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Chapter 2 Section 2 –Necessities of Life. 4 Necessities of Life. Water (Most chemical reactions for “metabolism” – all organisms activities, including getting energy from food, growing. etc – requires water. May get from food.)
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4 Necessities of Life • Water (Most chemical reactions for “metabolism” – all organisms activities, including getting energy from food, growing. etc – requires water. May get from food.) • Air (Need for chemical process to get energy from food. Some organisms (anaerobic) do not need air; some types of bacteria are examples.) • Shelter (Actually means having a place to live with access to all needs.) • Food (Need to have energy and materials to carry out life processes.)
Competition Organisms often have to compete for food, water, shelter or other necessities.
“Making” vs. “Taking” Food • Producers: Make their own (produce) food via photosynthesis • Consumers: Must eat other (consume) organisms to get food • Types of Consumers:Herbivores (eat producers; ex: zebra) Carnivores (eat consumers; ex: lion)Omnivores (eat both; ex: brown bear)Detritivores (eat dead organisms; ex: vulture)Decomposers (detritivores that break down complex molecules in dead tissue/ wastes into simpler molecules; ex: mushrooms)
Putting It All Together • All organisms need to breakdown food to get/use nutrients. • Nutrients are made of molecules (substance made of >2 atoms). • Organisms’ molecules mostly made from 6 elements:carbon / hydrogen / nitrogen / oxygen / phosphorus / sulfur • Elements combine to make:proteins/ carbohydrates / lipids / ATP / nucleic acids
Proteins • Necessary for almost all life processes of cell • Made of amino acids (smaller molecules) • Many functions: • Some form structures (hair, spider webs) • Some help cells do jobs ( hemoglobin delivers oxygen thru body) • Some are enzymes (speed chemical reactions) • Needed to build and repair the body
Carbohydrates (Carbs) • Made of sugars • Provide and store energy • Simple Carbs • Made from 1 sugar or just a few sugar molecules • Examples: table sugars and fructose (sugar in fruit) • More common than complex carbs • Complex Carbs • Made from 100’s of sugar molecules which are linked • Example: potato starch
Lipids • Molecules that cannot mix with water • Have many jobs • Some store energy • Fats - animals • Oils – plants • Phospholipids • Make cell membranes • Pair up; “heads” attracted to water, and “tails” avoid water
ATP • Molecules called Adenosine Triphosphate • Job: major energy carrying molecule of cells • Energy from carbs or lipids are transformed to ATP to provide fuel
Nucleic Acids • Molecules that carry directions for how to make proteins • Made of smaller molecules called nucleotides • Sequence stores information • DNA is an example of a nucleic acid which directs making proteins
Additional Information • For additional information…especially chemistry…go to http:\\my.hrw.com . User name: minerva13 password: minervaThen visit the visual concepts for Ch 2 Section2