2.6 CHAPTER 2. ORGANICMACROMOLECULES
- Take a plastic shopping packet and squash itinto a tight ball.
(a) Measure the approximate length, breadth anddepth of your squashed
plastic bag.
(b) Calculate the approximate volume that is occupied by the packet.
(c) Now calculate the approximate volume of your classroom by measur-
ing its length, breadth and height.
(d) Calculate the number of squashed plastic packets that would fit into
a classroom of this volume.
(e) If South Africa produces an average of 8 billion plastic bags each year,
how many classrooms would be filled if all of these bags were thrown
away and not re-used? - What has South Africa done to try to reduce the number of plasticbags
that are produced? - Do you think this has helped the situation?
- What can you do to reduce the amount of plastic that you throw away?
2.6 Biological Macromolecules
ESCAM
A biological macromolecule is one that is found in living organisms. Biological macro-
molecules include molecules such as carbohydrates, proteins and nucleic acids. Lipids
are also biological macromolecules. They areessential for all knownforms of life to
survive.DEFINITION: Biological macromolecule
A biological macromolecule is a polymer that occurs naturally in living
organisms. These molecules are essential to thesurvival of life.Carbohydrates ESCAN
Carbohydrates include the sugars andtheir polymers. One key characteristic of the
carbohydrates is that they contain only the elements carbon, hydrogen and oxygen. In
the carbohydrate monomers, every carbon except one has a hydroxylgroup attached
to it, and the remainingcarbon atom is doublebonded to an oxygen atom to form a
carbonyl group. One ofthe most important monomers in the carbohydrates is glucose
(figure 2.10). The glucose molecule can exist in an open-chain (acyclic) and ring (cyclic)