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Cells The Building Blocks of Life What are the Needs of Living Things? • In order to survive all living things need: – Energy – Food – Water – Oxygen – Living space – To maintain a proper temperature Characteristics of Living Things • All living things share characteristics, they: – Are made of cells – Are able to move – Perform complex chemical activities – Are able to grow and develop – Are able to respond to their environment – Are able to reproduce All living things are able to move All living things perform complex chemical activities “building up and breaking down” • Metabolism is the sum total of all the chemical reactions that occur in a living thing. – In humans these chemical reactions are ingestion, digestion, respiration, and excretion. Ingestion • Ingestion is taking in food to process. Digestion • Digestion is the process of breaking down food into simpler substances. Respiration • Respiration is the process of taking in oxygen and using it to produce energy. Excretion • Excretion is the process of getting rid of waste material. All living things are able to grow and develop • Life span is the maximum length of time that an organism is expected to live. All living things are able to respond to their environment • A stimulus is something that comes from outside the organism or from within the organism that triggers a reaction. Examples: cold breeze stomach growl • A response is the reaction that occurs as a result of the stimulus. Examples: goose bumps eat food All living things are able to reproduce “Like produces like” • Sexual reproduction: – Requires two parents – Results in offspring that show variations • Asexual reproduction: – Requires one parent – Results in identical offspring with no variations Both forms of reproduction give a chemical “blueprint” to the next generation. Cellular Reproduction Egg and Sperm Cells Fertilization Meiosis - Sexual Reproduction Result is daughter cells with half the chromosomes Mitosis – Asexual Reproduction Result is two identical cells What is Competition? • Competition is the struggle among living things to get the proper amounts of food, water, oxygen and space. • Competition plays an important role in shaping a community. How Do Living Things Maintain Proper Temperature • Homeostasis is the ability of an organism to keep the conditions inside the body the same even though external environmental conditions change. • Warm blooded animals maintain a constant body temperature at all times. – Examples are man and mammals • Cold blooded animals have body temperatures that change with the environment. – Examples are fish and reptiles What Makes Up All Living Things? “The Chemistry Of Life” • All living things are made of elements and compounds. What is an Element? • An element is a pure substance that can not be broken down into any simpler substances. – Only 90 natural elements exist on earth. – Only 11 elements are common in living things. – 4 elements (carbon, nitrogen, oxygen and hydrogen) make up 96% of the weight of the human body. What is a Compound? • A compound is formed when 2 or more elements join together chemically. – Examples are: water H2O, and sugar C6H12O6 A water molecule is an example of a compound There are 2 Types of Compounds • Inorganic Compounds: are compounds that do not contain carbon. (carbon dioxide, CO2, is an exception) – Examples: salt NaCl, Ammonia NH3, Rust Fe3O2 • Organic Compounds: are compounds that do contain carbon; many are basic to life. – There are many types of organic compounds including: carbohydrates, fats, oils, proteins, enzymes, and nucleic acids. Organic Compounds Carbohydrates • Carbohydrates are the main source of energy for living things. – Examples are sugar, starch (fruits, vegetables) – Carbohydrates are made of carbon, hydrogen and oxygen. Carbohydrates Organic Compounds – Fats and Oils • Fats and oils: known as “lipids” are energy rich compounds. – At room temperature fats are solid and oils are liquid. – Fats and oils are made of carbon, hydrogen and oxygen. Fats and Oils Organic Compounds - Proteins • Proteins are necessary for growth and repair of the body. • In addition to carbon, hydrogen and oxygen, proteins are also made of nitrogen (sometimes made of sulfur and phosphorous). – Amino acids are the building blocks of proteins. Proteins Organic Compounds - Enzymes • Enzymes are special proteins that regulate chemical activities in the body. • Enzymes act as catalysts. – A catalyst is a substance that speeds up or slows down a chemical reaction. Enzymes Organic Compounds – Nucleic Acids • Nucleic acids are the “blue prints” of life. • They are large compounds that store information that helps the body make the proteins it needs. – Example: DNA or deoxyribonucleic acid Nucleic Acids What Is Cell Specialization? • In multicellular organisms, cells not only complete its own life activities, but also performs a function that contributes to the life of the organism. • Within multicellular organisms there is division of labor or specialization. – The work of keeping the organism alive is divided up among different parts of the organism. Levels of Specialization Cells combine to form Tissues combine to form Organs combine to form Organ systems combine to form Organism More Specialization Students combine to form Classes combine to form Grades combine to form Schools combine to form District What are Tissues? • Tissues are cells that are similar in structure and function that combine together. – Example: bone cells form bone tissue – Other examples: muscle tissue, nerve tissue, connective tissue. Bone Tissue and Muscle Tissue What are Organs? • Organs are groups of different tissues that work together. – Example: the heart is an organ made of muscle tissues and blood tissue – Other organs: brain, stomach, skin Organs – Heart and Stomach What are Organ Systems? • Organ systems are a group of organs working together to perform a specific function for the organism. – Examples: skeletal system, muscular system, digestive system. Organ Systems What are Organisms? • Organisms are an entire living thing that carries out all the basic life functions. – Examples: Humans, cat, fish, fly Some Organisms