Protein

Question 1

What is the monomer of protein?

Answer 1

Amino acid

Question 2

What is the structure of amino acid?

Answer 2

An amino group - NH2
Carboxylic acid group - COOH
A variable R group
(Search structure on internet)

Question 3

What bond is used to join amino acid?

Answer 3

Peptide bond

Question 4

What is a dipeptide?

Answer 4

It contains two amino acids

Question 5

What is a polypeptide?

Answer 5

It contains three or more amino acids

Question 6

What is the primary structure of protein?

Answer 6

The sequence of amino acid
only bond involved is peptide bond

Question 7

What is the secondary structure of protein?

Answer 7

The chains of amino acids coil or fold to produce an alpha helix or beta sheet
These are held in place with hydrogen bonds

Question 8

What is the tertiary structure of protein?

Answer 8

The 3D shape of the protein formeed when secondary structure coil and fold

Question 9

What bonds are holding the tertiary structure of protein?

Answer 9

• Disulphide bond - if two cytosine amino acids are near each other
• Ionic bond - if R groups carry an opposite charge
• Hydrogen bond - between slightly charged R groups
• Hydrophobic and hydrophilic interaction - weakinteraction between polar and non-polar R groups

Question 10

What are two types of tertiary structure of protein?

Answer 10

Globular and fibrous

Question 11

What is the quaternary structure of protein?

Answer 11

The association of two or more protein subunits

Question 12

What is the general properties of globular protein?

Answer 12

Spherical, water soluble protein because they have hydrophilic amino acid on their surface and hydrophobic amino acid in the centre

Question 13

What is conjugated protein?

Answer 13

Globular proteins that contain a non-protein component called a prostheic group

Question 14

What is the general properties of fibrous protein?

Answer 14

Long, strand-like structure, insoluble

Question 15

What are the three examples of fibrous protein?

Answer 15

Collagen, keratin and elastin

Question 16

What is the structure of collagen?

Answer 16

Rope-like structure - made of 3 chains wound around each other, each chain is a coil.
Minerals bind to the structure to increase its rigidity

Question 17

What is the structure of keratin?

Answer 17

Contains sulphur
containing acid - cysteine

Question 18

What is the structure of elastin?

Answer 18

Made from stretchy molecules called tropoelastin

Question 19

What types of bonds are used in collagen?

Answer 19

Hydrogen bonds from between the chains
Each collagen molecule forms covalent bonds called cross links which staggered along the molecules
This makes a fibril, lots of fibrils makes a fibre

Question 20

What type of bonds is used in keratin?

Answer 20

Lots of strong disulphide bonds

Question 21

What type of bonds is used in elastin?

Answer 21

Cross linked covalent bonds

Question 22

What is the function of collagen?

Answer 22

Connective tisse found in bone, muscle, skin, tendons, ligaments and the nervous systems

Question 23

What is the function of keratin?

Answer 23

Present in hair, skin, nails, feathers and horns

Question 24

What is the function of elastin?

Answer 24

Present in the walls of blood vessels, skin, some ligaments and alveoli in lungs

Question 25

How collagen is adapted to perfoem its function?

Answer 25

Flexibility

Question 26

How keratin is adapted to perform its function?

Answer 26

Strong, inflexible, insoluble The more disulphide bonds - the less flexibility

Question 27

How elastin is adapted to perform its function?

Answer 27

Allow flexibility and the ability to return to normal size insoluble

Question 28

What are the three examples of globular protein?

Answer 28

Insulin, Haemoglobin, catalase

Question 29

What is the structure of haemoglobin?

Answer 29

* A globular protein with four polypeptide subunits * Two are alpha subunits and two are beta subunits. * Each subunit contains the prosthetic group haem. * Each haem group contains an Fe2+ ion, which binds to the oxygen. * One haemoglobin molecule can bind to four oxygen molecules

Question 30

What is the function of haemoglobin?

Answer 30

Bind reversibly to oxygen

Question 31

What is the structure of insulin and how it is adapted to carry out its function?

Answer 31

Contains two polypeptide chains they are linked by disulphide bonds The shape of insulin is complementary to the receptors on the plasma membrane so it can regulate glucose level

Question 32

What is the structure of catalase and how it is adapted to carry out its function?

Answer 32

It contains four haem prosthetic groups. The presence of iron II ions in teh prosthetic groups allow catalse to interact with hydrogen peroxide and speed up its breakdown. Hydrogen peroxide is damaging to the cells.