Cell Development-Growth, Differention And Adaptation Flashcards
What is development and stages
-systematic sequence of gene directed steps during an organisms life cycle
1 growth
2 differentiation
3 morphogenesis / pattern formation
What is cell growth and how does it occurs
-increase in cell size and number
-occurs through
1 mitotic divisions
2 cleavage ( rapid mitotic divisions of zygote )
3 synthesis of more structural components through metabolism
Limitations of growth
1 stress on DNA ( telomeres shorten )
2 decrease in surface are to volume ratio with increase in size
3 contact inhibition - if cell is overcrowded no room for division or growth
What is potency
-different number of possible fates a cell can acquire
Stem cells and functions
-unspecialized cells capable of infinite mitotic divisions ( due to telomerase reconstituting telomeres )capable of self-renew and from which differentiated cells arise
- organ maintenance and repair
- therapeutic effect ie reparing worn out body parts.
Allometric growth
-diff growth rates of diff body parts
Asymmetric division of stem cells
- one daughter will become a stem cell ( self renew )
- the other becomes committed and is a progenitor
Types of stem cells and description
1 Embryonic stem cells
- totipotent : can become any cell
- pluripotent : can become most but not all cells ( any of the 3 germ layers )
2 Adult stem cells
- multipotent : most but not all
- ogliopotent : most but not all
- Bipotent and unipotent : 1 or 2 cell types
3 Induce pluripotent stem cell :
-This is when somatic cells have genes introduced into them and then the cell becomes a stem cell it is reprogrammed
Use of adult stem cells
-renewal of worn out tissue
Cell determination and types
-committing of a cell down a specific differentiation path
1 cell-to-cell interactions
2 inheritance of cytoplasmic determinants
Adaptation and types and causes
-conformational changes taken by a cell to respond to a stimuli
1 auto trophy
2 hypertrophy
3 hyperplasia
4 metaplasia
1 reduced workload, nutrient deficiency
2 increased workload , hormone stimulation
3 compensation for damage, hormonal dysfunction
4 current tissue unable to withstand stimuli
What is pattern formation
- aka morphogenesis
- the way an organism develops from a single cluster of cells into a complex system
- taking shape of an organism
What is cell lineage
-cell types arising from a stem cell or progenitor
Types of Tissue in terms of regeneration capability
- labile
- stable
- permanent
What is regeneration
-the replacement of dead or infected tissue with an exact type through mitotic divisions of stem cells
What is cell fete
-
How are cells commited
-turning on and off of specific genes through transcription factors
How do stem cell renew themselves
- obligate asymmetric replication
- stochastic differentiation: One stem cell divides into two daughter cells which both differentiate and another stem cells recognize this and divide by mitosis into two other stem cells to make up the cell population
How do stem cells stay undifferentiated and what triggers them to be differentiated
They have genes which code proteins to stop transcription factors from causing differentiation
signals in the environment stimulate the stem cells to differentiate example Mitogens in bone marrow
Use of embryonic and somatic cells
- build the body tissue and organs
- renewal of worn out tissue
How does cell to cell interacts occur ( how are the signals sent )
Direct contact of surface proteins
signals diffuse from one cell to another
signals a pass to gap junctions
Describe asymmetric segregation of cytoplasmic determinants
The Zygote has transcription factors in the cytoplasma (along with the precursors mRNA )
which it inherits from the parent
these transcription factors turn off and on specific genes thus differentiating cells
as the zygote divides, the region with the determinants will get those specific transition factors and go on to differentiate
