exam 2- animal & plant development Flashcards
first rudimentary organs are the ___ and ___
these are formed from ___ and give rise to most of the ___
neural tube and neural crest
ectoderm and give rise to nervous system
___ is the developing CNS
neural tube
tissue differentiation during neurulation begins with the formation of the ___ and the ___
notochord
hollow dorsal nerve chord
during neurlation, once the notochord is formed, ___ cells above it invaginate, forming the ___ down the long axis of the embryo
ectodermal
neural groove
during neurlation, mesoderm tissue on the lateral sides of the developing notochord forms the ___, which will give rise to…
somites
muscles, vertebrae, and connective tissues
organogenesis begins with the development of which organ first?
the nervous system
organogenesis begins with nervous system development…
notochord grows and induces overlying ectoderm to form the neural plate
cells of the neural plate fold to form the neural groove and the surrounding neural folds
neural folds fuse, forming a hollow neural tube
after the nervous system develops, what happens next?
anterior-posterior development into the brain and spinal cord
describe TFs and the neural tube
TGF-betas (BMPs)
SHH (Sonic Hedgehog)
- dorsal-ventral specification of the neural tube
the expression & interaction of these proteins and their signaling pathways control the dorsal-ventral axis specification
describe SHH (sonic hedgehog) in the neural tube
SHH made in notochord cells, diffuses to the bottom of the neural tube and the bottom of the somites
plant development includes the same 4 processes as other organisms:
1- cell division
2- cell growth
3- differentiation
4- morphogenesis
3 stages of sporophyte development:
1- embryogenesis
2- vegetative development
3- reproductive development
discuss polarity and establishment of the root-shoot axis (plant embryo)
first zygotic cell division is asymmetric, generating 2 cells with 2 diff fates:
1- apical cell: becomes all shoot tissue (SAM)
2- basal cell: becomes all root tissue (RAM) and forms the suspensor (linking embryo to parent)
apical meristems
3 basic tissue systems are established in the plant embryo:
1- dermal tissue from the protoderm
2- ground tissue from the ground meristem
3- vascular tissue from the procambium
once polarity in the plant embryo is established, the ___ are formed, nearly all tissues and organs are derived from these ___
meristems
meristems
plant cell proliferation and organ development initiates from ___ regions (______)
meristematic
SAM & RAM
how are plant and animal cells different during embryogenesis & gastrulation
animal cells can adjust to new positions during embryogenesis, but at gastrulation most cells lose this ability and develop autonomously
plants, however, can develop organs continuously in the postembryonic phase and most living cells remain totipotent
SAM stands for ___
RAM stands for ___
shoot apical meristem
root apical meristem
hormones can affect embryo polarity signaling at multiple levels:
perception
signal transduction
concentration levels:
- biosynthesis
- transport
- breakdown (metabolism)
timing
positioning
example of a plant hormone
auxin
name 3 ways to measure hormone levels in plants
1- direct measurements- for auxin (GC-MS) can be done, but difficult
2- antibodies- rarer, difficult
3- reporters- transgenic lines (AREs-DR5:GFP, Pin:GFP) - indirect, but simpler, more widely used
how are reporter lines (indirect) used to measure hormone expression
hormone- cis element + reporter
DR5:GFP expression in the embryo
TGTCTC (cis-element) ligated upstream of the minimal 35s promoter to GFP
this synthetic auxin-responsive promoter has been used to visualize the spatial pattern of auxin response, which indirectly reflects the distribution of auxin
determine hormone localization: auxin
what do reporter lines allow
the determination of auxin levels throughout the plant
- knowing how these levels get established is very important in development
auxin transport is regulated by ___ that control the polar movement of auxin ___ the cell
efflux carriers (PINs)
into the cell
