Development I Flashcards
What are the three major subdivisions of the vertebrate brain structure?
Forebrain
including Telencephalon or cerebral cortex and diencephalon including the thalamus and hypothalamus
Midbrain
includes superior colliculus inferior colliculus
Hindbrain
include the cerebellum, the pons, the medulla
What is the seven major processes of the development of the nervous system?
(1) Cell proliferation
(2) Cell migration
(3) Cell death
(4) Differentiation
(5) Axon Guidance (Axon outgrowth and pathfinding)
(6) Synapse formation
(7) Developmental plasticity
Cell proliferation
The single fertilized egg cell needs to _____________cycle of cell division in order to give rise to the adult nervous system.
undergo many
Cell migration
True or False: Cells are often not born at the location they need to be in the adult nervous system.
Therefore they have to move around during development.
True
Cell death
Depending on the species of the animal between 10% and 50% of cells which are born during the development of the nervous system _______ before the animal is mature.
This play an important role in ____________ and ________________ which prevent cell death are lethal to the animal.
will die
development and mutations
Differentiation
Precourse cells early in development are _____________.
Precursor cells produced final __________cell types which have specific
_______________
______________
______________
features
undifferentiated
differentiated
anatomical
physiological
biochemical
Axons Guidance
True or False: Neurons need to make proper connections with other neurons or target tissues.
True
After the axons reach their target, they must form ______ to allow communication with the target cell.
Synapses
Developmental plasticity
After synapse form, connection can be selectively _____________ or ______________ to ensure that the proper information will be carried by the pathways.
strengthened or eliminated
What are some ways to study neuronal development?
Cell Lineage Studies
Cell Fate Determination -Cell Autonomy Studies
Using model organisms
What is the purpose of cell lineage studies?
Designed to follow single cells and their progeny throughout development in order to determine which specific precursor cells in a young embryo give rise which fully differentiated cells in the adults.
What do we know about cells due to cell lineage studies?
We know about cell proliferation
migration
death
differentiation
What is one of the major principles learned through cell lineage studies?
Most precursor cells in the young embryo are multipotent (give rise to more than one differentiated cell type)
What are the two techniques for cell lineage studies?
Sing cell labeling
Genetic markers
For single-cell labeling (early days)
Label a single cell in an early embryo with a marker substance such as _______________.
Allow the embryo to continue developing normally and then we look for labeled cells
Any cell containing the label must be ______________________ cell.
The problem is that every time cells divided ____________________.
fluorescent dye
descended from the original labeled cells
they dilute the marker substance
For genetic marker –> modern lineage studies are often performed by adding a ______________ to a precuroiser cell.
The marker which is inserted into the __________ will be replicated with the cell’s own genetic material every time the cell divide and thus the marker (will/will not) be diluted
genetic marker
genome of the cell
will not
What is the purpose of cell autonomy studies?
Show us whether the cell fate is either
(1) environmentally determined
or (2) genetically determined’
What are other terminology for
environmentally determined
or
Genetically determined?
Environmentally
indeterminate
inductive
cell non-autonomous
Genetically determined
Determinate
cell autonomous
True or False: The cell lineage studies show us the final fates of the progeny of a particular precursor cell.
However, cell lineage studies cannot tell us whether the fate of cells in a particular lineage was wither genetically determined or environmentally determined.
True
Experiments altering a cell’s environment during development
Cell culture experiments
By growing a dissociated cell in cell culture, it is theoretically possible to remove all ____________ and then watch to see what the ______________.
environmental cues
cell and its progeny differentiate into
Ablation experiments
Neighboring cells can be _________ from a system to subtly change a cell’s environment.
These experiments can remove only cues which come from the neighboring cells ______________________________.
If a cell’s fate were changed by _________ of neighboring cells: we can conclude that
________________________________________.
removed
while leaving the rest of the cell’s environment the same
ablation (surgical removal of body tissues)
The cell’s fate is determined by the environmental cues from the ablated neighboring cells.
Transplantation experiments
What is the purpose of this experiment?
A cell or small group of cells can be removed from one embryo and transplanted into another embryo.
If cell differentiates due to environmental factors, this cell’s fate will be the same as the fate of cells in the recipient (host) embryos
Are the cells non-autonomous (environmentally determined) or autonomous (genetically determined)?
Cells are non-autonomous –> inductive
If cell differentiates due to genetic factors, this cell’s fate will be same as donor cell fate
Will the cells be non-autonomous or autonomous?
Cell-autonomous
For example, if you transplant cells from the head of a caterpillar to the tail and end up with a
A normal adult butterfly –> head cell fate is _____________________
Environmentally determined (inductive)
If we transplant a head to the tail and end up with a two-headed butterfly then the cells fate is __________________.
Genetically determined
What are the two types of transplants that are often done?
(1) Heterotropic transplants
remove the cell from one part of the donor embryo and transplant it into a different place in the recipient embryo.
(2) Heterochronic transplants
which is transplant from one age of donor embryo into the same location in a younger or older host embryo
What are isolating mutations?
Experiments that altering a cell’s genetics during development
Mutation in a single gene can have profound effects on development.
Generating transgenic and conditional knockout animals
In a mutant animals, both the _______ and its ___________ are changed.
To get around this problem –> animals can be created using ________________
which can have a gene turned off not in the whole animal as in a conventional mutant but only in a particular group of cells at a particular time during development.
cell’s genetics
cell’s environment
molecular biology techniques
True or False: Simple organism tend to rely on cell-autonomous (cell genetic mechanism of development)
True
C. elegans has a total of ___________
____ of these cells are neurons.
There are ________ protein-coding genes in C. Elegans
1030
302
20,000
In humans, it is estimated there are only _____________ to __________ protein coding genes in human
there are ________ neurons in our nervous system
Hint: the stars in the galaxy
30,000 to 40,000
100 billion neurons like 100 billion stars in the milky way
Cell lineage studies in C. elegans have shown that ____________________________________.
many of the development of this organism does occur thru genetic cell-autonomous process.
_________________ and ______________ studies have shown that changing a cell;s enivonemnt during development generally do not affect the cell fate
Transplantation
Ablation
What are the other three model organisms?
Zebrafish
Its embryo is transparent, allowing direct observation of cells, and its development is fast
Xenopus and Chick –> Their embyro are easily accessible, allowing direct cell lineage or cell autonomy studies
Mouse –> a model that is close to us
What are more complex, meaning having more neurons, than C.elgans?
(Hint: Bio 402 Lab)
Drosophila
Fruit Fly
True or False: Drosophila, still takes advantage of genetic mechanisms for much of its development.
True
What is the first event in the development of the Drosophila embryo?
Maternal effect Genes –> Genetic mechanisms
Setting up the dorsal-ventral and the anterior-posterior axes of the animal
True or False: The maternal-effect genes are evenly distributed in the egg.
False, unevenly distributed in the egg
For example, bicoid mRNA is concentrated at the anterior end of the egg
while
oskar mRNA is at the posterior end
(Oskar/bicoid) regulates the development of abdomen structures, while (oskar/bicoid) development of head structure
Oskar
bicoid
What occur to embryos who lack the bicoid gene>
The embryos will have no head or thorax.
How can you add a head or thorax in a lacking bicoid gene embryo?
Inject bicoid mRNA in the egg.
What are the two genes that control the development of body segments?
Segmentation genes
Homeotic selector genes (Hox Genes)
What do segmentation genes control?
They control the formation of the segments themselves.
What do Hox genes control?
Control the fate of particular segments.
Flies with a mutation in the Hox genes tend to have structures inappropriate to a given segment
For environment determined
What are the two mutants that are lacking in the #7 photoreceptor in the ommatidia?
Sevenless (sev) –> receptor
and
bride of sevenless (boss) –> ligand molecule
How the ommatidia develop in normal?
Check the image
