Proteins

Question 1

describe how amino acids are joined

Answer 1

condensation reaction between carboxyll group of one and an amine group of another removing a molecule of water forming a peptide bond

Question 2

what are dipeptides?

Answer 2

2 amino acids joined together

Question 3

what is a polypeptide?

Answer 3

many amino acids joined together

Question 4

describe the primary structure of a protein

Answer 4

sequence of amino acids in a polypeptide chain are joined by peptide bonds

Question 5

describe the secondary structure of a protein

Answer 5

folding of the polypeptide chain into alpha helix or beta pleated sheet due to the hydrogen bonds between amino acids

Question 6

describe the tertiary structure of a protein

Answer 6

3D folding of polypeptide chain due to interactions between amino acids R group forming hydrogen bonds, ionic bonds, and disulfide bridges

Question 7

describe the quaternary structure of a protein

Answer 7

more than one polypeptide chain formed by interactions between polypeptide

Question 8

describe the test for proteins

Answer 8

1, add burette reagent to sample
2, positive test results in lilac colour indicating presence of peptide bonds

Question 9

What is an amino acid?

Answer 9

A monomer that makes up proteins, and has a central carbon atom which is bonded to a carboxylic acid group, an amine group and a R group

Question 10

Define “Protein”

Answer 10

A polymer which is made up of amino acids which are linked by peptide bonds.

Question 11

Draw the general structure of an amino acid

Answer 11

R
I
H2N—-C—COOH
I
H

Question 12

What is the role of Hydrogen bonds in proteins?

Answer 12

Hydrogen bonds make structures stable in large numbers, though are easily broken

Question 13

What is the role of the disulfide bridge in forming the quaternary structure of an antibody?

Answer 13

Joins two different polypeptide chains

Question 14

Describe how the structure of a protein depends on the amino acids it contains.

Answer 14

The structure of a protein is determined by the sequence of amino acids in a polypeptide chain in the primary structure of a protein and the interactions with hydrogen bonds, ionic bonds, and disulfide bridges. The secondary structure of a protein is formed by hydrogen bonds between amino acids, forming alpha helices or beta pleated sheets. The tertiary structure of a protein is formed by interactions between R groups, which creates the complimentary shapes in molecules, like antibodies and receptors. The quaternary structure is more than one polypeptide chain.

Question 15

How do amino acids differ from each other?

Answer 15

Differ from the R group the each have

Question 16

How are dipeptides formed?

Answer 16

Formed from the condensation reaction between two amino acids where a peptide bond is formed ,which removes a molecule of water

Question 17

How are polypeptides formed?

Answer 17

Formed from the condensation reaction between three or more amino acids where a peptide bond is formed, which removes a molecule of water

Question 18

what is the role of disulphide bridges?

Answer 18

They are strong covalent S-S bonds between molecules of amino acid

Question 19

What is the role of ionic bonds?

Answer 19

Relatively strong bonds between the charged R groups