MOLECULAR CELL BIOLOGY CHAPTER 18
STUDY GUIDE SUMMARY WITH TESTED
QUESTIONS AND 100% CORRECT SOLUTIONS
◉Apoptosis in mouse paw . Answer: spades --> digits
- if cells don't have a function, they are removed
◉Apoptosis and tail regression during frog metamorphosis . Answer:
Tail slowly regresses
- cells slowly die because they are not needed for terrestrial life
◉Apoptosis . Answer: series of energy dependent cellular changes that
lead to programmed cell death
- an ACTIVE process triggered by *DNA damage*, *viral infection*, or
as part of a *developmental program*
- it may be initiated by internal cues or external signals
◉Cellular events in apoptosis . Answer: 1. chromatin formation
- caused by the activation of a *proapoptotic DNase*
- DNA fragmentation
- chromatin condensation
, 2. Fragmentation of the nucleus
- cased by *proapoptotic proteases* that target lamin
3. Fragmentation of the cell
- caused by *proapoptotic proteases* that target cytoskeletal proteins
result: apoptotic bodies, which are removed by phagocytic cells
◉Necrosis . Answer: NOT apoptosis
- passive process, not controlled
- something damages the cell (ex: takes up too much water and cell lysis
occurs and hurts other cells)
- *cell death due to accident or acute injury*
◉Phagocytosis of apoptotic bodies . Answer: Apoptotic bodies express
*phosphatidylserine* on the OUTER layer of the cell membrane
- phosphatidylserine is one of the phospholipids that is commonly found
in the plasma membrane but only occurs in the INNER layer of the
membrane in normal cells
- *"eat me" signal* on the cell surface that is recognized by surface
receptors on the phagocytic cell, which responds by initiating
phagocytosis
◉The nematode Caenorhabditis elegans . Answer: The adult worm has
*959 somatic cells*, plus the germ cells
STUDY GUIDE SUMMARY WITH TESTED
QUESTIONS AND 100% CORRECT SOLUTIONS
◉Apoptosis in mouse paw . Answer: spades --> digits
- if cells don't have a function, they are removed
◉Apoptosis and tail regression during frog metamorphosis . Answer:
Tail slowly regresses
- cells slowly die because they are not needed for terrestrial life
◉Apoptosis . Answer: series of energy dependent cellular changes that
lead to programmed cell death
- an ACTIVE process triggered by *DNA damage*, *viral infection*, or
as part of a *developmental program*
- it may be initiated by internal cues or external signals
◉Cellular events in apoptosis . Answer: 1. chromatin formation
- caused by the activation of a *proapoptotic DNase*
- DNA fragmentation
- chromatin condensation
, 2. Fragmentation of the nucleus
- cased by *proapoptotic proteases* that target lamin
3. Fragmentation of the cell
- caused by *proapoptotic proteases* that target cytoskeletal proteins
result: apoptotic bodies, which are removed by phagocytic cells
◉Necrosis . Answer: NOT apoptosis
- passive process, not controlled
- something damages the cell (ex: takes up too much water and cell lysis
occurs and hurts other cells)
- *cell death due to accident or acute injury*
◉Phagocytosis of apoptotic bodies . Answer: Apoptotic bodies express
*phosphatidylserine* on the OUTER layer of the cell membrane
- phosphatidylserine is one of the phospholipids that is commonly found
in the plasma membrane but only occurs in the INNER layer of the
membrane in normal cells
- *"eat me" signal* on the cell surface that is recognized by surface
receptors on the phagocytic cell, which responds by initiating
phagocytosis
◉The nematode Caenorhabditis elegans . Answer: The adult worm has
*959 somatic cells*, plus the germ cells
