Developmental Biology

Question 1

why is drosphilia important?

Answer 1

key model organism
rapid life cycle
small size
genetically tractable

Question 2

what is homeosis?

Answer 2

changing of one body part so it resembles another

Question 3

what is polarity?

Answer 3

regional difference in a state of commitment

Question 4

what is axis?

Answer 4

rotation is of some pratical significance

Question 5

what is potency?

Answer 5

total of things into which tissue can develop

Question 6

why do we need model systems?

Answer 6

easy to manipulate
quantity 
short gen times 
genomes
can allow in vivo visualisation

Question 7

vertebrate and invertebrate model systems?

Answer 7

invertebrates - drosophila, c.elegans, sea urchin, sea squirt
vertebrate - chick, zebra fish, mouse, african clawed frog

Question 8

what is good about plant model organisms?

Answer 8

easy and inexpensive, genetic and imaging tools, mutants

arabidopsis - mustard family

Question 9

what makes a suitable model organism?

Answer 9

rapid life cycle
small size
genetically tractable
accessible embryos

Question 10

what is special about drosophila?

Answer 10

morphogen gradients, positional info, developmental fields, boundaries

Question 11

what are morphogens?

Answer 11

signal molecules that can affect behaviour of a cell

Question 12

what is a bicoid?

Answer 12

first example of a morphogen, found in drosophila

Question 13

how does bicoid mRNA work?

Answer 13

localised to anterior pole, translated into protien spreading to posterior forming an anterior-posterior gradient

Question 14

how does bcd work?

Answer 14

changes the levels of morphogen protein gradient shifting the position of where the target genes are activated

Question 15

what happens with drosophilia segmentation?

Answer 15

morphogen gradient activates or represses various downstream genes depending on different thresholds for response

Question 16

what does hox gene code determine?

Answer 16

differentiation pathways

Question 17

what is the embryonic field?

Answer 17

the area of embryo tissue within which a certain process occurs

Question 18

what are compartments?

Answer 18

region within which progeny of every cell remains confined - needs boundaries either physical or determination

Question 19

what is xenopus laevis

Answer 19

african clawed frog

Question 20

what is cleavage?

Answer 20

cell division without growth

Question 21

what is induction?

Answer 21

process by which one embryonic region interacts with a second region to influence the second regions differentiation or behaviour

Question 22

how do competent tissues become differentially determined?

Answer 22

in response to conc of chemical signals from another region of the embryo

Question 23

how is the secondary axis formed?

Answer 23

new notochord arises from host donor tissue

new neural tube and somite formed by host and donor tissue

Question 24

what is fate?

Answer 24

the final stage of development

Question 25

how do we map fate?

Answer 25

vital dyes - inflorscence fluoresenclty tagged proteins transplantation of pigmented into albino tissue

Question 26

what is determination?

Answer 26

progressive restriction in developmental protential of different cell types irreversible

Question 27

if graft appears how do we know if its determined?

Answer 27

- old position - determined | new position - undetermined

Question 28

what is specification?

Answer 28

isolating cells and they still become what they should

Question 29

what is competence?

Answer 29

cells able to recieve signals for only a short time

Question 30

what is special about c.elegan?

Answer 30

illustrates development via cell lineage easy to observe can name each cell all the way through

Question 31

what is lineage?

Answer 31

embryos with invarient cleavage patterns such that a family tree can be drawn state of commitment inherited from determined parent cell

Question 32

what is mosaicism?

Answer 32

map of specified regions matches fate map

Question 33

what is regulation?

Answer 33

specification of isolated parts doesn't correspond to the fate map also reestablishment of the fate map on a domain of uncomitted tissue

Question 34

what are p granules?

Answer 34

in p cell lineage that become germ lines

Question 35

what happens when ced-3 joins?

Answer 35

apoptosis and its a cell death defective caspase

Question 36

what does vulva development show?

Answer 36

signalling

Question 37

what is laser ablations?

Answer 37

when cells could become the vulva but only some do

Question 38

features of mosaic development?

Answer 38

determinate | separation of blastopore results in incomplete parts of embryos

Question 39

features of regulation development?

Answer 39

undetermined | remaining cells can compensate for tissue loss

Question 40

what is the pathway a cell takes as it becomes specialised?

Answer 40

undifferentiated - specified - determined - differentiated