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Chapter 2 Section 2 • Objectives: –Explain why organisms need food, water, air, and living space. –Describe the chemical building blocks of cells Water • Very crucial in most chemical reactions in the body require this • Body is 70% water. • Survive 3 days without water Air • Many organisms need oxygen for metabolic (chemical) reactions. • Plants, algae, and some bacteria need carbon dioxide for photosynthesis A place to live • Every organism needs a place that contains what they need. • Organisms compete for space. Food • Food gives organisms energy that allow them to carry on life processes such as: –Nutrients to replace cells –Build body parts Food Makers • Producers –Organisms that make their own food through the process of photosynthesis. –Changes Carbon Dioxide into Oxygen Food Takers • Consumers –Must eat other organisms to get energy • Decomposers –One type of consumer –Breaks down dead organisms and animal wastes 4 Classes of Organic Compounds: • • • • Carbohydrates Lipids Proteins Nucleic Acids A. Carbohydrates: 1) Organic compounds made of Carbon, Hydrogen, & Oxygen in a 1:2:1 ratio A. Carbohydrates: 2) Key source of energy 3) Found in most foods, including fruits, vegetables, and grains A. Carbohydrates: 4) Simple carbohydrates - Made of single sugars called monosaccharide . (ex: table sugar and sugar in fruits) 5) Two sugars are disaccharides. 6) Complex carbohydrates – Made of hundreds of sugar molecules linked together. (ex: Potato plant store extra sugar as starch) A. Carbohydrates: 7. Starch is a carbohydrate that stores energy in plants 8. Glycogen is a carbohydrate made by animals to store energy A. Carbohydrates: 9. Cellulose is an indigestible carbohydrate that provides structural support for plants B. Lipids: 1. Mostly insoluble in water 2. Include fats, phospholipids, steroids, and waxes. B. Lipids: 3. Phospholipids - Important part of cell membranes (double layer) - Head attracts water - Tail does not attract water tails come together in double layer. 4. Fats are lipids that store energy Fats a. Contain 3 fatty acids bonded to a glycerol molecule backbone Fats b. Glycerol is a 3-carbon organic molecule c. A fatty acid is a long chain of carbon atoms with attached hydrogen atoms Fats d. Unsaturated fats – liquid at room temperature. Contain double bonds. e. Saturated Fats – Solid at room temperature. No double bonds. Fat C. Proteins 1. Proteins– large molecule formed by linked amino acids. 2. Twenty amino acids make up all proteins. a. Order and number of amino acids determine protein. b. Amino acids fold and twist into a compact protein. Hemoglobin C. Proteins 3. Importance a. Structural b. Enzymes- speed up chemical reactions c. Immune system d. Muscle contraction D. Nucleic Acids 1. Nucleic acids– long chain of nucleotides, codes for genetic information. 2. Nucleotides– contains a sugar phosphate back bone and a base. a. There are 4 bases b. Variation on pattern and number of bases creates genetic variation. DNA D. Nucleic Acid 3. DNA– deoxyribonucleic acid, two strands form a double helix. Contained in chromosomes. 4. RNA– Ribonucleic acid, single or double stranded, involved in manufacture of proteins. E. ATP 1. ATP – Adenosine Triphosphate, Energy storage molecule used by all living things. 2. Cells require ATP to function. ATP