
belong to different chains.between specific pairs OH OH protein. (1 Mark)
nucleotides. monomeric units called (1 Mark 0bos h (b) Nucleotide a Mark) (b) Lactose is a disaccharide. (1Mark)
5. (c) (1Mark) Note
Vitamin C is a
water - e(b) When a nucleotide from DNA containing thymine (c) Vitamin K is responsible for the coagulation of
soluble vitamin that is Adenine forms H-bonds with is hydrolysed, thymine B-D-2- deoxyribose and
released from our body through Thymine : 2H-bonds blood. (1 Mark)
urine and H
cannot be stored in our body. therefore phosphoric acid are obtained as products. (1 Mark)
Note
Therefore, Assertion (A) is true but bor NH. CH,
13. (a) Pentaacetate of glucose does not react with
hydroxylamine because of the absence of a free -
false. Reason (R) is Deficiency of vitamin Kis rare, but, in severe cases, it
CHO group in the cyclic structure of glucose. can increase clotting time, leading to the hemorrhage and
HN excessive bleeding
Therefore, option (c) is correct. (1Mark)
6. (a) The (1Mark) [Adenine (A)J
backbone of both DNA and RNA Note
15. ) Cellulose is a linear polymer made up of B-glucose
consists of a chain of molecules Guanine pairs with cytosine : Thymine (T) having the C1-C4 glycosidic linkage, whereas
nucleotides which 3H-bonds H
heterocyclic nitrogeneous base (eitherconsists
a of The cyclic structre of glucose is : starch is a polymer of a-glucose having two
CH,OH components: amylose and amylopectin. Amylose is
guanine, cytosine or thymine in DNA or adenine, -HN HA -O OH
a long, unbranched chain with 200-1,000 a-D-(+)
RNA), pentose sugar molecule uracil in KOH H glucose units held by the C1-C4 glycosidic linkage.
ts DNA and (deoxyribose
in -H-. OHN
ribose in RNA) and a OH Amylopectin is a branched-chain polymer of a-D
phosphate glucose unit in which the chain is formed by the C1
Nucleosides contains only sugar and a base group. C4 glycosidic linkage and branching occurs at the
nucleotides contain sugar, base and a while &
H
NH--------0ir H
Cytosine (C)
6al
(b) Amino acids behave like salts because they have
both. an acidic COOH group and basic - NH, C1-C6 glycosidic linkage. (1Mark)
phosphate group. Guanine (G) group due to which it forms a dipolar zwitter ion.
7. (1 Mark)
ntani (ii) Three types of linkage are found in nucleic acids.
(a) (1 Mark)
(i)-(D); (ii) (C): (iii)aod2o2hl (1 Mark) 12. (a) (I) Hydrogen bonds
8
(b) Nucleoside is formed by the attachment of a cbeddstgn R R
(A); (iv) - (B) T5Ws to base
Amino acids form proteins and exist as l'-position of sugar while a nucleotide is formed (2) Glycosidic linkage
d b when a H,N-CCOOH HNC-Co0
Thymine is a nitrogenous base in DNA, zwitter ion., nucleoside is linked to phosphoric acid at (3) Phosphodiester linkage (1Mark)
protein, phosphodiester linkage is foundInsulin is a
in nucleic
tquos e 5-position sugar moiety.n o auCi
of ino A H
(iii) Fibrous protein: Keratin
acids so also in
DNA and
Zwitter-ion

found in RNA which is a Uracil is nitrogenous base

Globular protein: Egg albumin (1 Mark)
be taken regularly
nucleic acid. (c) Water - soluble vitamins must
(1 Mark) out of our body
in diet because they are excreted
through urine.
 218
219
16. () Two monosaccharndes obtained on
hydrolysis of
lactose sugar are B-D-glucose and B-D-galactose.
(i)) Amino acids are
exist as zwitterionamphoteric
in nature Chemistry
because thev
Biomolecules

0 (a) Pentacetate of
glucose does not
react with
indicates the
anomeric
carbor
and react with both
(1 Mark) as bases, acids as well hydroxylamine (NH,OH). This "CH,OH "CH,OH
(1 Mark)
absence of aldehyde (-CHO) group.
(u) Vitamin C cannot be stored in our body
because Reaction with acids
it is water soluble in
nature so it repeatedly gets vitamin. That is why it -0, H H -0. OH
(b) Vitamin C is a water soluble H
eliminated through urine.
(m) When a base (purine or
(1 Mark)
pyrimid1ne) get attached
R-CH-CO0
+NH, R-ÇHCOOH cannot be stored in body but excreted in urine,.
'KOH
HO VOH
H
HO
OH H
to 1' position of a
formed.
pentose sugar a nucleoside is Reaction with bases *NH, (1Mark)
(c) () Peptide linkage is nothing but the amide linkage
3
H
2
OH H OF

When a nucleoside is further linked

acid at 5' position of the
to phosphoric R-CH-CO0
*NH, R-CH-Coo
which is formed between - COOH group and
NH, group of two same or different amino
a-D-Glucose B-D-Glucose

(1Mark)
sugar moiety, we get a *NH, acid molecules. This results to the elimination
nucleotide. (i) Glycosidic Linkage:
(iii) Vitamin C cannot be stored in the (1 Mark) of a water molecule and formation of a peptide
body because it is °CH,OH 'CH,0H
HOH.C Base O-P-0- H.c water soluble, so easily bond - CO - NH -
a Base excreted through urine. -0, H H 0, H

H 2/HH
18. (i)
Maltose is a (1 Mark)
H,NCH,C
OH+HNCHH0 OH
glucose units disaccharide,
as it consist of two a-D HO
OH OH coOH
Nucleoside OH OH (1 Mark) H HO H OH
Nucleotide
Note a-1, 4-Glycosidíc
(1 Mark)
HOH, C-(CHOH)4 -CHO +NH,OH -H,0_,
D-Glucose (iü)
Starchisapolysaccharide, whereasfructoseandglucose
are monosaccharides H,NCH,-C-NH,CH
COOH
linkage
The two monosaccharides are joined together
by an oxide linkage formed by the loss of a
HOH,C -(CHOH)4-CH = NOH Fibrous Protein Peptide linkage water molecule. Such a linkage between two
Glucose oxime a)
They are made up of TheGlobular Protein (1 Mark)
monosaccharide units through oxygen atom is
(1 Mark) parallel polypeptide
chains polypeptide chains in these called glycosidic linkage. (1 Mark)
which are folded protein
are held together
(ii) Denaturation: When a protein, in its native
21. (a) A=100 so T=100
Note with H-bond around form, is subjected to aphysical or chemical
themselves, giving C=150 soG= 150
The structure of
evidances which areglucose can be confirmed by various
disulphide bond. andthese proteins a change like change in temperature, or pH,
the native conformation of the molecule Total nucleotides = 100+100+150+150 =500
as follows.
(b) They are spherical structure.
) Reagent
HUA
Product
Conformation in water but insolubleThey are soluble in
soluble
is disrupted as the secondary and tertiary (1 mark)
n-hexane
Confirms the presence in strong acid and water, alkalies, salt inkages get destroyed but primary linkage (b) They studied the nucleotide composition of DNA.
of
six carbon atoms base solution and acid remains intact. This phenomenon is known as It was the same so they concluded that the samples
which are linked ina solution. denaturation of protein. (1 Mark) belong to same species. (1 mark)
() straight chain. (1 Mark)
NH,OH/HCN Oximelcyano Confirms the presence
(iii) Deficiency of vitamin Dcauses bone OR (c) A=T= 20%

(ii) Br, water hydrin of carbonyl group. children. deformities in (c) i) Anomers: Carbohydrates which differ in But G is not equal to C so double helix is ruled out.

Gluconic Confurms the presence 19. (i) The (1 Mark) configuration at the glycosidic carbon (i.., (1/2 mark)
acid of aldehyde group.
deficiency of vitamin A causes night blindness.
(iv) Acetic C, in aldoses and C, in ketoses) are called The bases pairs are ATGC and not AUGC so it is
ankydride Glucose Confirms the presence (ii) Uracil (U) is the (1 Mark) not RNA (1/2 mark)
() HNO, pentaacetate of 5-OHgroup. base that is found in nucleotide of
anomers.

Saccharic RNA only. e.g. a-D-Glucose and B-D-Glucose are The virus is a single helix DNA virus (1 mark)
acid Confirms the presence (1 Mark)
of primary alcoholic (iii) On prolonged heating with Goo anomers. OR
HI,
group.
n-hexane. This shows that all the sixglucose forms
carbon
inglucose are linked in a straight chain. (1 atoms
Mark)
 220 The incident lisplayed
that Mrs Anundha
Chemistey
rule, alldouble helix DNA 24, ) Valueslu
Accoring to Charagaft
wvell asC e nice bumn beingas60ciated willh some
and T as
will have the same amount of A kind hearted,
will be same amount as G. Irthis is not the case thenuth h presence of mind, helping
atue,
the helix is single stranded. (2 marks)concerm for others ete
() Vitamn B,, deficiency causes pernicious anaemia,
Marky)
22. (a) The vales displayed by Rupali are self awareness,
confidence, decision-nmaking and concern towards ( Mark)
adverse of'eet of harnmful ingredients used in school
soluble vitamin,
canteen, (2 Marks)
(ii) Vitamnin Cis a types of water
(b) Polysaccharide component commonly present in
oithd o eoloqugH (1Mark)
bread is starch. (1Mark)
expressed by Sonali are concern for heslh,
(c) a-helix and B-pleated sheet are the two types of 25. (a) The values
sevOndary structure of proteins. (IMark) btqg of her school mates, observation ánd analysis of a
(d) Water soluble vitamins are B and C.(IMark) problem.
23. 0 Caring, concemed, socially alert and leadership Taking initiative for a good cause agreeing to
values displaced by Ritu. Ho (1 Mark) valuable ideas of others, taking prompt action for
() Starch is commonly present in bread. (IMark)
() (a) a-Helix structure the valuable ideas given by Sonali are some values
(b) B-Pleated sheet structure (1 Mark) expressed byPrincipal of the school. (2 Marks)
(iv) water soluble vitamins: vitamin B, vitamin C (b) Two water soluble vitamins are Vitamin B, and
(1 Mark) Vitamin C. (1 Mark)
1H003