1. (4) Genes and proteins in health and disease
(A) Structure and functions of proteins
(B)
Gene and Chromosome Mutations

2. Genes and proteins in health and disease (a)
State how polypeptide chains are formed
State the result of folding a polypeptide chain
State how proteins are held in a 3D shape
State why there is a variety of protein structures and shapes
Give examples of different protein functions

3. Protein Structure
Proteins are large _____ molecules, containing _____, _____, _____ and _____. They sometimes contain _____ too.
Proteins are made up of _____ _____which are linked together into long chains by _____ bonds.
During _____, the amino acids are built into a specific sequence.
The _____ of this amino acid chain and the _____ produced during the folding process determine the protein’s 3D structure and _____ .
Shape / amino acid / function / nitrogen / oxygen / translation / transcription / hydrogen / peptide / carbon dioxide / sulphur / protein / organic / inorganic / nucleotides / carbon / bonds / folding

4. Protein Structure
Proteins are large organic molecules, containing CARBON, NITROGEN, HYDROGEN and OXYGEN. They sometimes contain sulphur too.
Proteins are made up of amino acids which are linked together into long chains by peptide bonds.
During translation, the amino acids are built into a specific sequence.
The folding of this amino acid chain and the bonds produced during the folding process, determines the protein’s 3D structure and shape.

5. Protein Structure 4 levels of protein structure: Primary Structure
Secondary Structure
Tertiary Structure
Quaternary Structure

6. Protein Structure Level of structure Main function Brief description
Primary
Arrangement of amino acids
Secondary
Tertiary
Quaternary

7. Primary structure (the arrangement of amino acids)
single chain of specific amino acids linked by peptide bonds to form polypeptides.

8. Secondary structure (the coiling of the amino acid chain)
Folding of the primary chain into coils or pleats
caused by hydrogen bonds.
Coil
Pleat
Hydrogen bonds

9. Tertiary structure (the coiling of the coils)
The secondary chain bends and folds further due to the interactions between individual amino acids:
H-bonds
Strong di-sulphide bridges (S-S)

10. Quaternary Structure (folding of many polypeptide chains)
Two or more polypeptide chains may fold and link together to form a protein with a 3D shape.
Different polypeptide chains

12. Fibrous Proteins Fibrous proteins are
built up from long parallel polypeptide chains
insoluble
involved in structural roles within the cell
examples:
keratin in hair,
collagen in bone
actin and myosin in muscle

13. Globular Proteins
Two or more polypeptide chains linked to form a roughly spherical shape.
Often soluble
Usually involved in cell activities:
- Enzymes
- Hormones
- Antibodies
Structural role …
protein channels in membrane

14. Conjugated Proteins
A globular protein associated with a non- protein chemical.
Examples :
- mucus (protein and carbohydrate)
- haemoglobin (protein and iron)
Haem (iron)
When proteins and carbohydrates combine – they form GLYCO-PROTEINS

15. Protein function Function Example Transport Haemoglobin Storage
Proteins have a wide variety of structures and shapes resulting in a wide range of functions.
Function
Example
Transport
Haemoglobin
Storage
Albumin (egg white)
Enzymes
Cellular reactions - catalase
Regulatory
Hormones - insulin
Movement
Muscles - actin
Structural
Membranes, keratin
Defence
Antibodies

16. TASK: use page 46 to label your diagram

17. Structure of Proteins Summary

18. Genes and proteins in health and disease (a)
State how polypeptide chains are formed
State the result of folding a polypeptide chain
State how proteins are held in a 3D shape
State why there is a variety of protein structures and shapes
Give examples of different protein functions