Dr. Carter’s Final Exam Review Guide
Subject Matter
Roughly half of the exam questions are taken from the previous exams and half are from the
new topics in this guide. This means you will be able to use the prior exam keys to supplement
this guide while studying. The exam is about 1.5X the length of the previous exams, and you will
have 2X the amount of time to take it.
New Topics of Emphasis
Membrane Proteins
Know the different types (integral, etc.).
- Integral membrane proteins are embedded in the hydrocarbon core of the membrane –
require detergent or organic extraction for release from the membrane.
- Peripheral membrane proteins are bound to the polar head groups of membrane lipids
or to the exposed surfaces of integral membrane proteins – can be released by high ionic
strength or pH changes.
- Some proteins are associated with membranes by attachment to a hydrophobic moiety
that is inserted into the membrane
Know that membrane-spanning regions of proteins are usually nonpolar alpha helices.
- Usually consist of nonpolar alpha helices.
- Alpha helices are stabilized by hydrophobic interactions within the membrane core.
Know what a porin is and how its structure is different from the typical alpha helices.
- Beta-barrel proteins found in the outer membranes of bacteria, mitochondria, and
chloroplasts.
- Form water-filled channels, in contrast to the typical alpha-helix structure of membrane
proteins.
Know what a hydropathy plot is and explain it.
, - A graph that predicts transmembrane segments based on hydrophobicity.
- Peaks above a threshold indicate hydrophobic regions likely to span the membrane.
Membrane Transporters
Explain active vs. passive transport.
- Passive Transport: Movement down the concentration gradient (no energy required).
- Active Transport: Movement against the gradient, requiring energy (e.g., ATP hydrolysis).
Describe classes of transporters: ATP-driven pumps, carriers, channels.
- ATP-Driven Pumps: Use ATP to move ions/molecules across membranes (e.g., Na⁺/K⁺
pump).
- Carriers: Undergo conformational changes to move substrates.
- Channels: Provide a pore for specific ions/molecules to diffuse through.
Explain K+ and Na+ levels in animal cells and how they’re maintained by P-type transporters.
- Na⁺/K⁺ Pump:
- Maintains high intracellular K⁺ and low intracellular Na⁺ levels.
- Pumps 3 Na⁺ out and 2 K⁺ in per ATP hydrolyzed.
- Mechanism: Cycles between E1 and E2 states, driven by phosphorylation and
dephosphorylation.
Explain the fundamental reaction mechanism of P-type transporters.
-
Explain what ABC transporters do and why they’re involved in antibiotic resistance.
- Use ATP to transport various substrates.
- Implicated in antibiotic resistance by exporting drugs out of bacterial cells.
Subject Matter
Roughly half of the exam questions are taken from the previous exams and half are from the
new topics in this guide. This means you will be able to use the prior exam keys to supplement
this guide while studying. The exam is about 1.5X the length of the previous exams, and you will
have 2X the amount of time to take it.
New Topics of Emphasis
Membrane Proteins
Know the different types (integral, etc.).
- Integral membrane proteins are embedded in the hydrocarbon core of the membrane –
require detergent or organic extraction for release from the membrane.
- Peripheral membrane proteins are bound to the polar head groups of membrane lipids
or to the exposed surfaces of integral membrane proteins – can be released by high ionic
strength or pH changes.
- Some proteins are associated with membranes by attachment to a hydrophobic moiety
that is inserted into the membrane
Know that membrane-spanning regions of proteins are usually nonpolar alpha helices.
- Usually consist of nonpolar alpha helices.
- Alpha helices are stabilized by hydrophobic interactions within the membrane core.
Know what a porin is and how its structure is different from the typical alpha helices.
- Beta-barrel proteins found in the outer membranes of bacteria, mitochondria, and
chloroplasts.
- Form water-filled channels, in contrast to the typical alpha-helix structure of membrane
proteins.
Know what a hydropathy plot is and explain it.
, - A graph that predicts transmembrane segments based on hydrophobicity.
- Peaks above a threshold indicate hydrophobic regions likely to span the membrane.
Membrane Transporters
Explain active vs. passive transport.
- Passive Transport: Movement down the concentration gradient (no energy required).
- Active Transport: Movement against the gradient, requiring energy (e.g., ATP hydrolysis).
Describe classes of transporters: ATP-driven pumps, carriers, channels.
- ATP-Driven Pumps: Use ATP to move ions/molecules across membranes (e.g., Na⁺/K⁺
pump).
- Carriers: Undergo conformational changes to move substrates.
- Channels: Provide a pore for specific ions/molecules to diffuse through.
Explain K+ and Na+ levels in animal cells and how they’re maintained by P-type transporters.
- Na⁺/K⁺ Pump:
- Maintains high intracellular K⁺ and low intracellular Na⁺ levels.
- Pumps 3 Na⁺ out and 2 K⁺ in per ATP hydrolyzed.
- Mechanism: Cycles between E1 and E2 states, driven by phosphorylation and
dephosphorylation.
Explain the fundamental reaction mechanism of P-type transporters.
-
Explain what ABC transporters do and why they’re involved in antibiotic resistance.
- Use ATP to transport various substrates.
- Implicated in antibiotic resistance by exporting drugs out of bacterial cells.
