3.7 Development of multicellular organisms Flashcards
Genome of all cells in an organism are
identical
Expression of genes is
different
What are the 4 major phases in development?
Cell division, cell differentiation, cell interaction. cell migration
Genes expressed by cell depend on what?
Environement both present and past
Homologous proteins are functionally what?
interchangeable
What is a blastula?
Ball of cells surrounding a hollow cavity
What is a gastrula?
Blastula that undergoes rearrangements, 3 major layers.
What does the blastula consist of ?
Sheet of epithelial cells
What is the ectoderm?
previrsor of nervous system and epidermis
What gives rise to the ectoderm?
the blastula
What gives rise to the endoderm?
ectoderm
The endoderm is the precursor of what 3 things?
Gut, lung, liver
What gives rise to the mesoderm?
The group of cells that move inbetween ectoderm and endoderm
Mesoderm is precursor to what?
muscle and connective tissue
What the definition of gastrulation?
Transformation of the blastula into a layered structure with a gut.
What do fruit flys and humans have in common?
Homologs
What is the most important for development?
gene regulatory proteins
What holds the instruction for producing a multicellular animal?
non coding regulatroy DNA
What serve as binding sites for gene regulatory proteins?
Regulatory elements
What sequence are similar in most organisms
coding sequences
What sequences make one organism dif from another?
non coding sequences
What comes first? Developmental decisions or differentiation?
Developmental decisions
What are determined cells?
Cells that are fated to develop into a specialized cell type despite changes in environment
What are completely undetermined cells?
Cells that can change rapidly due to alteration in environment
What are committed cells?
Cells that have some attributes of a particular cell type but can change with environment.
Position specific character of cell is called what?
positional value.
How can cells become different?
Asymmetric division
How can cells born the same can become dif?
Change in environment after birth
What is the most important environmental cues?
Signals from neighboring cells
What is inductive signaling?
Induction of a dif developmental program in select cells in a homogenous group leading to altered character
What are short range signals?
cell to cell contact
What are long range signals?
substances that can diffuse through the extracellular medium
What is a morphogen?
a long range inductive signal that imposes a pattern on a field of cells.
What 3 main factors are due to diversity in pattern?
Gene duplication, presence of other signals and previous experiences of the cell
What is the ultimate result of inductive events?
change in DNA transcription
Signaling pathways response depends on what two things?
spatial and temporal expression
