KINE 2P09 Lecture Notes - Lecture 1: Transfer Rna, Extracellular Fluid, Nuclear Pore
9 May 2018
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KINE 2P09
Molecular mechanisms of a single action potential action potential
1. Opening of Na+ channels increase the membrane permeability
2. More positives enter the cell than are leaving, inside of the cell becomes more positive
reaches threshold, and depolarizes
3. Action potential
4. Na+ channels close, K+ channels open, repolarization
5. Too far negative is hyperpolarization
6. Na/K pump returns membrane to resting potential
Events at a synapse
1. An action potential is propagated to the terminal of a presynaptic neuron
2. Ca2 enters the synaptic knob (presynaptic terminal) by voltage gated channels
3. Neurotransmitter is released by exocytosis into the synaptic cleft
4. Neurotransmitter binds to receptor sites on the post-synaptic neuron
5. Specific ion channels open in the sub synaptic membrane on the post synaptic neuron
Events at the post-synaptic membrane
1. Neurotransmitters bind to ligand gated channels
2. Ion channels open to move membrane towards or away from threshold
3. Small local depolarization of the membrane
4. Neurotransmitters taken up by pre-synaptic membrane or degraded by enzymes
What are neurotransmitters and what do they do
- Chemical messengers that signal a cell to perform certain ways
What are the receptors on the post- synaptic membrane
- Protein receptors specific to the neurotransmitters
What are ligand gated ion channels
- Channels that a molecule binds to the receptor or near the channel to change the
conformation or shape and open it
How is an action potential propagated down a nerve cell axon
- Sequential opening and closing of voltage-gated channels (Na+ and K+)
- flow of action potential caused by local changes in membrane potential
- i eliated aos there is saltator coductio fro ode to ode
reducing the area that needs to be polarized
Process
- Transcription: copy of DNA strand is made into mRNA
- mRNA is spliced
- mRNA leaves nucleus through nuclear pores and attaches to ribosomes
find more resources at oneclass.com
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Document Summary
Events at the post-synaptic membrane: neurotransmitters bind to ligand gated channels, ion channels open to move membrane towards or away from threshold, small local depolarization of the membrane, neurotransmitters taken up by pre-synaptic membrane or degraded by enzymes. What are neurotransmitters and what do they do. Chemical messengers that signal a cell to perform certain ways. What are the receptors on the post- synaptic membrane. Channels that a molecule binds to the receptor or near the channel to change the conformation or shape and open it. How is an action potential propagated down a nerve cell axon. Transcription: copy of dna strand is made into mrna. Mrna leaves nucleus through nuclear pores and attaches to ribosomes trna brings appropriate amino acids as it reads mrna codons. A molecule binds to the receptor or near the channel to change the conformation/shape and open it.
