Lysosomes (95Q)

Question 1

What are Lysosomes?

Answer 1

• Specialized vesicles that digest material either inside or material that’s brought in from the outside of the cell
• They can be used to recycle “old” organelles

Question 2

How do Lysosomes break down Macromolecules?

Answer 2

-Via hydrolysis reactions

Question 3

What do Lysosomes contain & what is it used for?

Answer 3

-Hydrolytic enzymes (protein catalysts) that are used to accelerate the degradation of macromolecules via hydrolysis reactions

Question 4

What are Hydrolysis Reactions carried out by?

Answer 4

-Hydrolytic enzymes

Question 5

What are the characteristics of Hydrolytic Enzymes?

Answer 5

• They’re GREAT at Breaking things down but they’re a DANGER for the rest of the cell & other macromolecules
• Must be segregated from the rest of the cell (cytoplasm)
• Function best in acidic pH= maintained inside the lysosome by pumping protons across the membrane

Question 6

What are Hydrolytic Enzymes a good example of?

Answer 6

-Proteins that are destined for an organelle, made on RER & pass through vesicles & golgi

Question 7

What are Primary Lysosomes?

Answer 7

-Vesicles that leave via trans face of golgi & then fuse w/ vesicles derived from endocytosis

Question 8

How are Primary Lysosomes made?

Answer 8

-Formed by combining 2 directions= Food coming from the outside in & meets w/ Hydrolytic enzymes going out

Question 9

In Primary Lysosomes, what happens during the outbound direction & inbound direction?

Answer 9

• In Inbound direction, vesicles from endocytosis (endocytic vesicles) engulf ingested material which accumulates in Endosomes
• In Outbound direction, primary lysosomes budd off trans Golgi & fuse w/ inbound endosomes!

Question 10

How is a Secondary Lysosome formed & what occurs on it?

Answer 10

• When outbound primary lysosomes fuse with inbound endosomes
• It is where enzymes meet what they’re supposed to be digesting which how the Hydrolytic (degradation) reactions occur

Question 11

What happens after ingested material is broken down in the Secondary Lysosome?

Answer 11

-The degraded contents like monomers, single amino acids, & single fatty acids can be reused by the cell (some cells take in & ingest their food this way)

Question 12

How do Lysosomes recycle “old” organelles?

Answer 12

• Primary lysosomes fuses w/ a special double membraned vesicle built around the old organelle which is called Autophagasome
• After fusion, the contents are degraded= allows for products to be recycled & reused by the cell

Question 13

What is Autophagasome?

Answer 13

-Form of recyling when the cell eats its old organelle

Question 14

How does the Recyling of “old” organelles increase?

Answer 14

• With exercise
• Benefits of exercise & experimentally extending the life span of lab animals (restricting their calorie diet)= enhances recyling & keeps our cells young