Chapter 10 CMB Apoptosis Flashcards
*What are the 5 Major stages of the embryonic development? (FCGNO)
- Fertilization
- Cleavage
- Gastrulation
- Neurulation
- Organogenesis
What happens during fertilization?
Produces a zygote
What happens during cleavage?
Cells divide to form a Blastula
What happens during gastrulation?
Cells move and fold to form layers from which tissues are built
What happens during neurulation?
The formation of a neural tube from which the nervous system develops
What happens during organogenesis?
Initiation of organ development in the embryo
What is apoptosis?
- The process whereby cells commit suicide
- Programmed cell death
- Involves the use of specialize cellular material
*What is the function of apoptosis? (2 functions)
Enables the body to:
1. Control cell numbers in the normal development and functioning of the organism
2. Eliminate cells that threaten the organism’s survival
What are the examples of “Control cell numbers in the normal development and functioning of the organism”? (3 examples) (RSR)
Examples:
a) Removal of tissues between toes and fingers during embryonic development.
b) Sloughing off of the inner lining of the uterus at the start of menstruation.
c) Removal of surplus cells between neurons in the brain to form synapses
What are the examples of “Eliminate cells that threaten the organism’s survival?” (4 examples)
Examples:
1. Cells infected with viruses
2. Immune cells that attack the body
3. Cells with damaged DNA
4. Cancer cells
*How does apoptosis occur? (5 steps)
- Cells shrink and develop “blebs” on their surface
- DNA and protein in the nucleus degrade
- Mitochondria break down and release cytochrome C
- Cytochrome C activates enzymes called caspases
- Caspases cause the cells to burst
What is the role of apoptosis in normal and abnormal embryonic development?
- Programmed cell death (apoptosis) plays an important role in the processes of gamete maturation as well as in embryo development, contributing to the appropriate formation of various organs and structures.
- Disordered apoptosis may lead to carcinogenesis and participates in the pathogenesis of Alzheimer disease, Parkinson disease, or AIDS.
What makes a cell decide to commit suicide? (2 causes) +-
- Withdrawal of positive signals needed for continued survival of cell (For example: Interleukin 2)
- Receipt of negative signals indicating that apoptosis should occur (For example: Damaged DNA/Proteins)
What is gene control of apoptosis?
Apoptosis is regulated by genes which code for apoptosis and genes which prevent apoptosis
What are the types of gene control of apoptosis? (2 types)
- Anti-apoptotic genes (Prevent cell death)
- Pro-apoptotic genes (Causes cell death)
What is anti-apoptotic genes?
- Produce proteins that prevent apoptosis
- Bcl-2 gene
What is the Bcl-2 gene?
It is an anti-apoptotic gene and the expression of the Bcl-2 gene prevents apoptosis from occurring
What is pro-apoptotic genes?
- Produce proteins that cause apoptosis
- Bax gene
*What is the Bax gene?
It is a pro-apoptotic gene and the expression of the Bax protein leads to destruction of the mitochondria => release of cytochrome C => necrosis
How does Bax kill a cell?
- The bax gene is a “pro-apoptotic” gene. The bax protein is coded by the bax gene.
- The bax protein binds to permeability pore of the cell’s mitochondria
- Increase in permeability triggers cell death
- Mitochondria plays a role in apoptosis as it facilitates cell death through apoptosis by releasing Cytochrome C
*What are the functions of the mitochondria? (2 examples)
- Produce energy
- Facilitate cell death through apoptosis