Cell Communication & Development + Cell Form & Function Flashcards
What are the three requirements to have complex multicellular life?
- cells must stick together
- cells must communicate with one another
- cells must participate in a network of genetic interactions that regulates cell division & differentiation
What are epithelia?
sheets of cells that line the inside and cover the outside of the body
What are the four essental elements of cell signaling?
- signaling cell
- signaling molecule
- receptor
- responding cell
What are the four steps of the signal transduction pathway?
- receptor activation
- signal transduction
- response
- termination
What happens in receptor activation?
the signal binds to a receptor, which activates it
What happens in signal transduction?
the signal is transmitted to the interior of the cell by a signal transduction pathway
What happens in the cellular response?
the cell carries out some sort of activity depending on the nature of the signaling molecule or responding cell
What happens in termination?
the cellular response is terminated so that new signals can be received and the cell is protected from overreacting to new signals
True or False:
A termination signal is necessary for termination.
False
The termination signal can dissociate by itself.
Which type of signaling travels long distances?
endocrine signaling
Which type of signaling travels short distances?
autocrine and paracrine signaling
Which type of signaling involves direct contact?
contact-dependent signaling
What is a ligand?
alternative term for a signaling molecule
What is the ligand-binding site?
the specific location on the receptor where a signaling molecule binds
What is a cell-surface receptor?
receptors located on the outside surface of the responding cell
Polar/nonpolar signaling molecules pass through cell-surface receptors.
polar
What is an intracellular receptor?
receptors located inside the cell
Polar/nonpolar signaling molecules pass through intracellular receptors.
nonpolar
What is a receptor tyrosine kinase?
a receptor that is an enzyme that undergoes phosphorylation when the signal is bound
kinase
an enzyme that phosphorylates
phosphorylation
the transfer of a phosphate group from ATP to a substrate
What are phosphatases?
enzymes that dephosphorylate other molecules
dephosphorylation
the removal of phosphate groups from another molecule
What is the process of RTK activation?
- signaling molecule travels to the RTK of the responding cell
- signaling molecule binds with the receptor, which causes dimerization
- each member of the active receptor pair phosphorylates the other member
- the phosphate groups provide binding sites for intracellular signaling proteins
What is dimerization?
the process in which the members of a receptor partner together
What is a short-term cellular response?
a temporary change that can be reversed
i.e. changing blood glucose level, activating/deactiviating
What is a long-term cellular response?
a permanent change
i.e. gene expression
G-protein receptors/receptor kinases facilitate short-term cellular responses.
G-protein receptors
G-protein receptors/receptor kinases facilitate long-term cellular responses.
Receptor kinases
What are stem cells?
cells that can differentiate into different cell types
What are totipotent cells?
cells that have the potential to give rise to a complete organism
What is an example of a totipotent cell?
zygotes
What are pluripotent cells?
cells that can give rise to any type of cell
What is an example of a pluripotent cell?
embryonic stem cells
What are multipotent cells?
cells that can form a limited number of types of specialized cell
What is an example of a multipotent cell?
neural cells
Why do differentiating cells lose their developmental potential?
- gene regulation: genes no longer needed are turned off
- genome reduction: as cells differentiate, they delete DNA for genes no longer needed