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94 Cards in this Set
- Front
- Back
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What is a process whereby cells become specialized and organized to carry out functions that enhance the survival of the organism (or species)?
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Biological development
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When does biological development take place?
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1. Embryonic and fetal development
2. Growth & maturation 3. Tissue maintenance & turnover 4. Tissue repair & regeneration 5. Aging |
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What is the ultimate controlling element of a cell's ability to make developmental decisions?
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The Genomic Repertoire of the organism
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What are the 3 keys that allow biological development to take place?
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1. Genomic Repertoire of the organism
2. Responding to signals in their environment 3. Decisions are made based upon a temporal and spatial framework. (depends upon previous decisions made by cell) |
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What is the process of differentiation of the primordial germ cell into egg and sperm?
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Gametogenesis
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What is the term for egg development?
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Oogenesis
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What is the term for sperm development?
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Spermatogenesis
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What is an example for aging?
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Osteoarthritis caused by fewer and smaller glycosoaminoglycan chains, which do not hold water in the cartilage as efficiently as younger people, so aging does play a role in biological development.
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How do cells make developmental decisions within a temporal and spatial framework?
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how a cell develops depends upon its stage of differentiation and the timing of signals applied.
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What is the mechanism of primordial germ cell formation?
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Signals from their environment tell them to become PGC.
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What are the specks at the vegetal pole of these frog eggs?
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Signaling proteins that were created and stored during oogenesis. Once fertilization takes place the signaling proteins trigger those cells to form primordial germ cells
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What is occuring in these C. elegans cells?
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At the 4 cell stage embryo 3 of the nuclei express Pes10 and the 4th cell does not. The 4th cell becomes a primordial germ cell.
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What are the two main events in gametogenesis?
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mitosis
meiosis |
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What is the function of mitosis?
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to expand the primordial pool
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What is the function of meiosis?
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reduces diploid genome to haploid genome
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What is A in the sea urchin egg?
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Sperm
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What is B in the sea urchin egg?
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Jelly Layer
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What is C in the sea urchin egg?
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Vitelline Envelope
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What is D in the sea urchin egg?
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Plasma Membrane
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What is E in the sea urchin egg?
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Cortical Granule
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What is F in the sea urchin egg?
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Mitochondrion
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What is G in the sea urchin egg?
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Nucleus
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What is the function of Cortical Granules?
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Specialized golgi structures that protect the egg against polyspermy
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What is a specialized golgi structure used by sperm to bind to and penetrate the egg coat?
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acrosomal vesicle
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What are the differences and similarities between sperm and eggs?
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See chart
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What is the centriole from the sperm used for?
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Organizing the mitotic spindle
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What is the yolk in the egg cell used for?
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Energy supply
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T/F
The unfertilized egg is totipotent |
True
(at least that was on his slide) |
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What is a chemotaxis factor that is released from the jelly layer of the sea urchin egg and what does it do?
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Resact is released into the seawater and the species specific sperm migrates toward the Resact soluble concentration gradient.
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What happens when Resact binds to receptors
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Sperm will turn towards the Ca++ concentration gradient and Increased metabolism causing the sperm to swim faster due to cGMP activating Ca++ channels.
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What are the different techniques that mammals have for recognizing sperm egg at a distance?
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1) Translocation - uterine contractions
2) Capacitation - sperm rxn to female repro secretions 3) Chemotaxis - factors from follicle cells |
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What recognition at a distance method for mammals involves transporting sperm by uterine contractions?
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Translocation
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What recognition at a distance method for mammals involves sperm interaction w/secretions in female reproductive tract that increases sperm metabolism and motility and is necessary for future sperm and egg binding?
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Capacitation
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What are two features of sperm capacitation in mammals?
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1) increase sperm motility and metabolism
2) Necessary for future sperm and egg binding |
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How is contact recognition in Sea Urchin facilitated?
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Facilitated by species specific carbohydrate receptors (3 ea) on the sperm plasma membrane.
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What does sperm recognition of the egg result in for sea urchin?
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Acrosomal reaction
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What are the two major components of the Acrosomal Reaction?
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1) Acrosomal Vesicle fuses w/plasma membrane causing release of digestive enzymes (controlled by increase in intracellular Ca++ concentration)
2) Acrosomal Process forms via actin monomer polymerization producing actin filament. (controlled by increase in intracellular pH) |
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What layer of the egg does bindin bind to oocyte receptors?
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Vitelline envelope
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Where is the acrosomal reaction initiated in the mouse?
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After sperm binds to the Zona Pellucida
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When does the acrosomal reaction occur in sea urchin?
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After the sperm contacts the jelly layer
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Which zona pellucida protein do sperm plasma receptors bind to for contact recognition and binding in mammals?
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Sperm plasma membrane receptors bind to ZP3
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What happens in the mammalian acrosomal reaction?
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The acrosomal and cell membrane fuse after binding to ZP3
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What happens during the acrosomal reaction in sea urchin?
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The acrosomal membrane and sperm plasma membrane fuse releasing digestive enzymes. Actin molecules assemble and extend the acrosomal process outward.
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What is the general goal in this figure?
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Cortical granule exocytosis leading to formation of the fertilization envelope and hyaline layer
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As the cortical granules are exocytosed they release proteases. What do these proteases do?
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Proteases cleave the proteins linking the vitaline envelope to the cell membrane
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As the cortical granules are exocytosed they release mucopolysaccharides. What do these mucopolysaccharides do?
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Mucopolysaccharides form an osmotic gradient causing water to enter and swell the space between the vitalline envelope and the plasma membrane.
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What is the fertilization envelope?
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The vitelline envelope hardened by other enzymes released by the cortical granules
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What initiates the cortical reaction?
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Influx of Ca++. (this comes from within the cell in both sea urchin and mammals, not from external sources)
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What is the initial signal for the IP3 DAG pathway to release Ca++ during fertilization?
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Phospholipase C enzymes (PLC) from the gamma family activate phospholipase.
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What are the early and late events in egg activation?
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Early Egg Activation - Increase in cell Metabolism (regulated by increased Ca++)
Late Egg Activation - Initiation of protein and DNA synthesis in preparation of first cleavage division. (regulated by increased intracellular pH caused by DAG activity) |
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Do fast blocks occur in sea urchins?
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Yes but NOT mammals
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What causes fast transient block to polyspermy?
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Membrane depolarization from an increase in Na+ concentration
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What creates the slow permanent block to polyspermy?
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The cortical reaction
1. Proteinases and glycosidases separate vitelline layer from plasma membrane 2. Mucopolysaccharides create osmotic gradient 3. Peroxidases crosslink macromolecules of the vitelline membrane 4. Hyalin protein coats outer surface of egg and used during early development |
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What is a series of cell divisions of the zygote that occur without cell growth or separation?
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Cleavage
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What are daughter cells generated from cleavage divisions?
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Blastomeres
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What is a solid ball of cells created from early cleavage divisions?
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Morula
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What is a hollow fluid-filled ball of cells formed as water flows osmotically towards the center of the morula?
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Blastula
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What are the proteins that prevent water seepage through the blastula walls?
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Tight junctions
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What is the cavity formed in the blastula that is important for future development of the organisms?
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Blastocoel
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What forms a contractile ring around a dividing cell?
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Microfilaments (actin)
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What pulls the chromosomes to their respective cell hemispheres during division?
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Microtubules
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What type of cleavage is displaced radial cleavage as in amphibians?
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Holoblastic cleavage (mesolecithal = moderate amount of yolk)
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What type of cleavage is superficial cleavage as in insects?
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Meroblastic cleavage (centrolecithal)
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What is the yolk content/distribution of sea urchin cleavage?
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Isolecithal (very little yolk)
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How many cleavages do the sea urchin blastomeres undergo before the size of the cells become dissimilair?
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Size identical through 3rd cleavage
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How many cleavages do the sea urchin blastomeres undergo before the identity of the cells change?
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Cell identity same through 2nd cleavage
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What is the cleavage pattern for sea urchin?
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Radial holoblastic
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What proteins must be bound for MPF to form and become an active protein kinase?
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Cyclin B & cdc 2
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What are the targets of MPF activity?
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1) Histones
2) Nuclear envelope lamin proteins 3) Regulatory subunit of cytoplasmic myosin |
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What is a series of movements of individual cells and sheets of cells that accomplishes at least 3 important developmental objectives?
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Gastrulation
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What are the 3 important objectives of gastrulation?
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1) Germ layers are established (ectoderm, mesoderm, endoderm)
2) Symmetry of organism is established (dorsal, ventral, lateral, etc.) 3. Gastrulation establishes new and unique cell interactions which influence future developmental events |
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What are the types of cell movements during gastrulation?
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Invagination
Involution Ingression Delamination Epiboly |
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What is the migration of individual cells into the embryo?
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Ingression
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What is the infolding of a sheet of cells into the embryo?
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Invagination
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During invagination of the vegetal plate what is secreted into the inner lamina that absorbs water, causing swelling?
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CSPG
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What do the large micromeres differentiate into?
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Skeletogenic cells
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What do the small micromeres differentiate into?
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Coelom
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What do the mesomeres give rise to?
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Aboral and Oral Ectoderm
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Why don't all of the mesomers become micromeres if they have the same potential?
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1) Autonomous Specification (mosaic development) i.e. micromeres
2) Conditional Specification 3) Syncitial Specification |
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What type of specification occurs when differential acquisition of certain cytoplasmic molecules are present in the egg and invariant cleavages produce the same lineages in each embryo of the species. (cells cannot change fate if a blastomere is lost)
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Autonomous Specification (mosaic development)
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What type of specification occurs due to interactions between cells and location is important. Variable cleavage produce no invariant fate assignments to cells/ (allows cells to acquire different functions)
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Conditional Specification (Regulative development)
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What type of specification occurs when body regions interact between cytoplasmic regions prior to cellularization of the blastoderm. variable cleavage produces no rigid cell fates for particular nuclei.
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Syncytial Specification
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What happens when the animal hemisphere alone developes?
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Complete animalization (Dauerblastula)
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What happens when animal hemisphere and micromeres only are allowed to form?
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Recognizable larva forms
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What happens when micromeres are transplanted onto the mesomeres?
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Secondary axis forms
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What is the pathway for Wnt Signalling?
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see figure
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What is the Wnt Pathway used for?
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Inhibiting beta-catenin thus preventing veg1 and veg2 from forming
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What happens in the presence of maternal nuclear beta-catenin?
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Skeletogenic differentiation genes activated by Tbr, Ets, & Dri via repressors
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During drosophila oogenesis oogonium goes through four cycles of mitotic cell divisions with incomplete cytokinese to form _____________.
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Cystocytes
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During drosophila oogenesis on of the 16 cystocytes will develop into the mature oocyte cystocytes with four ________ (cytoplasmic bridges) most posterior cystocyte in the ovary.
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Ring canals
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during drosophila oogenesis the other 15 cells become _____, which provide the developing oocyte virtually all of the machinery and raw materials that it will need for early development.
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Nurse Cells
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During drosophila oogenesis high rate of transcriptional activity is mediated by formation of _______ chromosomes (512 copies of each chromosome)
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Polytene
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Which protein is responsible for anterior axis formation of drosophila?
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Bicoid
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Which protein is responsible for forming the posterior axis of drosophila embryo?
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Nanos
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