Endomembrane and Bulk Transport System

Question 1

What is the Endomembrane System?

Answer 1

A membrane system interconnected by direct physical contact or transfer by vesicles.

Question 2

What are functions of the Smooth Endoplasmic Reticulum?

Answer 2

Metabolism of carbohydrates
Lipid synthesis for membranes
Detoxification of drugs
Storage of Ca2+

Question 3

What are functions of the Rough Endoplasmic Reticulum?

Answer 3

Rough appearance due to ribosomes
Involved in protein synthesis
Secreted and membrane bound proteins enter the lumen of rER and are processed for release from the cell

Question 4

What are the functions of the Golgi Complex?

Answer 4

Receives, modifies, sorts and ships proteins arriving from rER
Glycosylation
Sorting proteins
Directing vesicle trafficking

Question 5

What is glycosylation (in regards to Golgi complex)?

Answer 5

Addition of carbohydrates to proteins
Important for secreted or cell surface proteins
Produces polysaccharides which may also be secreted from the cell

Question 6

What is sorting proteins (in regards to Golgi complex)?

Answer 6

Adds molecule markers to direct proteins to the correct vesicle before budding from the ‘trans face’

Question 7

What is directing vesicle trafficking (in regards to Golgi complex)?

Answer 7

Adds molecule tags to vesicles leaving trans face to direct them to correct targets (lysosomes, secretory pathways, plasma membrane)
Acts as docking sites when they reach their target

Question 8

What are vesicles?

Answer 8

Membrane bound cytoplasm/fluid filled organelles involved in transport and secretory processes

Question 9

What is exocytosis?

Answer 9

Transports material out of the cell or delivers it to the cell surface

Question 10

What is constitutive exocytosis?

Answer 10

Releases extracellular matrix proteins

Question 11

What is regulated exocytosis?

Answer 11

Releases hormones and neurotransmitters

Question 12

What is endocytosis?

Answer 12

The cell takes in molecules and particulate matter at the plasma membrane

Question 13

What is phagocytosis?

Answer 13

Cell ‘eating’, uptake of food particles, forms a phagocytic vacuole which is digested by lysosomes, in humans this occurs in macrophages

Question 14

What is pinocytosis?

Answer 14

Cell ‘drinking’, uptake of extracellular fluid, uptake vesicle formed with aid of a coat protein (non-selective)

Question 15

What is receptor mediated endocytosis?

Answer 15

Specialised form of pinocytosis, allows the cell to take up specific water-soluble molecules that are present at low concentrations in the extracellular environment

Question 16

What are lysosomes ?

Answer 16

Membrane bound organelles made by rER and golgi body containing hydrolytic enzymes
Interior is acidic (required for enzymes to be active)
They degrade proteins, lipids, carbohydrates and nucleic acids and release products into cell

Question 17

What are lysosomes function?

Answer 17

They digest and recycle unwanted cellular materials (autophagy)
Important for cell death and cell health

Question 18

What are vacuoles?

Answer 18

Organelle surround by a single membrane, highly selective
Large vesicles derived from rER and Golgi
Food vacuoles involved in phagocytosis