exam 2- animal & plant development

Question 1

first rudimentary organs are the ___ and ___

these are formed from ___ and give rise to most of the ___

Answer 1

neural tube and neural crest

ectoderm and give rise to nervous system

Question 2

___ is the developing CNS

Answer 2

neural tube

Question 3

tissue differentiation during neurulation begins with the formation of the ___ and the ___

Answer 3

notochord
hollow dorsal nerve chord

Question 4

during neurlation, once the notochord is formed, ___ cells above it invaginate, forming the ___ down the long axis of the embryo

Answer 4

ectodermal
neural groove

Question 5

during neurlation, mesoderm tissue on the lateral sides of the developing notochord forms the ___, which will give rise to…

Answer 5

somites
muscles, vertebrae, and connective tissues

Question 6

organogenesis begins with the development of which organ first?

Answer 6

the nervous system

Question 7

organogenesis begins with nervous system development…

Answer 7

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

Question 8

after the nervous system develops, what happens next?

Answer 8

anterior-posterior development into the brain and spinal cord

Question 9

describe TFs and the neural tube

Answer 9

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

Question 10

describe SHH (sonic hedgehog) in the neural tube

Answer 10

SHH made in notochord cells, diffuses to the bottom of the neural tube and the bottom of the somites

Question 11

plant development includes the same 4 processes as other organisms:

Answer 11

1- cell division
2- cell growth
3- differentiation
4- morphogenesis

Question 12

3 stages of sporophyte development:

Answer 12

1- embryogenesis
2- vegetative development
3- reproductive development

Question 13

discuss polarity and establishment of the root-shoot axis (plant embryo)

Answer 13

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

Question 14

3 basic tissue systems are established in the plant embryo:

Answer 14

1- dermal tissue from the protoderm
2- ground tissue from the ground meristem
3- vascular tissue from the procambium

Question 15

once polarity in the plant embryo is established, the ___ are formed, nearly all tissues and organs are derived from these ___

Answer 15

meristems
meristems

Question 16

plant cell proliferation and organ development initiates from ___ regions (______)

Answer 16

meristematic
SAM & RAM

Question 17

how are plant and animal cells different during embryogenesis & gastrulation

Answer 17

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

Question 18

SAM stands for ___
RAM stands for ___

Answer 18

shoot apical meristem
root apical meristem

Question 19

hormones can affect embryo polarity signaling at multiple levels:

Answer 19

perception
signal transduction
concentration levels:
- biosynthesis
- transport
- breakdown (metabolism)
timing
positioning

Question 20

example of a plant hormone

Answer 20

auxin

Question 21

name 3 ways to measure hormone levels in plants

Answer 21

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

Question 22

how are reporter lines (indirect) used to measure hormone expression

Answer 22

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

Question 23

determine hormone localization: auxin

what do reporter lines allow

Answer 23

the determination of auxin levels throughout the plant
- knowing how these levels get established is very important in development

Question 24

auxin transport is regulated by ___ that control the polar movement of auxin ___ the cell

Answer 24

efflux carriers (PINs)
into the cell

Question 25

there are ___ PINs in Arabidopsis involved in auxin transport in diff tissues

Answer 25

8