Chemistry Of Proteins-2

1- What is the nature of a prosthetic group in a lipoprotein?

 (Lipoprotein is a conjugated protein with lipid as a prosthetic group)

 2- What is the significance of Sakaguchi test?

 (This test is undertaken for the detection of Arginine)

 3- What is the distance traveled per turn in an alpha helix?

 (0-54 nm)

 4- Name an imino acid.

 (Proline, hydroxy proline)

 5-Choose the chromo protein out of the followings-

 Collagen, Keratin, hemoglobin                       

 (Hemoglobin)

 6-Carbonic anhydrase is an example of simple or conjugated protein?

 (It is a conjugated protein, with metal as th prosthetic group)

 7- Name a peptide which acts as an artificial sweetener.

 (Aspartame)

 8- Name the agents which can bring about denaturation of proteins

 (Heat, acids, alkalis, heavy metal salt, UV light, vigorous shaking etc)

 9- Name a tripeptide which acts a reducing agent in the tissues.

 (Glutathione)

 10- Name a peptide which acts as vasoconstrictor

 (Angiotensin-II)

 11- Name the amino acid which is deficient in pulses

 (Methionine)

 12- Choose the odd one out- Collagen, Elastin, Keratin, Histones

 (Histones- The rest three are scleroproteins)

 13- Name two nano peptides

 (Oxytocin, Vasopressin)

 14- Name two globular proteins

 (Hemoglobin, Myoglobin)

 15-Which test should be undertaken for the detection of cysteine in a protein solution?

 (Lead acetate test)

 16-What is the nature of peptide bond- Single, double or partial double bond ?

(Partial double bond)

 17- Out of all the primary amino acids which amino acid gives yellow color on Ninhydrin test?                  

 (Proline and hydroxy proline )

 18- Histamine is formed from Histidine by-

 Deamination, decarboxylation or transamination

 (Decarboxylation)

 19- Name two non alpha amino acid

 (GABA, beta Alanine, Delta amino Levulinic acid)

 20- Choose the odd one out-

 Aspartic acid, lysine, Arginine, Cysteine                   

 (Cysteine- Amino acid with uncharged side chain at physiological p H

 21- Choose the odd one out-

Tyrosine, Tryptophan, Threonine                   

 (Tyrosine- non essential Amino acid from the nutritional perspective or threonine if considered non aromatic amino acid)

 22- Name a purely ketogenic amino acid             

 (Leucine)

 23- Name a peptide used as an anticancer drug            

 (Bleomycin)

 24- Name the defense proteins                                     

 (Complement, immunoglobulin)

 25- Choose the odd one out- Silk fibroin, Hemoglobin, Carbonic anhydrase

 (Hemoglobin- The rest are proteins with beta pleated sheet

 26- The proteins with a carbohydrate content > 10 % are called as Mucoproteins- True or false?         

 (True)

 27- The most abundant amino acid in keratin?             

 (Cysteine)

 28- The most abundant amino acid in Collagen—-?      

 (Glycine)

 29- Xanthoproteic test does not specify for—- ?

 Tyrosine, Tryptophan, Serine               

 (Serine)

 30- Give the characteristics of a peptide bond in one line-

 (Rigid, partial double bond, Trans and stable)

31-Name the branched chain amino acids 

 (Valine, Leucine, iso Leucine)

 32-Choose the hydrophobic amino acid out of the followings-

 Aspartic acid, Arginine, Serine, Isoleucine

 (Isoleucine)

 33-Which amino acid acts as Methyl group donor?

 (Methionine)

 34- What is the difference between Deamination and Transamination?

(Deamination is the removal of amino group of the amino acid while Transamination is the transfer of amino group from one  donor amino acid to an acceptor keto acid for the formation of a new amino acid)

 35- Out of the 20 amino acids which amino acids participate in the formation of phosphoproteins

 (Serine and Threonine)

 36- Formation of carbamino compound for the transportation of carbon dioxide is a property of amino group, carboxyl group or both groups?

 (Amino group)

 37- Hopkins Cole test is a confirmatory test for which amino acid?

 (Tryptophan)

 38- How many peptide bonds are there in a tripeptide?

 (Two)

 39- The alpha helix is right or left handed?         

 (Right handed)

 40- What is the direction of hydrogen bonds in the beta pleated sheet structure?

 (Perpendicular to the axis)

 41-What is the direction of beta pleated sheets in flavodoxin?

 (Parallel)

 42-Name the most abundant protein in mammals        

 (Collagen)

 43-Name a defect in the primary structure responsible for the causation of a disease

 (Sickle cell disease)

 44-What is the defect in Alzheimer disease?

 (Protein misfolding leading to formation of insoluble protein aggregates)

 45-What is the isoelectric p H of casein?

(4.6)

 46- What is the effect on the solubility of a protein upon denaturation?

 (Solubility decreases upon denaturation)

 47- Name the lipo proteins of biological significance

 (Chylomicrons, VLDL, LDL, HDL)

 48- Which amino acid is lacking in cereals?

 (Cereals lack Lysine)

 49- Which amino acid forms disulphide linkages between two polypeptide chains in oligomeric proteins?                       

 (Cysteine)

 50- Which peptide is used in clinical practice to induce uterine contractions?

 (Oxytocin)

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Chemistry of Proteins-1

1-Give an example of reversible denaturation

(Denaturation of Ribonuclease by urea)

 2. Give example of a circular peptide.

(Gramicidin S)

 3-What is the difference between Salting in and Salting out?

(Salting in is addition of a pinch of salt to increase the solubility of a protein, while salting out is addition of excess of salt to precipitate it out)

4. Name the proteins containing alpha helical structure predominantly.

(Hemoglobin, Myoglobin etc)

5. Name the super secondary structures

(Greek key, beta meanders, Beta alpha beta)

6. Name the respiratory proteins

(Hemoglobin, Myoglobin, cytochromes)

 7. What is the class of Zein protein?

(Poor protein- it lacks Tryptophan and Lysine)

 8. Name the contractile proteins 

( Actin, Myosin, flageller proteins)

 9-What are the features of isoelectric pH?

(Decrease in solubility, electric charge, Electrophoretic migration, loss of biological activity)

 10-What is the basis of protein precipitation by organic solvents?

(Decrease in dielectic constant of the medium)

11-What is the difference between flocculum and coagulum?

(Flocculum is a reversible state of denaturation while coagulum is a an irreversible state of denaturation)

12-What are the forces that stabilize the alpha helical structure?

(Hydrogen and Vander waals forces mainly)

13-What is the basis of cauterization by silver nitrate during surgery to control bleeding?

(Silver nitrate is a heavy metal salt and by causing precipitation of proteins seals the oozing points of the blood vessels)

14-What is meant by a domain?

(Domain is a term used to denote a compact globular functional unit of a protein)

15-Why is Glutathione called a pseudo peptide?

(In glutathione instead of alpha carboxyl group, the gamma carboxyl participates in the peptide bond formation)

16-Covalent forces stabilize the tertiary structure in a protein- True or false?

(False- the non covalent forces stabilize the tertiary structure in a protein)

17- Which tests should be carried out for the detection of Tryptophan in a given solution?  

(Xanthoproteic and Hopkins Cole test)

18- Which amino acids contribute towards ionic interactions?

(Positively charged amino acids like Arginine , Lysine and negatively charged amino acids like Aspartic acid and Glutamic acid)

19- Which protein is precipitated by full saturation with Ammonium sulphate?

(Albumin)

20- What is the relationship of amount of salt required and the molecular weight of a protein?

(More the molecular weight and lesser is the amount of salt required by the protein and vice versa)

21-What are the functions of proteins?

(Nutritive, buffering, defense, viscosity, osmotic pressure, enzymes, hormones etc)

22-Name mono amino dicarboxylic acids

 (Aspartic and Glutamic acid)

 23-Name heterocyclic amino acids

 (Tryptophan and Histidine)

 24-Name the 21st and 22 nd amino acid

 (Seleno cysteine and Pyrrolysine)

 25-Which amino acids are involved in forming N- Glycosidic linkages?

 (Asparagine and Glutamine)

26-Name the semi essential amino acid

(Arginine and Histidine)

27-Which amino acid acts as the precursor of vitamin Niacin?

 (Tryptophan)

28-Name the amino acids with a non polar side chain

(Alanine, Valine, Leucine Isoleucine, Methionine, Phenyl Alanine)

29-Which protein structure determines the relationship of amino acids which are 3-4 residues apart ?

 (Tertiary structure)

30-Which test will be negative for a protein lacking tryptophan ?

 (Hopkins cole test)

 31-Name the essential amino acids

( Valine, Leucine, Isoleucine, lysine, Phenylalanine, Methionine and Threonine)

 32-Which amino acid is optically inactive ?

(Glycine)

 33-Which amino acid is abundantly present in prolamines ?

(Proline)

 34-Which protein is mostly found attached to DNA?

(Histone)

 35-Name the amino acids which are both glucogenic as well as ketogenic

(Isoleucine. Phenyl Alanine, Tyrosine and Tryptophan)

35-Name a specific test for the detection of alpha amino acids

(Ninhydrin test)

 36-Name a  specific test for the detection of cysteine

(Lead acetate test)

37-Covalent bond is formed at which level of protein’s structural organization?

(Primary structure)

38-Name the peptide hormones

 (ACTH, TRH, FSH, Glucagon, PTH, ADH, Oxytocin, Secretin, Pancreozymin, Cholecystokinin)

 39-What is the effect on the biological activity of a protein when exposed to UV light ?

 ( It will lose its biological activity since it will be denatured)

 40-Give two examples of protein misfolding causing disease?

 ( Prion’s and Alzheimer disease)

41-What is the class of casein ?

 (Class 1- complete protein) 

42-What are the forces that stabilize quaternary structure of a protein ?

 (Mainly non covalent)

 43-Which amino acid acts as the best buffer of the plasma?

 (Histidine)

 44-What will be the product of decarboxylation of Tyrosine?

 (Tyramine)

 45-Why can’t albumin and majority proteins acquire the native configuration upon denaturation?      

 (Chaperones and other proteins assisting proper folding are not there)

 46-What are Beta bends?

 (Short loops to turn the direction of the beta sheets?

 47-What are the forces that stabilize the beta bends?

 (Hydrogen and electrostatic)

 48-Name a peptide to regulate the volume of urine excreted?

 (ADH)

 49-Which protein is present in the tendons and cartilages? 

(Collagen)

 50-Name the storage proteins

 Ferritin, ceruloplasmin)

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Plasma Proteins-3

1- The deficiency of which plasma protein is responsible for Wilson’s disease ? 

 (Ceruloplasmin)

2-Which immunoglobulin is pentameric in structure?                    

(Ig M)

3-Which plasma protein is a transporter of free fatty acids?

(Albumin)

4-Which protein acts as reservoir of oxygen?                        

(Myoglobin)

5-What is the normal level of Fibrinogen in the blood?      

(300mg %)

6-Which Immunoglobulin is present at the mucosal surfaces?

( IgA)

7-Complement activation is a function of which part of the Immunoglobulin?

(Fc segment)

8-Which antibody is the first to be synthesized in a fetus ?

(Ig M)

9-What is the function of Hinge region of an immunoglobulin?

(The hinge region confers flexibility and allows both Fab arms to move independently, thus helping them to bind to antigenic sites that may be variable distances apart (eg, on bacterial surfaces).)

10-Name the storage protein of iron                            

(Ferritin)

11-Name a plasma protein that binds extra corpuscular Hb        

(Haptoglobin)

12- γ Globulins are synthesized in the plasma cells- State true or false

(True)

13-What is the nature of apoprotein present in HDLc?                  

(α1- globulin)

14-What is specified by C_L   in the structure of immunoglobulin?

(Constant region of light chain)

15-What are the consequences of α1- Antitrypsin deficiency?

(Emphysema and cirrhosis of liver)

16-Name a plasma protein which acts as a transporter of Iron

(Transferrin)

17-Maximum contribution to the buffering capacity of plasma proteins is by- ?

(Albumin- due to the presence of histidine residues )

18-Maximum contribution to the viscosity of plasma is by—–?

(Fibrinogen- Since it is an elongated molecule)

19-What is Analbuminemia?

( Congenital absence of Albumin in the plasma)

20- The plasma level of gamma globulins is decreased in chronic liver  diseases True or false ?

(False- The level of gamma globulins is increased in chronic liver diseases)

21-What is the clinical significance related with Alpha feto protein?

  (Its plasma level is increased in liver cell carcinoma and teratoblastomas)

22-What is the function of Alpha 1 acid Glycoprotein?

( Acute phase protein and transporter of Progesterone)

23- What is the significance of the variable region of the immunoglobulins and why is it so-called variable region?

( It is variable in amino acid sequence and is involved in antigen binding)

24- Which plasma protein is a transporter of bilirubin?    

(Albumin)

25- What is meant by acute phase proteins?

(Acute phase proteins are those proteins, the synthesis and thus the plasma level of which are increased in response to inflammation or tissue damage.)

26–What is the difference between plasma and serum?

(Plasma contains clotting factors, while serum lacks them)

27-Out of Albumin, hemoglobin and immunoglobulin, which one has the least molecular weight?                                             

(Hemoglobin)

28-What is the difference between Haemopexin and hemoglobin?

(Haemopexin binds free haem while Haptoglobin binds free hemoglobin.)

29-What is the function of IgD?

(It acts as a receptor on the surface of B lymphocytes)

30-Name the Acute phase proteins

(Alpha 1 Antitrypsin, Alpha 1 acid glycoprotein, Haptoglobin, C-reactive protein)

31-What is the actual meaning of C-reactive protein, what does C mean?

(CRP, so-named because it reacts with the C polysaccharide of pneumococci)

32-Out of lipoproteins, immunoglobulins and Albumin, which one  is a simple protein ?     

(Albumin)

33-Name the plasma proteins involved in the clotting of blood?

(Fibrinogen and clotting factors)

34-Name the defense proteins of plasma

(Immunoglobulins, complement proteins and Beta 2 microglobulin)

35-How is copper transported in the blood?

(It is transported complexed with ceruloplasmin and Albumin)

36-Kayser-Fleischer ring is diagnostic of which disease?

(Wilsondisease)

37-What types of enzyme activities are associated with ceruloplasmin ?

(It has copper dependent Ferro- oxidase activity, it oxidizes iron  from ferrous to ferric form

38-Out of the following proteins which protein has mainly alpha helical structure-

(Collagen, immunoglobulin, myoglobin)               

(Myoglobin)

39-What is the chemical nature of Bence jone’s proteins?

(Light chain of immunoglobulins)                             

40-Name the commonly occurring haemoproteins

(Hemoglobin, Myoglobin, Cytochromes, Peroxidase and Tryptophan Pyrrolase)

41-How does smoking inactivate the Alpha 1 Antitrypsin protein?

(Smoking oxidizes this methionine to methionine sulfoxide and thus inactivates it. As a result, affected molecules of alpha 1-antitrypsin no longer neutralize proteases.)

42-Name three conditions of hyperproteinemia

(Hemoconcentration, chronic infections and malignancies)

43-What is the significance of M band , where is it located ?

(M band is present between beta and gamma globulin regions on electrophoresis of plasma proteins and is diagnostic of Multiple myeloma)

44- How many polypeptides are present in the structure of globin part of hemoglobin ?

(4)

45-Which amino acid contributes maximally to the structure of collagen molecule?

(Glycine)

46- Which immunoglobulin has the cytophilic property?

( Ig E)

47-The number of antibody secreting  plasma cells are decreased in Multiple myeloma that is why there is impaired humoral immune response . True or false?

(False- The number of plasma cells secreting antibodies are increased but these are abnormal and useless antibodies not targeted against any antigen, but the actual humoral response against a specific antigen is decreased.)

48- Which antibody is considered the most potent agglutinating antibody?

(IgM)

49-Which protein is precipitated by full saturation with Ammonium sulphate?

  (Albumin)

50-What is Pre albumin? Why is to so named? Is it a precursor of Albumin?

( Ii is a plasma protein and not a precursor, it is so named because of its faster electrophoretic migration in the electric field).

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proteins of plasma-2

1- Name the major proteins of plasma.

(Albumin, Globulin and Fibrinogen)

2-Name the transport proteins

(Albumin, Lipoproteins, Prealbumin, Transthyretin, Retinol Binding protein, Thyroxin binding Globulin)

3-How many copper atoms can bind to one molecule of ceruloplasmin?

(6-8)

4-What is A: G ratio, what is its range in the normal health?                  

(1.2:1 to 1.5:1)

5-What is the most significant sign of hypoproteinemia?

 (Edema)

6-Almost all proteins except Globulins are synthesized in the liver, True or false?

(True)

7-Name the negative phase proteins

(Albumin, Transthyretin, Transferrin etc.)

8-What are the different types of light chains?

( Kappa and Lambda)

9-Which immunoglobulin is the major antibody of primary immune response

 (IgM)

10-What is the function of the secretory piece of the IgA?

(It protects the antibody from proteolytic digestion)

11-What is the actual meaning of Fc and Fab ?

(These are the two portions of immunoglobulins produced after proteolytic cleavage of immunoglobulin. Fc denotes fragment crystallisable and Fab denotes antigen binding fragment)

12-Which form of Ig M – monomeric or polymeric acts as a receptor on the surface of B lymphocytes.

( Monomeric form)

13-Which form (Alpha helical, Beta pleated sheet or triple helical) predominates in the structure of collagen?                                    

(Triple helical)

14-What are the different types of heavy chains present in different types if immunoglobulins?

(α, β,γ,δ, Σ)

15-What types of globin chains  are present in Fetal Hemoglobin?

(Two alpha and 2 Gamma)

16-What is methaemoglobin?

( Hb in which iron is in the oxidized form(Ferric form )

17-25 % of the structure of hemoglobin is in the alpha helical form- state true or false?

(False- 75% is in the alpha helical form)

18-Name the beta globulins of biological significance

(Transferrin, Haemopexin, Complement etc)

19-What is the nature of ceruloplasmin?

(Alpha 2 globulin)

20-What is the function of Transferrin?

(Transfer of iron)

21-What is the function of fibrinogen?

(Blood clotting and viscosity)

22-What is the clinical significance of C- reactive protein ?

(Acute phase protein, activates complement, also helps in the formation of haem)

23-What is meant by opsonization?

(Coating the surface of antigen by antibodies)

24-What is the difference between monoclonal and polyclonal antibodies?

(Monoclonal means antibodies of only one specificity while polyclonal means antibodies of different specificities)

25-Hepato lenticular degeneration is observed due to deficiency of which plasma protein?

(Ceruloplasmin)

26-What is the function of complement protein ?

(These are defense molecules present in the plasma in the inactive form, required for pathogenic killing)

27-Enumerate the causes of hypo Albuminemia?

(Hypovolemia, mal nutrition, cirrhosis of liver, losses from the body ),

28-Give two causes of hyperproteinemia

(Hemoconcentration, malignancies, chronic infections)

29-What is class switching?

(The switch from one class of immunoglobulin to another class is called class switching)

30-How are the light chain and heavy chains linked together?

 ( By disulphide linkages)

31-What is the function of carbohydrate in the structure of immunoglobulins?

( It is required for the secretion of antibodies by the plasma calls)

32-Which antibody is called as the mucosal barrier?

( Ig A)

33-Which antibody is called as the Millionaire molecule?

 ( Ig M )

34-How is the rate of catabolism of Ig G affected by its serum concentration?

( It is a direct relationship, more the concentration more is the rate  of catabolism

 35- How many polypeptide chains are present in the structure of myoglobin?

(One)

36-Which out of the two (Myoglobin and hemoglobin) has more affinity for Oxygen?

(Myoglobin)

37-Name two proteins that bind thyroid hormone

(Thyroxin binding protein and Transthyretin)

38-What will be the effect of excessive vomiting on plasma protein concentration ?

( It will result in hyperproteinemia due to hemoconcentration)

39-In a chronic alcoholic patient plasma protein concentration should be lower than normal or higher?

(Lower than normal)

40- What is the function of Transcobalamine?

(Transporter of B12)

41-What are Bence jone’s proteins?

These are light chain Immuno globulins excreted in the urine of a patient suffering from multiple myeloma.

 42- What are the clinical features observed in a patient of multiple myeloma ?

(Weight loss, punched out lesions, anemia , increased frequency of infections)

43-What are the component chains in HbA1?

( 2 alpha and 2 delta)

 44 What is the cause of emphysema in alpha 1 anti trypsin deficiency?

(Inactivated Elastase which causes damage to the lung tissues)

------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 

Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------