Common Substances essential to living things

1. Common Substances essential to living things Lesson Objective: Students will identify common organic and inorganic substances that are essential to living things.

2. Review: • Fossil fuels are also known as?

3. What are little boys made of? Snips and snails, and puppy dogs tails,
That's what little boys are made of.


4. What are little girls made of? Sugar and spice and all things nice, That's what little girls are made of.

5. Actually… • The composition of the human body is: • Water, proteins, fats, sugars, starch, DNA, minerals, vitamins, salts, acids, and bases.

6. Our bodies need about 25 elements for normal growth (page 197).

7. 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. • Because these complex molecules contain carbon, they are called organic compounds. • Substances that do not contain carbon are called inorganic compounds. • What are some examples you can think of for inorganic compounds?

9. On earth, there are way more organic molecules than inorganic!

10. Nutrients • Nutrients are elements and compounds need 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).

11. Animals get nutrients from?

12. macronutrients • Macro means large or large-scale

13. micronutrients • Micro means very small or small-scale.

14. 6 elements make up 99% of the human body • Oxygen, carbon, hydrogen, nitrogen, calcium & phosphorus.

15. Maintaining 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:

16. The farmer has been applying phosphorus & potassium • To soil expecting to get high yields from the crops. • Soil tests show low levels of magnesium & high levels of potassium. Farmer 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!

17. Optimum Amounts: • Reservoir built in California in 1980 to control the flow of irrigation water to farms.

18. Shortly after it was built: • Fish in 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.

19. Micronutrient selenium is an element that is required in trace amounts • Too much or too little can cause harmful health effects.

20. If 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.

21. Optimum 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.

22. Types of organic molecules: • Four important classes of organic compounds… • Carbohydrates • Lipids • Proteins • Nucleic Acids

23. Carbohydrates: • Are organic molecules made up of atoms of carbon, hydrogen, and oxygen.

24. These atoms can form simple molecules, such as sugar, or large, complex molecules, such as starch, cellulose, and glycogen.

25. Glucose 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: C6H12O6

26. Complex Carbohydrates • Such as cellulose, starch, and glycogen are composed of many molecules joined together:

27. Lipids: • Are compounds composed of many carbon, hydrogen, and oxygen atoms.

28. Both 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.

29. Fat molecule: made up of 3 chains of fatty acids connected to 1 molecule of a compound called glycerol.

30. Proteins and Amino Acids:

31. Proteins: • Have many functions. • Used by organisms for growth, repair, and as a source of energy. • They are the main component of enzymes. • Remember that enzymes are catalysts that control chemical reactions in organisms.

32. Proteins 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.

33. Each 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.

35. Nucleic Acids • Are the largest and most complicated molecules found in living things. • All cells contain two important nucleic acids- DNA (deoxyribonucleic acid) & RNA (ribonucleic acid).

37. Dna and Rna are made up of 3 substances: • Phosphates, a simple sugar called ribose, and nitrogen-containing molecules. • Nucleic acids play a major role in heredity and in controlling a cell’s activities. • DNA transfers information about an organism’s body from one generation to the next. • RNA transmits genetic information from DNA to proteins produced by the cell.

38. Check & Reflect • Page 203, #s 1-7 • Page 209, #s 1-4