Major categories of Proteins

Question 1

Proteins that regulate gene expression

Answer 1

Make RNA from DNA, synthesise polypeptides from RNA

• RNA Polymerase
• ribosomal proteins, translates mRNA into protein

Question 2

Transporter proteins

Answer 2

Mediate the movement of solutes such as ions and organic molecules across plasma membranes
- ion channels (integral proteins in plasma membranes)

Question 3

Enzymes

Answer 3

Increase reaction rates
- eg reactions required for cellular metabolism, like the hydrolysis of macromolecules into smaller molecules for absorption into the smaller intestine

Question 4

Cell signalling proteins

Answer 4

Enable cells to communicate with each other, themselves and external environ.
- receptors in the plasma membrane bind to hormones or neurotransmitters in extracellular fluid

Question 5

Motor proteins

Answer 5

Initiate movement

- myosin (found in muscle cells) provides the contractile force that shortens muscle

Question 6

Structural proteins

Answer 6

Support, connect and strengthen cells, tissues and organs

-collagen and elastin provide support for ligaments

Question 7

Defense proteins

Answer 7

Protect against infection and disease due to pathogens

-antibodies attack foreign cells and proteins such as those from bacteria and viruses