C OMMON S UBSTANCES ESSENTIAL TO LIVING THINGS Lesson Objective: Students will identify common organic and inorganic substances that are essential to living things. R EVIEW : Fossil fuels are also known as? Why? Ever wonder what you are made of? A CTUALLY The composition of the human body is: Water, proteins, fats, sugars, starch, DNA, minerals, vitamins, salts, acids, and bases. O UR BODIES NEED ABOUT 25 ELEMENTS FOR NORMAL GROWTH ( PAGE 197). Carbon(C), oxygen(O) & hydrogen(H) are the most common elements found in living things. They make up complex molecules that form sugar, starch, fat, oil, wax, and proteins. O RGANIC C OMPOUNDS Because these complex molecules contain carbon, they are called organic compounds. Atomic Number: Shows how many protons are in the nucleus. Atomic Weight (Mass): The total mass of all the protons and neutrons in an atom. Electrons: so tiny they have very little effect on the mass of an atom. I NORGANIC C OMPOUNDS Substances that do not contain carbon are called inorganic compounds. I NORGANIC E XAMPLES : O N EARTH, THERE ARE WAY MORE ORGANIC MOLECULES THAN INORGANIC ! N UTRIENTS Nutrients are elements and compounds needed for living, growing, and reproducing. Plants get nutrients they need from the air and water (carbon, hydrogen, oxygen), and from the soil (nitrogen, phosphorus, potassium, magnesium, calcium, sulfur). A NIMALS GET NUTRIENTS FROM ? MACRONUTRIENTS Macro means large or large-scale MICRONUTRIENTS Micro means very small or small-scale. 6 ELEMENTS MAKE UP 99% OF THE HUMAN BODY Oxygen, carbon, hydrogen, nitrogen, calcium & phosphorus. M AINTAINING THE RIGHT LEVEL OF NUTRIENTS Consider a farmer who notices that crops are not growing well; lower leaves of plants show distinct yellow striping, and plants are not as tall as they should be: The farmer has been applying nitrogen, phosphorus & potassium To the soil expecting to get high yields from the crops. B UT Soil tests show low levels of magnesium & high levels of potassium. Farmers know high levels of potassium can interfere with absorption of magnesium by the plant. One solution: stop applying fertilizer with potassium and apply a fertilizer containing magnesium. Same with humans Protein is good, but O PTIMUM A MOUNTS : Reservoir built in California in 1980 to control the flow of irrigation water to farms. S HORTLY AFTER IT WAS BUILT : Fish in the reservoir died. Birds living on or near reservoir died/dying; produced abnormal chicks. Tests showed surviving fish and birds contained a high level of selenium. Selenium was traced back to soil in and around reservoir. M ICRONUTRIENT SELENIUM IS AN ELEMENT THAT IS REQUIRED IN TRACE AMOUNTS Too much or too little can cause harmful health effects. I F PLANTS HAVE TOO LITTLE SELENIUM, ANIMALS THAT EAT THEM WILL ALSO BE DEFICIENT IN SELENIUM Studies: selenium deficiency in humans can be linked to cancer and heart disease. Selenium, along with vitamin E, helps protect cell membranes from damage caused by hydrogen peroxide, a poison that is produced by some chemical reactions in cells. O PTIMUM AMOUNTS : The amount of a substance/nutrient that provides an organism with the best health. For humans, at least 70 ug (micrograms) of selenium per day is recommended. T YPES OF ORGANIC MOLECULES : Four important classes of organic compounds Carbohydrates Lipids Proteins Nucleic Acids C ARBOHYDRATES : Are organic molecules made up of atoms of carbon, hydrogen, and oxygen. These atoms can form simple molecules, such as sugar, or large, complex molecules, such as starch, cellulose, and glycogen. G LUCOSE IS THE SIMPLE SUGAR MADE BY GREEN PLANTS IN PHOTOSYNTHESIS. The atoms in a molecule of glucose usually join together to form a 6 sided figure: C 6 H 12 O 6 C OMPLEX C ARBOHYDRATES Such as cellulose, starch, and glycogen are composed of many molecules joined together: L IPIDS : Are compounds composed of many carbon, hydrogen, and oxygen atoms. B OTH ANIMALS & PLANTS PRODUCE LIPIDS Our skin produces oils, and our bodies store food in the form of fat. Plant products such as canola seeds, corn, peanuts, soybeans, walnuts, and cashews contain large amounts of oils. F AT MOLECULE : MADE UP OF 3 CHAINS OF FATTY ACIDS CONNECTED TO 1 MOLECULE OF A COMPOUND CALLED GLYCEROL. P ROTEINS AND A MINO A CIDS : P ROTEINS : Have many functions. Used by organisms for growth, repair, and as a source of energy. P ROTEINS : Are the main component of enzymes. Remember that enzymes are catalysts that control chemical reactions in organisms P ROTEINS ARE ORGANIC COMPOUNDS THAT ARE MADE UP OF AMINO ACIDS The way amino acids form proteins is similar to the way glucose units join together to form complex carbohydrates such as starch. E ACH PROTEIN HAS ITS OWN NUMBER AND ARRANGEMENT OF AMINO ACIDS. Usually, a protein contains between 40 and 500 amino acid units. Insulin (which regulates carbohydrate and fat metabolism in the body- diabetes) contains 51 amino acid units arranged as two chains. 20 different kinds of amino acids are common in proteins. Green plants convert glucose into amino acids. N UCLEIC A CIDS Are the largest and most complicated molecules found in living things. All cells contain two important nucleic acids- DNA (deoxyribonucleic acid) & RNA (ribonucleic acid). D NA AND R NA ARE MADE UP OF 3 SUBSTANCES : Phosphates A simple sugar called ribose Nitrogen-containing molecules. Nucleic acids play a major role in heredity and in controlling a cells activities. DNA transfers information about an organisms body from one generation to the next. RNA transmits genetic information from DNA to proteins produced by the cell. C HECK & R EFLECT Page 203, #s 1-7, Due Monday, Feb 2.