Cells Diffentiation Flashcards
(28 cards)
Cell Differentiation
All body cells the same DNA, yet differ and function and shape
Cell Differentiation (2)
1) Process by which a cell becomes different from its parent or sister cell
2) Differentiation = different gene expression
Differentiation in Early Development (2)
1) After fertilization, zygotes begin to divide up to 16 or 32 cells into a ball lol
2) After 8 -cell stages, cells are exposed to different enviroments inside versus outside the ball
Cell Differentiation - Cloning
Can occur by embryo splitting 8 cell stage because cells are not yet differentiated
How early Differentiation might occur (2)
1) before the 8 cell stage, all cells are exposed to the same environment and thus equal
2) After 8, typically 16 a cell at the surface will be exposed differently than a cell in the centre
Differentiation Later in Development (2)
1) Developmental history of earlier cells & local environment
2) Genes are turned on and off at various staged of development
What do you call genes that are turned on
unwinding of chromatin
What do you call genes that are turned off
Closing of Chromatin
When are cells differentiated? (2)
1) After 16 cell stages (after the surface is exposed differently than a cell in the centre)
2) Blastocyst
When are genes unwound (turned on, active) and wound (turned off and not active) ?
During differential is the key moment of gene expression and the unwinding of chromatin and the closing of other chromatin
What does Reproductive Cloning require? (2)
1) Embryo splitting *agriculture
2) Somatic Cell Nuclear Transfer * Dolly
Reproductive cloning
Producing a copy of an entire organism - Dolly
Producing Identical Offsprings: Embryo Splitting (3)
1) Egg is divided into vitro, and allowed to divide to the eight cell stage (vitro =refers to the technique of performing a given procedure in a controlled environment outside of a living organism)
2) Cell are separated and each implanted into different surrogates (mothers)
3) EIGHT identical offsprings not related to surrgate mother
Cloning by Embryo summarized (4)
1) Egg + sperm
2) Fertilize vitro
3) Let it go to the 8 cell stage (all identical)
4) Impregnate 8 mothers / surrogates
5) 8 identical copies
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - Somatic Cell
1) Any cell other than a haploid
2) Each somatic cell has a full diploid set of chromosomes
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - Somatic Cell - Diploid cell importance
1) Note that these cell are DIFFERENTIATED unlike cloning by embryo
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - Procedure (4)
1) Somatic Cell NUCLEUS is inserted into the UNUCLEATED fertilized egg
2) Implanted into surrogate mother
3) Offspring identical to the nuclear donor animal none from mother
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - After the nucleus is applied to the egg how is activate?
Electrical current is applied to fuse cells
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - Is there mitochondrial DNA in the egg?
Yes
Somatic Cell Nuclear Transfer Produces a Clone of an Adult - Does the egg reprogram the donated chromatin
Yes
Reprogramming during normal development and cloning
The reprogramming of epigenetic becomes essential
Reprogramming during normal development and cloning - Define epigenetics
non- coding hereditary information
The reprogramming of epigenetic becomes essential (3) **
1) The donor nucleus needs to be reprogrammed in cloning
2) The sperm and egg need to be reprogrammed during fertilization
3) Epigenetic helps define the genes that are turned off, by providing signal of tighter chromatins
What is composed of a chromosome? (3)
1) Chromatin
2) Histones
3) DNA
