Lecture 13- From Cell to Organism Flashcards
cell proliferation
producing many cells from one
cell specialization
creating cells with different characteristics
cell interaction
coordinating the behavior of one cell with that of its neighbors
cell movement
rearranging the cells to form structured tissues and organs
major events of embryonic development (embryogenesis)
- fertilization
- cleavage
- gastrulation
- neurulation
- organogenesis
fertilization
- unites two haploid genomes forming a diploid zygote
- species-specific
- one sperm fertilizes one egg
- activates embryonic development
oocyte (egg)
- haploid nucleus
- maternal components
maternal components of oocyte
- nutrients
- biosynthetic machinery
- mitochondria
- information (mRNAs and proteins) essential for early embryonic development
sperm
- haploid nucleus
- centrosome (microtubule organizing center)
- activates development
embryonic development
- very early phase almost entirely driven/controlled by maternal components
- embryo makes its own gene products later
cleavage
- special type of cell division characterized by rapid cell division without cell growth
- cleavage cell cycles lack G1 and G2 phases
- divisions rely on maternal components
blastomeres
cells generated by cleavage
blastula
term for embryo at the end of cleavage
gastrulation
- reorganizes embryo and results in formation of 3 distinct germ layers: Endoderm, Mesoderm, Ectoderm
- first morphogenetic event in embryogenesis
germ cells
usually set aside early in development even before gastrulation (insert picture)
morphogenesis
- generation of organized forms
- based on different behaviors of cells
3 major axes visible in most organisms
- anterior-posterior (head/tail)
- dorsal-ventral (back/belly)
- left-right (lateral)
neurulation
- formation of the central nervous system
- another major morphogenetic event in embryogenesis
organogenesis
- formation of organs (internal organs, limbs, sensory organs)
- another major morphogenetic event in embryogenesis
order from single cell to organism
(see chart)
how do we study development?
- descriptive embryology
- experimental embryology
- developmental genetics
- comparative embryology
fate mapping (lineage tracing)
label one or a group of cells early during development, and monitor what they become later
experimental embryology
- experimentally manipulate the embryo: remove, rearrange, transplant, or grow part in isolation, etc.
- possible in embryos that are relatively big and easy to manipulate such as sea urchin/chick/frog
developmental genetics
- the study of mutants
- possible in organisms that are amenable for genetic analysis such as worm/fly/mouse
comparative embryology
evolutionary developmental biology (evo devo)
