Midterm 1- Excludes Lecture 1,3,5,13

Question 1

Compartment

Answer 1

boundary restricting movement of cells

Question 2

Gap gene

Answer 2

a type of gene involved in the development of the segmented embryos of some arthropods. Gap genes are defined by the effect of a mutation in that gene, which causes the loss of contiguous body segments, resembling a gap in the normal body plan

Question 3

PAL-1

Answer 3

caudal-like transcription factor specifying C and D fates

Question 4

Holometabolous Development

Answer 4

a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult)

Question 5

Role of B-catenin in sea urchin development

Answer 5

β-catenin and Otx activate expression of Pmar1 in micromeres
Pmar1 represses HesC, a repressor of micromere fate. Without micromeres there is no vegetal fate

Question 6

Hox genes

Answer 6

!Specify parasegment! identity through the control of expression domains which work together to give rise to the unique parasegments. It does this through the production of homeobox transcription factors

Question 7

Cell-autonomously specification

Answer 7

Cell fate develops through the localization of Determinants being asymmetrically distributed in the dividing cell

Question 8

Methods of Cell fate specification

Answer 8

1)Autonomously
2)Cell-cell interactions
3)Cell-cell interactions through use of morphogens

Question 9

SKN-1

Answer 9

Disables PAL-1 in the EMS cells, transcription factor specifying EMS fate

Question 10

APX-1/GLP-1

Answer 10

Homologous to Delta/Notch pathway and signals for ABp cell fate

Question 11

Relation between Bicoid, Caudaul, Nanos, and hunchback

Answer 11

Nanos prevents translation of hunchback mRNA in the posterior of the embryo and Biccoid prevents the translation of Caudal in the anterior and activates
zygotic hunchback
expression

Question 12

Relationship between Sog, Dpp, and Tld in forming the Dorsal/ Ventral axis

Answer 12

Sog-Sog binds to Dpp and inactivates it

Dpp- specifies amnioserosa and dorsal ectoderm and only forms when dorsal protein is not present

Tld-cleaves Sog, leading to a peak of Dpp activity in the dorsal most region

Question 13

Nurse cell

Answer 13

produce (among other things) mRNAs for morphogens for a-p patterning of the embryo. These mRNAs are transported and localized within the oocyte

Question 14

Three levels of description and Understanding

Answer 14

1)Macroscopic, Descriptive-Focuses on describing the phenomenon instead of explaining it
2)Cellular, “Conceptual”-Describes the steps involved in triggering a phenomenon
3)Molecular- Describes the exact chemicals and genes necessary for an event to occur

Question 15

Determination

Answer 15

Implies a stable change in the internal state of a cell that cannot be altered usually due to gene expressions

Question 16

Special properties of C.elegans

Answer 16

• Soil nemotodes composed of 959 cells
• Invarient development

Question 17

Draw the Bicoid and Nanos effect of Hunchback

Answer 17

Orginally maternal Hunchback is farily evenly spread between the Anterior and posterior but interaction with bicoid greatly increases zygotic hunchback in the anterior with the interaction of nanos disabling zygotic hunchback

Question 18

Neuroblasts in Drosophila

Answer 18

The nervous system starts to form,
when neuroblasts delaminate from the
ventral ectoderm.

Question 19

Draw the fate map and appropriate proteins involved in the first 8 cells of C.elegans

Answer 19

Question 20

Draw the founder cell cleavage pathway with the end tissues formed

Answer 20

Question 21

Morphogen

Answer 21

a substance involved in pattern formation that forms a gradient and elicits at least two different responses at different thresholds (at the same time)

Question 22

Nanos localization

Answer 22

Localized to the Posterior Axis

Question 23

Experiment that corresponds to the three levels of understanding

Answer 23

1)Macroscopic-Observations
2)Cellular-graft or transplant experiment
3)Molecular- gene expression experiments

Question 24

How is Kruppel regulated by Hunchback

Answer 24

Kruppel is only activated in a specified area where hunchback is in high enough concentration to activate the gene but not high enough concentration to deactivate the gene.

Question 25

Dorsal/Ventral Axis

Answer 25

Top and Bottom axis

Question 26

How is bicoid spread throughout the embryo?

Answer 26

bicoid mRNA is localized to the anterior, but Bicoid protein can diffuse freely through the syncytium and forms a gradient

Question 27

How are EVE strips determined?

Answer 27

generalized activation by bcd and ubiquitous transcription factors combined with localized repression by gap genes. Each of the eight stripe borders of these four stripes is shown to be under the control of a particular gap gene expression domain.

Question 28

Imaginal Disks

Answer 28

give rise to certain adult structures (wing, leg, eye). They are patterned during embryogenesis

Question 29

Proteins involved in making the Dorsal Protein

Answer 29

**Pipe**- begins the pathway by binding to an unknown subtrate **Spatzle**-Activates the Toll Receptors **Toll**-Triggers the degredation of Cactus **Cactus**-Binds to Dorsal and prevents it from entering the Nucleus and altering gene expression

Question 30

Gastrulation

Answer 30

During gastrulation future endodermal and mesodermal cells move to the inside of the embryo to form the inner cavities of the body.

Question 31

Bicoid localization

Answer 31

Localized to the anterior axis

Question 32

Regulative Development

Answer 32

embryos using external signals have the potential to replace missing cells

Question 33

Bithorax Complex Genes

Answer 33

UBX, abd-A, Abd-B

Question 34

Lithium treatment of sea urchins

Answer 34

Li treatment of sea urchin embryos causes vegetalisation. This is because Li is known to block the GSK-3 kinase, which negatively regulates the Wnt/Wg pathway by mediating degradation of the effector β-catenin

Question 35

Anterior/Posterior Axis

Answer 35

Front and Back axis

Question 36

Germ Layers and their organs formed

Answer 36

1)Mesoderm-Skeleton, Muscles,kidney,heart, blood 2)Endoderm-Gut,Liver,lungs 3)Ectoderm-Skin, Nervous System

Question 37

Dorsal Protein

Answer 37

Morphogen which helps define the ventral axis. At high concentrations it activates the twist genes and at low concentrations it activates the dpp gene

Question 38

Caudal protein

Answer 38

responsible for the formation of abdominal structures

Question 39

Homeobox transcription factors

Answer 39

Transcription factors recognizing specific DNA sequences and regulate target genes and are coded for by HOX genes

Question 40

What happens when wingless is lost?

Answer 40

leads to a loss of genes normally expressed in the posterior part of the segment. The cells adopt an anterior fate and produce denticles

Question 41

Parasegment

Answer 41

mark the position of boundaries that separate every segment of the Drosophila embryo into anterior and posterior compartments. Each segment is formed through pair-rule and gap gene expression

Question 42

Vegetal Pole

Answer 42

Half of the sea urchin blastomere which goes on to form the gut and skeletal elements

Question 43

Antennapedia complex

Answer 43

specifies PS 1-4

Question 44

Mosaic Development

Answer 44

if development was exclusively controlled by cytoplasmic determinants, the fate of every cell would depend uniquely on its lineage, while its position in the embryo would be totally irrelevant.  Thus, in "mosaic embryo" (which is an abstraction) the fate of the cell is governed entirely by its intrinsic characteristics, i.e. cytoplasmic determinants it inherits at cell division. If the cells are removed from the embryo they should, in principle, develop according to their intrinsic instructions and differentiate into the appropriate part of the embryo even if the rest of the embryo is not there. 

Question 45

Label the Following diagram

Answer 45

A)Nurse cell B)Oocyte C)Posterior follicle cell D)Nucleus E)Follicle cell F)Anterior Follicle cell G)Stalk

Question 46

Sea urchin blastula fate map

Answer 46

Question 47

Bithorax complex

Answer 47

specifies PS 5-14

Question 48

Gastrulation in drosophilla

Answer 48

mesoderm invaginates on the ventral side first forming a furrow and then an internalized tube.

Question 49

POP-1

Answer 49

Must be removed form the cell by MOM-2 pathway to allow transcription to occur in the E cell which derives from the EMS cell

Question 50

Cellularization

Answer 50

creates an individual cell membrane for each nucleus

Question 51

Pair Rule gene

Answer 51

promote the formation of alternate body segments in Drosophila,A parasegment corresponds to the posterior part of one segment and the anterior part of the following segment ex. eve

Question 52

Cell-cell signalling specification

Answer 52

a signal received by a cell changes its developmental potential from one fate to a different one either through diffusion of a or direct contact between cells to transmit the signal.

Question 53

Maternal effect genes for Drosophilla

Answer 53

Bicoid, Nanos, Pipe, and Gurken, and Torso

Question 54

Relationship between the P2, ABa, ABp, and EMS cell

Answer 54

P2 cell produces the signal form MOM-2 and GLP-1 which MOM-2 will help differentiate EMS into E and MS, while GLP-1 will differentiate ABp from ABa

Question 55

Describe the location of PAR genes in the embryo of a C.elegans

Answer 55

PAR-3,Par-6 and PKC-3 are localized into the Anterior where as PAR-2 and PAR-1 are localized into the posterior

Question 56

Draw the flow chart to go from maternal genes to specified cells

Answer 56

Question 57

Draw the Localization of Pipe, Nanos, Bicoid, and Torso-like in early embryo of drosophilla

Answer 57

Question 58

Axis formation in sea urchins

Answer 58

Vegetal- Animal is determined during oogenesis and appears to be related to the site of attachment in the ovary (Equivalent to the anterior and posterior in other animals) Oral-Aboral-first molecular differences appears around the 60 cell stage (equivalent to the dorsal ventral axis)

Question 59

Example of a maternal gene, gap gene, pair rule gene, segment identity gene, and segment polarity gene

Answer 59

Maternal gene:Biccoid Gap gene: Kruppel Pair rule gene: Eve Segment identity gene:UBX, Abd-a,ABd-b Segment Polarity gene:Wingless, HH

Question 60

MEX-5

Answer 60

Localized in the anterior by PAR-1 and Responsible for degrading PIE-1 in the AB cell

Question 61

Wingless path way

Answer 61

1)Hh interacts with wingless to activate it’s expression 2)wingless binds to frizzled 3)Frizzled binds to axin and GSK-3 complex which has the proteosome that degrades B-cantenin 4)B-cantenin is not degraded and can move to the nucleus to activate genes

Question 62

How is the Ventral axis determined in Drosophilla?

Answer 62

1)Gurken signalling blocks the synthesis of Pipe on the dorsal side 2)Pipe binds to an unknown substrate triggering a cascade which leads to Spatzle binding Toll. Toll degrades the protein Cactus allowing for Dorsal to be freed and enter the nucleus of the cell. This creates a gradient along the cell. High concentrations leads to the development of the **Ventral** side. 3) A number of genes are activated or repressed by different concentrations of Dorsal protein (transcription factor) leading to a series of distinct fates along the dorso-ventral axis.

Question 63

Gurken

Answer 63

Prevents Synthesis of pipe of the dorsal side. Signal which causes the dorsalization of follicle cells

Question 64

Draw the distribution for Bicoid,Nanos, Hunchback and Caudal protein gradient in the embryo

Answer 64

Question 65

Favoured Model organisms and why

Answer 65

1)Chicken- Large embryo, easily accessible 2)Sea Urchins/ Amphibians- Easy to manipulate, large quantity, easy to observe 3)Drosophilla/ Mouse-Small, easy to culture, short generation times, developed genetic tools

Question 66

Role of Nanos in Anterior/Posterior Axis formation

Answer 66

Nanos prevents the translation of hunchback mRNA in the posterior

Question 67

Syncytium

Answer 67

Refers to a single cell with multiple nuclei. A syncytium provides the rapid communication and transfer of information to allow cells to function as a coordinated unit

Question 68

Fate

Answer 68

describes what a cell (group) will develop into

Question 69

Par and the first division of a C.elegans embryo

Answer 69

PIE-1 moves into the P1 cell right before cell fertilization. After the first division some PIE-1 remains in the AB cell but is degraded - Occurs due to phosphorylation of MEX-5 by PAR-1 in the posterior end allowing it to travel to the anterior end. There it is dephosphrylated and become trapped in the anterior. MEX-5 Degrades PIE-1 - A similar phosphylation/deposphoryation event occurs to trap PIE-1 in the posterior

Question 70

Specification

Answer 70

implies a change in the internal state of a cell (group) leading to differentiation into their normal fate, when isolated. Cells can still respond to outside influence and potentially change their fate.

Question 71

Draw the Distribution of bicoid,nanos,caudal and hauncback mRNA in the Oocyte

Answer 71

Question 72

How are the A-P and D-V axis set up in C.elegans

Answer 72

- a-p axis is determined by sperm entry. Entry position becomes the posterior cell - d-v axis is determined by the tilting of cleavage plane of the AB blastomere due to oval egg shape

Question 73

Isolation experiment

Answer 73

Removal of a cell from it’s original location of the blastula to observe weather it will develop normally when separated from the embryo. If develops normally this can tell us that the cell fate is either Specified or Determined

Question 74

Maternal effect Genes

Answer 74

those genes whose products, RNA or protein, are produced or deposited in the oocyte or are present in the fertilized egg or embryo before expression of zygotic genes is initiated.

Question 75

Blastomere experiments in sea urchins

Answer 75

Separation experiment- allows for the vegetal and animal to develop into two separate incomplete halves Recombination experiment- by adding micromeres to the animal half the embryo can fully form Recombination experiment- by adding micromeres to the side of a blastomere leads to the development of a secondary gut

Question 76

How is the Dorsal axis formed

Answer 76

Dpp protein is expressed when Dorsal is not present in the cell. Sog protein prevents it from spreading too far from inactivation of Dpp. Tld cleaves Sog in the dorsal most region leading to a clean line of Dpp in the upper regions.

Question 77

Hemimetabolous Development

Answer 77

Immature forms of these insects are called nymphs and these gradually increase in size and change form

Question 78

Engrailed function

Answer 78

defines a compartment by establishing a cell-lineage boundary effectively confining cells to one particular parasegment.

Question 79

Determinants

Answer 79

Cytoplasmic factor (e.g. a protein or RNA) in the egg and in embryonic cells that can be asymmetrically distributed at cell division and so influence how the daughter cells develop.”

Question 80

Ventralized Embryo

Answer 80

Embryo forms denticle belts on the dorsal and ventral side where normally the would only form on the ventral side

Question 81

PAR proteins

Answer 81

Act as adapters and kinases in the developing C.elegan leading to the uneven cleavage of cells. proteins become asymmetrically localized before the first cleavage

Question 82

Understanding gene names and their meanings

Answer 82

*dorsal* (lower case, italic): gene name Dorsal (Capitalized, regular): protein name dorsal (lower case, regular): plain English Ex. *dorsal* codes for the Transcription Factor Dorsal

Question 83

Competence

Answer 83

The ability for a cell to receive and act upon a signal produced by another cell.

Question 84

Long germ vs Short germ insects

Answer 84

Long germ-late cellularisation simultaneous formation of all segments Short germ-early cellularisation sequential formation of abdominal segments but Expression of gap and pair-rule genes in short-germ and long germ insects is similar

Question 85

SYS-1

Answer 85

Binds to POP-1 in the E cell to activate transcription of genes required to form the gut

Question 86

How is segment polarity obtained in Drosophilla

Answer 86

In between parasegments there are zones that lack denticles. The anterior will contain denticles but the posterior will not. A feedback loop involving Wg and Hh signalling establishes the parasegment border

Question 87

Notch Signalling pathway

Answer 87

The receptor (Notch) is cleaved upon ligand binding to Delta.The intracellular domain moves to the nucleus, where it acts as a transcription factor

Question 88

MOM-2/MOM-5

Answer 88

Homologous to Wingless/Frizzled. MOM-2 is produced by the P2 cell and activates the MOM-5 receptor to differentiate EMS into E and MS

Question 89

Pipe

Answer 89

Signal on the ventral side of the drosophilla embryo

Question 90

Oogenesis

Answer 90

the process by which the female gametes, or ova, are created.

Question 91

PIE-1

Answer 91

Disables PAL-1 and SKN-1 in the P2 cell line. Acts as a general transcriptional repressor specifying germ cell fate

Question 92

Role of Bicoid in Anterior/posterior axis formation

Answer 92

1)Anterior, the mRNA is localized to the posterior and diffuses using a syncytium. Forms the Acron, Head, and Thorax 2) Bicoid prevents the translation of caudaul mRNA in the anterior letting it form a gradient along the anterior-posterior axis 3) Biscoid also acts as a transcription factor for hunchback

Question 93

Animal Pole

Answer 93

Half of the sea urchin blastomere which Form the ectoderm

Question 94

Cell-Cell Interactions using a Morphogen specification

Answer 94

allows the co-ordinated specification of several different cell fates simultaneously through a Morphogen gradient. Different concentrations of Morphogen induces multiple cell fates

Question 95

Transplant experiment

Answer 95

Removal of cell from it’s original position on a blastula and transplanting it onto a different segment of a separate embryo and recording what occurs. If the cell develops based on it’s original position on the embryo then it is Determined, if it develops into a cell type that matches the transplant location it is Specified.