Unit 4 Flashcards
Plasmodesmatas
Tiny channels in plant cell walls that let molecules pass between cells
Signal Transduction Pathway
Process where a signal (ie. a hormone) causes a chain of events inside a cell
Ligand
A signal molecule that binds to a receptor
Receptor
The ligand binds to the receptor on the cell’s surface or inside
Transduction
Signal is passed along proteins inside the cell, involving phosphorylation cascades
Response
The cell does something (ie. turning a gene on, dividing, releasing something)
Phosphorylation Cascade
One protein activates another by adding a phosphate, causes signal AMPLIFICATION
Second Messenger
Small molecule inside the cell that helps pass on the signal (ie. cAMP)
cAMP
Secondary messenger that activates proteins in the signal pathway
Transcription Factors
Proteins that turn genes on of off by binding to DNA in the nucleus
Activators
Boost process
Inhibitors
Slows or stops process
Mutations
Changes in DNA and lead to abnormal proteins
Negative Feedback
Response reduces the original signal to keep balance (ie. insulin regulates blood sugar)
Positive Feedback
Response increases the signal (ie. when you have contractions during labor, it signals to have more contractions)
Interphase
Cell grows & prepares to divide, takes of 90% of the cell cycle
G1
Interphase; the cell grows
S
Interphase; DNA is copied & synthesized
G2
Cell prepares to divide
M
Mitosis (cell division)
G0
Resting phase where the cell is not dividing
Checkpoints
Control points in the cycle where the cell checks: is DNA ok, is cell big enough, is division needed?
Apoptosis
Programmed cell death, healthy to remove damaged or unneeded cells
Cyclins
Regulatory proteins that rise and fall to control timing of the cell cycle
