Biochemistry is the chemistry of living things. This course concentrates on the chemistry of the plants. Some secondary school chemistry will be helpful but not essential to your understanding of the course. This course is very similar to Biochemistry (Animals) though focused on plants so there is no need to take both.




The purpose of this course is to allow you to appreciate the application of biochemistry to your area of applied science and to use biochemical applications and services in a very practical way in your study area.

Student Comment: 'Having not finished high school myself and never studied biochemistry my confidence is a little low but the encouragement I am receiving from Honor [tutor] is a tremendous help and making it easier for me as I go. [The course] is helping me realize what I am actually capable of and that I am smarter than I thought. Thank you for making it possible for me to study my passion while still being able to work.' Melissa Smith, Australia, Biochemistry 1 (Diploma in Horticulture).


There are nine lessons as follows:

  1. Introduction
  2. Lipids and Proteins
  3. Enzymes
  4. Nitrogen and the Nitrogen Cycle
  5. Photosynthesis and Respiration
  6. Assimilation and Transpiration
  7. Acidity and Alkalinity
  8. Chemical Analysis
  9. Biochemical Applications



  • Identify characteristics of common chemical compounds important in plant biochemistry.
  • Explain the characteristics of major biochemical groups including; carbohydrates, lipids and proteins.
  •  Explain the characteristics of chemicals which control biological processes, including enzymes and hormones.
  • Identify the role of nitrogen in plant biological processes, including the nitrogen cycle.
  • Identify the role of photosynthesis in biological systems.
  • Explain the role of respiration in plants.
  •  Explain characteristics of assimilation and transpiration in plants.
  • Explain the effect of acidity and alkalinity on biochemical systems.
  • Develop simple chemical analysis skills relevant to testing plants and soils.
  • Identify applications and uses for biochemical processes and products.


  • Explain the formulae of ten specified, chemical compounds commonly found in plants
  • Calculate the percentages of elements contained in two specified chemical compounds
  • Differentiate between characteristics of major groups of biochemicals
  • Compare differences between monosaccharides and polysaccharides
  • Differentiate between a fat and an oil
  • Explain the characteristics of a specified protein formula
  • Compare two fibrous proteins with two globular proteins
  • Explain the functions of carbohydrates in plants
  • Explain how one specific enzyme functions in a living organism
  • Explain how one specific hormone functions in a living organism
  • Compare differences in nitrogen deficiency symptoms in monocotyledons and dicotyledons
  • Analyse the nitrogen cycle with diagrams
  • Perform an experiment comparing the growth of 4 plants grown under differing light conditions
  • Explain the processes of photosynthesis, with diagrams
  • Identify the differences between anaerobic and aerobic respiration
  • Explain glycolysis, including the sequence of chemical reactions which take place
  • Explain the Krebs cycle, including the sequence of chemical reactions involved.
  • Compare respiration in a plant with respiration in an animal
  • Perform, a simple experiment, showing the movement of dyed water into and through a plant
  • Explain how nutrients are moved about in a plant
  • Define pH terminology including; acid, alkaline, base and neutral
  • Explain plant responses to changes in soil pH
  • Analyse the effects of three different fertilizers on the pH of growing media.
  • Explain the effects of abnormal pH levels in a specific case study of a physiological process, in a living organism.
  • Identify factors involved in controlling acidity and alkalinity in a specific case study.
  • Differentiate between chemical toxicity and tolerance.
  • Explain the implications of LD50 characteristics with five different chemical substances.
  • List the active toxins in ten poisonous plants which commonly occur in your home locality.
  • Explain the effects of two naturally occurring toxins on the human body.
  • Determine three different applications for plant tissue culture.

What is Biochemistry?

Understanding chemistry starts with understanding the types of particles that make up atoms; then understanding how different types of atoms combine to create different types of chemicals.
Biochemistry is the study of just one area of chemistry - the chemistry of living things -in this course focusing on plants.

All matter is made up of atoms. An atom is composed of a core of protons and neutrons, surrounded by orbiting electrons which move extremely fast. Protons and neutrons are referred to as subatomic particles. 

Atomic mass is the weight of the neutrons, protons and electrons. Electrons are much smaller and weight much less than protons or neutrons.

The parts of an atom can have electrical charges. 

  • Electrons have a negative charge 
  • Protons have a positive charge  
  • Neutrons are electrically neutral.

When the positive and negative charge is balanced, the atom is electrically neutral (i.e. the positive and negative charges cancel out each other).


When an atom carries a charge, either positive or negative, we refer to it as an ion. Remember ions can be charged positively if they have more protons or negatively if they have more electrons. 

  • A positively charged atom (ion) is called at cation. 

  • A negatively charged atom (ion) is called an anion. 

Knowing these terms allows you distinguish between ions based on their type of charge.  
Stability is important to understand as ions are less stable than neutral atoms. Chemical stability in this respect refers to the ion’s tendency to resist change when exposed to changes in the environment such as heat, light, pressure etc.   
As a result of their instability, ions will generally seek a partner to bind to, to form an overall neutral molecule and become stable. The bond between two charged atoms is called an ionic bond.  

If two neutral atoms bond to each other by sharing electrons the bond is called a covalent bond.  
In an example where two atoms are joined, a covalent bond may have 2, 4 or 6 electrons in total with each atom contributing 1, 2 or 3 electrons.