Energy and the Cell © 2015 Pearson Education, Inc. 1.

Cells transform energy as they perform work
Cells are miniature chemical factories, housing thousands of chemical reactions. Some of these chemical reactions release energy, and others require energy. Energy changes forms By definition, “Living Systems” can take in energy and use it. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. © 2015 Pearson Education, Inc. 2

Cool “Fires” Attract Mates and Meals
Fireflies (family Lampyridae) use light to send signals to potential mates instead of using chemical signals like most other insects The light comes from a set of chemical reactions that occur in light producing organs in its abdomen

Examples of energy conversions:
Females of some species produce a light pattern that attracts males of other species, which are then eaten by the female – Yummy! Examples of energy conversions: - Chemical bonds to light - Chemical bonds to new chemical bonds and movement

There two basic types of energy forms: ENERGY AND THE CELL
Energy is the capacity to perform work Work = defined as the capacity to cause change All organisms require energy to change “Maintain homeostasis” and stay “alive” Change = “work” There two basic types of energy forms:

Gravity can move this biker down the mountain,
However – How’d he get up there? You know there is “stored energy” in this system, it’s just that – You don’t know how much. © 2015 Pearson Education, Inc.

Kinetic energy is the energy of motion
Potential energy is stored energy - can be converted to kinetic energy & vice versa Figure 5.1A–C

Energy is the capacity to cause change or to perform work. There are two basic forms of energy. Kinetic energy is the energy of motion. Potential energy is energy that matter possesses as a result of its location or structure. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. © 2015 Pearson Education, Inc. 8

hermal energy is a type of kinetic energy associated with the random movement of atoms or molecules. Thermal energy in transfer from one object to another is called heat. Light is also a type of kinetic energy; it can be harnessed to power photosynthesis. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 9

Chemical energy is the potential energy available for release in a chemical reaction and the most important type of energy for living organisms to power the work of the cell. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. © 2015 Pearson Education, Inc. 10

Thermodynamics is the study of energy transformations that occur in a collection of matter. The word system is used for the matter under study. The word surroundings is used for everything outside the system; the rest of the universe. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. © 2015 Pearson Education, Inc. 11

1st Law of Thermodynamics, and – 2nd Law of Thermodynamics
Two laws govern energy transformations Thermodynamics Is the study of energy transformations 1st Law of Thermodynamics, and – 2nd Law of Thermodynamics

The First Law of Thermodynamics
Energy cannot be created or destroyed The total amount of energy in the universe is constant, However – Energy can be changed from one form to another So, it might look like it’s being made or destroyed, but it’s just changing forms -

What are all the different forms of energy you see in this room?
Which ones are stored energy or kinetic energy?

What are all the different forms of energy you see in this room?

Second Law = Energy transformations do not convert 100% of one type of energy into only one other type - Most of the energy is converted to other types we cannot measure – that is, entropy

Energy for cellular work
The Second Law of Thermodynamics States that energy transformations increase disorder or “entropy” Some energy lost as heat that organism uses anyway Living systems have adapted to transfer energy efficiently Heat Chemical reactions Carbon dioxide + Glucose + ATP ATP water Oxygen Energy for cellular work Figure 5.2B

Kinetic energy of movement
Fuel Energy conversion Waste products Heat energy Gasoline Carbon dioxide + + Combustion Kinetic energy of movement Oxygen Water Energy conversion in a car Heat energy Cellular respiration Figure Energy transformations in a car and a cell Glucose Carbon dioxide + + ATP ATP Oxygen Water Energy for cellular work Energy conversion in a cell

Automobile engines and cells use the same basic process to make the chemical energy of their fuel available for work. In the car and cells, the waste products are carbon dioxide and water. Cells use oxygen in reactions that release energy from fuel molecules. In cellular respiration, the chemical energy stored in organic molecules is used to produce ATP, which the cell can use to perform work. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 19

Discussion &/or Homework Assignment: What is a “perpetual motion machine?” The second law says that such a thing cannot exist . . .

Two laws govern energy transformations in organisms. Per the first law of thermodynamics (also known as the law of energy conservation), energy in the universe is constant. Per the second law of thermodynamics, energy conversions increase the disorder of the universe. Entropy is the measure of disorder or randomness. Student Misconceptions and Concerns Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. Teaching Tips • Some students can relate well to the concept of entropy as applied to the room where they live. Despite cleaning up and organizing the room on a regular (or irregular) basis, the room becomes increasingly disorganized, a victim of entropy, until another energy input (or effort) is exerted to make the room more orderly again. Students might even get to know entropy as the “dorm room effect.” • The heat produced by the engine of a car is typically used to heat the car during cold weather. However, is this same heat available in warmer weather? Students are often unaware that their car “heaters” work very well in the summer, too. Just as exercise can warm us when it is cold, the same extra heat is released when we exercise in warm conditions. A car engine in the summer struggles to dissipate heat in the same way that a human struggles to cool off after exercising when the weather is warm. Active Lecture Tips • Challenge your students to come up with examples of common energy conversions in their lives. Have students turn to someone seated near them to find at least two examples. In our daily lives, we rely upon many energy transformations. On our classroom walls, a clock converts electrical energy to mechanical energy to sweep the hands around the clock’s face (unless it is digital!). Our physical (mechanical) activities walking to and from the classroom rely upon the chemical energy from our diet. This chemical energy in our diet also helps us maintain a steady body temperature (heat). • Challenge your students to explain why they feel warm when it is 30C (86F) outside if their core body temperature is 37C (98.6F). Shouldn’t they feel cold? Have students work in groups of two or three to think this through. The answer is, our bodies are always producing heat. At these higher temperatures, we are producing more heat than we need to maintain a core body temperature around 37C. Thus, we sweat and behave in ways that help release our extra heat generated in cellular respiration. • See the Activity Keeping an Organized Dorm Room Requires Energy, Just Like in a Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. • See the Activity Universal Currency in the Cell on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 21

Chemical reactions either release or store energy
release energy (exergonic reactions) or require an input of energy and store energy (endergonic reactions). Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) 22

Exergonic reactions release energy. These reactions release the energy in covalent bonds of the reactants. Burning wood releases the energy in glucose as heat and light. Cellular respiration involves many steps, releases energy slowly, and uses some of the released energy to produce ATP. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) 23

Amount of energy released
Reactants Amount of energy released Energy Products Potential energy Figure 5.11a Exergonic reaction, energy released

An endergonic reaction requires an input of energy and yields products rich in potential energy. Endergonic reactions start with reactant molecules that contain relatively little potential energy but end with products that contain more chemical energy. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) 25

Amount of energy required
Products Energy Amount of energy required Reactants Potential energy Figure 5.11b Endergonic reaction, energy required

Photosynthesis is a type of endergonic process. In photosynthesis, energy-poor reactants (carbon dioxide and water) are used, energy is absorbed from sunlight, and energy-rich sugar molecules are produced. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) © 2015 Pearson Education, Inc. 27

A living organism carries out thousands of endergonic and exergonic chemical reactions. The total of an organism’s chemical reactions is called metabolism. A metabolic pathway is a series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) © 2015 Pearson Education, Inc. 28

Chemical reactions either store or release energy
Endergonic reactions absorb energy and yield products rich in potential energy Anabolic reactions (anabolism) Potential energy of molecules Reactants Energy required Products Amount of energy required

Exergonic reactions = release energy and yield products that contain less potential energy than their reactants = Catabolic reactions, catabolism Reactants Energy released Products Amount of energy released Potential energy of molecules

Energy coupling uses the energy released from exergonic reactions to drive endergonic reactions, typically using the energy stored in ATP molecules. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • All too often we hear or read that some thing or reaction creates energy. We might hear or read that a power plant “produces” energy or that mitochondria “make” energy. Even in our classroom conversations, we may occasionally slip into this error. When discussing the first law of thermodynamics, consider emphasizing the inaccuracy of such statements. • Although typically familiar with the concept of dietary calories, students often struggle to think of calories as a source of potential energy. For many students, it is not clear that potential energy is stored in food as calories. Teaching Tips • The same mass of fat stores nearly twice as many calories (about 9 kcal per gram) as an equivalent mass of protein or carbohydrates (about 4.5–5 kcal per gram). Thus, when comparing equal masses of fat, protein, and lipid, the fat has nearly twice the potential energy. Fat is therefore an efficient way to store energy in animals and many plants. To store an equivalent amount of energy in the form of carbohydrates or proteins would require about twice the mass, adding a significant burden to the organism’s structure. (For example, if you were 20 lb overweight, you would be nearly 40 lb overweight if the same energy were stored as carbohydrates or proteins instead of fat.) • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) 31

Metabolism = The sum of all the chemical reactions in an organism
Metabolism = The sum of all the chemical reactions in an organism. {Cells carry out thousands of chemical reactions} Energy coupling = shuttle energy from exergonic reactions to fuel endergonic reactions ATP couples chemical energy and drives cellular work = Energy Exchange Molecule ATP powers nearly all forms of cellular work

ATP drives cellular work by coupling exergonic and endergonic reactions
ATP, adenosine triphosphate, powers nearly all forms of cellular work. ATP consists of adenosine and a triphosphate tail of three phosphate groups. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well. Teaching Tips • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) • When introducing ATP and ADP, consider asking your students to think of the terms as A-3-P and A-2-P, noting that the word roots “tri” = 3 and “di” = 2. It might help students to keep track of the number of phosphates more easily. • Recycling is essential in cell biology. Damaged organelles are broken down intracellularly, and chemical components, the monomers of the cytoskeleton, and ADP are routinely recycled. There are several advantages common to human recycling of garbage and cellular recycling. Both save energy by avoiding the need to remanufacture the basic units, and both avoid an accumulation of waste products that could interfere with other “environmental” chemistry (the environment of the cell or the environment of the human population). © 2015 Pearson Education, Inc. 33

Triphosphate Adenosine P P P ATP H2O Diphosphate Adenosine P P P
Energy Figure 5.12a-2 The hydrolysis of ATP yielding ADP, a phosphate group, and energy (step 2) Phosphate ADP

The energy in an ATP molecule is carried in the bonds between its phosphate groups
Hydrolysis Adenine Ribose H2O Adenosine diphosphate Adenosine Triphosphate + ADP Nite Class end 9/19 Start for 9/26

Cellular work can be sustained, because ATP is a renewable resource that cells regenerate
ATP Cycle: ATP ADP + P Energy for endergonic reactions Energy from exergonic reactions Phosphorylation Hydrolysis

A cell uses and regenerates ATP continuously. In the ATP cycle, energy released in an exergonic reaction, such as the breakdown of glucose during cellular respiration, is used in an endergonic reaction to generate ATP from ADP. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well. Teaching Tips • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) • When introducing ATP and ADP, consider asking your students to think of the terms as A-3-P and A-2-P, noting that the word roots “tri” = 3 and “di” = 2. It might help students to keep track of the number of phosphates more easily. • Recycling is essential in cell biology. Damaged organelles are broken down intracellularly, and chemical components, the monomers of the cytoskeleton, and ADP are routinely recycled. There are several advantages common to human recycling of garbage and cellular recycling. Both save energy by avoiding the need to remanufacture the basic units, and both avoid an accumulation of waste products that could interfere with other “environmental” chemistry (the environment of the cell or the environment of the human population). 37

ATP synthesis is endergonic ATP ATP hydrolysis is exergonic
Energy from cellular respiration (exergonic) Energy for cellular work (endergonic) Figure 5.12c The ATP cycle ADP + P

There are three main types of cellular work: chemical, mechanical, and transport. ATP drives all three of these types of work. Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well. Teaching Tips • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) • When introducing ATP and ADP, consider asking your students to think of the terms as A-3-P and A-2-P, noting that the word roots “tri” = 3 and “di” = 2. It might help students to keep track of the number of phosphates more easily. • Recycling is essential in cell biology. Damaged organelles are broken down intracellularly, and chemical components, the monomers of the cytoskeleton, and ADP are routinely recycled. There are several advantages common to human recycling of garbage and cellular recycling. Both save energy by avoiding the need to remanufacture the basic units, and both avoid an accumulation of waste products that could interfere with other “environmental” chemistry (the environment of the cell or the environment of the human population). © 2015 Pearson Education, Inc. 39

Hydrolysis of ATP releases energy by transferring its third phosphate from ATP to some other molecule in a process called phosphorylation. Most cellular work depends on ATP energizing molecules by phosphorylating them. ATP drives endergonic reactions by phosphorylation Transferring a phosphate group onto a molecule to make it more reactive Student Misconceptions and Concerns • Students with limited exposure to physics may have never understood the concepts of energy and the conservation of energy. They also may not have distinguished between potential and kinetic energy. Understanding such broad and new abstract concepts requires time and concrete examples. • Energy coupling at the cellular level may be new to many students, but it is a familiar concept when related to the use of money in our society. Students might be discouraged if the only benefit of work was the ability to make purchases from the employer. (We all might soon tire of a fast-food job that only paid its employees in food!) Money permits the coupling of a generation of value (a paycheck, analogous to an energy-releasing reaction) to an energy-consuming reaction (money, which allows us to make purchases in distant locations). This idea of earning and spending is a common concept we all know well. Teaching Tips • The amount of energy each adult human needs to generate the ATP required in a day is tremendous. Here is a calculation that has impressed many students. Depending upon the size and activity of a person, a human might burn 2,000 dietary calories (kilocalories) a day. This is enough energy to raise the temperature of 20 liters of liquid water from 0 to 100C. This is something to think about the next time you heat water on the stove! If you can bring in ten 2-liter bottles, you can help students visualize how much liquid water can be raised from 0 to 100C. (Note: 100 calories raises about 1 liter of water 100C, but it takes much more energy to melt ice or to convert boiling water into steam.) • When introducing ATP and ADP, consider asking your students to think of the terms as A-3-P and A-2-P, noting that the word roots “tri” = 3 and “di” = 2. It might help students to keep track of the number of phosphates more easily. • Recycling is essential in cell biology. Damaged organelles are broken down intracellularly, and chemical components, the monomers of the cytoskeleton, and ADP are routinely recycled. There are several advantages common to human recycling of garbage and cellular recycling. Both save energy by avoiding the need to remanufacture the basic units, and both avoid an accumulation of waste products that could interfere with other “environmental” chemistry (the environment of the cell or the environment of the human population). 40

Protein filament moved
Chemical work P ATP P ADP + P Reactants Product formed Transport work ATP ADP + P P P Transport protein Solute transported Figure 5.12b How ATP powers cellular work Mechanical work ATP P ADP + P P Motor protein Protein filament moved

Metabolism = all the chemical reactions in an organism
Cells need a mechanism for linking chemical reactions, by 1. Coupling energy between endergonic & exergonic reactions. = ATP Cycle couples anabolism to catabolism 2. Reactions need to occur fast enough to pass their products onto the next reaction. So – Run reactions in a series, one after another, in Metabolic pathways - using protein catalysts called ENZYMES:

Energy and the Cell © 2015 Pearson Education, Inc. 1.

Similar presentations

Presentation on theme: "Energy and the Cell © 2015 Pearson Education, Inc. 1."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Energy and the Cell © 2015 Pearson Education, Inc. 1.

Similar presentations

Presentation on theme: "Energy and the Cell © 2015 Pearson Education, Inc. 1."— Presentation transcript:

Similar presentations

About project

Feedback