Development Of Multicellular Org I

Question 1

T/F: Genes expressed by a cell depend on the PAST Environment.

Answer 1

False

Both PAST and PRESENT

Question 2

Gastrula

Answer 2

• Mature form of Blastula

- Has 3 major layers

Question 3

Gradients in morphogenesis are formed by what?

Answer 3

1. Localized production of an INDUCER that diffuses AWAY from its source
2. Localized production on an INHIBITOR that diffuses AWAY from its source
   - Block the action of a uniformly distributed inducer

Question 4

What are the most important Environmental cues for inductive signaling?

Answer 4

Signals from Neighboring cells

Question 5

What do Cells do BEFORE acquiring a particular fate?

Answer 5

• Cells express genes that are markers of their Location

- Regionally determined

Question 6

Which cell wins in Delta Notch Signaling?

Answer 6

The cell with the ACTIVE Delta

• Inhibits its neighbors from doing likewise

Question 7

Response to whether genes are turned “on” or “off” are in response to what?

Answer 7

Spatial and Temporal expression of different sets of genes

Question 8

How do Zebras get their stripes or Leopards get their spots?

Answer 8

Pattern generation by Reaction Diffusion

• Long range inhibition

Question 9

Characteristics of Committed Cells

Answer 9

• Cell that have some attributes of a particular cell type

- But CAN change with Environment

Question 10

Characteristics of Completely Undetermined cells

Answer 10

Cells that Rapidly change due to alterations in environment

Question 11

Characteristics of Inductive Signaling

Answer 11

Induction of DIFFERENT developmental program in select cells of homogenous group

• Leading to altered character

Question 12

Conserved mechanism for development

Answer 12

1. The cleaved cells do NOT feed
   - depend on the food STORED in egg by the mother
2. Genome is Inactive
3. Once activated cells form blastula
   (Hollow ball of cells)

Question 13

Instructions for producing a Multicellular Animal is contained where?

Answer 13

NON-Coding Regulatory DNA

• Associated with each gene

Question 14

Diversity is a pattern due to what # factors?

Answer 14

1. Gene Duplication
2. Presence of other signals
   - Combinations create variety
3. Previous experiences of the cell

Question 15

Gene Duplication

Answer 15

Higher organisms have several homologous of the SAME gene

Question 16

Endoderm is the precursor to what?

Answer 16

• Gut
• Lung
• Liver

Question 17

4 stages of a. Developing Embryo

Answer 17

1. Cell Proliferation
2. Specialization
3. Interaction
4. Cell Movement

Question 18

T/F: HOMOLOGOUS proteins are functionally Interchangeable

Answer 18

True

Fly protein can be put into a Mouse to rescue development of Cerebellum

Question 19

What controls development?

Answer 19

Gene Expression

Question 20

Asymmetric Division

Answer 20

Significant sets of Molecules distributed unequally between daughter cells

Question 21

Asymmetry and Positive Feedback timeline

Answer 21

• System starts symmetrical
• Environment poses a Weak Asymmetry
• Poz feedback amplifies it
• IRREVERSIBLE

Question 22

How many genes does a human share with a fruit fly?

Answer 22

50%

Question 23

When are developmental decisions made for differentiation?

Answer 23

Long before they show any outward signs of differentiation

Question 24

What is Positional Value?

Answer 24

Position Specific Character of a Cell

Question 25

Mesoderm is the precursor to what?

Answer 25

• Muscles

- Connective tissue

Question 26

What proteins are most important for development?

Answer 26

Gene Regulatory Proteins

Question 27

What sequence makes one organism different from the other to provide uniqueness?

Answer 27

NON-Coding Sequences

Question 28

Characteristics of Determined Cells

Answer 28

• Cella that are fated into SPECIALIZED cell type

- Despite changes in environment

Question 29

Common Signaling Pathways

Answer 29

1. Receptor Tyrosine Kinase (RTK)
2. Transforming Growth Factor (TGFβ)
3. Hedgehog
4. Notch
5. Wnt

Roy Touches Hung Narrow Wieners

Question 30

What is a morphogen?

Answer 30

• A long range inductive signal
• Imposes a pattern on a field of cells
• Exert graded effects by forming gradients of different [ ]

Question 31

What is the ultimate result of Inductive events?

Answer 31

Change in DNA transcription

Question 32

Short Range vs Long Range signaling

Answer 32

Short:
- Cell to cell contact

Long:
- Substances that can diffuse through the EC medium

Question 33

Ectoderm is the precursor to what?

Answer 33

• Nervous System
• Epidermis
• Gives rise to the ENDODERM