1.3 Proteins

Question 1

What are amino acids?

Answer 1

The monomers containing an amino (CH2) group, a carboxyl (COOH) group and a varibale R group that make up proteins

Question 2

What are fibrous proteins?

Answer 2

Long chain proteins that are generally insoluble in water and typically have structural roles

Question 3

What are globular proteins?

Answer 3

Spherical shaped proteins that are generally soluble in water and typically have metabolic roles

Question 4

What is collagen and what does it do?

Answer 4

It is a type of fibrous protein that provides strength to many different cell types and makes up connective tissues

Question 5

What is haemoglobin and what does it do?

Answer 5

It is a globular protein with a quatenary structure composed of two alpha chains and two beta chains that contain haem groups and is specialised to transport blood around the body

Question 6

What are hydrogen bonds and what are their purpose within proteins?

Answer 6

They are a type of intermolecular bond between delta positive hydrogen atoms and delta negative atoms such as oxygen or nitrogen that are used to hold together the secondary, tertiary and quaternary structures of proteins

Question 7

What are ionic bonds and what are their purpose within proteins?

Answer 7

They are a type of bond between two charged R-groups that help to stabilise the tertiary and quaternary structures of proteins

Question 8

What are peptide bonds?

Answer 8

A type of bond joining the amino group in one amino acid to the carboxyl group in another amino acid in a condensation reaction

Question 9

What are proteins?

Answer 9

Polymers made up of amino acid monomers joined by peptide bonds in condensation reactions

Question 10

What is the primary structure of a protein?

Answer 10

The individual sequence of amino acids in the protein

Question 11

What is the secondary structure of a protein?

Answer 11

The interactions between the amino acids in the polypeptide chain held together by hydrogen bonds in the form of alpha helices or beta pleated sheets

Question 12

What is the tertiary structure in a protein?

Answer 12

The way that the whole protein folds to make a three dimensional structure

Question 13

What is the quaternary structure of a protein?

Answer 13

The interactions between the polypeptide chains in molecules that contain multiple polypeptide chains

Question 14

What bonds are found in the primary structure of a protein?

Answer 14

Peptide bonds

Question 15

What bonds are found in the secondary structure of a protein?

Answer 15

Hydrogen bonds

Question 16

What 3 types of bonds are found in the tertiary structure of a protein?

Answer 16

Hydrogen bonds, ionic bonds and disulphide bridges

Question 17

What are the disulphide bridges found in the tertiary structures of proteins?

Answer 17

Covalent bonds between sulphur atoms in cysteine

Question 18

What are the properties of firbous proteins?

Answer 18

• They are typically used for structural purposes
• They are insoluble
• They contain mostly secondary structure with little tertiary or quatenary structure
• They have occasional cross-linkages which form microfibres for tensile strength

Question 19

What are the properties of globular proteins?

Answer 19

• They are used typically for metabolic purposes (hormones, antibodies etc.)
• They form colloids in water
• They have complex tertiary and quatenary structures