Chapter 22/23 - Cellular Development Flashcards
What are the 4 steps of cellular development?
Cell division
Differentiation
Pattern formation
Morphogenesis
Describe cell division?
production of new individual cells
Meiosis: forms gametes, which will fuse to form a zygote
Mitosis: division of previously existing diploid cells
Begins post-fertilization
Describe Diferentiation.
As cells divide, changes in gene expression result in differences between cells which results in cell specialization.
In differentiated cells, certain genes are expressed at particular times, but other genes may not be expressed at all.
Cells change their gene expression to become specialized for specific functions
What am I?
Differentiation
Describe Pattern Formation.
Cells in a developing embryo must become oriented to the body plan of the organism the embryo will become
Involves cells’ abilities to detect positional information that guides their ultimate fate.
Describe Morphogenesis.
Involves: cell death, cell division, cell migration, changes in cell shape and differentiation.
organs and anatomical features will develop from dividing cells
Body is generated
Process of Development - Cell Division
In animal embryos, the period of rapid cell division following fertilization is called
cleavage
Process of Development - Cell Division
What happens to a zygote during cleavage?
- the enormous mass of the zygote is subdivided into a larger and larger number of smaller and smaller cells, called blastomeres
- The zygote maintains its size
- G1 and G2 phase during which a cell increases its mass and size, are shortened or eliminated
Process of Development - Cell Division
Process of Development - Cell Division
During cleavage, cells have extremely short G1 and G2 phases of the cell cycle due to ____________ ?
Rapid Cell Division
Process of Development - Cell Division
How many Somatic Cells does a C. Elegans, or nematode contain?
959
How are C. elegans useful in research?
- Can use them to follow or observe how each cell is derived from the fertilized egg and or the first division (of zygote) to the last cell division (full development of all structures)
Plant growth occurs in specific areas called __________?
Meristems
Process of Development - Cell Division
Undifferentiated plant tissue from which new cells arise is called ___________?
meristems
Process of Development - Cell Division
As _____________ cells continually divide, they produce cells that can differentiate into the tissues of the plant.
meristematic stem
Process of Development - Cell Differentiation
Cells become determined prior to differentiation (T/F)
true
Process of Development - Cell Differentiation
Cells must ____________ to accommodate their specialization of function
differentiate
Process of Development - Cell Differentiation
A human body contains more than ______ types of differentiated cells.
210
Process of Development - Cell Differentiation
Differentiated cells are distinguishable from one another by
particular proteins that they synthesize, their morphologies, and their specific functions.
Process of Development - Cell Differentiation
The molecular “decision” process by which a cell becomes destined for a particular developmental pathway. This occurs before overt differentiation and can be a stepwise process.
Cell Determination
Process of Development - Cell Differentiation
Molecular process to determine specialization of a cell is called:
cell determination
Process of Development - Cell Differentiation
Used to understand determination and timing of determination
Transplanting studies, or Tracking determination
Process of Development - Cell Differentiation
Describe Tracking determination.
Move the donor cell(s) to a different location in a host (recipient) embryo. If the cells of the transplant develop into the same type of cell as they would have if left undisturbed, then they are judged to be already determined
Process of Development - Cell Differentiation
What are the requirements of cell determination?
Positional details from surrounding cells
Timing and number of cells
Need commitment from cells for a specific fate
Transcription factor changes to induce cells to a specific fate
Process of Development - Cell Differentiation
Cells are committed via one of two pathways called :
Inheritance of cytoplasmic determinants
Cell-cell interactions
Process of Development - Cell Differentiation
Which pathway is maternally produced and deposited into the egg during oogenesis?
A) Inheritance of cytoplasmic determinants
B) Cell-cell interactions
A) Inheritance of cytoplasmic determinants
Process of Development - Cell Differentiation
Determination can be due to cytoplasmic determinants (T/F)
True
Describe Tunicates.
Tunicates are marine invertebrates
Adults are attached to substratum (rock, ocean floor, etc)
larvae are mobile
Process of Development - Cell Differentiation
- Yellow pigment molecules in tunicates determines _____________
- Transplanting these yellow pigment molecules to other areas of the developing embryo causes:
Expression of __________ (a transcription factor) within the egg post-fertilization allows some of the dividing cells to express yellow pigment, thus sealing its fate to become the tail muscle
- which dividing cells becomes the tail muscle
- those regions to turn to muscle cells
- macho-1 gene
Process of Development - Cell Differentiation
The elimination of macho-1 function leads to a
loss of tail muscle in the tadpole
Process of Development - Cell Differentiation
A transcription factor that can activate the expression of several muscle-specific genes.
macho-1 gene
Process of Development - Cell Differentiation
leads to the formation of additional (ectopic) muscle cells from nonmuscle lineage cells.
misexpression of macho-1
Process of Development - Cell Differentiation
Induction can lead to _______________
cell differentiation
Process of Development - Cell Differentiation
Cell-cell interactions results in changing of cell fates
What am I?
induction
Process of Development - Cell Differentiation
Signaling molecules released from one cell can change gene expression in adjacent cells, altering their fates
What am i?
induction
Process of Development - Cell Differentiation
- Embryos have three germ layers which are :
- (the “animal pole”) develop features of :
- Blastomeres from the opposite pole of the embryo (the “vegetal pole”) develop features:
- If animal-pole cells and vegetal-pole cells are placed next to each other, he animal-pole cells develop as :
- Ectoderm, Endoderm, Mesoderm
- ectoderm
- endoderm
- mesoderm
Process of Development - Cell Differentiation
- Gives rise to muscle, notochord, and mesenchyme:
- releases FGF to mesoderm cells
- Induces formation of notochord and mesenchyme
- Mesoderm
- Endoderm cells
- fibroblast growth factor (FGF)
+mesodermal cells receive signals from the underlying endodermal precursor cells that lead to the formation of notochord and mesenchyme
Process of Development - Cell Differentiation
Induces the o_verlying marginal zone cells to differentiate_ into either notochord (anterior) or mesenchyme (posterior)
fibroblast growth factor (FGF)
Process of Development - Cell Differentiation
Depending on the signal and combination of signals will determine
cell fate
Process of Development - Pattern Formation
- Multicellular organisms have body plans, with the basic body plan laid out during ____________ of the embryo, in early stages.
- May involve morphogenesis of organs in later stages
- Axial differences between dorsal-ventral and anterior-posterior structures
- The positional axis of dorsal-ventral and anterior-posterior structures determines :
- pattern formation
- pattern formation
- Polarity (Describes patteren formation)
- the location of each body part
Process of Development - Pattern Formation
Studies to determine pattern formation uses:
Drosophila embryos
