homework 1
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
How does the yolk affect the pattern of cleavage?
Yolk generally impedes cleavage.
The yolk-rich side of an egg is called _______.
vegetal side
Cell specification by differential acquisition of certain cytoplasmic determinants present in the egg is called _______.
autonomous specification
features of gastrulation
• A multi-layered body plan consisting of the ectoderm, endoderm and mesoderm is established. • The body axes (anteroposterior, dorsoventral, right-left) are determined. • Presumptive ectodermal cells in the animal hemisphere spread to cover the outer surface of the embryo.
A state in which a cell’s developmental fate has become restricted even though it is not yet displaying overt changes is called __________.
commitment
a group of cells from a frog blastula that normally give rise to dorsal tissues are transplanted into the presumptive ventral region of another embryo. The results provide evidence for ______.
conditional specification
RNA in situ hybridization is used to detect patterns of __________.
transcription (RNA synthesis)
_______ is the fluid-filled cavity that exits in blastula stage embryos.
blastocoel
sequence of vertebrate early development
fertilized egg –> morula –> blastula –> neurula
Fate mapping is a method for tracing cell lineages in developing embryos. Which techniques can be used for fate mapping?
Staining cells with a vital dye Introduction of a GFP (green fluorescent protein) expression construct into cells Chick-quail chimera
A 16-64 cell stage of vertebrate embryo is called ________.
morula
Which tissues differentiate from the mesoderm?
Notochord Bones Blood cells
During development, Pax 6 is expressed in many different tissues including the neural tube, retina, lens, cornea, and pancreas. This differential expression is partly regulated by the DNA sequences in the Pax6 gene called _________.
enhancers
Each somatic cell nucleus has the complete genome established in the fertilized egg, and the DNA of all differentiated cells is identical. This is known as _________.
genomic equivalence
Once a tissue is induced, it can act back on the original inducing tissue and induce it. (i.e. The inducer becomes the induced.) This phenomenon is called ______.
reciprocal induction
In ____________, a cell surface molecule on one cell binds to a different type of cell surface molecule on an adjacent cell.
heterophilic interactions
______________ is a form of cell signaling in which a cell secretes a hormone or chemical messenger that binds to receptors on that same cell
autocrine signaling
For lens induction, Pax6 expression is required in the ________________, but not in the ________________.
surface ectoderm, optic vesicle
The ability of cells or tissues to respond to a specific inductive signal is called __________.
competence
A type of cell-cell communication that occurs between nearby cells through secreted factors are called _________.
paracrine signaling
typical feature of an epithelial cell
Interacts with basement membrane via its basal surface.
features of classical cadherins
Examples of the classical cadherins include E-cadherin and N-cadherin. Can transduce intracellular signals. Their cytoplasmic domains are linked to the cytoskeleton thorough catenins.
results of cell recombination assay by Philip Townes and Johannes Holtfreter
When two types of cells are mixed, each type sorts out to become spatially segregated. The final positions of the reaggregated cells reflect their respective positions in the embryo. Differential cell adhesion may mediate this cell segregation.
During early development of vertebrates, the neural tube separates from surface epidermis. Specific expression of _________ in the presumptive neural tissue is critical for this separation.
N-cadherin