variable than the inorganic fertilisers. As a result it is difficult to know for sure whether the
particular nutrient required by the plant is actually being supplied by the natural fertiliser.Figure 2.5: Sample of compost created
through processes involving degradation of
dead organic matter by bacteria and fungi.Figure 2.6: A homemade compost tumbler.2.4 Organic compounds
An organic compound is a compound whose molecules contain C, and usually at least one
C-C or C-H bond. Very small carbon-containing molecules that do not follow the above
rules, such as CO 2 and simple carbonates, are considered inorganic. Life on earth would
not be possible without carbon. Other than water, most molecules of living cells are carbon-
based, and hence are referred to as organic compounds. The main classes of organic com-
pounds we will investigate in this section include carbohydrates, lipids, proteins and nucleic
acids.Each of these classes of compounds consists of large molecules built from small subunits.
The smallest of these subunits is called amonomer. Several monomers bond together to
formpolymers. Each of these polymers is characterised by a specific structure owing to
the chemical bonds formed. These structures are related to the function of the compound
in living organisms. We will therefore study each class of compounds under the following
headings:- molecular make-up: the main elements that make up the class of compounds
- structural composition: how the monomers join up together to form polymers
- biological role: importance of these molecules to animals and plants
- chemical test: how to detect the presence of each class of compounds
Carbohydrates DUMMY
Molecular make-upCarbohydrates consist of carbon (C), hydrogen (H) and oxygen (O).30 2.4. Organic compounds