lecture 8

Question 1

cytoskeleton

Answer 1

• composed of protein fibres
• gives the cell shape and structural stability
• aids cell movement and transport of materials within the cell
• organizes all the organelles and other cellular structures into a cohesive whole

Question 2

endomembrane system

Answer 2

• composed of the smooth and rough ER and the golgi apparatus
• primary system for protein and lipid synthesis
• ion, ATP, amino acids and other small molecules diffuse randomnly throughout the cell
• the movement of proteins and other large molecules is energy demanding and tightly regulated

Question 3

secretory pathway hypothesis

Answer 3

• proposes that proteins intended for secretion from the cell are synthesized and processed in a highly prescribed set of steps
• proteins are packages into vesicles when they move from the RER to the golgi appartus and from the golgi apparatus to the cell surface
• RER and golgi appartus function as an integrated endomembrane system

Question 4

what happens inside the golgi apparatus?

Answer 4

• has a dynamic composition
• new cisternae form at the cis face
• old cisternae break off from the trans face
• protein products enters at the cis face and pass through the cisternae containing enzymes for attaching specific carbohydrate chains before exiting on the far side (trans face)

Question 5

how are products shipped from the golgi?

Answer 5

• each protein that comes out has a molecular tag that places it in a particular type of transport vesicle
• each type of transport vesicle also has a tag that allows it to be transported to the correct destination

Question 6

exocytosis

Answer 6

• some proteins are sent to the cell surface in vesicles
• process where these vesicles fuse with the plasma membrane, releasing their contents to the exterior of the cell

Question 7

how are materials delivered to the lyosomes?

Answer 7

• phagocytosis
• autophagy
• receptor-mediated endocytosis

Question 8

endocytosis

Answer 8

process by which the cell membrane can pinch off a vesicle to bring outside material into the cell

Question 9

pinocytosis

Answer 9

• third type of endocytosis
• brings fluid to the cell, in addition to phagocytosis and receptor-mediated endocytosis