Flashcards in Multicellular Organisms 1. 29 Deck (28):
What is a genome?
And organism with identical genes but can alter the expression of the genes
What are the basic machinery for development that can be altered by preset and past environment?
Are homologous proteins functionally interchangeable?
What is the ectoderm?
External sheet of epithelial cells.
What does the ectoderm give rise to?
Nervous system and epidermis
What is the endoderm and what does it give rise to?
1. Consists of epithelial tissue rolled interiorly
2. Gives rise to gut, lung, liver
Where is the mesoderm and what does it give rise to?
1. Cells migrate in between the ectoderm and endoderm.
2. Muscle and connective tissue precursor
What is gastrulation?
1. Transformation of a hollow sphere into a structure with a gut
What is common amongst all animals that undergo development?
Mouth, anus, endoderm, ectoderm, mesoderm. All arranged in the same pattern also
What are the two classes of proteins that are most important for development?
1. Cell adhesion/ protein signaling
2. Gene regulatory proteins: control expression of genes
What is the purpose of gene duplication?
Making multiple homologs of a gene for higher order organisms
What is a non-coding regulatory DNA that is a associated with each gene?
Instructions to produce a multicellular animal
What are instructions for producing a multicellular animal that are associated with each gene?
Non-coding regulatory DNA
Where do gene regulatory proteins bind to DNA?
Bind on DNA at regulatory elements
WHat is the purpose of regulatory elements on the DNA?
Allows for binding of gene regulatory proteins
What provides "uniqueness" to organisms when they have similar coding sequences?
What are determined cells/
Cells whose fate is determined into specialized cell type without influence from the environment
What are completely undetermined cells?
Cells that respond rapidly to the changes in the environment
What are cells that are committed?
Cells with attributes of a specific cell type but are able to change with influence from the environment
What are unique methods to provide cellular differentiation
1. Asymmetric division.
2. Unequal distribution of molecules between daughter cells
3. Environment changes can influence the cells development
4. The molecules can alter gene expression
WHat is short range signaling?
WHat is long range signaling?
Substances that diffuse through the extracellular medium
What is inductive Signaling?
Induction of different developmental program in select cells of a homogenous group leading to altered character.
What does irreversible imply?
Once achieved external signals become irrelevant
What provides cells with memory?
Positive feedback which amplifies an effect especially after environment starts asymmetry
What is a morphogen?
Long range inductive signal that imposes a pattern on a field of cells
What produces a gradient of the morphogens?
1. Localized production of inducers that diffuse away from source
2. Production of inhibitor that diffuses away from source and block the action of uniform distribution