29-30 multicellular organism developmetn

Question 1

why do cells undergo differentiation during developmetn?

Answer 1

differentiation provides different tissues to perform different tasks

Question 2

Stages of embryo develpment

Answer 2

1. proliferation
2. specialization
3. interact with cells
4. movement

Question 3

WHat does it mean if cells have memory?

Answer 3

they retain signals from previous embryonic development.

Question 4

What is ectoderm

Answer 4

sheet of epithelial cells that form the nervous system and epidermis.

Question 5

The endoderm is what

Answer 5

forms from the ectoderm folding in, and will become the gut, lung, and liver

Question 6

What is mesoderm

Answer 6

the layer between ectoderm and endoderm. forms the connective tissue and muscle

Question 7

Gastrulation

Answer 7

formation of a gut structure from a sphere of cells

Question 8

what proteins class are important for development

Answer 8

cell adhesion, signaling proteins, gene regulatory proteins

Question 9

what is a non-coding regulatory DNA?

Answer 9

instructions to form multicellular organism that associates with each gene

Question 10

what is a non-coding sequence

Answer 10

sequence of DNA that will not code for anything, but makes organisms unique from one another.

Question 11

why are non-coding sequences inmportatn for DNA

Answer 11

coding seqeunces are very similar . non-coding provides uniqueness to organism

Question 12

when does a cell make a develpmental decision

Answer 12

before showing signs of differentiation

Question 13

what does a cell do before showing signs of differentiation

Answer 13

developmental decision must be made

Question 14

what is a determined cells

Answer 14

cell that is not influenced to differentiate by environmental factors

Question 15

completely undetermined cells

Answer 15

cells undergo rapid changes due to altering environments

Question 16

committed cells

Answer 16

cells contain some form of another cell type but are still influenced by changing environment

Question 17

positional value

Answer 17

position specific character of a cell

Question 18

is positional value a memory of the cell

Answer 18

yes

Question 19

what is the relevance of a cells ability to maintain memory of a positional value?

Answer 19

allows an arm to be relocated to a thigh, and development will still continue as an arm

Question 20

how can cells become different

Answer 20

asymmetric division, has an unequal distribution of molecules and then can directly alter patterns of gene expression among the 2 cells

Question 21

where are the most important environmental signals normally from

Answer 21

neighboring cells

Question 22

what is inductive signaling

Answer 22

induction of a different developmental program in select cells of a homogenous group which changes the groups character

Question 23

What are the different types of inductive signaling present?

Answer 23

1. short range: cell-cell contact

2. Long-range: these substances diffuses through ECM

Question 24

What provides cells with memory and amplifies the weak asymmetry initiated by the environment

Answer 24

positive feedback

Question 25

what provides cells with memory

Answer 25

positive feedback

Question 26

what is a morphogen

Answer 26

long range inductive signal that imposes patterns on fields of cells based on concentration gradients

Question 27

what type of gradient can morphogens form?

Answer 27

inducer and inhibitor. both diffuse away from the source, but inhibitor can block activity of the inducer

Question 28

what is teh result of inductive events that stimulate signaling pathways

Answer 28

altering DNA transcription

Question 29

what is signaling pathway dependent on in terms of resposne time

Answer 29

spatial and temporal expression of different gene sets

Question 30

phases of neural development and function

Answer 30

1. phase 1: deifferent cell types develop independently at varying locations based on local signals Phase 2: axons and dendrties grow along specific routes forming provisional ordered network of connections phase 3: connections are adjusted and refined through different interactions with distant regions and electrical signals

Question 31

where does the neural tube develop into

Answer 31

the cns

Question 32

what does the neural crest cell develop into

Answer 32

pns

Question 33

what is the process for neural tube formation

Answer 33

neural groove, neural fold, neural tube as the folds meet up in midline. neural canal is the hollowed- out portion inside the tube

Question 34

what provides lateral inhibtion of the neural tube

Answer 34

delta notch signaling

Question 35

where do neural crest cells originate

Answer 35

from the dorsal end of the neural tube

Question 36

when will neural crest cells begin theif migration

Answer 36

after neurlation, when the neural tube closes

Question 37

what different cells types does the neural crest provide?

Answer 37

1. neurons/glial cells of PNS 2. catecholamine producing cells in adrenal gladn 3. skeletal and connective tissue components for the head

Question 38

how do neurons migrate?

Answer 38

crawl along the radial glial cells that extend from the inner to outer end of the neural tube

Question 39

what are the different type of neurons that develop in the spinal cord

Answer 39

1. dorsal: sensory 2. ventral: motor 3. intermediate: interneurons

Question 40

what is teh growth cone

Answer 40

it uses chemotaxis to migrate through tissue. leaves a trail of axon-specific proteins to allow for axon growth, along this trail

Question 41

what controls where the growth cone goes?

Answer 41

filopodia and lamelopodia which use monomeric GTPases Rho and Rac to control actin assembly

Question 42

What do growth cones use to migrate through tissue along the proper path?

Answer 42

extracellular matrix environment and chemotactic factors

Question 43

what specific components are used in extracellular matrix migration of the growth cones

Answer 43

immunoglobulin superfamily and cadherin family class receptors. chondroitin sulfate inhibits growth.

Question 44

homophilic cell adhesion molecules mediate growth cone movement via extracellular matrix mechanisms

Answer 44

yes

Question 45

what are teh attracting chemotactic factors for growth cone

Answer 45

netrin

Question 46

what are the repulsive chemotactic factors for growth cone

Answer 46

slit and samphorin. the combination of these provides a single slot that the growth cone will migrate in between

Question 47

what happens when netrin binds with its receptor?

Answer 47

opens the transient receptor potential C channels, which release large amounts of calcium. this activates teh movement of the growth cone, by activating filopodia

Question 48

where are netrin receptors not located and what is the significance of this

Answer 48

not located on non-commissural neurons. prevents migration of neurons to the floor plate

Question 49

where is slit secreted from

Answer 49

midline cells

Question 50

what repulsive receptor is found on commissural neurons

Answer 50

roundabout with binds with slit

Question 51

what do neurotrophic factors have control over?

Answer 51

communicating and forming synapses with target cells when they reach their destination. tissue signals regulate the growth cone synapses and where

Question 52

what happens to neurons that do not receive enough neurotrophic factors from the target tisseu

Answer 52

the neurons die via apoptosis

Question 53

true/fasle | target cells produce the limited amount of neurotrophic factors that are required for neuron survival

Answer 53

true

Question 54

what is nerve growth factor

Answer 54

neurotrophic factor that belongs to neurotrophins and binds with tyrosine kinase A

Question 55

what is the function of nerve growth factor

Answer 55

promote survival of sensory and parasympathetic neurons

Question 56

what are the short term effects of nerve growth factor

Answer 56

act on nerve growth cone and neurite extensions. cause local, rapid, and independent communication with the cell body

Question 57

What are the effects of long term nerve growth factor

Answer 57

promote cell survival. use receptor-mediated endocytosis to enter cells and stimulate downstream effects