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Embryology Note ?'s
Review of slides
66
Biology
Graduate
10/07/2009

Additional Biology Flashcards

 


 

Cards

Term
Big players in preformation and what they did.
Definition
Malpighi/chick
Bonnet/aphids
Term
Big players in epigenesis and what they did.
Definition
Wolf- structures diff in cell early and late
Spallanzani - sperm and egg req
Pander - earliest description of induction
Hertweig - 1st to describe interaction b/t egg and sperm
Term
Four principles of Baer's Law
Definition

1. Gen features appear prior to spec. features

2. Less gen char. dev from the more gen until most spec appear.

3. Embryos of given species depart from adult stage of lower animals.

4. Early embryo of a higher animal is never like an adult, only embryo

Term
Define regulation......
Definition
ability of cells to change their dev. fate according to location w/ the whole organism
Term

Developmental Dynamics of Cell Specification

(in order)

Definition

1. specification - capable of diff. autonomously (reversible)

 

2. determination - cell fate is fixed and irreversible even if environment is changed

 

3. differentiation - dev of specialized cells

Term
Three modes of specification
Definition

1. autonomous - positioning of the morph determinants in the cytoplasm. (mosiac dev.)


2. conditional - ability of cells to change their dev fate according to location (regulation)


3. syncytial - spec of body regions by interactions b/t cytoplasmic regions prior to cellularization

Term
What is the Germ Plasm Theory?
Definition

1. sperm and egg contribute equally

2. chromosomes carry inherited pontential (determinants)

3. not every determinant inherited by all cells (diff distribution)

4. only cells with all determinants are those destined to b/c germ cells

 

Weismann 1893

Term
How can you test hypothesises?
Definition

1. Fate mapping

2. 4 Experimental Techniques

Term
What are the 4 experimental techniques and describe them.
Definition

1. Defect - (extirpation) - remove parts and see what doesn't form.

2. Isolation - (explantations) 

3. Recombination - (autoplastic) - move parts to another area w/in embryo

4. Transplantation - replace parts of embryos with parts of diff ones. 

Term

When prospective potency and prospective significance are equal what does this mean?

 

Who defined this?

Definition

The cell is specified and determined.

 

Dreisch, used isolation experiments.

Term
What are the 6 variations of cellular processes during morphogenesis?
Definition

1. Direction and # of cell divisions

2. Cell shape changes

3. Cell movements

4. Cell growth

5. Cell death

6. Changes in cell membrane or secreted products

Term
What did Townes and Holtfreter do in 1955?
Definition
Showed reaggregation in cells that were spatially seperate. They took nueral plate and epidermal cells and got them to reaggregate. Final positions reflect embryonic orgins. (Neural cells inside)
Term
When the prospective potency of cells in a later stage embryo exceeds the prospective signal of dev. pattern of the embryo is probably?
Definition
regulative
Term
What regulates fluid mosiac model?
Definition
cholesterol
Term
What are the two typical components of the extracellular matrix?
Definition

1. Collagens - glycoprotein, effects cell adhesion

2. Proteoglycans - more carb than protein, carbs are GAGs

Term
The extra-cellular matrix consistency depends on the ratio of what?
Definition
collagen to proteoglycans
Term
What is the major amino acid that hold cells around most mammalian eggs together?
Definition
hyaluronic acid
Term
What is a GAG?
Definition

Glycosaminoglycan


Linear polysaccharide chains made of repeating disaccardie units containing either glucosamine or galactosamine.


Roles : lubricant, intracellular adhesive, interactions with GF, anti-coagulant, adhesion promotor

Term
What is a proteoglycan aggregate?
Definition
Known as a spacer molecule. Allows for cells to migrate in cell free space.
Term
What are the extracellular matrix cell-substrate adhesion molecules?
Definition
fibronectin (road signs) and lamin (highway)
Term
Where are the RGD binding sites?
Definition
on fibronectin
Term
What is integrins function in extracellular binding?
Definition

beta subunit connects to RGD binding site on fibronectin outside of cell, connects to talin inside of cell, which attaches to actin microfilament.

 

Known as bridge.

Term
What are CAMS?
Definition

Cell Adhesion Molecules

 

1. Cadherins 

2. Immunoglobulin superfamily

Term
What is a cadherin?
Definition

CAM

 

The major cell adhesion molecule. Ca dependant. Anchored by cantenins inside cells, bind to actin inside cells. Spacial segregation.

 

See in blood/brain and blood/testes barriers

Term
What is the immunoglobulin superfamily?
Definition

CAM

 

binding domains resemble those of antibodies.

dev of nervous system

Term
Seven major types of Cadherins
Definition

1. E-Cadherins - uvomorulin, drive compaction

2. P-cadherins - placental

3. N-cadherins - nueral crest cells

4. R-cadherins - retinal cells

5. B-cadherins - brain cells

6. EP-cadherins - critical for blastomere positioning

7. Protocadherins - lock connections to cytoskelton, seperation of notocord from other mesoderm

Term
Which developmental model are cadherins used for cell sorting. What type of specification is it?
Definition

Steinburg's 

 

conditional 

Term

What three adhesive systems are used in adhesion of embryo to placental wall?

 

Describe.

Definition

1. E & P cadherins - primarily expressed in syncytiotrophoblast

2. Integrin receptors - collagen and heparin sulfate

3. Syncytiotrophoblast - glycosyltransferase enzymes, remains adherent b/c no glucose to finish rxn. Doesn't let go

Term
What type of binding do cadherins express?
Definition
homophillic - only want to bind to one another
Term
What are the four types of cell migrations and describe them briefly.
Definition

1. Chemotaxis - cell follows chemical gradient (sperm and egg)

2. Hapotaxis - follows chemical concentration gradient on a substrate. ex. fibronectin

3. Galvanotaxis - follow electirical gradient (nuerons)

4. Contact guidance and inhibition - doesn't stop moving until locked in by other cells.

Term
What are some simple way to ID the extracellular matrix?
Definition
Proteolytic enzymes, denaturing conditions
Term
What are some complex ways to ID a extracellular matrix?
Definition

monoclonal antibodies

lectins

western blot

Term
What is Morgan known for?
Definition
producing mutation linking sex and the X-chromosome
Term
Who invented XX, XY, XO?
Definition
Wilson
Term
What is the strongest way to prove evidence of genomic equivalence
Definition
metaplasia
Term

The ultimate test would be to remove the nucleus of a ____ ______ ____ and transfer to an enucleated egg. Result must be a fully differentiated _____  ______ _______ developed from the egg.

 

Definition

fully-differentiated cell

adult reproductive organism

Term
Briggs and King were early pioneers in what?
Definition
somatic cell nuclear transfer
Term
Who disproved that cloning shortens the lifespan of clones?
Definition

Yanagimachi

 

(mice)

Term
What are the light and dark regions of polytene chromosomes when probed with RNA respectively?
Definition

light - euchromatin - activity transcribing

dark - heterochromatin - not transcribing

Term

How can you control gene expression?

 

(4)

Definition

1. differential gene transcription

2. selective mRNA processing - remove introns

3. selective mRNA translation 

4. post-translational modifications - insulin, trypsin, folding of proteins.

Term
What provides strongest evidence for genetic constancy?
Definition
somatic cell nuclear transfer
Term
How are prokaryotic cells different from eukaryotic cells in relation to gene structure?
Definition
not colinear with peptide products
Term
Where is the TATA box found?
Definition
promoter region of RNA
Term
What drives differential gene expression?
Definition
transduction and induction
Term
What experiment was done to show regulation of an entire chromosome?
Definition

Irradiating mealy bugs.

 

Males don't get active chromosome from dad. When only female exposed there were many deaths. When males exposed only females died. 

Term
During dosage compensation what forms?
Definition
barr body
Term
When introns are removed and processed out of cytoplasm for activation this is called?
Definition
selective nuclear RNA processing
Term
Give an extreme example of an organism that exhibits differential RNA splicing.
Definition

Drosophila DSCAM

38,000 different proteins possible

Term

How can you control gene expression?

 

(3)

Definition

1. differential mRNA 1/2 life

2. Selective inhibition of translation

3. Cytoplasmic localization (bicoid and nanos)

Term
Describe differential mRNA half-life.
Definition

Dependant in part on length of poly a tail and product presence, both alter the half life. Length is regulated by 3' UTR sequence.

 

short tail - short half-life

Term
Describe selective inhibition of translation.
Definition

Masked message in the oocytes.

Sans methylation (no cap) or biding of inhibitory proteins.

Poly a tails (short, no translation, but not degraded) (drosophilia bicoid RNA)

Term
Descrice cytoplasmic localization (bicoid and nanos).
Definition

3'UTR of bicoid mRNA allows attachment to microtubules, stabilizes position in anterior, dependant on two necessary proteins.

 

3' UTR of nanos mRNA allows transport to posterior pole via microtubules - bound in posterior by association with other cytoskeletal elements.

Term
Describe post-translational regulation.
Definition

Folding patterns - tertiary structure

Address in cell - membranes, compartments (oxidative enzymes of mitochondria)

Alteration of protein chain (removal of AA's) pro-insulin and trypsinogen

Assembly - hemoglobin

Ionic requirements - Ca, phosphate

Term
Cellular communication at a close range is called?
Definition
proximate interaction/induction
Term

What is cellular competance?

 

Name a competancy factor.

Definition

ability of cell to respond to a specific inductive signal.

 

Pax-6

Term
What is reciprocal induction?
Definition
induced tissue influences another tissue so that tissue becomes and inducer too.
Term
What are the major modes of induction?
Definition

Instuctive interaction/informative - nec for gene inducing new gene

 

Permissive interaction/environmental - only needs correct environment to express potentials.

Term
What are the two properties associated with induction?
Definition

Regional specificity - instructive orgin of the organ based on the position of the inducer

 

Genetic specificity - genome limits extent of response to regional specificity

Term
What are the paracrine factors 4 major families?
Definition

1. Fibroblast growth factor

2. Hedgehog family

3. WNT family

TGF-B superfamily

Term
Describe the fibroblast growth factor.
Definition

angiogenesis, mesoderm formation, axon text.

 

functions through tyrosine kinase receptors

Term
Describe WNT family
Definition

  • found in nearly all mammals
  • patterning dorsal portion of somites polarity of limbs, urogenital dev and stem cell proliferation.
  • cysteine-rich glycoproteins

Term
Describe TGF-B superfamily
Definition

Generally have to mature peptide at carboxy terminal end of processed peptide.

 

May dimerize to themselves (hemodimers) or to other TGF-B peptides (heterodimers)

Term

The __________ family is a member of the TGF-B superfamily.

 

Definition

BMP 

 

bone formation, cell division, apoptosis, cell migration, differentation.

 

Regulated by AA's

Term
TGF-B member are responsible for 
Definition
formation of extracellular matrix
Term
What is kinase
Definition
adds phosphate group, alters composition, activates or deactivates something
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