Secretion

Question 1

Describe growth hormone (GH).

Answer 1

• Mammalian hormone.
• Synthesised and secreted by anterior pituitary.
• Acts on many tissues to promote growth - stimulates cells to take up amino acids.
• Overproduction > gigantism, underproduction > pituitary dwarfism.

Question 2

Describe gibberellins.

Answer 2

• Plant hormone.
• Secreted by plant embryos.
• Triggers changes in aleurone layer to synthesis and secrete enzymes that digest proteins and starch stored in the endosperm.

Question 3

Give reasons for protein secretion?

Answer 3

• Construction of cell wall.
• Enzyme-mediated extracellular degredation.
• Cell communication.

Question 4

Describe sex pheromones.

Answer 4

Allows fungi to recognise cells of the opposing mating type and promotes mating.

Question 5

Describe the secretory pathway.

Answer 5

Endoplasmic reticulum > Golgi apparatus > vesicles > secretion or lysosomes.

Question 6

Name and describe the three types of protein modifications which may take place after translation.

Answer 6

• Proteolysis (cleavage)
• Glycosylation (adding sugars)
• Phosphorylation (adding phosphate groups).