Proteins

Question 1

What can combo to from proteins

Answer 1

Polypeptides

Question 2

How many amino acids have been identified and how many occur naturally in proteins

Answer 2

About 100 amino acids have been identified of which only20 occur naturally in proteins

Question 3

Describe the amino acid chemical groups

Answer 3

Every amino aid has a central carbo atom to which are attached 4 different chemical groups:
-amino group (NH3)
-carboxyl group (COOH)
-hydrogen atom (H)
-R group

Question 4

Draw the general structure of an amino acid

Answer 4

Answer on paper

Question 5

What bond is formed when two amino acids combine

Answer 5

Peptide bond

Question 6

Draw the condensation reaction between who amino acids

Answer 6

Answer on paper

Question 7

What is the primary structure of a protein

Answer 7

The sequence if amino acids bonded by covalent peptide bonds. DNA of a cell determines the primary structure of a protein by instructing the cell to add certain a i acids in specific quantities in a certain sequence.This affects the shape ad therefore the structure of the protein

Question 8

What is the secondary structure of a protein

Answer 8

The secondary structure of a protein occurs when the weak negatively charged nitrogen and oxygen atoms interact with the weak positively charged hydrogen atoms to form hydrogen bonds.These hydrogen bods can be broken by high temperature and PH.Alpha helix shape forms when the hydrogen bonds form between every fourth peptide bond. Beta pleated sheet shape forms when the protein folds so that two parts of the polypeptide chain are parallel to each other

Question 9

What is the tertiary structure f a protein

Answer 9

Further conformational change of the secondary structure leads to additional bonds forming between R groups. This structure is common in globular proteins. Bonds in this structure include:
-peptide
-hydrogen
-disulphide bridges
-ionic
-hydrophobic interactions

Question 10

What is the quaternary structure

Answer 10

Occurs in proteins that have more than one polypeptide chain working together as a functional macromolecule

Question 11

What is the test for proteins called

Answer 11

Buret test

Question 12

What is the method for the test for proteins

Answer 12

1- plane sample being tested into a test tube and add a equal volume of sodium hydroxide solution at room temperature
2- add a few drops of very dilute copper (II) sulphate solution a mix gently
3- a purple colouration indicates the presence of peptide bonds and hence a protein