Lysosomes And Peroxisomes

Question 1

Describe the formation of lysosomes;

Answer 1

Formed by fusion of vesicles from the trans Golgi network

Also fuse with endosomes - vesicles formed from endocytosis

Question 2

Describe the function of lysosomes;

Answer 2

Compartmentalisation of lyric enzymes

Principal sites of intracellular digestion

Autophagy of obsolete organelles

Question 3

The compulsion of membranes varies through?

Answer 3

• highly glycosylated membrane proteins
• transport proteins
• vacuolar H+ ATPase

Question 4

What is phagocytosis?

Answer 4

Degradation of pathogens

Question 5

What is endocytosis?

Answer 5

Degradation of macromolecules

Question 6

What is autophagy?

Answer 6

Degradation of organelles

Question 7

How are hydrolases packaged?

Answer 7

Hydrolases are tagged with mannose-6-phosphate (M6P) during glycosylation

Question 8

What are peroxisomes?

Answer 8

Contain oxidative enzymes

Oxidases produce hydrogen peroxide from organic substrates;
RH2+O2—>R + H2O2

Catalases use hydrogen peroxide to oxidise other substrates,
H2O2 + R’H2 —> R’ + 2H2O

Question 9

Outline the function of B-oxidation(

Answer 9

• removal of carbons from alkyl chains of fatty acids to form acetyl CoA

Question 10

Describe the regulation of oxygen tension in the cell;

Answer 10

• use more O2 when the pressure rises
• mitochondria cannot do this

Question 11

Describe the formation of plasmalogens;

Answer 11

• class of phospholipid in myelin (insulates axon of nerve cells)
• myelin deficiencies lead to disease

Question 12

What do peroxisomes contain?

Answer 12

Oxidative enzymes and have a role in detoxification