Question

The physical structure of a protein often reflects and affects its function.

Discuss how the structure of a protein affects the function of TWO of the following.

a) Muscle contraction
b) Regulation of enzyme activity
c) Cell signaling

Answer 1

a) The protein molecules form filaments. There are two types of filament; thick and thin. Thick filament contain myosin, thin filaments contain actin, troponin and tropomyosin. Muscles contract by the two types of filament sliding over each other so that they overlap more.

b) Proteins change shae as temperature change. Because so much of an enzyme's activity is based on its shape, temperature changes can mess up the process and the enzyme won't work. High enough temperatures will cause the enzyme to denature and have its structure start to break up.

c) Cells have proteins called receptors that bind to signalling molecules and initiate a physiological response. Different receptors are specific for different molecules. Dopamine receptors bind dopamine, insulin receptors bind insulin and so on.