Protein Structure and Function - Lecture 4

Question 1

What is a Primary Structure of Proteins?

Answer 1

A Sequence of amino acid residues

Question 2

What is a Secondary Structure of Protein?

Answer 2

Localised conformation shape of the polypeptide backbone

Question 3

What is the tertiary structure of protein?

Answer 3

The three dimensional structure of the entire polypeptide, including all its side
chains.

Question 4

What is the Quaternary Structure of Proteins?

Answer 4

Spatial arrange of polypeptides chains in a protein with multiple chains.

Question 5

What type of structures are amino acids?

Answer 5

Planar Structures

Question 6

What bond helps form the secondary structure of proteins?

Answer 6

Hydrogen Bonds

Polypeptide Backbone

Question 7

What are the examples of secondary structure?

Answer 7

Alpha Helix

Beta Sheet

Question 8

How would you describe the type of twists in an alpha helix?

Answer 8

Right Handed Twists

Question 9

What is Proline’s effect on an Alpha Helix?

Answer 9

Proline residues break alpha helices - Proline puts in a left handed 90 turn

Question 10

What are the two types of Beta Sheets?

Answer 10

Parallel

Aniparallel

Question 11

Describe the structure of a Beta Sheet?

Answer 11

Polypeptide backbone almost completely extended.

Beta Pleated sheets have a zigzag structure

Question 12

What is Collagen?

Answer 12

Component of Bone or Connective Tissue

Question 13

What is the repeating sequence of Collagen?

Answer 13

Amino Acid
Proline
Glycine

Question 14

Describe the Strucutre of Collagen?

Answer 14

Beta Pleated sheets have a zigzag structure
Can have flat sheets or pleated sheets
There are only inter-chain H bonds, no intra chain.
There are inter and intra-molecular covalent bonds.

Question 15

What are the two groups of Tertiary Protein?

Answer 15

Fibrous Protein

Globular Protein

Question 16

What are the features of a Fibrous Protein?

Answer 16

Insoluble in water and dilute salt solutions

Polypeptide chains organised approximately parallel along a single axis.

Mechanically strong

Structural roles.

Question 17

What are the features of a Globular Protein?

Answer 17

Soluble in water and salt solutions

Spherical shapes.

Polar side chains are on the outside and interact with the aqueous environment

Non polar components are buried inside

Substantial Secondary Structures articulate

Question 18

What are the forces that stabilies a tertiary protein?

Answer 18

Covalent disulphide bonds

Electrostatic interactions = salt bridges

Hydrophobic interactions

Complex formation with metal ions

Question 19

What are the features of a Disulphide bond?

Answer 19

Readily reversible

Detects oxygen free radicals, can cause ion channels to open and to
close

Question 20

What may occur to a protein if an amino acid is omitted?

Answer 20

Leads to significant functional changes

Question 21

What helps the folding process of a protein?

Answer 21

A Chaperone protein

Question 22

What causes Creutzfeldt -Jacob Disease?

Answer 22

Disease Prion Protein (PrPsc)

Question 23

What is the normal form of Prion Protein?

Answer 23

Normal form of Prion protein termed PrPc

Question 24

What is disruption of a protein called?

Answer 24

Denaturation

Question 25

How many Oxygen can Haemoglobin carry?

Answer 25

4

Each Haem group can carry one

Question 26

What is the redox centre of Haemoglobin?

Answer 26

Iron atom