It’s Alive!! Or Is It? Chapter 2 Preview Section 1 Characteristics of Living Things Section 2 The Necessities of Life Concept Mapping
Section1 Characteristics of Living Things Chapter 2 Bellringer • What are four living and nonliving things that you interact with every day? How do you know whether each is living or nonliving? Do you know what the word inanimate means? If so, write out a definition. Does nonliving mean the same thing as dead? Explain your answer. • Write your answers in your science journal.
Section1 Characteristics of Living Things Chapter 2 Objectives • Describe the six characteristics of living things. • Describe how organisms maintain stable internal conditions. • Explain how asexual reproduction differs from sexual reproduction.
Section1 Characteristics of Living Things Chapter 2 Living Things Have Cells • All living things are composed of one or more cells. • Unicellular organisms – made of only 1 cell • Multicellular organisms – made of 2 or more cells • A cell is a membrane-covered structure that contains all of the materials necessary for life. • Some organisms are made up of only one cell and some are made up of trillions of cells. In an organism with many cells, different kinds of cells perform specialized functions.
Section1 Characteristics of Living Things Chapter 2 Living Things Sense and Respond to Change • Astimulusis anything that causes a reaction or change in an organism or any part of an organism. • Homeostasisis the maintenance of a stable internal environment. • Responding to External Change Organisms must respond to change in the external environment in order to maintain their homeostasis.
Section1 Characteristics of Living Things Chapter 2 Living Things Reproduce • Organisms make other organisms similar to themselves. • In sexual reproduction, two parents produce offspring that will share characteristics of both parents. • In asexual reproduction, a single parent produces offspring that are identical to the parent.
Section1 Characteristics of Living Things Chapter 2 Living Things Have DNA • The cells of all living things contain the molecule deoxyribonucleic acid, or DNA. • DNA controls the structure and function of cells. • The passing of traits through DNA is called heredity.
Section1 Characteristics of Living Things Chapter 2 Living Things Use Energy • Organisms use energy to carry out the activities of life. • An organism’s metabolism is the total of all of the chemical activities that the organism performs.
Section1 Characteristics of Living Things Chapter 2 Living Things Grow and Develop • All living things, whether they are made of one cell or many cells, grow during periods of their lives. • Living things may develop and change as they grow.
Chapter 2 Section2 The Necessities of Life Bellringer • What do you think your mass would be if there were no water in your body? What else besides water is your body composed of? Where do you think you get the minerals that make up your body mass? • Record your answers in your science journal.
Chapter 2 Section2 The Necessities of Life Objectives • Explain why organisms need food, water, air, and living space. • Describe the chemical building blocks of cells.
Section2 The Necessities of Life Chapter 2 Water • Your cells and the cells of almost all living organisms are approximately 70% water. Most of the chemical reactions involved in metabolism require water. Air • Air is a mixture of several different gases, including oxygen and carbon dioxide. Most living things use oxygen in the chemical process that releases energy from food.
Section2 The Necessities of Life Chapter 2 A Place to Live • All organisms need a place to live that contains all of the things they need to survive. Space on Earth is limited, so organisms are often in competition with each other. Food • All living things need food. Food gives organism energy and the raw material needed to carry on life processes.
Section2 The Necessities of Life Chapter 2 Food, continued • Making Food Some organisms, such as plants, are called producers. Producers can make their own food by using energy from their surroundings. • Taking Food Other organisms are called consumers because they must eat (consume) other organisms to get food. Decomposers are consumers that get their food by breaking down the nutrients in dead organisms or animal wastes.
Section2 The Necessities of Life Chapter 2 Comparing Consumers and Producers Click below to watch the Visual Concept. Visual Concept
Section2 The Necessities of Life Chapter 2 Putting It All Together • All organisms need to break down that food in order to use the nutrients in it. • Nutrients are made up of molecules. • Molecules found in living things are usually made up of six elements: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
Section2 The Necessities of Life Chapter 2 Proteins • Proteins are large molecules made up of amino acids. • Making Proteins Organisms break down the proteins in food to supply their cells with amino acids that are then linked together to form new proteins. • Proteins in Action Some proteins form structures that are easy to see. Other proteins help cells do their jobs. Proteins called enzymes start or speed up chemical reactions in cells.
Section2 The Necessities of Life Chapter 2 Carbohydrates • Molecules made of sugars are called carbohydrates. • Simple Carbohydrates Simple carbohydrates are made up of one sugar molecule or a few sugar molecules linked together. • Complex Carbohydrates Complex carbohydrates are made of hundreds of sugar molecules linked together. Organisms store extra sugar as complex carbohydrates.
Section2 The Necessities of Life Chapter 2 Lipids • Lipids are compounds that cannot mix with water. • Phospholipids are the molecules that form much of the cell membrane. • Fats and OilsFats and oils are lipids that store energy. When an organism has used up most of its carbohydrates, it can get energy from these lipids.
Chapter 2 Section2 The Necessities of Life
Section2 The Necessities of Life Chapter 2 ATP • Adenosine triphosphate, or ATP, is the major energy-carrying molecule in cells. • The energy in carbohydrates and lipids must first be transferred to ATP, which then provides fuel for cellular activities.
Section2 The Necessities of Life Chapter 2 Nucleic Acids • Nucleic acids are large molecules made up of subunits called nucleotides. • Nucleic acids are sometimes called the blueprints of life because they have all the information needed for a cell to make proteins. • DNA is a nucleic acid.
Section2 The Necessities of Life Chapter 2 Nucleic Acid Click below to watch the Visual Concept. Visual Concept
Chapter 2 It’s Alive!! Or Is It? Concept Mapping Use the terms below to complete the concept map on the next slide.
Chapter 2 It’s Alive!! Or Is It?
Chapter 2 It’s Alive!! Or Is It?