Question

Use your knowledge of protein structure and function to make predictions concerning the properties of the R-groups on amino acids located in different locations within a protein that spans a membrane.

Answer 1

Generally proteins of biological membranes are transmembrane pretein, phospholipis. These proteins have lipid molecules as in place of side chain (R). these proteins have polar head group of amin acid and hydrophobic , non-polar lipid tail. Polar head provide free charges for other molecules to binds hence hydrophilic and non polar tail group do not have free charges to bind, so its repels water molecules, hydrophobic. Combination of polar group and non-polar side R group (lipid) makes the biological membrane a selective membrane.

so the R group of phospholipid are,

non polar

hydrophobic

water insoluble

no free charges available