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Resources Bellringers Chapter Presentation Transparencies Standardized Test Prep Visual Concepts Image and Math Focus Bank

It’s Alive!! Or Is It? Chapter 2 Table of Contents Section 1 Characteristics of Living Things Section 2 The Necessities of Life

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 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. • 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. You may stop the video at any time by pressing the Esc key. 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. You may stop the video at any time by pressing the Esc key. Visual Concept

Chapter 2 It’s Alive!! Or Is It? Concept Map Use the terms below to complete the concept map on the next slide.

Chapter 2 It’s Alive!! Or Is It?

End of Chapter 2 Show

Standardized Test Preparation Chapter 2 Reading Read each of the passages. Then, answer the questions that follow each passage.

Standardized Test Preparation Chapter 2 Passage 1Organisms make other organisms similar to themselves. They do so in one of two ways: by sexual reproduction or by asexual reproduction. In sexual reproduction, two parents produce offspring that will share characteristics of both parents. Most animals and plants reproduce in this way. In asexual reproduction, a single parent produces offspring that are identical to the parent. Most single-celled organisms reproduce in this way.

Standardized Test Preparation Chapter 2 1. In the passage, what does the term asexual reproduction mean? AA single parent produces offspring. BTwo parents make identical offspring. CPlants make offspring. DAnimals make offspring.

Standardized Test Preparation Chapter 2 2. What is characteristic of offspring produced by sexual reproduction? FThey are identical to both parents. GThey share the traits of both parents. HThey are identical to one parent. IThey are identical to each other.

Standardized Test Preparation Chapter 2 3. What is characteristic of offspring produced by asexual reproduction? AThey are identical to both parents. BThey share the traits of both parents. CThey are identical to one parent. DThey are usually plants.

Standardized Test Preparation Chapter 2 4. What is the difference between sexual and asexual reproduction? Fthe number of offspring produced Gthe number of parents needed to produce offspring Hthe number of traits produced Ithe number of offspring that survive

Standardized Test Preparation Chapter 2 Passage 2In 1996, a group of researchers led by NASA scientists studied a 3.8-billion-year-old meteorite named ALH84001. These scientists agree that ALH84001 is a potato-sized piece of the planet Mars. They also agree that it fell to Earth about 13,000 years ago. It was discovered in Antarctica in 1984. According to the NASA team, ALH84001 brought with it evidence that life once existed on Mars. Continued on the next slide

Standardized Test Preparation Chapter 2 Passage 2, continuedScientists found certain kinds of organic molecules (molecules containing carbon) on the surface of ALH84001. These molecules are similar to those left behind when living things break down substances for food. When these scientists examined the interior of the meteorite, they found the same organic molecules throughout. Because these molecules were spread throughout the meteorite, scientists concluded that the molecules were not contamination from Earth. The NASA team believes that these organic compounds are strong evidence that tiny organisms similar to bacteria lived, ate, and died on Mars millions of years ago.

Standardized Test Preparation Chapter 2 1. How old is the meteorite named ALH84001? A13,000 years old Bmillions of years old C3.8 billion years old D3.8 trillion years old

Standardized Test Preparation Chapter 2 2. Which of the following would best support a claim that life might have existed on Mars? Fremains of organisms Gwater Hmeteorite temperatures similar to Earth temperatures Ioxygen

Standardized Test Preparation Chapter 2 Interpreting Graphics The graph below shows an ill person’s body temperature. Use the graph below to answer the questions that follow.

Standardized Test Preparation Chapter 2 1. A fever is a spike in temperature. On which day does this person have a fever? ASunday BMonday CWednesday DSaturday

Standardized Test Preparation Chapter 2 2. A body with a fever is often fighting an infection. Fevers help eliminate the pathogens that cause the infection. According to the chart, when does this person probably have the highest fever? FSunday GMonday HWednesday ISaturday

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