2nd ppt specifying Flashcards
Development of organism begins after fertilization
Single celled zygote becomes multicellular by ______
Mitosis
_____
Developing cells acquire different ____ depending on their relative _____ within the embryo
Patterning
Identities
spatial positions
_____
ensures that tissues and organs develop in the correct place and orientation
Pattern Formation
Four processes of Development:
_____ sets the fate of the cell. restricts developmental fate
_____ cell ceases to divide, and develops specialized structural elements and distinct functional properties
_____ is the organization and spatial distribution of already differentiated cells
_____ increase in body size by cell division and expansion
Commitment
Differentiation
Morphogenesis
Growth
Stages of Commitment:
1._____
The fate of a cell or tissue is said to be _____ when it is capable of ____ when placed into a neutral environment
At this stage, commitment is ____
Specification
Specified
Differentiating autonomously
Labile reversible
Stages of Commitment:
2._____
A cell is said to be _____ when it is capable of _____ when placed into another region of cells different to it
At this stage, commitment is ____
Determination
Determined
Differentiating autonomously
Irreversible
Order of development of an undifferentiated cell during embryogenesis (3)
Specification
Determination
Differentiation
Modes of specification ( the ways commitment of cell can take place) (3)
Autonomous spefification
Conditional Specification
Syncytial Specification
Modes of Specification:
_____
Very early on, it “knows” what it is without interacting with other cells
Here, the blastomeres of the early embryo are apportioned a set of critical ____ within the egg cytoplasm.
______
maternal substances in the egg that influence early development. This also leads to different gene expression
Autonomous Specification
Determination factors
Cytoplasmic/Morphogenetic determinants
True or false, in autonomous specification, substances are distributed evenly in the unfertilized egg:
FALSE. it is distributed unevenly
Modes of Specification (Autonomous specification):
_____
cell that turns into the flagellated part of the snail patella
Trochoblast
Modes of Specification (Autonomous specification):
Characteristic of most _____
____ produce the same lineages in each embryo of thee species
Produces ____/____ development, cells cannot change fate if blastomere is lost
Invertebrates
Invariant cleavages
Mosaic/Determinative
Modes of Specification (Autonomous specification):
The association of _____ with autonomous specification was confirmed by _____
_____ provided biochemical confirmation of cytoplasmic segragation of tissue determinants in early tunicate embryos
Conklin’s fate map
Cell-removal experiments
J.R. Whittaker
Modes of Specification (Autonomous specification):
_____
muscle-specific transcription factors that give rise to muscle cells
Macho
Modes of Specification :
_____
The process where cells achieve their respective fates by interacting with other cells
For example _____ (separated but using soluble growth factor) and _____ (attached)
Conditional Specification
Paracrine
Juxtacrine
Modes of Specification (Conditional specification):
Factors that determine fate (3)
Cell-to-cell contacts
Secreted signals
Physical properties of local environment (mechanical stress)
Modes of Specification :
_____
A cytoplasm that contains many nuclei is called a ____. Specification of cells within it is this type of specification.
Usually occurs in insects, involves the action of ____. They influence nuclei in ____ manner.
Syncytial Specification
Syncytium
Morphogen gradients
Concentration-dependent
Morphogens involved in the Syncytial Specification of Drosophila Embryo:
The _____ (front) produces the ____ morphogen that is highest in concentration there
The _____ (back) produces the _____ and (_____) moprhogen that is highest in concentration there
They’re both transcription factors so different ratios activate different sets of genes
Anterior
Bicoid
Posterior
Caudal (and Nanos)
Parts produced in the morphogen gradients (4
_____ high bicoid low caudal and nanos
_____ less bicoid small amount caudal and nanos
_____ low bicoid high caudal and nanos
Head
Thorax
Abdomen
Tail
