Lecture 1 - Overview of Cell Biology and Function Flashcards
Why are epithelial cells adhered to each other?
- forms protective barrier
- no adherence = cells start moving on their own and can form cancer
ex. if epithelial sheet is not properly formed, leaks can occur –> leaky intestine means bacteria from GI can enter serum of body and cause inflammation
What holds adjacent epithelial cells together?
- tight junction
- adherens junction
- desmosome
- gap junction
What holds epithelial cells to the extracellular matrix?
- actin-linked cell-matrix junction: anchors actin filaments in cell to EM
- hemidesmosome: anchors intermediate filaments in cell to EM
are types of cell-matrix anchoring junctions
Tight junctions
Seals gap between epithelial cells
Adherens junction
a type of cell-cell anchoring junction
Connects actin filament bundle in one cell to that in the next cell
A = A
Desmosomes
a type of cell-cell anchoring junction
Connects intermediate filaments in one cell to that in the next cell
Gap junctions
a type of channel-forming junction
Allows the passage of small water-soluble molecules from cell to cell
What fragments first in apoptosis of a cell?
The nucleus
What happens with necrotic cell death? Why?
Example
May cause inflammation because necrotic cell death is a nonphysiological death process
Blisters = necrotic cell death in one area (inflammation)
What are the 3 effector proteins in cell signaling and their functions?
- metabolic enzyme: alters metabolism
- transcription regulatory protein: alters gene expression
- cytoskeleton protein: alters cell shape or movement
What occurs with a constitutively active EGFRvlll?
Epithelial growth factor receptor 8
Cancer growth
- increased cell growth/replication leads to tumor formation in cancers such as lung + breast
Gefitinib
drug that blocks the EGFR pathway (EGFR inihibitor) by competing with EGF to prevent binding
leads to less cell growth, is a tyrosine kinase inhibitor
What is significant about the localization of mitochondria?
Mitochondria is located near sites that need more energy
- ex. cardiac cells: mitochondria located by the contractile apparatus to provide the energy needed for contraction
How are junctions typically organized in a cell?
Their location
Apical junctions are generally found in this order: tight junctions, adherens junctions, desmosome, gap junctions
tight junctions, adherens junctions, desmosomes form a junctional complex
