Science 9: Unit C – Environmental Chemistry Topic 1: A Hair-Raising Dilemma

Nutrients Needed for Survival A nutrient is a chemical that our bodies need for life. Our body needs many different chemicals to survive. Most of these chemicals are obtained by the digestion of food. The chemicals are organized into two groups: Organic Compounds – Compounds containing carbon atoms. Inorganic Compounds – Compounds which do not contain carbon. There are four kinds of organic nutrients in the body: Carbohydrates – Sugars. Used for energy for life processes. Contains carbon, hydrogen and oxygen. Lipids – Fats. Used to store unused energy for later use. Larger than carbohydrates, but containing the same elements. Proteins/Amino Acids – Used to help repair and grow the body’s tissues. Nucleic Acids – DNA and RNA. Used for genetic processes of the body. The body needs 25 different elements to survive and thrive. Some elements are needed in large amounts (macrominerals), and others in very small amounts (micronutrients or trace elements).

How Sugars are broken down into Glucose. Hydrolysis – A chemical reaction in which one or more water molecules is chemically bonded to another compound. This is how sugars and starches are broken down into blood sugar (glucose). A molecule of Glucose C 6 H 12 O 6(s)

Optimum Amounts Having too much or too little of any nutrient, even a trace element can lead to harmful effects. The optimum amount of a substance is the amount that gives the organism the best health. The Canada Food Guide informs the public to the optimum amounts of various nutrients on a daily basis.

How Nutrients Move through organisms. Nutrients enter the plant through the roots by the process of diffusion. Diffusion is the process where particles go from an area of high to low concentration. Diffusion continues until the concentrations in the soil and the plant are equal. Osmosis is a special type of diffusion where water moves from an area of high to low concentration of water. This is how a plant ‘drinks.’ Because diffusion and osmosis happen automatically the plant uses no energy in either process. Active Transfer – Some nutrients are required in greater amounts than diffusion can supply so the plant spends energy taking in these nutrients. This process also serves another purpose by restricting nutrients from competing plants. Substrate – Material that an organism attaches itself to, moves through or lives off of. For example the substrate of the Earthworm is soil.

The Food Cycle All living things need a constant supply of raw materials and energy to survive and grow. The food cycle begins with plants taking in inorganic compounds and solar energy and chemically changing them to organic compounds which consumers use for energy, growth, and repair of tissues.

Farming and Fertilizer Fertilizers are identified by three numbers: (eg ). The first number represents the percent of nitrogen, the second number the percent of phosphate, and the third number the percent of potassium. The other 80% of fertilizer is made up of trace elements and filler. Until 1900s plants received all of their nitrates (nitrogen based nutrients) from nature (soil and manure). Then commercial fertilizers were created and the amount of nitrogen in the environment has increased by 140 million tons/year. Nitrogen is needed for tissue growth and repair so plants have grown larger and healthier as more nitrogen has become available. Crop production has doubled worldwide.

The Problems with Modern Farming A lot of water is being used on farming. Monoculture farming has led to a decrease in genetic variety in plants making crops more at risk for diseases. Pests have increased as well and because of this, the use of chemical pesticides has also increased.