Chapter 24, Problem 1RC

Summary Introduction

To determine: The eukaryotic cell envelope and the function of its constituents.

Introduction. The proteins are made of amino acids. The amino acids are of 20 types that combine in a varied manner to form proteins. The amino acids join together by peptide bonds. Proteins act as major substrates and reactants for the metabolic pathways. All the enzymes in the body that are crucial for the biochemical reactions are proteins.

Explanation of Solution

Pictorial representation: Fig.1; The eukaryotic cell envelope and its constituents.

The eukaryotic cell membrane is made up of phospholipids and no cell wall in animal cells. The phospholipids are arranged in the form of bilayer that is present on both the sides that are upper and lower side of the cell membrane with proteins in between the layers. The phospholipid bilayer has two types of proteins extrinsic and intrinsic proteins. The cell membrane is composed of phospholipids bilayer that has two layers of phospholipid and has protein embedded into the membrane. The phospholipids present in cell membrane are of four types phosphatidylcholine, sphingolipid, phosphoethanolamine and cholesterol.

The phospholipid composition of the membrane is amphipathic in nature with polar (hydrophilic) heads and non-polar (hydrophobic) tails. These molecules allow the direct passage of molecules that are hydrophobic like steroid derivatives. The other molecules like proteins need to be transported through channel proteins as they are water-soluble