29-30 multicellular organism developmetn Flashcards Preview

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Flashcards in 29-30 multicellular organism developmetn Deck (57):
1

why do cells undergo differentiation during developmetn?

differentiation provides different tissues to perform different tasks

2

Stages of embryo develpment

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

3

WHat does it mean if cells have memory?

they retain signals from previous embryonic development.

4

What is ectoderm

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

5

The endoderm is what

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

6

What is mesoderm

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

7

Gastrulation

formation of a gut structure from a sphere of cells

8

what proteins class are important for development

cell adhesion, signaling proteins, gene regulatory proteins

9

what is a non-coding regulatory DNA?

instructions to form multicellular organism that associates with each gene

10

what is a non-coding sequence

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

11

why are non-coding sequences inmportatn for DNA

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

12

when does a cell make a develpmental decision

before showing signs of differentiation

13

what does a cell do before showing signs of differentiation

developmental decision must be made

14

what is a determined cells

cell that is not influenced to differentiate by environmental factors

15

completely undetermined cells

cells undergo rapid changes due to altering environments

16

committed cells

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

17

positional value

position specific character of a cell

18

is positional value a memory of the cell

yes

19

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

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

20

how can cells become different

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

21

where are the most important environmental signals normally from

neighboring cells

22

what is inductive signaling

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

23

What are the different types of inductive signaling present?

1. short range: cell-cell contact
2. Long-range: these substances diffuses through ECM

24

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

positive feedback

25

what provides cells with memory

positive feedback

26

what is a morphogen

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

27

what type of gradient can morphogens form?

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

28

what is teh result of inductive events that stimulate signaling pathways

altering DNA transcription

29

what is signaling pathway dependent on in terms of resposne time

spatial and temporal expression of different gene sets

30

phases of neural development and function

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

31

where does the neural tube develop into

the cns

32

what does the neural crest cell develop into

pns

33

what is the process for neural tube formation

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

34

what provides lateral inhibtion of the neural tube

delta notch signaling

35

where do neural crest cells originate

from the dorsal end of the neural tube

36

when will neural crest cells begin theif migration

after neurlation, when the neural tube closes

37

what different cells types does the neural crest provide?

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

38

how do neurons migrate?

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

39

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

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

40

what is teh growth cone

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

41

what controls where the growth cone goes?

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

42

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

extracellular matrix environment and chemotactic factors

43

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

immunoglobulin superfamily and cadherin family class receptors.

chondroitin sulfate inhibits growth.

44

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

yes

45

what are teh attracting chemotactic factors for growth cone

netrin

46

what are the repulsive chemotactic factors for growth cone

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

47

what happens when netrin binds with its receptor?

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

48

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

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

49

where is slit secreted from

midline cells

50

what repulsive receptor is found on commissural neurons

roundabout with binds with slit

51

what do neurotrophic factors have control over?

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

52

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

the neurons die via apoptosis

53

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

true

54

what is nerve growth factor

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

55

what is the function of nerve growth factor

promote survival of sensory and parasympathetic neurons

56

what are the short term effects of nerve growth factor

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

57

What are the effects of long term nerve growth factor

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