DPR Exam 1 vocab Flashcards
Price chapters 1 -4 // campbell chp.6,7,11,18
Homologue
a gene or structure that is similar in different species since it was derived from their common ancestor during evolution
Line
a collection of organisms related by breeding that is relatively pure genetically because of continued inbreeding and artificial selection
Phenotype
the observable characteristics of an organism, such as its physical appearance or behavior
forward genetics
Working from phenotype to gene
reverse genetics
one starts with an interesting-looking gene and manipulates its activity to learn about its function.
Gain-to-function approach:
the genome is activated by the experimenter to discover what they do
Loss-of-function approach:
activating genetic inhibitors manufactured by the experimenter to produce a molecule that blocks the actions of a specific Drosophila gene
RNAi
RNA interference can be used to block gene function experimentally,
Process includes:
1.Inside normal cells, genes are transcribed to make single-stranded messenger RNA (mRNA) that is translated by ribosomes to generate specific proteins
2.To block gene function, antisense RNA molecules with sequences complementary to sense sequences of specific mRNAs are introduced into cells where they interact with their target mRNAs and block their translation
The Germ Layers
An outer layer called ectoderm
A middle layer called the mesoderm
An inner layer from the endoderm
Epithelium
a tissue that lines the external and internal surfaces, including internal cavities and organs and other free open surfaces of the body, of all animals and their immature developing forms
Gastrulation
is the formation of the germ layers once the repeated division of a fertilized egg has generated a collection of cells large enough to be rearranged
Neurulation
The process by which the neural tube is formed and acquires increasingly complex morphology
epiboly
Cells derived from the animal pole spread over the embryo with ectoderm ( epiboly is the process of which this is happening)
Fate
What the cell will do and what it will become
Homologous recombination
a phenomenon in which nucleotide sequences are exchanged between two similar or identical strands of DNA
Neuroectoderm
neurogenic region of the ectoderm
Gastrulation
formation of the germ layers occurs once the repeated division of fertilized egg has generated a collection of cells large enough to be rearranged
Blastomere
(mentioned in C.elegans development) any of the cells resulting from the first few cleavages of a fertilized egg during early embryonic development
Blastoderm
(mentioned in frogs and chicks)
the superficial layer of the early embryo in species whose eggs contain relatively large amounts of yolk; cell division occurs in this layer which surrounds the yolk in insects but is a flat disc at one pole of the egg in birds
Blastopore
(mentioned in frogs) Gastrulation involves the inward movement of cells from the embryo’s outer layer at a region
- organizer in frogs
Blastula
(mentioned in the frog) Before gastrulation, a fluid-filled cavity known as the blastocoel opens beneath the animal cap; the embryo is now
The first cells to move in migrating anteriorly from the dorsal lip of the blastopore
Their movement displaces the blastocoel anteriorly
Notochord
These cells form the endoderm which lines the primitive gut, the mesoderm of the future head, and the transient dorsal mesodermal structure
Blastocyst
(mentioned in mouse development)
- The mouse blastocyst comprises three tissues: the epiblast, situated at one pole of the embryo, the primitive endoderm beneath it, and the trophectoderm surrounding both tissues and the blastocoel cavity
- This is equivalent to the blastula of amphibians
Neuroblasts
(mentioned in drosophila) the formation of the CNS involves individual cells in the neuroectoderm enlarging and moving inside the embryo, a process called delamination
Neural Tube
The process of primary neurulation begins in the overlying neuroectoderm with the formation and folding of the neural plate to form the neural tube
Neural Plate
The neural plate is broader anteriorly and the folds it generates are larger than those made posteriorly.
Neural Crest
Originates from the lateral edges of the neuroectoderm; once these edges have joined to form the neural tube, neural crest cells end up dorsally along the line of fusion
Neurlation
occurs through rapid growth at rates that vary from region to region; cell movements; changes shape in cell
Primary Neurlation
the process by which a sheet of neuroectoderm called the neural plate rolls up as it grows to form the neural tube
Secondary Neurulation
achieves the same results as primary neurulation, but through a different process known as cavitation that involves the hollowing out of an initially solid rod of tissue
Animal cap
(mentioned in frog)
As cell division progresses the embryo’s dorsal region, called the animal cap, becomes packed with many small cells
Notochord
(mentioned in frogs) transient dorsal mesodermal structure
Ventral Nerve Cord
(mentioned in Drosophila) Neuroblasts are progenitor cells that divide many times to form numerous intermediate cells called ganglion mother cells (GMCs). Each GMC divides just once more to form neurons and glia. GMCs and their progeny pile up on the neuroblasts, forming the bilaterally symmetrical ventral nerve cord.
Primitive Streak
(mentioned in the chick)
As epiblast cells are produced they move posteriorly in the plane of the epiblast towards
Koller’s sickle from where they move anteriorly along the midline forming a structure called the primitive streak
Formation of the primitive streak involves the ingression of epiblast cells into the interior of the embryo
Hensen’s node
(mentioned in the chick)
As the primitive streak lengthens from posterior to anterior a bulge called
Hensen’s node appears at the anterior tip of the streak.
Hensen’s node is equivalent to the dorsal lip of the blastopore in frogs– the organizer in the chick
Epiblast
(mentioned in the chick) The pellucida area is transparent because there is a fluid‐filled cavity, initially cell‐free, between the yolk and an overlying single‐cell‐thick layer of epithelial cells. The epithelial layer is called the epiblast
- As in the developing chick embryo, gastrulation in the mouse embryo involves the movement of cells in the plane of the epiblast towards and through the primitive streak to form a new mesodermal layer between the outer endoderm and the inner ectoderm
Prechordal mesoderm
(mentioned in mouse development) The notochord grows anteriorly from the node, forming a narrow midline rod ending in the broader prechordal mesoderm under the future forebrain. The notochord comes to lie along the midline of the embryo beneath the part of the ectoderm that will form the nervous system, the neuroectoderm
Neural Induction
the inducing tissue tells the responding tissue to adopt a neural fate
The process often involves the binding of signaling molecules produced by one cell to receptor proteins on the surface of another
Hans Spemann and Hilde Mangold Experiment
Neural Induction concept:
Working on amphibian embryos, these scientists discovered that if the dorsal lip of the blastopore is transplanted to a new location in a different embryo, it induces the formation of a second body axis, complete with a second neural plate, which becomes a second neural tube and eventually a second mature nervous system
Neural Plate
becomes a second neural tube and eventually a second mature nervous system
Organizer
Might promote neural induction because it produces molecules that inhibit BMPs in the animal cap, preventing its cells from acquiring an epidermal fate
the dorsal lip of the blastopore in amphibians
Hensen’s node in birds, fish, and mammals
Default Model
the model came mainly from work on tissue that is induced to a neural fate in the blastula of amphibian embryos
