l14

Question 1

the products of maternal effect genes form _______ that define the AP axis

Answer 1

long range gradients

Question 2

as the embryo is a synctium, only a single _______ is needed for this morphogen system

Answer 2

transcription factor

Question 3

this graded information is translated into more _____ of zygotically-expressed ___ whose effects are ____ range

Answer 3

discrete blocks
gap genes
short

Question 4

gap genes regulate the expression of the ________, which are expressed with double segmented periodicity in ____ transverse stripes

Answer 4

pair rule genes

7

Question 5

where do adult vertebrate segments come from?

Answer 5

embryonic structures called somites

Question 6

what does it mean to be a transient structure?

Answer 6

later stages - they disappear

Question 7

three regions of somites - what are they

Answer 7

sclerotome (vertebrae and ribs)
myotome (skeletal muscles- apart from some facial muscles)
dermotome (demis of back)

Question 8

what is the henson node in the chick involved in?

Answer 8

synchronizing gene expression across the emrbyo

Question 9

what does the henson node have?

Answer 9

a population of somatic stem cells

Question 10

FGF8 is a negative regulator. what does it do?

Answer 10

blocks somite formation

Question 11

what does retinoic acid do in terms of somite formation?

Answer 11

it is positive

Question 12

what is the determination front? / wavefront?

Answer 12

gradient of the two opposing signals
FGF and RA

Question 13

can RA inhibit the effect of FGF8 on somite formation?

Answer 13

yes

Question 14

somites can only form where there is not enough _____ to stop them from doing so

Answer 14

FGF8

Question 15

n-cadherin causes cells to

Answer 15

stick to one another

Question 16

eph/ephrin causes cells to

Answer 16

repel one another

Question 17

_______ controls physical formation of somites

Answer 17

balance between attraction and repulsion

Question 18

tissue will separate where ____ expressing cells meet _____ expressing cells

Answer 18

Eph
Ephrin

Question 19

notochord is an ______ which provides _____

Answer 19

elastic rod
support

Question 20

the henson node in the chick has a population of ___________ which have the ability to self renew to leave the node and generate ________

Answer 20

somatic stem cells
presomatic mesoderms

Question 21

in vertebrates, segments bud off ________

Answer 21

one by one

Question 22

in drosophila, segments all emerge at the __________ by ______ of existing space

Answer 22

same time
subdivision

Question 23

somites for at a ______ from the node, and the presomitic mesoderm maintains a ______ length

Answer 23

given distance
constant

Question 24

what are the three features of somite formation?

Answer 24

temporal
spatial
physical

Question 25

so far, only genes related to ____ have been found operating in both simute formation and drosophila segmentation

Answer 25

hairy

Question 26

changes in hairy expression match a ___ minute rhythm

Answer 26

90

Question 27

Notch ____ hairy, hairy _____ notch

Answer 27

activates inhibits

Question 28

a stable equilibrium between notch and hairy is ________. the system _____

Answer 28

not reached oscillates

Question 29

does notch cycle? how is it expressed?

Answer 29

no it is expressed constantly

Question 30

notch signalling is important for ___ formation

Answer 30

somite

Question 31

the stage of gene expression of these notch signalling components decide ___ a somite can form

Answer 31

when

Question 32

FGF8 is a ______ regulator, which _____ somite formation

Answer 32

negative blocks

Question 33

FGs bind ________ receptors, and stimulate signalling in the ____ cell

Answer 33

transmembrane recipient

Question 34

blocking FGF8 function shifts the _____ where the somites form

Answer 34

position

Question 35

retenoic acid is _____ on somite formation

Answer 35

positive

Question 36

'the determination front' is what?

Answer 36

the two opposing signals or the 'wavefront'

Question 37

FGF8 forms a _______ gradient from the node, whereas RA formes a ________ gradient

Answer 37

posterior high anterior high

Question 38

FGF8 ______ somite formation, and RA can _____ this effect of FGF8

Answer 38

inhibit inhibit

Question 39

somites can only form where there is not enough ____ to stop them doing so

Answer 39

FGF8

Question 40

human axioloids capture ________ of the segmentation clock

Answer 40

oscillatory dynamics

Question 41

N-cadherin causes cells to _____

Answer 41

stick to one another

Question 42

Eph/Ephrin causes cells to ______

Answer 42

repel one another

Question 43

balance between attraction and repulsion controls __________ of somites

Answer 43

physical formation

Question 44

tissue will separate where ______ expressing cells meet ______ expressing cells

Answer 44

Eph Ephrin