Organism Health and Chemistry

 Chemicals can be solid, liquid, or gas  Can be:  natural : already on Earth  Synthetic : man-made

 For an organism to interact with a chemical, it must first be exposed to the chemical.  Exposure : when an organism comes into contact with a chemical, and the chemical gets inside the organism’s body.  Ways to get exposed: inhalation, absorption, and consumption  Just because an organism comes in contact with a chemical, does not mean it will become sick. Some chemicals are harmful while others are helpful.

 Potency is how much of a chemical substance an organism is exposed to and how the organism reacts to the chemical. It is how strong the chemical is.  Dose : is how much of a chemical an organism is exposed to. It refers to the amount of a chemical.

 Susceptibility : how sensitive an organism is to a chemical substance.  Factors that determine susceptibility: dose, potency, exposure route, frequency of exposure, organism age, and the genetic makeup of the individual organism.  Exposure route : how an organism contacts a chemical. Remember organisms touch, inhale or consume chemicals. Chemicals that get on the skin aren’t always absorbed into the body. But chemicals that are inhaled or ingested are of concern because these chemicals can get into the tissues and cause harm.

 Frequency : the more times you come into contact with a chemical, the greater the chances are that the chemical will harm you.  Age : Elderly are more sensitive than younger people, babies (both born and unborn) are highly sensitive than other individuals  Genes: some people are just more susceptible to chemicals because other people in their families were more susceptible.

 Chemicals and Human Health

 Some chemicals do not cause harm: example water  Some do: example, cigarette smoke  Carcinogens: chemicals that cause cancer. There are literally thousands of chemicals that can cause every type of cancer known to humankind.  Diseases linked to chemicals: autoimmune disease, birth defects, heart disease, diabetes, behavior disorders, kidney disease, asthma, and learning disabilities.

 Remember it all depends on:  Who is exposed  When they are exposed  And how long they were exposed  These three factors will determine if a disease develops.

 Chemicals must undergo rigorous analysis before they can be approved for use.  Medicines : a chemical agent used to treat disease or an injury. Medications sold in the US are tested by the Food Drug Admin before they can be used by consumers. Doctors and scientists analyze harmful side effects along with potential benefits.  Food preservatives : called food additives, are substances added to food by humans. They usually slow down the growth of bacteria and fungi in food and they can make the food stay fresh longer.

 Crop yield: how much crop (food) a piece of land produces. Increasing crop yield is a goal of many scientists and farmers because it can protect crops from pests and increase the rate of plant growth.  Sanitation: the promotion of cleanliness by preventing or reducing human exposure to harmful wastes. Sanitation can help keep foods safe to eat, clean water before people drink it or clean-up oil spills in the ocean.