[44] Apoptosis and Necrosis Assays

Question 1

What is apoptosis?

Answer 1

A form of programmed cell death that occurs in multicellular organisms.

Question 2

What is necrosis?

Answer 2

A form of cell injury which results in the premature death of cells in living tissue.

Question 3

What is the key difference between apoptosis and necrosis?

Answer 3

Apoptosis is a controlled, regulated process, whereas necrosis is uncontrolled and often occurs due to injury or disease.

Question 4

What are apoptosis and necrosis assays used for?

Answer 4

They are used to detect and quantify apoptotic and necrotic cell death.

Question 5

How do apoptosis assays work?

Answer 5

They typically detect characteristics of apoptosis such as cell shrinkage, nuclear fragmentation, chromatin condensation, and membrane blebbing.

Question 6

Name three common apoptosis assays.

Answer 6

• TUNEL Assay
• Annexin V Assay
• Caspase Activation Assays

Question 7

What is a TUNEL assay?

Answer 7

It is used to detect DNA fragmentation resulting from apoptotic signaling cascades.

Question 8

What is an Annexin V assay?

Answer 8

It is used to detect phosphatidylserine on the outer leaflet of the cell membrane, a hallmark of apoptosis.

Question 9

What is a Caspase Activation assay?

Answer 9

It is used to detect the activity of caspases, a family of protease enzymes playing essential roles in apoptosis.

Question 10

How do necrosis assays work?

Answer 10

They typically detect characteristics of necrosis such as loss of membrane integrity and release of cellular contents.

Question 11

Name two common necrosis assays.

Answer 11

• LDH Release Assay
• Trypan Blue Exclusion Assay

Question 12

What is a LDH Release Assay?

Answer 12

It is used to measure the release of lactate dehydrogenase (LDH), an intracellular enzyme released upon cell membrane damage.

Question 13

What is a Trypan Blue Exclusion Assay?

Answer 13

It is used to measure cell viability by the ability of live cells to exclude the Trypan blue dye, while necrotic cells with damaged membranes will absorb it.

Question 14

Why are apoptosis and necrosis assays important in research?

Answer 14

They allow researchers to understand the effects of drugs or treatments on cell death pathways, which is important in areas such as cancer research and drug development.

Question 15

Define TUNEL.

Answer 15

Terminal deoxynucleotidyl transferase dUTP nick end labeling, a method for detecting DNA fragmentation by labeling the terminal end of nucleic acids.

Question 16

Define LDH.

Answer 16

Lactate dehydrogenase, an enzyme that is found in nearly all living cells and is released into the cell culture medium following loss of membrane integrity.

Question 17

What is the role of caspases in apoptosis?

Answer 17

They are protease enzymes that play essential roles in programmed cell death (apoptosis), by cleaving certain proteins in the cell.

Question 18

What does phosphatidylserine exposure on the cell surface indicate?

Answer 18

It is an early indicator of apoptosis, as in normal, live cells it is located on the inner leaflet of the cell membrane.

Question 19

What is the role of chromatin condensation in apoptosis?

Answer 19

It is one of the key features of apoptosis, indicating that the cell is undergoing programmed cell death.

Question 20

What is the main drawback of the Trypan Blue Exclusion Assay?

Answer 20

It cannot differentiate between apoptotic and necrotic cell death, only between viable and non-viable cells.