PSYC 3800: The Resting Membrane Potential (Ch. 3) - Quiz 3 Review

I) Lipid Bilayer

II) Membrane-spanning channel proteins inserted into lipid bilayer

III) Receptor Proteins

What are the three key structures to building a prototypical neuron?

Twenty

How many Amino Acids (AA) are there?

mRNA

What type of RNA binds to the small ribosome subunit?

tRNA

What type of RNA binds to the large ribosome subunit?

I) Central carbon atom (alpha carbon); covalently bonded to 4 molecular groups:

• Hydrogen atom

• Amino group (NH3+)

• Carboxyl group (CO2-)

• Residue group (R-group) → can be hydrophilic or hydrophobic

What are the 5 key components that all amino acids possess?

Peptide bonds

Join the amino group of one amino acid to the carboxyl group of another

Polypeptide

Chain of amino acids

I) Primary: sequence

II) Secondary: alpha-helix (spiral-like)

III) Tertiary: Interactions with R groups (folded individual peptides) → individual subunit

IV) Quarternary: Multiple peptide subunits aggregate of subunits via weak molecular bonds

What are the 4 key protein shapes in neurons?

Polar R groups

R groups that are hydrophilic and will avoid lipid environments

No polar R groups

Hydrophobic and will associate with lipids

Embedded (suspended) proteins

Proteins arranged so that middle groups are non-polar & ends are polar

4-6

How many subunits typically make up a channel protein?

• Size of pore/size of ion

• R groups lining

What factors determine ion selectivity in channel proteins?

I) Transporter (active)

II) Non-gated (leaky; always open)

III) Voltage-gated (open or closed)

IV) Mechanically-gated

What are the four types of channel proteins?

I) Diffusion (concentration gradient)

II) Electrostatic Charge (electrical processes)

What are the two passive processes that facilitate ion movement in neurons?

Diffusion

• Dissolved ions distribute evenly

• Ions flow down concentration gradient (high → low)

• Diffusion of ions:

  • Channels permeable to specific ions

  • Concentration gradient across membrane

Current (I)

Movement of electrical charge; measured in Amps (A)

Conductance (g)

Relative ability for charge to migrate; Measured in Siemens (S)

Resistance (R)

Inability of charge to mitigate; measured in Ohms

Electrical Potential (V)

Difference in charge between an anode and a cathode (two different points); measured in Volts (V)

-65 to -70 mV

What is the average membrane potential at rest?