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Short Answer Type Questions

  1. Name the muscular protein.
    Myoglobin

  2. Lack of beta chain in haemoglobin results in which disease ?
    Beta-thalasaemia

  3. What will occur when normal protein misfolds or undergoes conformational changes ?
    Disease will develop eg., mad cow disease.

  4. Who developed  the protein sequencing method first ?
    Frederick Sanger.

  5. Name the protein to be sequenced first.
    Haemoglobin.

  6. Thermodynamically which conformation of protein is most stable in solution ?
    Secondary and tertiary structure of protein.

  7. Which of the interactions of protein determine the 3D shape ?
    Hydrophobic interactions.

  8. How are active sites exposed on protein surface ?
    Through protein folding.

  9. Why do hydrophobic regions of a protein form the core of a folded protein ?
    Because in proteins, the hydrophobic regions are preferentially present away from the surface of the molecule and form the core (interior) of the folded protein.

  10. In isolating recombinant insulin from a culture of E.coli, the cells were filtered and filterate was subjected to a purification protocol. However, no insulin was obtained. Why ?
    Because the E-coli cells do not contain insulin gene in plasmid.

  11. When are most enzymes denatured ?
    At adverse conditions

  12. How can protein stability be increased ?
    Using gene cloning and mutagenesis.

  13. How can changes be incorporated into a protein ?
    By site-directed mutagenesis and rDNA technology.

  14. Who gave first the structure of protein through crystallography ?
    Max Perutz and John Kendrew

  15. Which method is used in prediction of protein structure ?
    Method of P.Y.Chou and G.D.Fasman

  16. Which packages are used for computer modelling of protein ?
    AMBER, CHARMm, X-PLOR

  17. What will you call the complements of mRNA ?
    Transcriptome

  18. Name two enzymes where protein engineering has been done.
    Beta-lactamase, triose phosphate isomerase

Short Answer Type Questions

  1. What is significance of proteins ?
    All the activities of cellular organisms from unicellular prokaryotes to humans are possible due to proteins.

  2. How does chymotrypsin work ?
    Chymotrypsin folds and three important amino acids (His 57, Asp 102 and Ser 105) are brought closer in a specific order and work through charge relay system.

  3. Why is feeding of colostrum necessary to new born babies ?
    Mothers must feed colostrum to their babies because it contains serum albumin and immunoglobulin in high amount that confer some resistance to infection.

  4. What are neutraceutical proteins ?
    The nutritional proteins (eg. lactose-free milk, protein concentrate, food formulations of  infants, etc) that provide therapeutic functions are called nutraceutical proteins.

  5. What is mass spectrometry ?
    It is a device to characterise and identify proteins and other chemical substances present even in a very low amount (picomoles). It creates gas phase of biomolecules to be characterised, ions are separated as per m/z ratio, molecular mass of separated ions are detected.

  6. What is the principle of two-dimentional gel electrophoresis ?
    The two-dimentional electrophoresis combines two  techniques i.e. isoelectric focussing and SDS-PAGE electrophoresis, and work according to the principles of these two.

  7. Indicate four general precautions to be observed for maximal stability of proteins during purification.
    (a) Maintenance of specific pH range of buffered solution,
    (b) Working around physiological conditions
    (c) Avoiding agitation or addition of chemicals
    (d) Use of inhibitor to check proteolytic enzymes.

  8. Why is milk a suitable source of nutrients during early growth in mammals ?
    During early growth (infancy) mammals depend on milk for nutrients because it contains all nutritional contents required by the developing infants for their nourishment and protection against several infections.

  9. Indicate three important non-covalent forces which contribute to protein folding and explain how they arise ?
    The three non-covalent forces that contribute to protein folding are : hydrogen bonds, van der Waals forces and hydrophobic interactions. They arise due to non-covalent interaction between side chains of different amino acids within the molecule and with the water molecules that surround it.

  10. The relationship between the number of genes and the number of proteins is non-linear. Explain the above statement.
    The amino acids that cannot be synthesized in our body but provided externally through food are called essential amino acids. Whey protein is a better nutritional protein among casein, egg protein, soy protein, rice protein and wheat because of presence of maximum branched chain amino acids eg., lle, leu and val, lys and trp. These amino acids must be  present in  muscle cell to promote protein synthesis. These also increase the bioavailability of high complex carbohydrates.

  11. What is proteome ?
    Proteome is total set of proteins expressed from transcriptome of a cell.

  12. What is proteomics ?
    Proteomics is the identification, analysis and large scale production of total protein components of an organism.

  13. What is structural proteomics ?
    Structural proteomics is the study of structure and nature of protein complexes in a specific cell organelle.

  14. You are interested in studying the effect of specific point mutations on the stability of an enzyme. How will you go ahead to induce specific point mutation ?
    Specific point mutation is done by Site-directed Mutagenesis. A gene to be cloned is mutated in M 13 based vector. It is allowed to anneal to single stranded target gene.

  15. Define proteomics. Write three major step in proteome analysis.
    Protemoics is the qualitative and quantitative comparison of proteomes i.e. a  complete set of proteins expressed during the entire life of a cell under different  conditions to further explore the biological processes. The steps involved in proteome analysis are :
    (i) Separation of protein by two-dimentional gel electrophoresis.
    (ii) Quantification and identification of protein usually in gel digestion and subsequent mass spectrometry.
    (iii) Identification of peptides of protein (by identifying the peptide obtained through in-gel degestion) by peptide mass fingerprinting or de nove sequencing.

  16. What are RFLPs and how are they generated ? Describe one application of RFLP analysis.
    The specific DNA fragments of different size generated by a restriction enzyme is called RFLPs. The isolated genomic DNA is treated with a restriction enzyme which  results information of various sized DNA fragments. These are subjected to agarose gel electrophoresis where DNA fragments are separated.

  17. Write Short note on Protein Data Bank (PDB).
    The Protein Data Bank (PDB) is the repository for 3-D structural data of proteins and nucleic acids obtained by crystallography or NMR spectroscopy. The databases store information about the exact location of all atoms in a large molecule. The databases store information about the exact location of all atoms in a large molecule. The structural data can be used to see the biomolecules by using suitable software.

Fill in the blanks

  1. Inactive form of chymotrypsin is called --------------
    Zymogen

  2. High grade proteins are used in ------------------
    Therapeutic and diagnostic purpose

  3. Mass spectrophotometry was introduced in 1900 first by --------------
    J.J.Thomson

  4. Head quarter of Indian Society for Mass Spectrometry is situated at ---------------
    BARC, Mumbai

  5. SELDI is a --------------- of affinity chromatography and time of flight (TOF).
    Combination

  6.  In 2002 --------- was awarded Nobel Prize for developing electrospray ionisation (ESI).
    J.B.Fenn

  7. The first genetically engineered vaccine produced in India was ----------------
    Hepatitis B vaccine

  8. ------------- were awarded Nobel Prize for discovery of monovlonal antibodies.
    Kohler and Milstein

  9. ------------ is used in ELISA.
    Horseradish peroxidase

  10. ----------------- is genetically engineered enzyme produced by Bacillus subtilis.
    Subtilisin.
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