Science 9: Unit C

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Science 9 Unit C Environmental Chemistry

• Topic 1 A Hair-Raising Dilemma

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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 bodys 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).

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How Sugars are broken down into Glucose.
A molecule of Glucose C6H12O6(s)

• 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).

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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.

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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.

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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.

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Farming and Fertilizer

• Fertilizers are identified by three numbers (eg.
  5-10-5). 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.

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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.