Biochemistry Important Questions & Answers

Answers :




H Essential and Non Essential -

AA :




Essential Amino ace 'd -
Their carbon skeleton can not be

synthesized by human
beings .




Histidine leucine Threonine
Arginine Isoleucine
°

, ,
, , ,

#

lysine Methionine Phenylalanine Tryptophan
, , ,



and Valine
I Any Help In Learning
8 in number These Molecules Proves

True ly Valuable ]
Non essential
- =
to in number
•
Their carbon skeleton can be
synthesized in body .




•

Glycine , Alanine , serine .
Cysteine Asparagine ,




Glutamine Glutamic Acid
.
Aspartic Acid , ,


Proline
Tyrosine .
.




② General R kn 7 AA :




③ structure 9 Proteins :


( as
Primary tune :



Denotes the number and A As in proteins
sequence g
•
.




Maintained
by Peptide linkages
•




°

If seq .
in
changed the peptide ,
in also
different .

,charactershis g Peptide Bond :


Partial oouble bond
o




•
c -
N bond in trans in nature and thus no
freedom g
rotation due to double bond
partial .




°
The distance in t 32 -
Ao
• The
angle g Rotation known Ramachandran Angles as


determines the
spatial arrangement / orientation g Peptide chain
.




Numbering g AA in
Proteins :



On the
left side there will be
free alpha
°


one amino
group
this end is Amino terminal ( N - terminal ) end .




and this is also called the first AA .




The other end chain in
Carboxy terminal end (C terminal )
°



g
-




and this in the last AA .




Primary structure determines
*
Biological Activity .




(b,
secondary structure 7 Protein :

ci , H bond
°
Preserved
by Non covalent forces or bonds like ciii Electrostatic bonds
( iiis
Hydrophobic Interaction
Vander Waals
Usually in ③ forms is
force
Most stable and conformation
cis Alp hehe line : common
g poly pepkglehain
Spiral structure stabilized
.




by Hydrogen bonds
°

;
between
NH and C O
groups
-
- .




handed
Generally Right
°
-




.
Proline and
hydroxy proline will not allow formation g a -
helin .




.
As in
Myosin . Actin . Myoglobin .




dis p Pleated
-

sheet :



Almost
fully extended
°




stabilised
by H bond btw NH
& C o
group
- -
. .




Proteins like Silk fibroin
Major structural motif Flay,¥
o
in
.




carbonic
and anhydrase .




•
In terchain disulfide bridges stabilize these bends .




( iiis Collagens helin : Triple helical structure in
Collagen .

, structure
(c)
Tertiary :



denotes structure whole
protein interaction
3D
Hydrophobic
o



g
Maintained coral lent bond such [
.



by Non -
as -


Electrostatic bonds

°


Tertiary structure
by protein
native no stable
! -
Vander Waals forces .




structure
°
Most
enzymes
and
biological active proteins are in
Tertiary .




Ids
Quaternary shucker :


certain
polypeptides aggregate to
form functional protein
o
one .




°
Protein loses it
properly if subunits are dissociated .




forces T H bond
May be chain Monomer
-



• . I -




Electrostatic bond
-




2 chain Dimer
L
-




Hydrophobic 4 chain Tetramer
der Waals force
-




L Van .




•
As ca ) H b : 2x & 213 chains .


( Heterodimer )
( bi Immuno
globin : 2
heavy & 2
light
( c '
Cma line kinase : Dimer
Id ) L DH : Tetramer .




④
Coning atedPI.es :


combinations
They protein with Non
protein ( prosthetic
•
are
g a -




group )
•
Classified as
follows :



i is
Glycoproteins - Protein +
Carbohydrates
•

hydroxy group g serine or threonine and a wide
group
and
asparagine
of glutamine form linkage with
carbohydrate
As and Proteins
group Antigens
=
Blood serum
many
When
carbohydrate 9 9 and called
by viscosity they
* 10% a
are


as
Mucoprotein / Proteoglycans .




Iiis Lipoproteins , Protein + Lipid
.
Present in Blood and on cell membranes .




ciiis Nucleoprotein : Protein + Nucleic Acid

As - Histones ; DNA contains -
re
charges which combines with
+ ve
changed proteins .




( in Chromo
proteins : Protein t Coloured
prosthetic group .




As - H b Heme ,
Red 5 Flavoprotein ( Riboflavin Yellow )
→
,