Cell to Cell Communication in Development & Principles of Experimental Embryology

Question 1

organs are formed by interactions between

Answer 1

cells & tissues

Question 2

define inducer

Answer 2

cells/tissues that produce a chemical signal which results in a change in another cell’s fate

Question 3

what is the name for the process where a cell’s fate is changed?

Answer 3

induction

Question 4

define responder

Answer 4

cells or tissues which receive the inducing signal

Question 5

define competence

Answer 5

the ability of cells/ tissues to respond to inducing factors

Question 6

competence is typically governed by _________. Give an example

Answer 6

chemical mediators

Ex: proteins

Question 7

define reciprocity

Answer 7

a cyclical pattern of induction between a community of cells

Question 8

give an example of an inductive interaction

Answer 8

the epithelial-mesenchymal interactions

Question 9

list the 3 types of inductive interactions

Answer 9

1. paracrine factors
2. juxtacrine factors
3. autocrine factors

Question 10

describe paracrine factors

Answer 10

the diffusion of proteins over a short distance

Question 11

describe juxtacrine factors

Answer 11

physical interactions between surface protein w/ cell receptor

Question 12

describe autocrine factors

Answer 12

cells respond to their own paracrine factors

Question 13

which factor travels greater distances: inducing or endocrine

Answer 13

endocrine

Question 14

describe the notch pathway

Answer 14

the physical interaction between adjacent cells for the induction process

Question 15

the notch pathway is an example of which type of signaling

Answer 15

juxtacrine signaling

Question 16

explain the mechanism of the notch pathway

Answer 16

a portion of the responder is cleaved by protease enzymes to activate target genes

Question 17

activation of what causes DNA to be exposed

Answer 17

histone acetyltransferases

Question 18

what type of signaling is commonly found in the nervous sytem?

Answer 18

juxtacrine signaling

Question 19

signal transduction is a a cascade of biochemical events that lead to

Answer 19

gene expression

Question 20

in signal transduction what happens to the receptor

Answer 20

ligand binding causes a conformational change

Question 21

signal transduction activates enzyme activity beginning w/ the

Answer 21

G-protein

Question 22

what is key in signal transduction

Answer 22

phosphorylation

Question 23

what are the 2 types of interactions between inducers and responders

Answer 23

• instructive interaction
• permissive interaction

Question 24

describe instructive interactions

Answer 24

inducing tissue gives instruction for responding cells to commit to a specific pathway of development

Question 25

give an example of an instructive interaction

Answer 25

mesenchyme and epithelial ectoderm leading to differentiation

Question 26

describe permissive interaction

Answer 26

responder is already specified but needs the proper environment to develop

Question 27

the RAS-G protein is a component of which signal transduction pathway

Answer 27

paracrine

Question 28

the RAS-G protein is used by growth factors to

Answer 28

initiate cell growth and differentiation

Question 29

mutation in RAS pathway leads to

Answer 29

human tumors

Question 30

the JAK-STAT pathway is responsible for the...

Answer 30

differentiation of formed elements in blood and limb formation

Question 31

mutations in the JAK-STAT pathway leads to

Answer 31

- dwarfism - deficiency in specific blood types

Question 32

why doesn't the loss of a signaling protein result in abnormal development or death

Answer 32

b/c there is a great amount of repetition in the process of signal transduction

Question 33

what provides additional sites to regulate signaling between pathways

Answer 33

cross talk between pathways such that they are intimately interconnected

Question 34

what is cell to tissue formation dependent on?

Answer 34

basement membrane attachment sites

Question 35

give examples of adhesion molecules

Answer 35

- collagen - fibronectin - proteoglycans - laminin

Question 36

proteoglycans aid in the delivery of

Answer 36

paracrine factors to receptor sites

Question 37

integrins are proteins which

Answer 37

bind the ECM to the intracellular network

Question 38

ECM binds to

Answer 38

actin filaments

Question 39

ECM induces transcription factors to control __________ ___________ or even prevent ____________.

Answer 39

gene expression apoptosis

Question 40

connexin is a group of 6 identical proteins that form

Answer 40

a pore that joins cytoplasms

Question 41

what is important in tightly connected cells like epithelia of the gut and neural tube

Answer 41

gap junctions

Question 42

temperature alterations influenced what in amphibians

Answer 42

sex typing

Question 43

seasonal variations affected the ________ ____________ in butterflies

Answer 43

phenotypic expression

Question 44

UV irradation caused exposed amphibians to

Answer 44

decreased fertilization & survival rates

Question 45

define mycosporin

Answer 45

melanin type protection produced by some species

Question 46

define differentiation

Answer 46

development of specialized cell types

Question 47

define commitment in cell specification

Answer 47

biochemical changes to determine a cells fate

Question 48

what are the 2 stages of commitment?

Answer 48

1. specification 2. determination

Question 49

describe the 'specification' stage of commitment

Answer 49

cell is capable of differentiating "autonomously" in vitro

Question 50

is specification reversible?

Answer 50

YES

Question 51

describe the 'determination' stage of commitment

Answer 51

capable of specification in vivo or when placed back into an embryo

Question 52

is determination reverible?

Answer 52

NO

Question 53

what are the 3 types of specification?

Answer 53

1. autonomous 2. syncytial 3. conditional

Question 54

describe autonomous specification

Answer 54

cells removed from blastomere develop normally

Question 55

autonomous specification is aka a

Answer 55

mosaic development

Question 56

autonomous specification is mostly seen in

Answer 56

invertebrates

Question 57

syncytial specification is mostly seen in

Answer 57

insects

Question 58

describe the syncytial specification

Answer 58

the nuclei divides within the egg and spreads throughout

Question 59

the specification of cells by protein concentration is known as? what type of specification is this specific to?

Answer 59

morphogens syncytial specification

Question 60

conditional specification is mostly seen in

Answer 60

vertebrates

Question 61

describe conditional specification

Answer 61

first forming cells in the blastomere have the ability to differentiate into various cell types

Question 62

in conditional specification what directs the determination of a specific cell type

Answer 62

interaction of neighboring cells

Question 63

define regulation

Answer 63

the ability of blastomeres to compensate the missing cell types

Question 64

what is the germ plasm theory

Answer 64

heritable info. is carried by just gametes and not somatic cells

Question 65

zygotes have inherited component for

Answer 65

various body regions

Question 66

what were the 4 types of experimental approaches to germ plasm theory

Answer 66

1. defect 2. isolation 3. recombination 4. transplantation

Question 67

what are stem cells

Answer 67

undifferentiated biological cells that can differentiate into specialized cells

Question 68

stem cells are found in

Answer 68

multicellular organisms

Question 69

what are the 3 different types of stem cells

Answer 69

1. totipotent 2. pluripotent 3. multipotent

Question 70

totipotent stem cells can differentiate into

Answer 70

embryonic and extraembryonic cell types

Question 71

totipotent stem cells can construct a

Answer 71

viable organism | egg + sperm

Question 72

pluripotent stem cells have the capacity to grow into

Answer 72

all cells of the embryonic body

Question 73

when and where are the pluripotent stem cells isolated from

Answer 73

- when: during the blastocyst stage - where: the inner cell mass

Question 74

pluripotent stem cells are aka

Answer 74

embryonic stem cells

Question 75

give an example of multipotent stem cells

Answer 75

hematopoietic stem cells | ONLY differentiate into different cell types

Question 76

which type of stem cell is the most limited in its differentiation

Answer 76

multipotent

Question 77

cadherins are

Answer 77

calcium adhesion molecules

Question 78

catenins are

Answer 78

actin binding proteins that anchor cadherins

Question 79

a deficiency in what can lead to embryonic abnormalities

Answer 79

calcium or cadherin