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Unit 3 Structure and Function Notes Part 1 It’s Alive or, Is It? M. Elizabeth Martin Luther King, Jr. JHS 2006 Chapter 2 It’s Alive, or Is It 2.1 Characteristics of Living Things 2.2 The Simple Bare Necessities of Life 2.3 The Chemistry of Life Chapter 2 Review 2.1 Characteristics of Living Things The six characteristics of Living Things: 1. 2. 3. 4. 5. 6. All living things have cells All living things sense and respond to change All living things reproduce All living things have DNA All living things use energy All living things grow and develop 2.1 Characteristics of Living Things All living things have cells 1. Unicellular (single celled organisms) Multicellular (organisms made of more than one kind of cells) Excludes viruses because virus are organisms that are made of DNA/RNA and a protein coat – not exactly a cell. 2. All living things sense and respond to change An important part of sensing and responding to environmental changes is maintaining homeostasis. Homeostasis– the maintenance of a stable internal environment despite a changing external environment 3. All living things reproduce There are two types of reproduction: Asexual – a single parent produces an identical offspring. Lots of organisms reproduce this way (bacteria and algae). When cells are cloned they are reproduced in this way. Sexual – requires two parents. Results in a lot better chance for genetic variation. 4. All living things have DNA DNA – deoxyribonucleic acid Provides instructions for making molecules – proteins that take part in all cellular functions and in the synthesis of other kinds of molecules needed for cells to exist. Sometimes called the blueprints of life. Reproduction involves making copies of DNA that is transferred to offspring. The transmission of characteristics/traits from one generation to another is called heredity ____________ 5. All living things use energy Metabolism – all chemical activities that use or make available energy. Producers – organisms that obtain energy from the sun (photosynthetic) or certain bacteria that use inorganic chemicals (chemosynthetic) Consumers – organisms that obtain energy by eating other organisms. Decomposers – Organisms that get their food from breaking down nutrients from dead organisms or animal wastes. 6. All living things grow and develop Even single celled organisms like bacteria grow slightly in size. Babies grow to adult from a single cell 2.2 The Simple Bare Necessities of Life Food Water Air A Place to Live Food Organisms use protein, fats, and carbohydrates as our basic food groups. Organisms may also need trace minerals or vitamins in addition to the basic food groups. Organisms differ in their food needs. Food We have discussed: - make their own food Producers - eat other organisms Consumers Decomposers - eat dead organisms Food eaters can also be broken down into type: Autotrophs - Create their own food Heterotrophs - Obtain food from others Essential Elements – Chemistry of Life The basic elements that make up most of biological molecules are Carbon Hydrogen Nitrogen Oxygen Phosphorous Sulfur Main Types of Molecules – Chemistry of Life The Main Types of Biological Molecules Proteins – made of amino acids. Enzymes are special proteins that allow cell reactions to occur. Carbohydrates – starches made of sugars Lipids – fats, phospholipids (what membranes are made of) Nucleic Acids – made of nucleotides ATP – useable cellular energy – adenosine tri phosphate Water Water is the essence of life 70 percent of most cells are made of water Humans can survive about 3 days without water The chemical formula for water is H2O Air Mixture of several different gases the main ones in order of highest concentration: Nitrogen Oxygen Argon Water Vapor Carbon Dioxide Oxygen and Carbon Dioxide Oxygen is used for aerobic respiration in both plant and animal cells Oxygen is not used for anaerobic (without oxygen) respiration Green plants and other photosynthetic organisms need carbon dioxide in addition to oxygen. The carbon dioxide is for photosynthesis and oxygen used for aerobic respiration. Photosynthesis The energy that powers photosynthesis comes from the sun light. Occurs in the chloroplasts within plant cells Chlorophyll a green pigment in chloroplasts absorb the sun’s energy that is then used to create glucose sugar Starch is the complex carbohydrate plants use to store the glucose sugar molecules that plants produce during photosynthesis. Photosynthesis The chemical reaction for photosynthesis is: 6CO2 + 6H2O Sunlight C6H12O6 + 6O2 C6H12O6 is the chemical formula for glucose Glucose is the main product of photosynthesis. Oxygen is produced as a byproduct of splitting water during photosynthesis Respiration Occurs in mitochondria found in both animal and plant cells Oxygen is used to convert stored sugar (glucose) into useable chemical energy (ATP) A Place to live Some organisms need a lot of space to live. This is why governments are starting to create habitat management plans so that there are places for animals to live. Animals need the help with finding a place to live because people have out competed animals for living place resources. Could life as we know it exist on Earth if air only contained oxygen? Life could not exist as we know it if air only contained oxygen because green plants, algae, and some bacteria need carbon dioxide gas as well as oxygen. Without carbon dioxide photosynthesis could not occur and there would not be producers which consumers need to eat. Review 1. 2. 3. 4. 5. phospholipids In the cell membrane, ________________ (protein or phospholipid) molecules form two layers. When a planarian worm is cut in half, each half develops into a whole worm. This is an example of __________ (asexual or sexual) reproduction. asexual Nucleic acids are (Proteins or Nucleic acids)______________ sometimes called the blueprints of life. (Homeostasis or Heredity) _______________is Heredity the passing of traits from one generation to the next. Metabolism (Metabolism or Homeostasis) _____________ refers to all of the chemical activities that an organism’s cells perform. 6. _________ is a complex carbohydrate Starch manufactured by plants. a. Oil b. Protein c. Starch d. Hemoglobin a. homeostasis. b. a stimulus. c. a reaction. d. an enzyme. 7. When a duck dives under water, its inner eyelids automatically raise to cover the duck’s eyes. In this case, water acts as__________ a stimulus 8. The molecule that provides energy for cellular processes is__________ ATP a. ATP. b. DNA. c. RNA. d. protein. amino acids. 9. The subunits of proteins are __________ a. enzymes. c. nucleotides. b. amino acids. d. sugar molecules. 10. The subunits of nucleic acids are nucleotides. __________ a. enzymes. c. nucleotides. b. amino acids. d. sugar molecules. acids 11. Cells do not use nucleic ___________for energy storage. a. fats c. carbohydrates b. oils d. nucleic acids 12. Plant cells need carbon dioxide which is used for photosynthesis __________ a. cellular respiration. c. photosynthesis. b. reproduction. d. fertilization. 13. The energy that powers photosynthesis comes from Light ______________. from the sun a. light from the sun. b. sugar breakdown. c. gas molecules. d. soil chlorophyll. Light energy 14. Chlorophyll absorbs ________________. a. water. c. light energy. b. carbon dioxide. d. soil oxygen 15. Food molecules are broken down to release energy by the _______________. mitochondria a. ribosomes. c. mitochondria. b. endoplasmic reticulum. d. chloroplasts. 16. Most of the ATP produced by a cell is mitochondria made in the __________________. a. ribosomes. c. mitochondria. b. endoplasmic reticulum. d. chloroplasts.