1.3 Common Substances Essential to Living Things

1. 1.3 Common Substances Essential to Living Things • Our body needs about 25 different chemicals for normal growth. • The complex organization of these chemicals produces organic compounds which contain Carbon, • Substances that do not contain Carbon are called inorganic compounds.

2. Macronutrients Nutrients, • are made up of elements and compounds, help living organisms survive. • Plants obtain carbon, oxygen and hydrogen from the air, and nitrogen, phosphorus, potassium, magnesium, calcium and sulfur from the soil. • These nine elements are called macronutrients (because they are in needed in large quantities) are essential for plants to grow. • There are other elements that are also needed, but not in large quantities. These elements are called micronutrients.

3. Abbreviate the table on page 197 into your science notes.

4. Maintaining the Right Level of Nutrients • By knowing how plants use each element, agriculturalists can diagnose deficiencies and excesses, and act accordingly, to alleviate the problem. • Problem: yellow striping on lower leaves & soil test indicates high levels of potassium and low levels of magnesium • Analysis: potassium is interferring with the plants ability to absorb the magnesium • Solution: stop applying fertilizer containing potassium and apply more fertilizer with magnesium

5. Optimum Amounts • A micronutrient may be present in larger amounts than normal. • If this occurs it can have harmful effects. • Too little can also have harmful effects. • The optimum amount of a substance, such as the micronutrient - selenium, is the amount that provides an organism with the best health.

6. TYPES OF ORGANIC MOLECULES • Most chemicals in humans and other living things are organic compounds. • Four important classes of organic compounds are: • carbohydrates, • lipids, • proteins, • and nucleic acids.

8. Carbohydrates • When we eat food such as pasta, rice, potatoes, fruits, and bread, we are eating carbohydrates. • Carbohydrates 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. • Glucose is the simple sugar made by green plants in photosynthesis.

9. Complex carbohydrates • Complexs carbs such as cellulose, starch, and glycogen are composed of many glucose molecules joined together

10. Lipids • Fats, oils, and waxes are lipids—compounds composed of many carbon, hydrogen, and oxygen atoms. • Both animals and plants produce lipids. • For example, 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.

11. That’s One Fat Molecule (ha ha)

12. Indicators (tests for…)

13. Proteins and Amino Acids • meat, fish, eggs, and dairy products add proteins to our diet. • Proteins help a body growth and repair. • Proteins are a source of energy. • They are the main component of enzymes. • enzymes are catalysts that control chemical reactions. • A protein is made up of units called amino acids. • The way amino acids form proteins is similar to the way glucose units join together to form complex carbohydrates such as starch. Figure 1.22 This diagram shows the structure of the amino acid glycine.

14. Nucleic Acids • Nucleic acids are the largest and most complicated molecules found in living things. • All cells contain two important nucleic acids, • deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). • DNA and RNA are made up of three 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.