Mechanisms of Development Flashcards

1
Q

Is early or late embryonic development similar in vertebrates?

A

early

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2
Q

Does the amount of genes determine the complexity of an animal?

A

NO simple worms have just as much genes as us

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3
Q

what percent of genes do we share with mice?

A

92%

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4
Q

What is a homologous gene?

A

a gene similar in structure and evolutionary origin-function, to a gene in another species

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5
Q

What is genome equivalence?

A

genetic material is identical in every cell, but different cells express different sets

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6
Q

Nuclear transfer provided evidence for what?

A

that all cells contain the same genes

genomic equivalence

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7
Q

What are the four levels gene expression is regulated at?

A
  1. differential transcription
  2. selective nuclear RNA processing
  3. selective mRNA translation
  4. differential protein modification
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8
Q

What does this describe” one group of cell changes the behavior of an adjacent group of cells”

A

induction

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9
Q

The ability of a cell to respond to a signal is what term?

A

competence

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10
Q

The optic vesicle in the frog induces what structure in what tissue type?

A

induces lens formation in head ectoderm

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11
Q

How was it proven that only head ectoderm is competent to respond to optic vesicle?

A

optic vesicle placed in different location - ectoderm doesnt form lens

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12
Q

If the optic vesicle is removed, does the lens form?

A

noo0ope

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13
Q

What transcription factor is responsible for making head ectoderm competent

A

pax6

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14
Q

Autosomal dominant mutations in pax6 cause what disease with what symptoms in humans?

A

aniridia

affects the iris, intraocular P, lens, cornea, optic nerve

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15
Q

define these terms: juxtacrine, paracrine

A

juxtacrine - contact btwn inducing and responding cells

paracrine - diffusion of inducers

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16
Q

What are morphogens ?

A

paracrine signaling molecules that cause concentration dependent effects

17
Q

How does TGF signal in the cell?

A

binds to receptor
signal is translocated to cytoplasm via smad proteins
phosphorylation turns smad on
gene transcription is altered

18
Q

What is the pathway for SHH?

A

SHH binds patched

  • inhibits smoothened
  • turns on Gli factors which turn on gene expression
19
Q

In the neural tube, describe where BMP, WNT, SHH are found?

A

BMP, WNT - dorsally - roof plate

SHH - ventrally - floor plate

20
Q

What is the term for normal left right orientation?

A

situs solitus

21
Q

What is the term for mirror left right reversal of all organs?

A

situs inversus

22
Q

What is the term for disturbance of the left right axis in only a subset of organs?

A

situs ambiguus or heterotaxy

23
Q

What are some examples of heterotaxy?

A

congenital heart defects
asplenia - right isomerism
polysplenia - left isomerism
malrotation of the intestine - volvulus

24
Q

What is kartageners triad?

A

bronchiectasis
male infertility
50% with situs invertus

25
Q

What is the ciliated organ of asymmetry?

A

the node

26
Q

Where is nodal expressed in vertebrates?

A

on the left side of the lateral plate mesoderm

27
Q

Describe the three effects of nodal

A

turns on:
nodal
Pitx2 - TF expressed on left side of heart, stomach, brain
Lefty - antagonist, keeps expression in check