general properties of proteins

Question 1

draw the general structure of an amino acid

Answer 1

R
|
H2N — C — COOH
|
H

Question 2

how many amino acids are common in all organisms? How do they vary?

Answer 2

20 amino acids
differ in only R group

Question 3

describe how amino acids join together

Answer 3

condensation reaction
removing a water molecule
between carboxyl and amine
forming peptide bond

Question 4

what are dipeptides and polypeptides

Answer 4

dipeptide - 2 amino acids joined together
polypeptide - many amino acids joined together

Question 5

what is a functional protein

Answer 5

may contain one or more polypeptides

Question 6

describe the primary structure of a protein

Answer 6

sequence of amino acids in polypeptide chain joined by peptide bonds

Question 7

describe the secondary structure of a protein

Answer 7

folding of polypeptide chain
eg. alpha helix or beta pleated sheets
due to hydrogen binding between amino acids
between NH of one and C=O of another

Question 8

describe the tertiary structure of a protein

Answer 8

3D folding of polypeptide chain
due to interaction of amino acid and R groups
forming hydrogen ionic and disulfide bridges

Question 9

describe the quaternary structure of a protein

Answer 9

more than one polypeptide chain
formed by interactions between polypeptides

Question 10

describe the test for proteins

Answer 10

1. add Biuret reagent
2. positive= purple