Development of Multicellular Organisms I Flashcards
What controls development?
differential gene expression
Homologous proteins are functionally ______
interchangeable
Genome become activated and cells divide and cohere to form a ______
blastula
A blastula undergoes massive rearrangements to form _____
gastrula
Blastula consist of a sheet of _______ cells facing the external medium
epithelial
What is the ectoderm?
precursor of nervous system and epidermis
What is the endoderm?
precursor of gut, lung and liver
What is the mesoderm?
precursor of muscles and connective tissues
What is the most important for development?
gene regularly proteins
Where is the instructions for producing a multicellular animal?
non coding regulatory proteins
Non coding sequences make organisms ______ from each other
different
What are determined cells?
cells that are fated to develop into a specialized cell type despite changes in environment
What are completely undetermined cells?
cells that can change rapidly due to alterations in environment
What are committed cells?
cells that have some attributes of a particular cell type but can change with environment
What are the most important environmental cues?
signals from neighboring cells
What is a short range signal?
cell- cell contacts
What is long range signaling?
substances that can diffuse through the extracellular medium
What are morphogen?
long rang inductive signal that imposes a pattern on a field of cells
What forms the morphogen gradient?
- localize production of an inducer that diffuses away from its source
- localized production of an inhibitor that diffuses away form its source and backs the action of a uniformly distributed inducer
What factors cause diversity in pattern due to many factors?
- combinatorial control
- cell memory
- sequential induction
What is combinatorial control?
response of a cell to a give signal may differ based on the presence of other signals (combinations create variety)
What is cell memory?
effect of a give signal depends on previous experiences of the cell (which may have altered its chromatin, regulatory proteins, transcription and RNA)
What is sequential induction?
different signals formed/secretion in a spatial and temporal manner
Ligand family of receptor tyrosine kinase (RTK)
EGF
FGF
Ephrins
