CHAPTER 14
BIOMOLECULES
Q1 – Give
an example of Vitamin which is (a)Water soluble (b) Fat soluble.
Ans.
(a) Vitamin C (b)Vitamin D.
Q2 – What are anomers?
Ans – Monosaccharide which differ only
in the orientation of the ―OH group at C-1.e.g, α-glucose and β-glucose.
Q 3 –
Where does the water present in the egg go after boiling the egg?
Ans – On boiling during denaturation
process water gets adsorbed/absorbed in the denatured proteins.
Q 4 –
Give three differences between DNA and RNA.
Ans -
DNA
|
RNA
|
1. It has deoxyribose as sugar.
2. It contains thymine along with
adenine, cytosine and guanine as bases.
3. It is responsible for
maintaining heredity traits from generation to generation.
|
1. It contains ribose as sugar.
2.It contains uracil in place of
thymine with other bases.
3. It is responsible for protein
synthesis.
|
Q.5
What are
essential and non-essential
amino acids ? Give two
examples of each
type.
Ans:
Essential amino acids: Amino acids which
cannot be synthesized
in the body
and must beobtained
through diet are
known as essential amino
acids.Example :Valine , Leucine.
Non-essential amino
acids:
The amino acids
which can be
synthesized in the
body are
known as non
– essential amino acids.Example
: Glycine , alanine.
Q.6 –
What happens when glucose reacts with
(a)HI (b) HNO3 (c)Br2
water
Ans –
(a) C6H1206
+ HI ------> n-Hexane C6H14
(b) C6H1206
+ HNO3------>Saccharic acid
(c) C6H1206
+Br2 water ----->Gluconic acid
Q.7. –
Which types of bonds are present in a protein molecule?
Ans
– Peptide bonds,
hydrogen bonds, sulphide bonds, ionic bonds etc.
Q.8 Name the enzyme that is used t dissolve
blood clots?
Ans Streptokinase
Q.9
Name two disease caused due to deficiency of enzymes ?
Ans
Albinism and phenylketonuria
Q.10 Write a short note on
(i) Co- enzymes (ii) Prosthetic groups
Ans (i) Co –enzymes: - These are usually derived
from vitamins such as thiamine, riboflavin, niacin etc. They are loosely held
to the protein and can be easily separated by dialysis.
(i)
Prosthetic
groups: - They are also derived from vitamins such as biotin but are tightly
held to the protein molecule by covalent bonds. They can be separated only by
careful hydrolysis.
(ii)
Q11. Fresh tomatoes are a better
source of vit C than that which have been stored for some time. Why?
Ans Vitamin C is destroyed on
prolonged exposure to air due to its oxidation.
Q.12 Although Glucose is a covalent
compound yet it is soluble in water. Why?
Ans Glucose is a covalent compound
but can form H bond with Water molecule because it has OH groups. So it is
soluble in to water.
HOTS
Q1.What
is denaturation of proteins? Explain with examples.
Ans.Disruption of the native conformation of a
protein by changing its environment like PH value, temperature etc. resulting
into loss of its biological activity is called denaturation of proteins. During
denaturation, secondary and tertiary structures get destroyed while primary
structure remains same e.g., coagulation of egg albumin by boiling.
Q2.Distinguish
between globular protein and fibrous protein.
Ans.They
both are examples of tertiary proteins made for their specialized role. The
differences between them are given below.
Difference between fibrous proteins and
globular proteins
Fibrous
proteins Globular proteins
1. They are long,
elongated, thread-like and asymmetric in shape they are spherical, oval or
Elliptical in shape
1. The
peptide chains are held together by strong intermolecular hydrogen bonds The peptide chains are held together by
relatively weak intramolecular hydrogen bonds
2. They
are insoluble in water but soluble in concentrated acids and alkalis They are soluble in water
3. Examples:
Keratin, Fibroin, Collagen Examples:
Insulin, Casein, Egg albumin, myoglobin, antibodies
Q 3
Except Vit B 12 , all the vitamins of group B should be supplied
regularly in diet. Why ?
Ans All vitamins of group B are soluble in water
and excreted , therefore they should supplied regularly in diet whereas vit B
12 is insoluble in water , therefore it can be stored in body and may not be
part of our diet.
Que
4. What is meant by zwitter ion ?
Ans
. Amino acids present in a dipoler molecule in which both ions present is
called zwitter ion .amino acids are more stable in this form.
Que
5.What is isoelectric point?
Ans. The isoelectric points (pI)
• are the pH at which zwitterions have
an overall zero charge
• of nonpolar and polar (neutral) amino
acids exist at pH values from 5.1 to 6.3
Q 6. Draw simple Fischer projections
of D and L- glucose. Are these enantiomers?
Q.7
Why cannot Vitamin C
be stored in
our body ?
Q.8 Name the tow comptometers of
starch. How do they differ from each other structurally?
Q.9
Mention the type
of linkage responsible
for the formation
of the following
:
i) Primary structure of
proteins ii) Cross linking of polypeptide
chains
iii)
Helix formation iv)
sheet structure
Q.10 Explain the term mutarotation
giving an example.
ANSWERS
Ans-1
CHO
CHO
H -|-OH
HO-|- H
HO -|-H
H -|-OH
H -|-OH
HO-|- H
H -|-OH HO -|-H
CH2OH
CH2OH
D-Glucose
L-Glucose
Yes these two Fischer projections are called enantiomers.
Ans2- Vitamin c is
water soluble ,
therefore it is
readily excreted in
urine and hence
cannot be stored in
the body.
Ans3- The two components of starch are:
i)
Amylose ii)
Amylopectin
Amylose is
a straight chain
polymer of
glucose , while
amylopectin is a
branched chain polymer of
glucose.
Ans4-
Biomolecule
|
Types of
linkage
|
1.
primary structure of
proteins
|
-
peptide bond or peptide linkage
|
2.Cross linking
of polypeptide chains
|
-
polypeptide linkage
|
3.
|
-
hydrogen bonds
|
4.
|
-
Intermolecular hydrogen bonds.
|
Ans5-
The
spontaneous change in
specific rotation when an
optically active substance
is dissolved in water is
called mutarotation. For example,
when
glucose is dissolved in water its specific rotation changes
because it gets converted into
glucose.
VALUE BASED QUESTIONS
Q.
1 Meena’s son who is 2 years old started walking that time she observed that he
has bow legs parents consulted a doctor and has suggested some remedy
a) What is the remedy suggested by the doctor?
b) Name the
sources in which the mentioned vitamin is present ?
c) What value you have gained from this?
Ans:- a)The doctor informed that it was due to the
deficiency of vitamin D.He suggested to include food containing more vitamin D
in the diet.
b) Cod liver oil, butter, milk, eggs, liver and
meat.
c) Vitamins play an important role in our day to
day life. Inorder to be healthy we must
take vitamins along with carbohydrates, proteins and fat.
Q.2
Humans, monkeys and guinea pigs do not have the enzymes necessary for the
synthesis of vitamin C, so they must include the vitamin in their diets. It is
also required for the synthesis of collagen, which is the structural protein of
skin tendors, connective tissue and bone.
(i)
Write structure of vitamin C and the functional groups therein.
(ii) Is
it acetic in nature?? What is the common name of vitamin C?
(iii)
What is the oxidation product of vitamin C?
Answers)
(i)
(ii) It
is acidic due to enolic-OH.
Common
name is ascorbic acid.
(iii)
Q. 3 Rahul’s father recovered from
a massive heart attack. As follow up doctor gave him Aspirin.
a.
Why?
After some time he started to develop some stomach ache.
Then his wife gave him some butter
milk
b.
Why?
c.
What
value do you get from this?
Ans:
a) Aspirin
is a blood thinner. Hence for a patient suffering from heart attack is given
Aspirin. Aspirin is acetylated salicylic
acid. In the presence of acid in the stomach it undergoes hydrolysis to form
two acids salicylic acid and acetic acid. This increases the acidity in the
Stomach.
b) To
neutralize this acidity butter milk is also given.
c) Being
dedicated and faithful.
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