Lysosomes

Question 1

What are lysosomes?

Answer 1

Small, tiny spherical sac-like structures formed by Golgi Apparatus at trans face.

Question 2

How many membranes does lysosomes have

Answer 2

Single

Question 3

lysosomes Discovered by

Answer 3

Christian de Duve

Question 4

What are lysosomes called in plant cells?

Answer 4

Sphaerosomes

Question 5

Size of lysosomes

Answer 5

0.2μ-0.8μ

Question 6

How do lysosomes activate?

Answer 6

At acidic pH ( pH=5 )

Question 7

How is the acidic pH is maintained?

Answer 7

Membrane of lysosome has H+ pump protein which actively pumps protons (H+) into the lumen(empty space) of lysosome, creating acidic pH

Question 8

Lysosomes are highly polymorphic? Why

Answer 8

Polymorphic means has many forms…this is because they have different physiological states.

Question 9

What are the types of lysosomes?

Answer 9

• Primary lysosomes
• Secondary lysosomes
• Tertiary lysosomes
• Autophagy vacuoles

Question 10

Which is the freshly formed lysosome also k/a storage granules and has enzymes in inactive form?

Answer 10

Primary lysosomes

Question 11

1° lysosome+ phagosome = ?
And
Autophagosomes are?

Answer 11

1° lysosome + phagosome= heterophagosome.
Autophagosomes are lysosomes containing cell organelles to be digested.

Question 12

What contains undigested material?

Answer 12

Residual bodies/ residual lysosomes

Question 13

How is the undigested material eliminated?

Answer 13

By Exocytosis/ cell vomiting.

Question 14

Functions of lysosomes?

Answer 14

• Intercellular digestion
• Extracellular digestion
• Autolysis

Question 15

What is Autophagy?

Answer 15

Digestion of old/dead cell organelle.
It takes place during starvation of cell.

Question 16

What is heterophagy?

Answer 16

It includes Endocytosis which further includes
* Phagocytosis - engulfment of food material in solid form
-cell eating
-phagosome
* Pinocytosis - engulfment of food material in liquid form
- cell drinking
- pinosome

Question 17

What is Extracellular digestion?

Answer 17

Digestion/ breakdown occur outside the cell.
WBCs contain large number of lysosomes.

Question 18

What is Autolysis?

Answer 18

Sometimes, all lysosomes of a cell burst to dissolve the cell completely, it is called Autolysis.
That’s why lysosomes are also called suicidal bags.
For eg:- during metamorphosis, lysosomes digest the tail of tadpole using cathepsin lysosome.