Development Of Multicellular Org I Flashcards
T/F: Genes expressed by a cell depend on the PAST Environment.
False
Both PAST and PRESENT
Gastrula
- Mature form of Blastula
- Has 3 major layers
Gradients in morphogenesis are formed by what?
- Localized production of an INDUCER that diffuses AWAY from its source
- Localized production on an INHIBITOR that diffuses AWAY from its source
- Block the action of a uniformly distributed inducer
What are the most important Environmental cues for inductive signaling?
Signals from Neighboring cells
What do Cells do BEFORE acquiring a particular fate?
- Cells express genes that are markers of their Location
- Regionally determined
Which cell wins in Delta Notch Signaling?
The cell with the ACTIVE Delta
- Inhibits its neighbors from doing likewise
Response to whether genes are turned “on” or “off” are in response to what?
Spatial and Temporal expression of different sets of genes
How do Zebras get their stripes or Leopards get their spots?
Pattern generation by Reaction Diffusion
- Long range inhibition
Characteristics of Committed Cells
- Cell that have some attributes of a particular cell type
- But CAN change with Environment
Characteristics of Completely Undetermined cells
Cells that Rapidly change due to alterations in environment
Characteristics of Inductive Signaling
Induction of DIFFERENT developmental program in select cells of homogenous group
- Leading to altered character
Conserved mechanism for development
- The cleaved cells do NOT feed
- depend on the food STORED in egg by the mother - Genome is Inactive
- Once activated cells form blastula
(Hollow ball of cells)
Instructions for producing a Multicellular Animal is contained where?
NON-Coding Regulatory DNA
- Associated with each gene
Diversity is a pattern due to what # factors?
- Gene Duplication
- Presence of other signals
- Combinations create variety - Previous experiences of the cell
Gene Duplication
Higher organisms have several homologous of the SAME gene
Endoderm is the precursor to what?
- Gut
- Lung
- Liver
4 stages of a. Developing Embryo
- Cell Proliferation
- Specialization
- Interaction
- Cell Movement
T/F: HOMOLOGOUS proteins are functionally Interchangeable
True
Fly protein can be put into a Mouse to rescue development of Cerebellum
What controls development?
Gene Expression
Asymmetric Division
Significant sets of Molecules distributed unequally between daughter cells
Asymmetry and Positive Feedback timeline
- System starts symmetrical
- Environment poses a Weak Asymmetry
- Poz feedback amplifies it
- IRREVERSIBLE
How many genes does a human share with a fruit fly?
50%
When are developmental decisions made for differentiation?
Long before they show any outward signs of differentiation
What is Positional Value?
Position Specific Character of a Cell
