Exam 3 Flashcards
Divisions of the animals (metazoans)…
- metazoans are organisms that go through the process of gastrulation
- diploplast are animals that have two germ layers, triploblasts have three
- tripoblasts can be protostomes (mouth first) or deuterostomes (anus first)
- protostomes can be lopho trocho zoan
- and choanozoans
Which of these summarizes the correct order of gene expression during early
development in Drosophila?
- maternal genes, to gap genes,to pair rule ,to segment polarity to homeotic genes
The spatial distribution of homeotic genes is…
- controlled by gap and pair rule genes
- important for the expression of body parts and their specific location
The genetic identity of each segment in drosophila is stabilized by the action of
- segment polarity genes
- homeotic genes
Which of the following genes are gap genes?
- giant
- knirps
- kruppel
- hunchback
- huckebein
- buttonhead
- tailess
- empty spiracles
- orthodenticle
Which cell lineage gives rise to …. cells in C. Elegans?
invariant cell lineage = each cell gives rise to the same number and type
- D lineage = muscle
- P4 lineage = germ line
- C lineage = Muscle hypodermis neurons
- E lineage = intestine
- MS lineage = muscle pharynx neurons somatic gonad
- AB lineage = hypodermis neurons pharynx
- P lineage = stem cells which form founder cells and other stem cells to form more founder cells
The Drosophila embryo cells that will produce gametes…
- During the ninth division cycle, five nuclei reach the surface of the posterior pole of the embryo
- nuclei become enclosed by cell membranes and generate the pole cells that give rise to the gametes of the adult
Addition of Bicoid mRNA to the early Drosophila embryo …
results in embryos where heads will form where bicoid is added
Which of the following is true in Drosophila?
During gastrulation the splitting of a sheet of cells into two relatively parallel
sheets is termed
Delamination
The thoracic segments in Drosophila …
prothorax (T1), mesothorax (T2) and metathorax (T3) from anterior to posterior
The protein Dorsal activates …
- activates genes that generate the ventrum
- it is a morphogen that ventralizes the region in which it is present
After fertilization occurs the ZP2 is
-clipped by the protease ovastacin to prevent the egg to bind sperm
Studies of Gurken-torpedo signaling demonstrate that
- gurken is required to be expressed in the germline
- torpedo is required in the follicle cell layer.
-The localization of Gurken protein expression to this corner of the oocyte, which it is secreted and from which it activates Torpedo in the overlying follicle cells, defines the dorsal side of the follicular epithelium
During oogenesis Bicoid mRNA localizes
dyenin moves toward the anterior part of the egg (Oskar moves toward the posterior)
Which of these is a homeotic gene?
- antennapedia
- bithorax
- engrailed
- distal-less
The differential anterior-posterior protein levels of the maternal morphogens in
drosophila is controlled by…
bicoid and nanos
Drosophila can generate a pair of wings in the T3 segment as the result of
- antennapedia
- deleting the ultrabithorax gene resulting in the transformation of the 3rd thoracic segment into another 2nd segment
During the early stages of Drosophila growth, nuclear replication and division
result in the formation of syncytia, True or False
True
After fertilization, Juno is
- is released from the plasma membrane to remove the docking site
- binds sperm between zp and oocyte to prevent it from seeing any Juno protein that may still reside in the oocyte membrane
The Drosophila gene engrailed is expressed in cells that
- will express hedgehog
- have high levels of even-skipped, fushi tarazu and paired
- have low levels of odd-skipped, runt or sloppy-paired
The acrosome reaction in mammals happens… to…: when…:during…
- to make sperm viable for fertilization
- when capacitation of the sperm happens
- during translocation in the oviduct
Nanos has the ability to….prevent…:provide…:bind…
- prevent/inhibit hunchback translation
- provide AP axis
- bind to cytoskeleton through 3’UTR in association with askar, valois, vasa, staufen and Tudor
Axis orientation in Drosophila’s egg..
-specified during oogenesis.
-The gradients of Bicoid and nanos provide the a/p axis. Anchored mRNA creates the protein gradients.
Gurken Torpedo signaling…Gurken is…and Torpedo is…
- gurken is active in the oocyte
- torpedo is active in the follicle
The polar lobe determinants in snail…
- are transferred to the D blastomere
- are responsible to heart and intestinal formation
The segment polarity gene Wingless is…: defines…
- is transcribed in the absence of even-skipped or fushi tarazu or paired
- defines cell specification by gradients (wingless found more towards the posterior)
Which of the following variables play roles in guiding the mammalian sperm to
the egg ( 4 variables)
- rheotaxis (sperm move against direction of flow of liquid from the oviduct)
- thermotaxis (sperm moves towards higher temperatures)
- chemotaxis (involvement of progesterone which binds to calcium ion channels in sperm tail)
- uterine muscle contractions
What happens after Removal of D macromere in Ilyanassa?
- there is incomplete larva that lack hearts, intestines, velum, shell gland, eyes, foot
The Anterior-posterior axis in C. Elegans
- is determined by the position of the sperm pronucleus
Which of the following molecules have a role in controlling dorso ventral axis in
drosophila?
- Delta
Which of these mutants would you expect to have a …..phenotype? the…:egg…:skn-1…:eff-1…:mutations…
- The direction of cleavage is determined by the genotype of the snail’s mother. i.e. a dd mother (left-coiling) will have left-coiling offspring even if they possess the dominant, D, allele
- Egg-laying defective (PAR) mutants: In these mutants, embryos that were not released instead hatched inside their mothers, and devoured their mothers as they fed, resulting eventually in bags of young worms filling their mothers’ cuticles.
- Skn-1 mutants: lack of pharyngeal mesoderm and endodermal derivatives
- Eff-1 mutants: cause inhibition of elongation and result in short and dumpy animals
- Mutations of kruppel, hunch back, and Knirps affects the entire segmented region of drosophila
Segment polarity is defined… by…:each…
- by pair rule genes
- each row of nuclei within a parasegment has its own array of pair rule genes: this pattern defines the expression of segment polarity genes
Gap genes play a role in …
-define broad territories of the embryo, gap genes enable the expression of the pair-rule genes, each of which divides the embryo into regions about two segments wide
What establishes gap genes
Maternal genes
What activates the gap genes
Caudal genes
The patter of expression of pair-rule genes
- are expressed with a stripped pattern
The main difference between mitosis during cleavage and mid-blastula
transition is (two answers)
- The slowdown of nuclear division, cellularization and increase in new RNA transcription is referred to as the mid-blastula transition
- mitosis occurs every 10 minutes for 2 hours
Which of the following cleavage patterns takes place with sparse yolk?
- holoblastic cleavage
The cleavage orientation of snails…
- Orientation of the oblique-angled cleavage planes to the right or left is controlled by cytoplasmic factors in the oocyte i.e. maternal regulation
- results in sinistral or dextral patterns
What is the result of cleavage orientation
results in sinistral or dextral patterns
PAR proteins play a role…
- in establishing and maintaining cell polarity
- encoding protein kinases and cell signaling molecules
- in C. elegans, required for correct position and orientation of the mitotic spindles
Development of invertebrates…
- is indirect
mRNA can be detected via in-situ hybridization while proteins can be detected
via immuno-labeling
True or False
true
The Zona pellucida
-made up of three major glycoproteins: ZP1, ZP2, ZP3 while humans have an additional fourth, ZP4
- Binding of the sperm to the zona is relatively species-specific and may require multiple mechanisms to achieve this binding
- cluster lipids on sperm can bind to the zona pellucida
Homeotic /Hox genes
- Homeotic selector genes encode homeodomain proteins which interact with Hox and other homeotic genes.
Torso and Torsolike …Boundries…:Unsegmented…
- The boundaries of the acron and telson are defined by the product of the torso gene, which is activated at the tips of the embryo.
- The unsegmented anterior and posterior extremities are regulated by the activation of Torso protein at the anterior and posterior poles of the egg.
Polar lobe determinants
- are transferred to the D blastomere
- are responsible to heart and intestinal formation
Formin
binds to actin helping to align the cytoskeleton and helps define plane of division of first blastomeres
The anterior posterior axis in c. Elegans
…. C.Elegans the interaction between MOM2 and its receptor MOM5
- P2 produces mom-2 which is received in the EMS cell by mom-5 which works like frizzled.
- MOM2 blocks POP1, POP1 blocks endodermal fate, POP1 KO all EMS become E.
The gradient of Nanos and Bicoid is…
- bicoid is higher at the head, lower at jaw, lowest at the thorax
- bicoid at anterior, nanos at posterios
Wingless and Hedgehog…
- defined by gradients
- pigmented spike
- smooth epidermal cuticle
- thick hairs
- fine hairs
Looking at the pattern of expression of Dorsal in this figure identify which
mutant is..
- specific promoter regions of the even-skipped gene control specific transcription bands in the embryo.
- in giant mutant the posterior border of stripe 5 is missing
The ABa and ABp cells in C. Elegans…
- ABa gives rise to neurons, hypodermis and anterior pharynx cells while ABp only gives rise to neurons and hypodermal cells.
- ABa and ABp are equivalent cells whose fates are determined by their positions in the embryo and interaction with the P2 cell
- Only ABp interacts with the P2 cell. If the P2 cell is killed at the early 4-cell stage, the ABp cell does not generate its normal complement of cells
Which of the following genes plays a role in controlling the P lineage in C.
Elegans?
- pal-1
- pie-1
Polar lobe and D macromeres
- determinants are transferred to the D blastomere
- are responsible to heart and intestinal formation
- · When the D (including 1D and 2D) blastomere is removed, you get an incomplete larva lacking a heart, intestine, velum, shell gland, eyes and foot. This is the same as when you remove the polar lobe.
- The D quadrant macromeres are involved in inducing other cells to achieve these fates
- Removal of 3D blastomere results in normal larvae with no heart or intestine. This is all contained in the 4d blastomere
At the time of sperm entry, the mammalian egg is
- in the second meiotic metaphase