17. Introduction to Development

Question 1

define differentiation

Answer 1

the process where cells specialise to perform a specific function

Question 2

define morphogenesis

Answer 2

the process of how cells grow and develop 3-dimensionally

Question 3

what are nematodes frequently used to study

Answer 3

neural development

Question 4

why are nematodes good to study in development

Answer 4

they are transparent - which allows the tracking of individual cells

Question 5

why are fruit flies good organisms to study development

Answer 5

rapid development

easy to generate mutants

Question 6

what is the benefit of studying zebrafish over mice

Answer 6

they are cheaper to maintain than mice

Question 7

why are Xenopus oocytes good to study

Answer 7

very large - good to generate cell extracts from

Question 8

what is the benefits of studying mice

Answer 8

genome very similar to humans

we have good knowledge of mice genes

Question 9

what are the benefits of studying chick embryos

Answer 9

similar to mammalian systems

tissues can be easily labelled, transplanted and cultured.

Question 10

what is cleavage

Answer 10

cell division in the early embryo

Question 11

what is gastrulation

Answer 11

cell movements which produce gut and three primary germ layers

Question 12

describe cleavages 1 and 2

Answer 12

equal holoblastic

nuclei is displaced

Question 13

describe cleavages 3

Answer 13

perpendicular but unequal holoblastic

Question 14

what are the three primary germ layers

Answer 14

ectoderm
mesoderm
endoderm

Question 15

what is the ectoderm

Answer 15

the outside of the embryo

Question 16

what is the mesoderm

Answer 16

the middle lining between ectoderm and endoderm

Question 17

what is the endoderm

Answer 17

the very inside of the embryo

Question 18

what does the ectoderm go on to form

Answer 18

skin

nervous system

Question 19

what does the endoderm go on to form

Answer 19

gut
liver
lungs

Question 20

what does the mesoderm go on to form

Answer 20

the skeleton, muscle, kidney, heart

Question 21

briefly describe the process of gastrulation in amphibians

Answer 21

1. population of cells evaginate to form the blastopore
2. population of cells above the blastopore migrate and extend across the embryo , pulling vegetal cells to form the archenteron
3. archenteron fuses with the opposite side of the embryo
4. 3 germ layers are formed
5. evagination begins: blastocoel shrinks, animal pole cells undergo epiboly

Question 22

what is the process of epiboly

Answer 22

where cells expand to completely cover the surface of the developing embryo & form the ventral lip

Question 23

what is induction

Answer 23

where cell fates are determined via signals from other cells

Question 24

what cells undergo epiboly

Answer 24

animal pole cells

Question 25

define the term morphogen

Answer 25

a signalling molecule that acts directly on cells to induce a specific cellular response depending on its concentration

Question 26

give an example of induction

Answer 26

vertebrate eye: - eye begins as diverticula (pouches) - pouches pinch off and form the optic cup - induce overlying ectoderm to evaginate inwards - this forms a ball of tissue that forms the retina - overlying ectoderm left over develops the cornea

Question 27

name 2 ways how induction can occur

Answer 27

direct cell- cell contact signalling molecules diffusing to distanced cells

Question 28

how do we know the optic cup is inductive

Answer 28

when transferred to another location on the body - the optic cup induces overlying ectoderm to form the retina = forming an ectopic eye

Question 29

what is the apical ectodermal ridge responsible for

Answer 29

required for limb outgrowth | secretes FGF

Question 30

what does the apical ectodermal ridge secrete

Answer 30

fibroblast growth factor (FGF)

Question 31

what does the ZPA stand for, and what does it do

Answer 31

zone of polarising activity | controls anterior- posterior digit formation via induction

Question 32

describe chick ZPA studies

Answer 32

transplant ZPA from posterior to anterior of a limb bud and allow it to develop observed fusion of digit 1 = mirror image structure formed

Question 33

what two tissues does kidney development begin

Answer 33

``` epithelium = uteric bud mesenchyme = metanephric blastema ```

Question 34

which tissue induces bud branching in developing kidneys

Answer 34

mesenchyme (metanephric blastema)

Question 35

what gene is involved in kidney development

Answer 35

RET gene

Question 36

describe mice kidney development studies

Answer 36

removal of RET gene results in complete kidney growth

Question 37

what 2 things can kidney growth not occur without

Answer 37

RET and GDNF

Question 38

what secretes GDNF

Answer 38

the mesenchyme

Question 39

who first described the concept of a morphogen

Answer 39

lewis Wolpert

Question 40

cell fate is determined by the .............. of the morphogen

Answer 40

concentration

Question 41

more notes on morphogen | using textbook

Answer 41

yeh