Cell Communication A.P. Biology Ch. 11. Goals & Objectives Describe in writing important...
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Transcript of Cell Communication A.P. Biology Ch. 11. Goals & Objectives Describe in writing important...
Cell Communication
A.P. Biology Ch. 11
Goals & Objectives• Describe in writing important communication
pathways for a cell• Describe in writing how each pathway works
Big Idea• How do you get a message from outside the
cell to inside?– Cell growth, cell division– Nerve cells
• Chemical messages are communicated by changing the shape of certain molecules– Change shape, trigger a response– “On/Off” switch
Local vs. Long Distance “Calling”
How Cell Communication Works
• Telephone Analogy
Caller (your friend)
Phone Tower/Switchboard
Parent
YouCaller = Ligand (chemical signal)
Phone Tower/Switchboard = Receptor protein in cell membrane (outside cell)
Parent = Membrane bound protein (inside cell)
You = Desired cell response
3 Phases in Cell Communication
(ligand)
Using a Chemical Signal• Ligand docks with receptor protein in
membrane, causes shape change– Often caused by phosphorylation– Returns to original shape when ligand detaches
• Change in receptor protein causes a chain reaction of shape changes in other proteins– Signal Cascade– More phosphorylation (ATP ADP + P)– Signal can be “amplified;” (think spam e-mail)
Example of a Signal Cascade
**Notice that the addition of a phosphate causes shape change in protein kinase
3 Types of Cell Communication • G protein
– Single communication within membrane
• Tyrosine kinase– Many signals (amplification)
• Ion Channels– Allows flow of ions into/out of cells
G Protein• Uses GTP
(similar to ATP)
• Completely membrane bound
• Examples:– Hormones– Neurotransmitt
ers– Epinephrine
Tyrosine Kinase• Combining of two
proteins, can phosphorylate 6 ATP at a time
• Massive phosphorylation causes multiple responses
• Cell growth/division
Ion Channel• Ligand causes protein
channel to open/close
• Ion flow causes cell response
• Nerve impulse/Nervous system
Apoptosis• Programmed cell death (suicide)
• Triggered many different ways– Mitochondrial chemicals/molecules– Nuclear chemicals/DNA damage
• Necessary for development of an organism– Development of limbs– Get rid of cells that are harmful