Development Flashcards
define development
how genotype (DNA sequences) becomes phenotype (form and function of an organism )
what 2 protein coding genes control development and how
1) transcription factor genes —> determine cell’s function
2) intercellular signaling genes —> cellular communication
what portion of your protein-coding genes are dedicated to development?
24%
role of transcription factor genes
encode transcription factor proteins that determine which other genes are turned on or turned off in a cell
2 type of intercellular signaling genes
1) intercellular signaling ligand genes: encode secreted protein ligands that allow cells to talk to other cells
2) intercellular signaling receptor genes: encode cell surface receptor proteins that allow cells to listen to other cells
purpose of using hundreds of different intercellular signaling ligands and receptors
makes up a cellular “language” for cells to communicate position, cell cycle status, timing, differentiation status, etc. during development
how do cells respond to each other?
by changing the expression of genes, including transcription factors
4 stages of development
1) growth: more cells
2) morphogenesis: cells form shape
3) patterning: embryonic cells allocated
4) differentiation: cells function in the right places
describe stage 1 of development (growth)
1 cell becomes millions (or billions or trillions)
describe stage 2 of development (morphogenesis)
embryonic cells take on the basic shape of an organism
describe stage 3 of development (patterning)
embryonic cells in specific parts of the embryo are “fated” to form different tissues, organs, and structures
describe stage 4 of development (differentiation)
embryonic cells mature into fully functional cells, tissues, organs, structures
can the 4 stages of development can occur at the same time?
yes
at what rate do cells divide in early development? what about late development into adulthood?
in early development, most cells divide at a similar max rate
in later development, different cell types divide at different rates
why is it important for different cell types to divide at different rates?
allows tissues/organs to grow at different rates to achieve different sizes
what is a cell’s division rate determined by?
“cell cycle check point” proteins
what are cell cycle check point proteins regulated by during development?
intercellular signaling receptors & ligands and transcription factors
does the zygote (fertilized egg) have all the resource it needs to get through early development?
yes, they were loaded into the egg cell made by the female, but no change in size is possible without additional nutrients and energy
what are larvae? % of animals on Earth that have free-living larval forms?
larvae can feed themselves to keep developing, they are feeding embryos
80% of animals on Earth
how does morphogenesis create the form or shape of an organism?
via morphogenetic movements, which are the coordinated movements of embryonic cells to give shape
3 types of morphogenetic movements
invagination, migration, apoptosis
describe invagination, what is it driven by?
indenting of a sheet of cells forms a groove, tube, or cavity driven by changes in cells shape caused by changes in the cytoskeleton