LS 10 Week 1 – 3 The Chemistry of Life
The Chemistryof Life
2 ½ weeks
Strand 1: Life at the Molecular, Cellular and Tissue Level
All living organisms are made of atoms which combine to form molecules. In turn, these molecules make up the basic units of life i.e. cells. Plant and animal cells have a complex organisation which enables them to carry out the basic processes of life, i.e. movement (movement in and around the cells and some cells move), nutrition (cells produce food or obtain food from elsewhere), respiration, excretion, growth, reproduction and responding to stimuli. Cells are specialised and form tissues which perform particular functions. The tissues are arranged into organs which are also specialised to carry out particular functions. This strand introduces learners to life at the molecular, cellular, tissue and organ level (links to Grade 9).
Molecules For Life
Organic molecules are made up of C, H, and O, and some contain other elements, such as N and P. Cells are made up of proteins, carbohydrates, lipids, nucleic acids and vitamins. (Only basic structural detail required.
The main functions of:
- water: 2 H and 1 O;
- minerals: e.g., Na, K, Ca, P, Fe, I, nitrates, phosphates; macro and micro elements;
Main functions and deficiency diseases (link to nutrition and Grade 9).
The need for fertilisers in over utilised soils, e.g., where crops are grown and regularly harvested, fertilizers are washed away into rivers, and nutrophication can take place
(link to ecology).
- carbohydrates – monosaccharaides (single sugars), e.g., glucose and fructose; disaccharides, (double sugars), e.g., sucrose and maltose; polysaccharides (many sugars), e.g., starch, cellulose and glycogen; lipids (fats and oils)
- 1 glycerol and 3 fatty acids: unsaturated and saturated fats; cholesterol in foods;and heart disease (link to Grade 9);
- proteins – amino acids (C,H, O and N and some have P, S, Fe) – are sensitive to temperature and pH: loss of structure and function; the role of enzymes in breaking down/synthesising molecules; the influence of temperature and pH on enzyme action; the Lock and Key Model of how enzymes work; enzymes in everyday life (for instance using washing powders);
- Mention of nucleic acids – DNA and RNA – consisting of C, H, O, N and P (no details of structure required);
- and vitamins – e.g., A, one of the B vitamins, C, D and E.