Pulmonary drug delivery system M.pharm -2nd sem P'ceutics
Biology 12 - Powerpoint - Energy Transformation - Section 5-1
1.
2. UNIT A: Cell Biology
Chapter 2: The Molecules of Cells
Chapter 3: Cell Structure and Function
Chapter 4: DNA Structure and Gene
Expression
Chapter 5: Metabolism: Energy and
Enzymes: Section 5.1
Chapter 6: Cellular Respiration
Chapter 7: Photosynthesis
3. UNIT A Chapter 5: Metabolism: Energy and Enzymes
Chapter 5: Metabolism: Energy
In this chapter you will learn about the numerous chemical reactions
in our bodies involved in breaking down food to produce essential
biological molecules and energy.
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and Enzymes
What is the role of
an enzyme?
What factors
influence the rate of
enzyme activity?
4. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
5.1 Energy Transformations and
Metabolism
Cellular metabolism is the sum of all chemical reactions of
the cell.
•Catabolism refers to reactions that break down large
molecules (products) into smaller molecules (reactants)
•Anabolism refers to reactions that make large molecules
(products) from smaller molecules (reactants)
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reactants product
s
5. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
Energy and Reactions
Free energy is the amount of energy available after a
chemical reaction has occurred.
The change in free energy of a reaction (ΔG) =
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free energy of products − free energy of reactants
− ΔG: products have less energy than reactants, and the
reaction will occur in the direction indicated.
exergonic reactions: spontaneous and release energy
endergonic reactions: require energy input
Many cell reactions use energy from exergonic reactions.
6. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
ATP: Energy for Cells
ATP is the energy currency
of cells.
•ATP is made from ADP and
inorganic phosphate
•Energy is released when the
bond on the terminal
phosphate of ATP is broken.
This energy is used for
endergonic reactions in the
cell.
Figure 5.1 The ATP cycle.
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7. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
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Check Your Progress
1. Explain whether an anabolic reaction is more likely to
be exergonic or endergonic.
2. Explain how the ATP pathway is similar to a
rechargeable battery.
8. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
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9. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
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10. UNIT A Chapter 5: Metabolism: Energy and Enzymes Section 5.1
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Editor's Notes
Presentation title slide
Chapter opener background notes
Are you lactose intolerant? Do you know someone who is? As much as three-quarters of the world's population has some difficulty digesting lactose. Digesting a piece of cheese pizza can be very uncomfortable for those who are lactose intolerant because cheese and other dairy products contain lactose. What causes lactose intolerance?
Lactose is a disaccharide sugar that must be broken down chemically into its two smaller building blocks (galactose and glucose) before it can be absorbed into the bloodstream and used for energy. If it is not broken down, lactose remains in the digestive tract and can cause uncomfortable digestive symptoms. The breakdown of lactose requires an enzyme called lactase. People who are lactose intolerant do not produce enough lactase. A lactose intolerant person who wants to consume dairy products without discomfort must consume products that have been specially treated with enzymes or a lactase enzyme supplement with the dairy in their meal. Yogurt and buttermilk can often be tolerated by those with lactose intolerance because they contain bacterial cultures that aid in the digestion of lactose.
Why is it that some people can easily digest lactose when so many other people cannot? After young mammals are weaned, milk becomes a smaller component of the diet. In most mammals, lactase activity decreases and lactose intolerance usually begins. However, some humans have developed what is called lactase persistency. These individuals continue to produce lactase. Factors that contribute to lactase persistency include diet, culture, and genetics.
The breakdown of lactose is just one of myriad chemical reactions that occur in the human body. Almost every reaction that takes place in our bodies requires a specific enzyme. In this chapter, you will learn about the characteristics of enzymes and how enzymes function in the flow of energy and metabolism.
metabolism the sum of all the chemical reactions that occur in a cell
catabolism: the breaking down of molecules
anabolism: the building up (synthesis) of molecules
reactants: in a chemical reaction, the substances that participate in a reaction
products: in a chemical reaction, the substances that form as a result of a reaction
free energy: the amount of energy available after a chemical reaction has occured
exergonic reactions: reactions that are spontaneous and release energy
endergonic reactions: reactions that require an input of energy to occur
Caption text
Figure 5.1 The ATP cycle. In cells, ATP carries energy between exergonic reactions and endergonic reactions. When a phosphate group is removed by hydrolysis, ATP releases the appropriate amount of energy for most metabolic reactions.
ATP (adenosine triphosphate): the common energy currency of cells; supplies energy for chemical work, transport work, and mechanical work by being converted to ADP plus a phosphate group
ADP (adenosine diphosphate): a nucleotide that can accept another phosphate group and become ATP
Answers
1. The reaction is likely to be endergonic, because it requires an input of energy to occur.
2. ATP with its three phosphate groups is analogous to a charged battery which can provide energy via a coupled reaction when one phosphate is cleaved off. ADP that s produced is like a discharged battery which requires an input of energy to become ATP again.
