Answer;
-On the polar end or the hydrophillic end of the protein.
Explanation;
-Each amino acid has at least one amine and one acid functional group as the name implies. The different properties result from variations in the structures of different R groups.The R group is often referred to as the amino acid side chain.
-Side chains which have various functional groups such as acids, amides, alcohols, and Amines will impart a more polar character to the amino acid. Polar amino acids include serine, threonine, asparagine, glutamine, histidine and tyrosine.
Therefore; serine being a polar or hydrophillic amino acid will be found on the polar side chain of the protein.
C. A wall of stones and mortar
This would act as a model describing the cell membrane.
Explanation;
A cell membrane is made up of a phospholipid bilayer with embedded proteins.
A cell membrane hold the different components of the cell together and to protect it from the environment outside the cell. It acts as a boundary between the inside environment and the outside environment of a cell.
It regulates the materials that enters and exits the cell; through selective movement of substances in and out of the cell.
