8/28 Lecture 2 Flashcards
In early cells when the first instructions for development were being made where were the instruction coming from?
The environment. The cells all existed in an aqueous environment.
Cell in our body where do they get their information and instructions from?
Their neighbors and through endocrinology the blood capillary networks.
Morphogenesis
ordered forms of organized groups of cells. coordination of cell movement, migration and death.
differentiation
cell diversity. one cell a single fertilized egg gives rise to many different types if cells
What is the formal name given to the “small toolkit”?
Molecular Parsimony
fertilization
fusion of male and female mature sex cells “gametes”=genome(embryo)
cleavage
rapid mitotic cell divisions
end of cleavage=blastula
gastrulation
extensive cell rearrangements creation germ layers
embryo in gastrula stage
organogenesis
tissue and organs produced
metamorphosis
Process of becoming sexually mature
gametogenesis
formation of gametes
Our life is not circular but a what relationship?
Linear
How does the egg know how and when to develop when fertilized?
Stored Messenger RNA
WHat evidence exists that supports the fact that life is a continuum?
Drosophila oocyte the bicoid and caudal messages that encode the head and thorax protein production
Give an example of how to use GFP?
Green Fluorescent Protein. Inject GFP into the pronuclei of the zygote and a site specific promoter for Pax6 genes. The eyes of all the organisms will be green because the lens is the location where the correct promoter, enhancer, transcription factor are present.
How do you know primordial germ cells migrate?
WHat part of the embryo forms the cells to become the adult frog bony skull?
EXP:
1. Infect the eggs of frog with active GFP gene.
- GFP virus incorporated into nuclear DNA and the viral GFP gene transmitted into the frog embryo.
- Tadpoles and adult frogs glow green under UV light all over.
- Removed cells from the neural tube and neural crest of the GFP transgenic embryo and transplanted them into a normal embryo.
- Embryo grows into adult frogs and the cartilage cells remained present and the lower jaw glowed bright green indicating that the original cells transplanted had migrated to form that portion of the skull.
What did Mary Rawles discover?
Showed that the pigmented cell (melanocytes) of the chick originate in the neural crest- a transient band of cells that joins the neural tube to the epidermis. When she transplanted small regions of neural crest tissue from a dark pigmented strain of chickens into a similar position in the embryo of white pigmented chickens, the migrating pigment cells entered the epidermis and later the feathers,
WHy do zebras have stripes?
They use the exact same ubiquitous mechanism as the chickens with migrating neural crest cells and some of their neural crest cells make pigment and some of them do not.
allows us to see where cells are.
How is a cell competent?
It is able to receive a signal from the environment.
How do signals from the environment enter the cell? (2 ways)
- receptor signal on membrane
2. signal passes through membrane and interacts with something inside the cell typicall transcription factor
For a promoter site to be able for biological events to take place what must happen?
- The promoter site must be packaged so that the DNA is open
What is the packaging in the promoter? How is DNA packaged?
octomer of histones and DNA is wrapped around it
How is a promoter site opened?
The loosening of histones the combination of methylation and acetylation of the histones.
Majority of the time what does methylation do to the histones? What does acetlyation mainly do to the hit ones?
Methylation tightens preventing transcription.
Acetylation loosens activating transcription.
What happens when histones are methylated very very much and the histones are extremely tight and compact?
They are called heterochromatin and they are silent genes that can not be transcribed. For example women have X chromosome inactivation from either our mom or dad.
Demonstrate how we know DNA is histone packaged?
Vitellogenin gene with the hens and rooster
