Welcome to the Proteins 2 debriefing.

Answer the questions below, and click on the Check buttons when you are ready.

1. Which of the following amino acids would you expect to find at the surface of a water-soluble protein? (Click on the amino acid structure icon at left to open a window showing the structures of the 20 amino acids found in proteins.)

Arg Phe His Leu Ala
Correct! Polar, basic, and acidic amino acids are usually found on the surface of water-soluble proteins.
You have chosen a hydrophobic amino acid. These are usually found in the interior of water-soluble proteins.
Correct! But is there another?

2. Which of the following amino acids would you expect to find facing the lipid bilayer in an integral membrane protein? (Use the amino acid structure icon above to see the structures of the 20 amino acids found in proteins.)

Glu Lys Val Tyr Ile
Correct! Hydrophobic amino acids face the bilayer in integral membrane proteins.
You have chosen a polar, basic, or acidic amino acid. These do not face the bilayer in integral membrane proteins.
Correct! But is there another?

3. Which type of secondary structure predominates in the following proteins?

Myohemerythrin is an oxygen-transport protein found in worms. Green fluorescent protein is found in some jellyfish and (surprise, surprise!) fluoresces green under certain conditions. Triose phosphate isomerase is a digestive enzyme found in all cells.
helix ß sheet Both helix ß sheet Both helix ß sheet Both
Correct!
Sorry, try again.

Congratulations!

You have completed the Proteins 2 module.

Click on the Proteins 2 icon below to return to the Biomolecules gateway page.