Saving for a Rainy Day Suppose you earned extra money by having a part-time job. At first, you might be tempted to spend all of the money, but then you decide to open a bank account. 1. What are the benefits of having a bank account? 2. What do you have to do if you need some of this money? 3. What might your body do when it has more energy than it needs to carry out its activities? 4. What does your body do when it needs energy?

Chapter 8.1 Energy and Life

Energy Energy = the ability to do work –ex. light, heat, electricity, stored in bonds of chemical compounds Living things depend on energy –Even when sleeping, your cells use energy to build new proteins and amino acids.

Autotroph vs. Heterotroph Autotroph (auto = “self”, trophe = “food”)  Organisms that make their own food Plants and some other organisms use light energy from the sun Heterotroph (hetero = “other”, trophe = “food”)  Obtain energy from the foods that they consume Eat autotrophs or other heterotrophs

Example Grass gets energy from the sun. The impala gets energy from eating the grass. The leopard gets energy from eating the impala. Which are autotrophs and which are heterotrophs? Explain why. -grass = autotroph (makes its own food) -impala and leopard = heterotrophs (get energy from foods they consume)

Partner Activity 1. Make a list of 15 different organisms. 2. Classify each organism as an autotroph or a heterotroph Were any of the types of organisms difficult to classify? Why?

Fuel of Life Glucose is called the fuel of life –Monosaccharide  C 6 H 12 O 6 Contains too much energy for cells to use all at once  Must convert this large amount of energy into a usable form Like getting change for a vending machine

ATP Parts ATP  Adenosine Triphosphate –Chemical compound that cells use to store and release energy Basic energy source of the cell 3 main parts: –Adenine –Ribose (sugar) –3 phosphate groups AdenineRibose 3 Phosphate groups

ATP and Energy  The energy that ATP carries is found in the bonds between the phosphates  Energy is released when these bonds are broken; energy is stored when these bonds are formed

ATP vs. ADP / AMP ADP = adenosine diphosphate –2 phosphate groups  Has less potential energy than ATP AMP = adenosine monophosphate –1 phosphate group  Has less potential energy than ADP Both of the above are recyclable

Section 8-1 ATP ADP Lose phosphate (break bond) = energy is released Gain phosphate (form bond) = energy is stored

ADPATP Energy Adenosine diphosphate (ADP) + PhosphateAdenosine triphosphate (ATP) Partially charged battery Fully charged battery Section 8-1 Figure 8-3 Comparison of ADP and ATP to a Battery

Endergonic / Exergonic Reactions either use energy or give off energy –Endergonic  reaction in which energy must be used –Exergonic  reaction in which energy is given off

ATP Formation Video ATP

Review Questions 1. What is energy? 2. What is the difference between an autotroph and a heterotroph? 3. What is the fuel for life? Why must it be converted into another form? 4. What is ATP? What are its 3 main parts? 5. How is ATP used to store and release energy? 6. What is the difference between an endergonic reaction and an exergonic reaction?