Download Proteins: Primary Structure

Lesson 6
 Textbooks
 Repro


Page 8-9 of ppq
Comparison sheet
 To
know about fibrous proteins
 Explain
the term quaternary structure
 Describe the properties and functions of
fibrous proteins

Including collagen, keratin & elastin
 Draw
the structure of a protein and label it
in as much detail as you can
- Explain the term quaternary structure
 Proteins
made of more than one polypeptide
chain
 May have an inorganic component
 Can’t function without all components

E.g. Haemoglobin and collagen
- Describe the properties and functions of fibrous proteins
3
polypeptides
 Wound together



Rope like structure
Triple helix
Hydrogen bonded
 Flexible
 Every


Small
Closely packed when wound together
 High

3rd amino acid is glycine
amounts of proline and hydroxyproline
Repel each other, adding stability
- Describe the properties and functions of fibrous proteins
 Complete
the table using page 104-105 in the
book and your flipped learning
- Describe the properties and functions of fibrous proteins
Feature
Type of biological
molecule
Type of protein
Protein
Haemoglobin
Protein
Fibrous
Globular
Main function
Strength
Carry oxygen
Inorganic component
No
Haem group (Iron)
Amino acid sequence
Every 3rd amino acid is
glycine (small)
High amounts of proline
and hydroxyproline
Only 1 type of
polypeptide chain
Microfibrils
Connective tissue
Variable
Structure
Where found in the
body
Collagen
2 types of polypeptide
chains
Red blood cells
- Describe the properties and functions of fibrous proteins
 Found
in hair, skin & nails
 Large amounts of cysteine


Lots of strong disulfide bonds
Less disulfide bonds means more flexible
- Describe the properties and functions of fibrous proteins
 Found

in elastic fibres
E.g. walls of blood vessels
 Lots
of soluble tropelastin
molecules cross linked


To create large, stable,
insoluble molecule
Can stretch and relax
 Have
alternating areas of
hydrophobic and lysinerich

Cross links caused by
hydrophobic interactions
and covalent bonds
involving lysine
 Past

Paper Questions
Q3 Jan 2008
 Past
paper question Jan 11 Q7
 Draw
the structure of a protein and label it
in as much detail as you can
 Complete
the summary table