Development Flashcards
Fertilisation is a what system
Self organising
What does development depend on
The genome
The oocyte contents
Oocyte
A developing egg which is maturing under neurotic division into an ovum
Holoblastic cleavage
Complete cleaver hat divides the whole egg into distinct blastomeres
Radial cleavage
Cell division occurs at right angles to previous divisions resulting 4 blastomeres being situated directly on top of 4 other blastomeres.
Spiral cleavage
Cells of early embryo divide and spiral around a pole to pole axis of the embryo so that 4 blastomeres sit in the grooves of 4 other blastomeres
Equal cleavage
4 blastomeres of similar size
Unequal cleavage
Blastomeres if very different size
How is the direction of spiral cleaver of molluscs determines
Way the shell coils
Teleoblastic cleavage
Embryos with a lot of yolk exhibit cleavage and only one part of the fertilised egg. This for example occurs in teleost fish.
Blastula
Hollow sphere of blastomeres produced suiting embryo development by repeated cleavage of the fertilised egg
Two sections of blastula
Blastocoel
Blastoderm
What is gastrulation
Process by which the gastrula, a hollow cup shaped embryo with three germ layers, forms the blastula
Three ways that development is controlled
- Differentiation
- Pattern formation
- Movement
What did John Gurdon prove in 1962?
That a matured tadpole intestinal epithelial cell still contains all of the genetic information to form all other types of cells
(Because if ur didn’t then a new frog wouldn’t have been able to form form it which is what happened)
