Biological molecules

Question 1

Examples and roles of fibrous proteins

Answer 1

Elastin- elasticity (blood vessels,alveoli)
Keratin- protection (skin, hair, nails)
Collagen- structure (connective tissue, bones, cartilage)

Question 2

Water

Answer 2

High boiling point and high specific heat capacity
- Weak but many hydrogen bonds
- Means it doesn’t experience rapid temperature changes- good stable habitat.

High latent heat of vaporisation
- Weak but many hydrogen bonds
- Acts as a coolant

Cohesive properties
- Due to polarity, water molecules are attracted to each other and stick together
- Helps as a transport medium e.g., capillary action in transpiration.
- Allows surface tension.

Adhesive properties
- Attraction between water and other charged and polar molecules/surfaces
- Help act as a transport medium e.g., capillary action

Polarity
- Attracted to the positive and negative charges on ionic molecules. Can dissolve ionic molecules.
- Useful as a solvent in living organisms. E.g., ions in blood

Less dense as a solid
- When freezes hydrogen bonds holds molecules in a fixed lattice. Less dense and can float
- Helps environments such as ice floats which insulates water