Protiensynthesis

Question 1

Cells synthesise proteins for

Answer 1

secretion and internal use

Question 2

secretion

Answer 2

transport out of the cell

Question 3

3 key organelles in protein synthesis

Answer 3

ribosomes, Endoplasmic reticulum , Golgi apparatus
(cytoskeleton is also invloved)

Question 4

Protein production steps (5)

Answer 4

1. Proteins are synthesised on the ribosomes bound to the ER
2. They pass into its cisternae and packaged into transport vesicles
3. these vesicles containing the newly synthesised protein move towards the Golgi apparatus via the cytoskeleton
4. The vesicles fuse with the cis face of the GA and the proteins enter. These proteins are structurally modified, then leave the GA from the trans face
5. Secretary vesicles carry proteins that are to be released from the cell. The vesicles move towards and fuse with the cell surface membrane, releasing their contents by exocytosis. Some vesicles form lysosomes which contain enzymes used in the cell.

Question 5

Whats a mRNA

Answer 5

• messenger RNA
• the gene that has coded instructions for a protein is transcribed onto a length of mRNA

Question 6

where does translation occur

Answer 6

at the ribosomes, the mRNA pass pout the nucleus via the nuclear pores in the nuclear envelope and travel to the ribosomes