Individual work. student of _____ group. Lesson 2. proteins. THEIR structure, Classification, functions and properties.. What is isoelectric point of amino acid?

Individual work

student of _____ group

_______________________________________________

^(name)

Lesson 2. proteins. THEIR structure, Classification, functions and properties.

1. Give the definition for the following terms:

Proteins _________________________________________________________________

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Enzymes ________________________________________________________________

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Enzymology ______________________________________________________________

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Hydrolysis _______________________________________________________________

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Denaturation _____________________________________________________________

2. Name the properties of enzymes as proteins:

1._______________________________________________________________________

2._______________________________________________________________________

3._______________________________________________________________________

4.______________________________________________________________________

5._______________________________________________________________________

6._______________________________________________________________________

3. Draw common formula of amino acid, show parts of molecule, named it.

4. Choose, what salts, written below can be used for salting out (underline correct):

Ag NO_{3 ,}(NH₄)₂SO_4, NaCl, Pb(CH₃COO)₂, MgSO₄, NH₄Cl, CuSO_{4 ,} HgCl₂

5. Draw the formulas of the following amino acids, indicate which of them are hydrophilic uncharged, aromatic, negatively charged, sulfur containing.

ALANINE TREONINE PHENYLALANINE

PROLINE ARGININE GLUTAMATE

6. Indicate correct answer.

What is isoelectric point of amino acid?

a) it is pH, when amino acid has positive charge;

b) it is pH, when amino acid has negative charge;

c) it is pH=7.0;

d) it is pH, when amino acid becomes electroneutral.

7. Distinguish in this scheme amino acid’s atoms (groups of atoms) that take parts in the formation of bond between two amino acids. How this type of bond is named? Distinguish this bond, name amino acids and new substance, its “ends”.

CH₃CH₂OHCH₃O CH₂OH

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NH₂ – CH – COOH + NH₂ – CH – COOH → NH₂ – CH – C – NH – CH – COOH

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8. Give the examples of denaturating agents.

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8. Write all levels of organization of protein’s molecule and bonds, which stabilize them:

9. Old book about proteins structure was found in library. Here you can find such sentence “ … molecule of this protein contains a lot of proline...it is possible that this long polypeptide chain has spiral structure, which is common for many globular proteins…”. In the modern view at secondary protein’s structure do you agree with this statement? Argument your answer.

10. What level of structure does molecule drawn below have?

11. Give the examples of amino acids pairs which can be base for:

hydrophobic interaction ________________________________________

ionic interaction ______________________________________________

disulfade bond ________________________________________________