8/28 Lecture 2

Question 1

In early cells when the first instructions for development were being made where were the instruction coming from?

Answer 1

The environment. The cells all existed in an aqueous environment.

Question 2

Cell in our body where do they get their information and instructions from?

Answer 2

Their neighbors and through endocrinology the blood capillary networks.

Question 3

Morphogenesis

Answer 3

ordered forms of organized groups of cells. coordination of cell movement, migration and death.

Question 4

differentiation

Answer 4

cell diversity. one cell a single fertilized egg gives rise to many different types if cells

Question 5

What is the formal name given to the “small toolkit”?

Answer 5

Molecular Parsimony

Question 6

fertilization

Answer 6

fusion of male and female mature sex cells “gametes”=genome(embryo)

Question 7

cleavage

Answer 7

rapid mitotic cell divisions

end of cleavage=blastula

Question 8

gastrulation

Answer 8

extensive cell rearrangements creation germ layers

embryo in gastrula stage

Question 9

organogenesis

Answer 9

tissue and organs produced

Question 10

metamorphosis

Answer 10

Process of becoming sexually mature

Question 11

gametogenesis

Answer 11

formation of gametes

Question 12

Our life is not circular but a what relationship?

Answer 12

Linear

Question 13

How does the egg know how and when to develop when fertilized?

Answer 13

Stored Messenger RNA

Question 14

WHat evidence exists that supports the fact that life is a continuum?

Answer 14

Drosophila oocyte the bicoid and caudal messages that encode the head and thorax protein production

Question 15

Give an example of how to use GFP?

Answer 15

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.

Question 16

How do you know primordial germ cells migrate?

Answer 16

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.

2. GFP virus incorporated into nuclear DNA and the viral GFP gene transmitted into the frog embryo.
3. Tadpoles and adult frogs glow green under UV light all over.
4. Removed cells from the neural tube and neural crest of the GFP transgenic embryo and transplanted them into a normal embryo.
5. 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.

Question 17

What did Mary Rawles discover?

Answer 17

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,

Question 18

WHy do zebras have stripes?

Answer 18

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.

Question 19

How is a cell competent?

Answer 19

It is able to receive a signal from the environment.

Question 20

How do signals from the environment enter the cell? (2 ways)

Answer 20

1. receptor signal on membrane

2. signal passes through membrane and interacts with something inside the cell typicall transcription factor

Question 21

For a promoter site to be able for biological events to take place what must happen?

Answer 21

1. The promoter site must be packaged so that the DNA is open

Question 22

What is the packaging in the promoter? How is DNA packaged?

Answer 22

octomer of histones and DNA is wrapped around it

Question 23

How is a promoter site opened?

Answer 23

The loosening of histones the combination of methylation and acetylation of the histones.

Question 24

Majority of the time what does methylation do to the histones? What does acetlyation mainly do to the hit ones?

Answer 24

Methylation tightens preventing transcription.

Acetylation loosens activating transcription.

Question 25

What happens when histones are methylated very very much and the histones are extremely tight and compact?

Answer 25

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.

Question 26

Demonstrate how we know DNA is histone packaged?

Answer 26

Vitellogenin gene with the hens and rooster