List the four macromolecules that make up cells and give a brief description of the structure and function of each. What will be an ideal response?

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ANSWER: Carbohydrates include small, water-soluble sugars and large polymers made of sugars. In the
cell, carbohydrates have three important functions: They are structural components of cells;
they act as energy sources for the cell; and, in combination with proteins on the surface, they
give cells a molecular identity.
Lipids are a structurally and functionally diverse class of biological molecules partially
defined by their insolubility in water. Lipids have many functions: They are structural
components of membranes, some serve as energy reserves, while others act as hormones and
vitamins. Lipids are classified into three major groups: fats and oils, phospholipids, and
steroids. The phospholipids play important roles in the structure and function of the cell
membrane.
Proteins are the most functionally diverse class of macromolecules. Proteins are polymers,
made up of one or more chains of subunits, called amino acids. The varied structures of
proteins are reflected in their diversity of functions.
Nucleic acids are polymers made from nucleotide subunits. Nucleotides themselves have
important functions in energy transfer, but nucleic acids are the storehouses of genetic
information in the cell. The information is encoded in the nucleotide sequence.