Copyright Pearson Prentice Hall Biology Copyright Pearson Prentice Hall

Energy and Life EQ How is ATP used in cells? What is photosynthesis? Photo Credit: ©Stone Copyright Pearson Prentice Hall

Autotrophs and Heterotrophs Living things need energy to survive. This energy comes from food. The energy in most food comes from the sun. Where do plants get the energy they need to produce food? Copyright Pearson Prentice Hall

Autotrophs and Heterotrophs Plants and some other types of organisms are able to use light energy from the sun to produce food are called autotrophs. Organisms that obtain their energy from the food they eat are called heterotrophs. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Questions What type of organisms get their energy from the food they eat? Heterotrophs What type of organisms get their energy from the sun? Autotrophs Copyright Pearson Prentice Hall

Chemical Energy and ATP Energy comes in many forms including light, heat, and electricity. Energy can also be stored in chemical compounds. Copyright Pearson Prentice Hall

Chemical Energy and ATP An important chemical compound that cells use to store and release energy is adenosine triphosphate, abbreviated ATP. ATP is used by all types of cells as their basic energy source. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Question What is the chemical name of the compound that is used to store energy? ATP Write out the full name of ATP three times. Adenosine triphosphate Copyright Pearson Prentice Hall

Chemical Energy and ATP ATP consists of: adenine ribose (a 5-carbon sugar) 3 phosphate groups Adenine Ribose 3 Phosphate groups ATP is used by all types of cells as their basic energy source. ATP Copyright Pearson Prentice Hall

Chemical Energy and ATP Storing Energy ADP has two phosphate groups instead of three. A cell can store small amounts of energy by adding a phosphate group to ADP. ATP ADP Energy + Energy Adenosine Triphosphate (ATP) Adenosine Diphosphate (ADP) + Phosphate Partially charged battery Fully charged battery Copyright Pearson Prentice Hall

Chemical Energy and ATP Releasing Energy Energy stored in ATP is released by breaking the chemical bond between the second and third phosphates. 2 Phosphate groups P ADP Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Questions Discuss with your partner the three components of ATP. Adenine, ribose and three phosphate groups Where is the energy in ATP stored? Between the second and third phosphate groups. Copyright Pearson Prentice Hall

Chemical Energy and ATP What is the role of ATP in cellular activities? Copyright Pearson Prentice Hall

Chemical Energy and ATP The energy from ATP is needed for many cellular activities, including active transport across cell membranes, protein synthesis and muscle contraction. ATP’s characteristics make it exceptionally useful as the basic energy source of all cells. Copyright Pearson Prentice Hall

Using Biochemical Energy Most cells have only a small amount of ATP, because it is not a good way to store large amounts of energy. Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The key cellular process identified with energy production is photosynthesis. Photosynthesis is the process in which green plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates and oxygen. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Question Without looking in your notes, decribe photosynthesis to your neighbor. Copyright Pearson Prentice Hall

Investigating Photosynthesis The experiments performed by van Helmont, Priestley, and Ingenhousz led to work by other scientists who finally discovered that, in the presence of light, plants transform carbon dioxide and water into carbohydrates, and they also release oxygen. Copyright Pearson Prentice Hall

The Photosynthesis Equation The equation for photosynthesis is: CO2 + H2O C6H12O6 + O2 carbon dioxide + water sugars + oxygen Light Light Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Question Write the balanced equation for photosynthesis. 6CO2 + 6H2O --------- C6H12O6 + 6O2 Copyright Pearson Prentice Hall

The Photosynthesis Equation Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high-energy sugars and oxygen. Copyright Pearson Prentice Hall

The Photosynthesis Equation Light energy H2O Light-Dependent Reactions (thylakoids) O2 ADP NADP+ ATP NADPH Photosynthesis is a series of reactions that uses light energy from the sun to convert water and carbon dioxide into sugars and oxygen. CO2 + H20 Sugar Calvin Cycle (stroma) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Light and Pigments Light and Pigments How do plants capture the energy of sunlight? In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Light and Pigments Plants gather the sun's energy with light-absorbing molecules called pigments. The main pigment in plants is chlorophyll. There are two main types of chlorophyll: chlorophyll a chlorophyll b Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Light and Pigments Chlorophyll does not absorb light will in the green region of the spectrum. Green light is reflected by leaves, which is why plants look green. 100 80 60 40 20 Chlorophyll b Estimated Absorption (%) Chlorophyll a Photosynthesis requires light and chlorophyll. In the graph above, notice how chlorophyll a absorbs light mostly in the blue-violet and red regions of the visible spectrum, whereas chlorophyll b absorbs light in the blue and red regions of the visible spectrum. 400 450 500 550 600 650 700 750 Wavelength (nm) Copyright Pearson Prentice Hall