Neurons to Brain

Question 1

Proteins

Answer 1

• embedded in membrane according to environment and genotype –> functional distinction
• proteins are the greatest difference between different parts of the cell

Question 2

Fluid mosaic bilipid membrane

Answer 2

• glycoproteins (proteins with carbohydrates attached)
• glycolipids (lipids with carbohydrates attached)
• proteins
• phospholipid bilayer made up of hydrophobic tails and hydrophilic heads

Question 3

Nernst & Goldman

Answer 3

• could not explain relationship between permeability and conductance of APs
• –failed to explain how channels select based on structure (only considered passive movement)
• current vs conductance
• –current is just passive movement
• –conductance is protein structures are active

Question 4

Gene by environment

Answer 4

• gene by environment interactions dictate cell differentiation
• environment = distribution of proteins in and around the cell
• –changes function of specific parts of neuron

Question 5

Flow of information

Answer 5

• information moves from the presynaptic cell to the postsynaptic cell
• –receives electrical signals from the dendrites, to the soma, down the axon across the synapse to the postsynaptic cell
• –neurotransmitter recognized by postsynaptic cell based on the proteins embedded in cell membrane (receptor proteins determine how the neuron interprets the neurotransmitter)

Question 6

Voltage-gated ion channels

Answer 6

• anion (e.g. Cl)
• cation (e.g. Na, K, Mg2)
• voltage-gated –> does not need a neurotransmitter to open or close (open and close at rest)
• these control the propagation of APs (electrical signals)
• chloride channels (open at rest –> Vm changes)
• –selective –> channel for chloride alone
• –non-selective –> based on size or diffusion (other ions could go through)

Question 7

Ligand gated ion channels

Answer 7

• mostly exist on dendrites
• difference between ionotropic and metabotropic is how they send their signal to the cell (receptors vs second messenger proteins)
• ionotropic is fast (immediate changes)
• metabotropic is slow (long-term changes)

Question 8

Protein folding

Answer 8

• proteins made up of a sequence of amino acids

- amino acids can have H+ or a negative charge depending on how acidic or basic the environment is (aka pH)

Question 9

Primary protein structure

Answer 9

sequence of a chain of amino acids

Question 10

Secondary protein structure

Answer 10

• occurs when the sequence of amino acids are linked by H-bonds –> folds into alpha helix or pleated sheet
• pH affects shape of amino acid formation

Question 11

Tertiary protein structure

Answer 11

• occurs when certain attractions are present between alpha helices and pleated sheets; folding is functional (hydrophobic and hydrophilic amino acids facing in proper directions)
• pH affects folding

Question 12

Quaternary protein structure

Answer 12

is a protein consisting of more than one amino acid chain

Question 13

The synapse

Answer 13

charge from axon causes Ca2+ channels to open at the axon terminal leading to the Ca2+ influx, signaling neurotransmitters to be released and cross the synapse to the receptors on the dendrites of the postsynaptic cell

Question 14

Structure of channels

Answer 14

• 5 subunits (pentameric)
• folded based on charge
• –hydrophobic (repels water)
• –hydrophilic (attracted to water)
• –amphipathic (is both)

Question 15

What affects protein folding?

Answer 15

pH