Week 14 Flashcards
Explain differential gene expression, and different levels of structural organization
o The development of multicellular organism requires interactions at many levels of organization.
Generations of distinct cell types requires:
Differential gene expression
Cell communication
Cell memory (inheritance of chromatin states, and DNA methylation.
o Epithelial Tissue
o lines the surfaces in the body
Muscle Tissue
is made up of fibers that contract
Nervous Tissue
consists of cells with projections that transmit electrical signals
Loose Connective Tissue
acts as padding under skin and elsewhere
Bone / Cartilage
are connective tissues made up of cells in a hard or stiff extracellular matrix.
Blood
is a connective tissue made up of cells in a liquid matrix.
Ectoderm (external layer)
skin of cells epidermis, neurons and pigment.
Endoderm (Internal layer)
Lung (alveolar cell), Thyroid cell, Pancreatic cell.
Mesoderm (middle layer)
cardiac muscle, skeletal muscle, RBC, smooth muscle, tubule cell of the kidney.
The extracellular matrix in connective tissue is composed of:
Insoluble protein fibers (collagen, elastin)
o Multi-adhesive proteins (laminins, fibronectins, nidogen)
o Proteoglycans (protein plus glycosaminoglycans)
o Hyaluronan (glycosaminoglycan)
how collagen is made and why the structure of triple stranded collagen is susceptible to dominant negative effects
o Formation of collagen fibrils takes place outside the cell.
o Lysine and proline side chains are modified by hydroxylases, The hydroxyl groups of these modified amino acids are important for stabilization of triple helical portions however, this can be susceptible to dominant negative effects.
o If vitamin C acts as a cofactor for the enzyme’s role as a catalyst for collagen fibrils to leave the cell and form.
explain “dominant negative”
o A mutation whose gene product adversely affects the normal, wild-type gene product within the same cell.
why posttranslational hydroxylation of proline and lysine is important for collagen function
o Formation of fibrils is strengthened by covalent cross-links between side chains of lysine and hydroxylysine.
