Proteins (Types of proteins - Fibrous Proteins) Flashcards
Define fibrous protein
long, insoluble, structural proteins
What are the characteristics of fibrous proteins?
Fibrous proteins are long, insoluble molecules with a high proportion of hydrophobic R groups. They typically have a repetitive primary structure, which leads to organised, strong, and often unstructured forms.
Give 3 examples of fibrous proteins
Collagen
Elastin
Keratin
Where is Keratin found?
In hair, skin, and nails
Which amino acid does keratin contain in a high proportion?
Cysteine
What does Cysteine contain in its R-group?
Sulfur
What type of bonding occurs a lot in keratin?
Disulfide bonds
How does a high proportion of disulfide affect the properties of keratin?
It makes it inflexible and strong
Where is elastin found?
In the walls of blood vessels and alveoli of lungs
What does elastin allow tissues to do?
Expand and return to size
Why is it beneficial for tissues to contain elastin?
It confers strength and elasticity
What makes up elastin?
Aggregates of tropoelastin
Where is collagen found?
In the skin, tendons, ligaments, and nervous system
Why does collagen contain glycine for every 3rd amino acid?
Glycine is the smallest amino acid and so they can pack together more tightly
What property does collagen have?
Flexibility
