Movement across membranes

Question 1

A transmembrane protein domain

Answer 1

• A sequence that is largely hydrophobic (uncharged) and spans across the PM

-This sequence permanently attaches the the protein to the PM

Question 2

Alpha Helix

Answer 2

The most common protein structure element crossing biological membranes

Question 3

Nine amino acids that have a hydrophobic side chain

Answer 3

• Glycine
• Alanine
• Valine
• Leucine
• Isoleucine
• Proline
• Phenylalanine
  -Methionine
• Tyrptophane

Question 4

Tetraspanins (TN4SFs)

Answer 4

• Super family of membrane proteins found in all multicellular eukaryotes
• Have four transmembrane alpha - helices and two extracellular domains one short EC1 and one longer EC2

-Some can be glycosylated (attachment of a carbohydrate molecule) on the long extracellular loop

• Tetraspanins play a role in cell adhesion, motility, ploliferation, and more