Proteins PPT Flashcards
during denaturation, proteins will not lose their structure, with regard to
primary structure
the characteristic features of the peptide bond include all the following, except
a. does not allow freedom of rotation
it is a partial double bond
always has cis configuration
absorbs UV light at 280 nm
always has cis configuration
the force maintaining the primary structure of a protein:
peptide bond
The forces maintaining the secondary, tertiary and quaternary structures of a protein are the follow-ing, except:
A. Electrostatic (ionic) bonds
B. Hydrophobic forces
C. Van der Waals forces
D. Peptide bond
peptide bond
The amino acid which did not allow formation of alpha-helix is
Proline
Tertiary structure of a protein describes
A. The sequence of amino acids B. Location of disulphide bonds
C. Amino terminal end amino acid D. The nature of protein folding
nature of protein foldng
One of the following proteins does not have a qua-ternary structure:
A. Albumin
B. Hemoglobin
C. Lactate dehydrogenase
D. Immunoglobulin G
albumin
All the following reagents are used for identifying the rst amino acid in a protein, except:
A. Cyanogen bromide
B. Fluorodinitrobenzene
C. Dansyl chloride
D. Phenyl isothiocyanate
cyanogen bromide
Proteins can be precipitated by the following meth-ods, except:
A. Adding alcohol and acetone
B. Saturating with ammonium sulphate
C. Using salts of heavy metals
D. Shifting the pH away from the iso electric point
D. Shifting the pH away from the iso electric point
Denatured proteins:
A. Are soluble
B. Are difcult to digest
C. Are biologically inactive
D. Peptide bonds are broken
C. Are biologically inactive
Which of the following is a simple protein?
A. Casein
B. Insulin
C. Hemoglobin
D. Tyrosinase
Insulin
In glycoproteins, the carbohydrate chains are com-bined through glycosidic linkages with:
A. Hydroxyl groups of serine or threonine residues of proteins
B. Epsilon amino nitrogen of lysine residues of pro-teins
C. Guanidium group of arginine residues of proteins
D. Phenol group of tyrosine residues of proteins
A. Hydroxyl groups of serine or threonine residues of proteins
The protein which does not answer the aldehyde test is
Gelatin
Proteins may be estimated by the following meth-ods, except
A. Biuret method
B. Heat coagulation
C. Kjeldahl’s digestion
D. Nephelometry
B. Heat coagulation
All the following are examples of tertiary structure of proteins, except:
A. Alpha helix
B. Beta pleated sheet
C. Triple stranded helix
D. Peptide bonds
Peptide bonds
Tertiary structure of a protein describes
D. The nature of protein folding
4-17. Proteins may be denatured irreversibly by:
A. Adding urea
B. Bringing to iso electric pH
C. Heat coagulation
D. Reduction with mercaptoethano
C. Heat coagulation
Lectins are:
A. Animal proteins having specic amino acid binding site
B. Antibody molecules acting against cells
C. Plant proteins having specic carbohydrate bind-ing site
D. Blood proteins having a lecithin group
D. Blood proteins having a lecithin group
Ultraviolet light at 280 nm is absorbed by which component of proteins?
A. Peptide bonds
B. Sulfhydryl group of cysteine
C. Indole ring of tryptophan
D. Imidazole ring of proline
Indole ring of tryptophan
The nature of the bond linking amino acids to each other is
A. Covalent
B. Co-ordinate
C. Ionic
D. Hydrophobic
covalent
How many peptide bonds are present in gluta th-ione?
A. 1 B. 2 C. 3 D. 4
c. 3
Basic difference between two polypeptides is in the —
A. Structural conformation
B. Primary sequence of amino acids C. Number of side chains
D. Number of hydrophobic bonds
B. Primary sequence of amino acids
Human insulin differs from bovine insulin in:
A. Biological activity
B. Number of amino acids
C. Position of disulde bonds
D. Sequence of amino acids
D. Sequence of amino acids
A covalent bond between the alpha carboxyl group of one amino acid and alpha amino group of the neighboring amino acid is called
A. Cis double bond
B. Isopeptide bond
C. Pseudopeptide bond
D. Peptide bond
peptide bond
Study of linear sequence of amino acids is done by all techniques listed except:
A. End group analysis
B. Hydrolysis by proteolytic enzymes
C. Analyzing the content of each amino acid
D. Denaturing the protein
D. Denaturing the protein
Different polypeptide chains are held together by:
A. Peptide bonds
B. Disulphide bonds
C. Glycosidic bonds
D. Ester bonds
B. Disulphide bonds
Primary structure decides:
A. Rate of synthesis of protein
B. Biological activity of the protein C. Rate of degradation of the protein
D. Effect of proteolytic enzymes on protein
B. Biological activity of the protein
Secondary and tertiary levels of protein structure are dependent on
a. Presence of disulde bonds
b. Primary structure
c. PH of the medium
d. PK value of component amino acids
b. Primary structure
The protein having predominantly alpha heli cal structure is
collagen
keratin
fibroin
myoglobin
collagen
Which of the following is NOT true regarding the tertiary structure of proteins
A. It is a random coil structure
B. Disulde bonds are formed between any two cys-teine residues C. Position of disulde bonds are predetermined and xed
D. Denaturation using reducing agents does not aff-ect the disulde bonds
D. Denaturation using reducing agents does not aff-ect the disulde bonds
Protein having a large number of disulde bonds is
A. collagen B. keratin C. hemoglobin D. albumin
keratin
Which of the following proteins does not possess a quaternary structure?
A. Myoglobin
B. Lactate dehydrogenase
C. Hemoglobin
D. Immunoglobulin M
A. Myoglobin
Which of the following is NOT true regarding hem-oglobin?
A. Has 4 independent subunits
B. Each subunit has one heme residue
C. Each subunit can bind one molecule of oxygen
D. All four subunits are similar
D. All four subunits are similar
draw glycine structure
+1
draw Alanine structure
+1
glycine letter code
Gly/G
glycine is
polar
nonpolar
+ charge
- charge
non-polar
Alanine is?
polar
nonpolar
+ charge
- charge
non-polar
alanine letter code
Ala/A
draw valine structure
+1
valine is ?
polar
nonpolar
+ charge
- charge
non polar
draw cysteine structure +1
+1
cysteine is
polar
nonpolar
+ charge
- charge
non polar
cysteine letter code
Cys/C
valine letter code
Val/V
Proline letter code
Pro/P
draw proline structure
+1
proline is
polar
nonpolar
+ charge
- charge
nonpolar
draw leucine structure
+1
leucine is
polar
nonpolar
+ charge
- charge
non polar
leucine letter code
Leu L
draw isoleucine structure
+1
isoleucine is
polar
nonpolar
+ charge
- charge
nonpolar
isoleucine letter code
Ile / I
methionine structure
+1
methionine is
polar
nonpolar
+ charge
- charge
nonpolar
methionine letter code
Met/M
Tryptophan structure
+1
Tryptophan is
polar
nonpolar
+ charge
- charge
nonpolar
Tryptophan letter code
Trp/W
Phenylalanine structure
+1
Phenylalanine is
polar
nonpolar
+ charge
- charge
nonpolar
Phenylalanine letter code
Phe/F
Lysine structure
+1
Lysine is
polar
nonpolar
+ charge
- charge
+ charge
Lysine letter code
Lys/K
Arginine structure
+1
Arginine is
polar
nonpolar
+ charge
- charge
+ charge
Arginine letter code
Arg/R
Histidine structure
+1
Histidine is
polar
nonpolar
+ charge
- charge
+ charge
Histidine letter code
His/H
serine structure
+1
serine is
polar
nonpolar
+ charge
- charge
polar
serine letter word
Ser/S
Threonine structure
+1
Threonine structure
+1
Threonine is
polar
nonpolar
+ charge
- charge
polar
Tyrosine structure
+1
Threonine letter code
Thr/T
Tyrosine letter code
Tyr/Y
Tyrosine structure
+1
Tyrosine is
polar
nonpolar
+ charge
- charge
polar
Asparagine structuer
+1