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2 Bisc 333- Developmental Biology > Final time Baby (should we kill ourselves!?!!) > Flashcards

Final time Baby (should we kill ourselves!?!!) Flashcards

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1
Q

inner membrane of the egg which is used to protect the developing fetus

A

Amnion

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2
Q

Function of A, B, and C genes in flower development

A
  • A function- Whorl 1, sepals
  • A+B function-Whorl 2 petals
  • B+C function- Whorl 3 Stamen
  • C function- Whorl 4 Carpel
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3
Q

Steps in neurlation in a chick

A

1)notochord forms
2)somites form
3) neural folds form and close to form the neural tube
4)gut forms
5) the anterior end is ahead in development

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4
Q

Neural Crest Cells

A

Cells formed adjacent to the neural plate which will migrate and differentiate into many different cell types at target locations. Required for formation of the head

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5
Q

Gastrulation in the zebrafish

A

1)Epiboly- animal pole cells spread over and around the vegetal axis, involves intercalcating of various cell layers

2)Involution- folding of the blastoderm inward of the embryo to form the gut

3)Convergence and extension- the cell layer elongates and converges along the dorsal layer to produce the fish shape

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6
Q

Draw the interaction between MACHO and FGF in ascidians to determine cell fate

A
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7
Q

Dickkopf

A

WNT inhibitor needed for head development

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8
Q

VegT (mesodermal development)

A

Signals for endodermal development and induces Nodal

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9
Q

encodes a signal of the TGF-β family playing a role in mesoderm induction

A

Vg-1

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10
Q

Protein that is transcribed in plants to produce FT protein which trigger flowers. In short cycles its peak production is at night where it is degraded and in long cycles it is able to accumulate in the budding flower

A

CO

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11
Q

Spemann organizer transplant experiment results

A

Transplant of Spemann organizer (early)- duplication of the embryo forming mesoderm and ectoderm

Transplant of the Spemann Organizer (late)- induction of posterior structures only
Meaning: Spemann organizer changes position and function through development

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12
Q

Consists of ectoderm and a mesenchymal core forming the skeletal structures

A

Limb bud

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13
Q

Ectodermin

A

(mesoderm development) Produced in the ectoderm and inhibits nodal

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14
Q

Signal produced by endoderm that leads to mesenchyme and notochord specification (asicdians)

A

FGF

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15
Q

Explain sex determination in C.elegans

A
  • C.elegans use XX=hemaphrodite and XO=male
    • Uses cell to cell interactions and a counting mechanism to turn on or off the Xol-1 gene
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16
Q

Vagal and sacral neural crest

A

parasympathetic ganglia of the gut

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17
Q

What happens when A, B, and C genes are lost in a flower?

A

Loss of A- Loss of sepals and petals, duplication of stamen and carpels

Loss of B -Loss of petals and stamen, duplication of sepals and carpel

Loss of C- Loss of stamen and carpel, duplication of petals and sepals

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18
Q

cavity formed during involution which will become the gut

A

archteron

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19
Q

Two signal model

A

Two opposing signals (FGF and retinoic acid) specify initial fates. Later cells in the middle, which are outside the range of both signals, form intermediate structures

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20
Q

How Limb position is determined

A

Hox genes Confine of specific transcription factors along the A-P body axis

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21
Q

Steps in drosophilla eye formation

A
  • Ato is uniformly expressed in the photo-receptor precursors by a hh signal
  • Lateral inhibition through Delta/Notch signalling ensures that only one cell in each group expresses Ato and becomes specified as R8 cell
  • Signals from R8 induce neighbouring cells to become R2 and R5
  • they signal to neighbouring cells to become R3 and R4.
  • R1 and R6 are induced on the other side and in combination with R8 induce R7
  • Cone cells are then specified
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22
Q

later developed axons that use the pioneer axons tracks to navigate the neuronal circuit

A

Follower axons

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23
Q

Signals required to develop endoderm and mesoderm

A

VegT- Develops endoderm

Nodal-Triggered by VegT and develops mesoderm by inhibiting Fox1 E

Ectodermin- Spawns in the ectoderm and degrades nodal pathway

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24
Q

acts as an attractive force for dorsal interneurons and is the homolgue to UNC-6 in vertebrates and forms a gradient out of the floor plate

A

Netrin-1

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25
Q

Germ cell differentiation in mammal eggs vs sperm

A
  • Mammals egg have primary oocytes that arrest development until sexual maturity and are stuck in metaphase 2
  • Mammal sperm- Primordial germ cells in males arrest in the G1 phase of a mitotic cell cycle in the embryo.Act like stem cells after signalling from cells in the testis
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26
Q

Human implantation of embryo

A
  • Trophoblast cells dig into uterine epithelium and froms a connection known as the body stalk
  • blood vessels grow into the body stalk
  • maternal blood vessels bath the fetal ones in blood
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27
Q

Cranial neural crest

A

form cartilage, bone, cranial neurons, glia and connective
tissue of the face; also bones of middle ear and jaws

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28
Q

Signals important in regionalization of the brain

A

Otx and GBX2- divide the brain into hind and forebrain and work as antagonists for one another.

ANR and MHB produce signals which pattern the regions adjacent to them

Notochord and floor plate determine D-V axis formation

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29
Q

a substance that can cause birth defects

A

Teratogen

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30
Q

Explain sex determination in Drosophilla

A
  • Drosophilla use an XY system but the mechanism behind sex is a binary switch turned on and off by the count of autosomal to X chromosome ratio
    • X chromosome makes an activator for the switch and the autsomal chromosomes make a repressor
    • Due to the ratio of X to autosomal genes in females the Sxl gene is on where as in males it is off
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31
Q

Nieuwkoop center formation and signal

A
  • Forms when the wnt signal is completed and maternal VegT is present
  • Signals for Spemann organizer and for duplication of the axis
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32
Q

movement of ectodermal cells to the outer surface of the blastula

A

Epiboly

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33
Q

Scleretome signal for development

A

Signal for development is Shh which induces Pax-1 expression which triggers Scleretome development. Induced the floor plate of the neural tube and the notochord

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34
Q

Explain a technique which can prevent polyspermie

A
  • Coritcal granules fuse with the membrane and this in combination with the vitelline membrane prevent additional sperm entry
  • Sea urchins use membrane depolarization
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35
Q

code for the different vertebrate identities

A

hox genes

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36
Q

How is leg axis formed?

A

Again uses en and hh but Dpp is only on the dorsal side and wingless on the ventral side
- Distalless is expressed in the center between Hh, Wg, and dpp
- Wh/hh will work to activate DII and Hth
- DII and Hth activate Dac working together to create the proximal-distal axis

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37
Q

movement of cells around the inner surface of the blastula

A

Involution

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38
Q

Reelin

A

Reeling gene codes for a protein that binds to ApoER2 and VLDLR which are receptors found on migrating neurons. It is either a stop signal for migration or an attactive cue to bring neurons to the correct locations

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39
Q

cell layer above the yolk in chickens that will form extra embryonic tissue providing access to the yolk.

A

Hypoblast

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40
Q

Explain a tactic for attracting sperm to egg

A

sea urchins- release peptides which attract sperm form the same species

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41
Q

Three different neuron types and their location of origin

A

Commisial neurons- Dorsal portion of neural tube

Motor neurons/interneurons- form from ventral portion of neural tube

Sensory neurons- neural crest cells

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42
Q

gene required for development of eyes, directly regulates opsin expression in
photoreceptors

A

Pax-6/eyeless

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43
Q

loop located within the primitive streak, regression of this node towards the posterior signify the end of gastrulation and begging of neuraltion and somite formation

A

Hensons node

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44
Q

Nodal

A

Triggered by VegT and triggers development of mesoderm as well as inhibition of Fox1 E

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45
Q

Pioneer Axons

A

Fist axons sent out in the growth pattern, using guidance clues for the environment the figure out the path for all remaining axons to take

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46
Q

Explain sex determination in mamals

A

In mammals we use the XY system where the presence of the Y chromosome has a transcription factor SRY which leads to the male phenotype

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47
Q

How to create a cDNA library

A

1)isolate mRNA from source material
2) reverse transcribe into cDNA
3)clone into expression vectors
4)transform bacteria with vectors (note: each cell
will have one plasmid with one cDNA

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48
Q

top layer of cells above the yolk that will develop into the embryo

A

Epiblast

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49
Q

Epiboly

A

Endoderm and mesoderm invaginates, epidermal cells extend to cover the entire embryo

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50
Q

A-P axis of retinal neuronal growth

A

EphA and ephrins form gradients (A-P) in the retina and tectum respectively. ephrin and EphA together cause growth cone collapse

High EphA neurons stop growing in areas of low ephrins

Low EphA neurons collapse at higher levels of ephrins

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51
Q

Robo Mutant

A

frequent crossing of neuron tracks , Robo is the receptor for Slit.

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52
Q

signals for ventral mesoderm (blood, kidney)

A

BMP

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53
Q

Portion of the paraxial mesoderm that forms the dermomyotome

A

all segmenets that are not the ventral lateral form dermomyotome- splitting later into the dermotome and myotome, giving rise to dermis and trunk muscles respectively.

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54
Q

How does the growth cone move?

A

Filopodia are dynamic structures with an actin core. Positive guidance signals lead to stabilization of filopodia, negative signals lead to collapse.

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55
Q

form in contact with ventral neural tube or notochord

A

Cartilage

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56
Q

Slit Mutant

A

collapse of axon track- everything gets spaced close together, Slit is a repulsive guidance

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57
Q

Explain how mesoderm leads to development of neural plate axis

A

Mesoderm produces a gradient of WNT signalling molecules that lead to A-P diffrentiation. With high WNT concentrations leading to posterior structures and low WNT concentrations leading to anterior ones

Inhibition of WNT and BMP is required for head development! Ex. dickkopf

58
Q

How is the A-P axis determined for drosophilla wings

A
  • Wings parasegment boarders are coded for by the feedback loop between Wg, Hh, and En
  • Posterior portion of the wing creates engrailed with hh which activates dpp expression
  • Dpp then acts like a morphogen activating Splat and Omb which in combination with dpp and engrailed leads to 6 different wing compartments
59
Q

Pole plasm

A

Cytoplasm containing organization proteins,germ cell differentiation proteins,and somatic differentiation blocking proteins all which are necessary for development of pole cells

60
Q

portion of the brain responsible for motor coordination, motor learning, balance and posture control, timing and rhythm of movements, ‘error correction’ of movement

A

Cerebellum

61
Q

Development of chick body along A-P axis due to movement of Hensons node

A
62
Q

Portion of the paraxial mesoderm that forms the scleretome

A

The vental-medial quadrant of each somite forms the sclerotome eventually giving rise to vertebrae and ribs. triggered by proximity with the notochord.

63
Q

Describe the three methods for dosage compensation in animals

A
  • Mammals- inactivate on of the X chromosomes
  • Drosophilla- increase transcription of single X chromosome
  • C.Elegans- Decrease transcription of double X chromosomes
64
Q

Fox1 E

A

Inhibited by Nodal so that mesdoderm may develop

65
Q

Cytoplasm from the vegetal pole of the ascidians that acts as a cell fate determinant for muscle cells

A

yellow crescent’ cytoplasm

66
Q

form the muscles and dermis

A

dermomyotome

67
Q

Draw the phenotype for a regular,slit,robo, and comm mutant

A
68
Q

Neurlation in Mouse

A
  • Anterior of the node begins to grow and notochord forms
  • Neural folds appear and neurlation formerly begins
  • somite formation and organogensis begins
69
Q

Label the different developmental zones of the Xenopus

A

a)epidermis
b)nervous system
c)blood and kidney
d)Somites/ heart
e)Notochod
f)Endoderm

70
Q

Mouse gastrulation

A
  • Epiblast cells begin to move towards the primitive streak
  • Primitive streak spreads out anteriorly and laterally to form the mesoderm between the visceral endoderm and ectoderm
  • visceral ectoderm is replaced by definitive ectoderm
  • Primitive streak continues until it reaches the bottom of the cup shape and forms a node (analogous to hensons node in chicks) which will later develop into the notochord
71
Q

Cortical rotation and its effects

A
  • Sperm enters the embryo and animal half with yolk will rotate 30 degrees with respect to the centre and aligns opposite the sperm entry site
  • Inhibition of the rotation leads to a lack of dorsal structures, double rotation of the dorsalizing factors leads to conjoined creatures. LiCl leads to a double dorsalization
    After Doralizing factors have completed the rotation Wnt pathway is activated and dorsal structures can form
72
Q

Hox genes and limb formation

A
  • Hox 9/10- Pattern the humerus
  • Hox 10/11-Ulna/radius
  • Hox 12-wrist
  • Hox 13-hand
73
Q

Germ cell formation in C.elegans, Drosophilla, and Mice

A
  • In C.Elegans the C4 cell containing PIE-1 protein is what differentiates into the germ line
  • Drosophilla and Xenopus germ line comes from pole cells which form at the posterior end of the embryo and develop when in contact with the pole plasm
  • Mouse germ cells form in the epiblast post fertilization based on a signal from the extra-embryonic ectoderm
74
Q

c-hairy I

A

one of the genes used in somite boundary formation and A-P somite axis formation

75
Q

Label the different signals needed to form the endoderm and mesoderm

A

A) FOX1 E
B)Ectodermin
C) Nodals
D) VegT

76
Q

Describe Drosophilla Neuroblast division

A
  • Asymmetrical division of neuroblast forms the smaller ganglion mother cell and the larger neuroblast.
  • This pattern continues as each time the neuroblast divides another ganglion mother cell is produced. As it divides different transcription factors are active (Hb, Kr, Pdm, Cas) leading to differing cell fates
77
Q

Hollow ball of cells stage in the embryo

A

Blastula

78
Q

extracellular protein that can act as a repulsive or attractive agent for neuronal growth

A

Unc-6

79
Q

Dorsal ventral patterning of the neural tube

A

Shh- created on the floor part of neural tube and BMPs created from roof plate

Shh is what specifies neuronal identity through use of a moprhogenic gradient it controls the expression of class 1 and class 2 transcriptional factors

80
Q

mRNA found in ascidians that causes the expression of muscle cells.

A

macho-I

81
Q

Steps involved in biochemical purification

A

1)fractionate source material

2) test fractions

3) repeat until substance is purified

4)determine identity (protein or organic molecule)

This is the same in modern times but utalizes cDNA libraries

82
Q

Hensons node

A

special portion of the primitive streak in chickens that is involved in somite formation via its movement along the A-P axis

83
Q

Family of ligands then when bound to the receptor triggers dimerization and phosphorylation of Smads which activate differing target genes

A

TGF-B

84
Q

Cardiac neural crest

A

artery walls, part of the septum; also neurons, cartilage

85
Q

Trunk neural crest

A

sensory neurons of dorsal root ganglia, sympathetic
ganglia, adrenal medulla; also melanocytes

86
Q

Functions of the Spemann organizer

A

1)produces chordin and noggin to allow neural tissue development
2)initiates gastrulation
3)turns into the notochord

87
Q

Cleavage of the chick embryo

A
  1. Cleavage begins but is incomplete, this leaves a gap
  2. Gap (subgerminal space) expands
  3. Cells move around this cavity (not gastrulation) over the yolk layer
  4. Top layer will form the embryo (epiblast) and bottom layer will form the connection point for nutrient uptake from the egg(hypoblast)
88
Q

Implantation of embryo for mouse

A
  • Trophoblast cells attach to the uterine lining
  • Epiblast (top half) elongates and develops into a cup shape
  • Afterwards the primitive streak will form at the posterior end marking the beginning of gastrulation
89
Q

How is Mesoderm specified?

A
  • Mesoderm is formed when there are interactions between vegetal and animal caps
    • Vegetal cells cause animal cells to form mesoderm
    • Dorsal vegetal cells lead to muscle and notochord
    • Ventral vegetal cells lead to blood
90
Q

Explain how sperm is able to enter the egg

A

zona pellucida proteins are recognized by the sperm and trigger the ‘acrosomal reaction’ leading to release of enzymes which help to break down zona pellucida components

91
Q

each of the optical units that make up a compound eye, as of an insect

A

ommatidium

92
Q

Neurlation in the Xenopus

A
  • Neural grooves form above the Notochord, the side walls pinch upwards and form a peak along the neural groove
  • Neural folds are elevated and apical constriction occurs
  • Hinge points fold inwards and the neural crest forms a closed loop at the top with the neural tube in the centre
93
Q

Outer membrane of the egg which is used to perform gas diffusions

A

Chorion

94
Q

determines position of growing limb bud on the A-P axis, determines the digit identity of the limb using a morphogenetic gradient

A

Polarizing region

95
Q

Migration of germ cells in Mouse, mammals, and reptiles

A
  • Migrate from the posterior into the hind gut then finally to the gonadal precursor cells
  • Mouse-primordial germ cells (PGC) migrate to the posterior end of the embryo above the primitive streak
  • Mammal germ cells migrate through the hind gut into the genital ridge
  • Reptiles- send their germ cells from the head into the bloodstream
96
Q

Somite derivative that gives rise to the vertebrae and ribs

A

Scleretome

97
Q

Signal for abaxial muscle development

A

BMP4 signals from the lateral plate mesoderm

98
Q

Draw the different cell types of a xenopus based on germ layer specifications

A
99
Q

bind BMPs thereby preventing binding to their receptors, effectively blocking BMP signalling leading to neural development.

A

Noggin and Chordin

100
Q

convergence of cells in the development of the zebra fish embryo along the animal pole that produces the elongated fish like shape

A

convergent extension

101
Q

Formed when somites develop alone

A

Mesenchyme

102
Q

Comm mutants

A

no crossing occurs at all. Comm’s function is to prevent robo from reaching the growth cone.

103
Q

What does the red and green dots represent in this image and what does this signal cause?

A

Red: chordin/noggin being produced from the spemann organizer
Green: BMP-4
Chordin and noggin block BMP-4 allowing for neurnal tissue to form from the ectoderm

104
Q

induces limb buds

A

FGF-10

105
Q

Forms the Notochord

A

Cells that are part of the Spemann organizer at the beginning of
gastrulation enter the embryo during gastrulation and eventually
differentiate into notochord

106
Q

What becomes of the cells that develop in the Blastocyst

A

Internal cells→ embryo and amnion

trophoblast cells→placenta and chorion

107
Q

How is the D-V axis formed in drosophilla wings?

A

Wingless acts as a morphogen like dpp, required to form wings (d/v barrier)

108
Q

Gastrulation in mouse

A
  • Epiblast cells begin to move towards the primitive streak
  • Primitive streak spreads out anteriorly and laterally to form the mesoderm between the visceral endoderm and ectoderm
  • visceral ectoderm is replaced by definitive ectoderm
  • Primitive streak continues until it reaches the bottom of the cup shape and forms a node (analogous to hensons node in chicks) which will later develop into the notochord
109
Q

How are the layers of the neural tube created?

A
  • Neurons are born in the ventricular zone and move outward to along radial glia to reach the outer surface
  • Neurons crawl past each layer in succession as they move towards the outer surface
110
Q

Cas-9

A

Cas9 encodes a nuclease that cuts DNA at a precisely defined point complementary to the sequence of a short ‘guide RNA’ that is part of the enzyme

111
Q

out shoot of the axon’s body that utilize fillapodia to screen the environment and determine direction of growth

A

Growth cone

112
Q

cavity the forms in between the yolk and embryo during chick development

A

subgerminal space

113
Q

How is the A-P axis patterned for a limb

A

Morphogenetic gradient induced by the polarizing region

114
Q

triggers the transition into floral development when the environmental signals are correct

A

LFY

115
Q

Lithium and Cortical rotation duplications

A
  • LiCl mimics wnt signalling through blocking of B-catenin degrading machinery allowing the signal to be utilized in absence of signalling pathway
116
Q

Midbrain- hindbrain organizer

A

Organizer which divides the Otx/GBX regions into 4 distinct patterns

117
Q

Attractive and repulsive cues in Neuronal movement

A

Unc-6 and Unc-40= attraction

Unc-6, Unc-40, and Unc-5= repulsion of the neuron

Floor plate also acts as a guidance cue

118
Q

Moves into the flower bud apex to trigger flower development. activates
together with FD and LFY floral meristem identity genes like AP1.

A

FT

119
Q

portion of the brain responsible for motor coordination, motor learning, balance and posture control, timing and rhythm of movements, ‘error correction’ of movement

A

Cortex

120
Q

How is a limb specified as hind or forlimb

A
  • FGF10-will work with either
    • Tbx5- Forelimb
    • Tbx4-Hind limb
121
Q

form when with dorsal neural tube or ectoderm

A

Striated muscles

122
Q

BMP-4

A

Promotes epidermal development and blocks neuronal development

123
Q

3 steps involved in embryo development

A
  • Cleavage
  • Implantation
  • Gastrulation/ turning
124
Q

Function of Otx and GBX2

A

Otx- Signal the forebrain

GBX2-signals the hind brain

125
Q

point along which the ingression of a chick embryo occurs, cells will move into the subgerminal cavity during this step

A

Primitive streak

126
Q

Specialized cells which help guide the direction of axon development

A

Guideposts

127
Q

Describe the two driving mechanisms of somite formation

A

FGF gradient- forms in high concentration at the posterior towards low concentration in the anterior. Important in forming boarders between Somites

Clock mechanism- every 90 minutes during somite formation genes will be expressed that move anterior to posterior leading to boundaries in the somites

128
Q

Progress zone model

A

Identity of a portion of a limb is dependant on the amount of time spent in the progress zone

129
Q

Name the 4 different signal types a neuron can be given

A

1) Chemoattraction
2)Chemorepulsion
3)Contact attraction
4)Contact repulsion

130
Q

How is ectoderm and endoderm specified in a xenopus

A

In early embryo Animal cells form the epidermal cells where as vegetal cells form the endoderm

131
Q

Proximal-distal patterning of limbs two models

A

1)Progress zone model
2)Two signal model

132
Q

Forms the dermis

A

dermotome

133
Q

Placenta

A

supply fetus with nutrients and oxygen, remove metabolic waste products (including
CO2), produce hormones (gonadotropins, steroids), prevent immunological rejection of the fetus, provide antibodies to help prevent infections of the newborn

134
Q

Forms the trunk muscles

A

myotome

135
Q

Forms cerebellum that is smaller disorganized, and improperly layered

A

Reeler mutatant

136
Q

Signal for myotome development

A

Wnt signals from dorsal neural tube which activate the transcription factors MyoD, Myf-5

137
Q

Turning step in mouse

A
  • epiblast turns inside out so umbilical cord faces outer surface
  • Embryo can now be covered in aminion
138
Q

How is ectoderm diffrentiated into epidermis and neuronal tissues?

A

Inducing event for neuron development is gastrulation.
Dorsal ectoderm will form neural tissue, ventral ectoderm will form epidermis

BMP-4 -blocks neuron development

chordin/ noggin- produced by spemann organizer and blocks the effect of BMP-4 on the dorsal side

139
Q

point along which gastrulation begins opposite to the site of sperm entry on the oocyte

A

Blastopore

140
Q

Signals for proximal/distal patterning in developing limb bud, without limb development stops

A

apical ectodermal ridge

141
Q

How are neuroblasts formed in drosophilla?

A

Neuroblasts start as a cluster in the neuroectoderm and express genes like scute and achete

Delta/Notch signalling initially down regulate scute and achete genes

This leads to lateral inhibition of neighbouring cells as Delta/notch work to down regulate genes while scute and achete act as enhancers to this down regulation signal

142
Q

Early cleavage pattern in asicdians

A
  • First cleavage is along the D-V axis followed by A-P axis
  • Has an animal and vegetal half

2 Bisc 333- Developmental Biology (3 decks)

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