Cell Death and Differentiation Flashcards
What is a stem cell?
An unspecialized cell that has the ability to reproduce and differentiate into a diverse range of specialized cells
Up to what point are embryonic stems cells totipotent?
When do embryonic stem cells become pluripotent?
Totipotent up until they are the inner cell mass
Become pluripotent at blastocyst stage when implant into endometrium
What is the difference between adult and embryonic stem cells?
- Adult stem cells can only give rise to a limited range of cell types
- They tend to develop into cell types that are closely related to the tissue in which they are found
- Their purpose is to replenish differentiated cells in the tissues in which they are found (Ex: intestinal crypts)
What is an induced pluripotent stem cell?
An adult stem cell that has been genetically reprogrammed to be in an embryonic stem cell-like state
Parkinson’s Disease
- What is the cause of this disease?
- How might induced pluripotent stem cells show promise for treating those with Parkinson’s?
- A slow deterioration of dopamine-producing neurons
- Could replace the affected neurons using new ways to identify, grow, sort and transplant the dopamine producing cells that are lost in the disease
Explain this image.
This is a diagram of therapeutic stem cell cloning. It shows the concept of regrowing an organ or tissue needed for a person with a defective organ/tissue. Cells would be removed from the patient and their nuclei would be isolated using electroporation. Healthy human ova would then be obtained and their nuclei would be removed. The patient nucleus would be inserted into the ova using electroporation again. The ova w/ patient’s DNA could be grown in culture and stimulated with the appropriate stimuli to regrow the organ/tissue needed.
What is a germline cell?
Cells that include the gametes and the cells that produce the gametes
What is cell determination?
When does it happen in relation to differentiation?
Point at which a cell commits to the final fate of what cell type it will become
Happens before differentiation
What is cell differentiation?
The process by which cells become specialized in structure and function
Describe what is meant by the term “cytoplasmic determinants”
The cytoplams of the egg contains important RNA, proteins and other substances that are unevely distributed in the unfertilized egg. After fertilization, as the zygote divides, cells contain different cytoplasmic determinants which lead to different gene expression and result in different cell types later on (ectoderm, mesoderm, endoderm, etc.)
Describe how neighboring cells in the blastocyst stage can influence determination?
Adjacent cells can produce signaling molecules that induce a response in nearby cells.
What is the function of TGF-Beta in normal cells? (8)
- Pattern formation during embryonic development
- Cell growth and proliferation
- Cellular differentiation
- Extracellular matrix production
- Angiogenesis
- Tissue repair
- Immune regulation
- Apoptosis
What are 2 reasons why the body would want to have mechanisms for killing its own cells?
- To maintain a constant number of cells
- Defense against foreign invaders/uncontrolled cell cycle/unrepaired damaged DNA
What is apotosis?
Programmed cell death
Necrosis
- What is Necrosis?
- What causes necrosis?
- Is it active or passive form of cell death?
- Does it require energy?
- What is the body’s immunological response?
- Decay and destruction
- Cellular damage/injury
- Passive
- No
- Triggers inflammation
What is Necroptosis?
Form of programmed necrosis
What is pyroptosis?
Signaling of cell death that only involves caspase 1
What is autophagy?
Consumption of the problematic cell by autophagosome, due to mitotic catastrophe
What are some examples of stimuli that can lead to necrosis? (3)
- Ischemia –> leads to lack of oxygen –> leads to lack of energy
- Chemical stress
- Physical stress
Necrosis
- Physiological
- Coagulation
- Liquefacation
- Enzymatic fat
- Caseous
- Gangrenous
- Normal –> due to bone growth, intestinal turnover
- Due to blood loss, cell outlines preserved
- Bacterial abscess filled w/ fluid pus
- Due to escape of lipases, due to trauma to fatty tissue
- Cheesy looking material, due to body trying to wall off and kill invader with macrophages
- Due to loss of blood supply –> loss O2
On a basic level, what is the difference between necrosis and apoptosis and necroptosis?
Necrosis is a pathological response to cellular injury
Apoptosis is a physiological response to suicide signals or lack of survival signals
Necroptosis is the same ultimate cellular response pathyway as necrosis but not due to random tissue damage, instead due to internal or external signals that initiate necrotic pathway
Why is apoptosis an important process?
- Promotes normal cell turnover
- Tissue homeostasis (maintenance of correct # cells)
- Immune tolerance
- Elimination of activated, damged or abnormal cells
There is a family of signals called Bcl-2 that are involved in apotosis. Which proteins in this family are anti-apototic?
Bcl XL
Bcl-w
There is a family of signals called Bcl-2 that are involved in apotosis. Which proteins in this family are pro-apototic?
Bax
Bak
Bad
Bid
Bim
Bik
There is a family of signals called caspases that are involved in apoptosis. Which of these caspases are initiator caspases?
2, 8, 9, 10
There is a family of signals called caspases that are involved in apoptosis. Which of these caspases are executioner caspases?
3, 6, 7
There is a family of signals called caspases that are involved in apoptosis. Which of these caspases are inflammatory caspases?
What do the executioner caspases do to trigger apoptosis?
Cleave nuclear lamins
Cleave cytosolic proteins
What is pyroptosis?
A form of regulated cell death triggerd by perturbations of extracellular or intracellular homeostasis related to innate immunity
What is autophagy?
A catabolic system by which the eurkaryotic cell can degrade or recycle proteins and organelles that are not functioning correctly
