Transformation of Energy Chapter 8 Cellular Energy 8.1 How Organisms Obtain Energy Transformation of Energy Energy is the ability to do work. Thermodynamics is the study of the flow and transformation of energy in the universe.

Laws of Thermodynamics Chapter 8 Cellular Energy 8.1 How Organisms Obtain Energy Laws of Thermodynamics First law—energy can be converted from one form to another, but it cannot be created nor destroyed. Second law—energy cannot be converted without the loss of usable energy.

Autotrophs and Heterotrophs Chapter 8 Cellular Energy 8.1 How Organisms Obtain Energy Autotrophs and Heterotrophs Autotrophs are organisms that make their own food. Heterotrophs are organisms that need to ingest food to obtain energy.

All of the chemical reactions in a cell Chapter 8 Cellular Energy 8.1 How Organisms Obtain Energy Metabolism All of the chemical reactions in a cell Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell Cellular respiration—organic molecules are broken down to release energy for use by the cell

ATP: The Unit of Cellular Energy Chapter 8 Cellular Energy 8.1 How Organisms Obtain Energy ATP: The Unit of Cellular Energy ATP releases energy when the bond between the second and third phosphate groups is broken, forming a molecule called adenosine diphosphate (ADP) and a free phosphate group. ATP

All of the energy from the food you eat comes from the sun. Chapter 8 Cellular Energy 8.1 Formative Questions All of the energy from the food you eat comes from the sun. true false A B FQ 2

Chapter 8 Cellular Energy 8.1 Formative Questions Which law of thermodynamics explains why the ladybug receives the least amount of usable energy? A B the first law of thermodynamics the second law of thermodynamics FQ 1

Why is cellular respiration a catabolic pathway? Chapter 8 Cellular Energy 8.1 Formative Questions Why is cellular respiration a catabolic pathway? Energy is used to form glucose and oxygen. Energy is converted from water to carbon dioxide. Energy that is lost is converted to thermal energy. Energy is released by the breakdown of molecules. A B C D FQ 3

Why is adenosine triphosphate (ATP) such an Chapter 8 Cellular Energy 8.1 Formative Questions Why is adenosine triphosphate (ATP) such an important biological molecule? It captures light energy from the sun. It is produced in anabolic pathways. It stores and releases chemical energy. It converts mechanical energy to thermal energy. A B C D FQ 4

Chapter 8 Cellular Energy Chapter Assessment Questions Look at the following figure. Which molecule is released when ATP becomes ADP? phosphate group water molecule ribose sugar energy cells A B C D CAQ 3

Overview of Photosynthesis Chapter 8 Cellular Energy 8.2 Photosynthesis Overview of Photosynthesis Photosynthesis occurs in two phases. Light-dependent reactions Light-independent reactions

Phase One: Light Reactions Chapter 8 Cellular Energy 8.2 Photosynthesis Phase One: Light Reactions The absorption of light is the first step in photosynthesis. Chloroplasts capture light energy.

Chloroplast Organelle that contains green chlorophyll to do photosynthesis.

Chloroplast – organelle of photosynthesis 2 outside membranes enclose stroma Stroma – gelatinous with enzymes, ribosomes, DNA, and grana Grana – stack of thylakoids Thylakoid – membrane studded with photosynthetic pigments enclosing thylakoid space

Accessory pigments What colors do you see? Used to illustrate why most leaves are green. This image has several yellow, orange, red, and purple dots mixed in with green. There are so many green pixels that we only see the green. If we took the green away, the dots are more visible against the white background.

Pigments Chlorophyll a Accessory pigments Most abundant photosynthetic pigment in plants, algae, and cyanobacteria Accessory pigments Chlorophyll b Carotenoids Only absorbed light is photosynthetically active Absorb red and blue Reflect green Accessory pigments extend used range of wavelengths used

Chapter 8 Cellular Energy 8.2 Photosynthesis Electron Transport Light energy excites electrons in photosystem II and also causes a water molecule to split, releasing an electron into the electron transport system, H+ into the thylakoid space, and O2 as a waste product.

Chapter 8 Cellular Energy 8.2 Photosynthesis The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane. The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I.

Photosystem I transfers the electrons to a protein called ferrodoxin. Chapter 8 Cellular Energy 8.2 Photosynthesis Photosystem I transfers the electrons to a protein called ferrodoxin. Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH. ATP is also formed during the light reactions.

Phase Two: The Calvin Cycle Chapter 8 Cellular Energy 8.2 Photosynthesis Phase Two: The Calvin Cycle In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.

Chapter 8 Cellular Energy

Chapter 8 Cellular Energy 8.2 Photosynthesis Six CO2 molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-PGA. The chemical energy stored in ATP and NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.

Chapter 8 Cellular Energy 8.2 Photosynthesis Two G3P molecules leave the cycle to be used for the production of glucose and other organic compounds. An enzyme called rubisco converts the remaining ten G3P molecules into 5-carbon molecules called RuBP. These molecules combine with new carbon dioxide molecules to continue the cycle.

Alternative Pathways C4 plants CAM plants 8.2 Photosynthesis Chapter 8 Cellular Energy 8.2 Photosynthesis Alternative Pathways C4 plants CAM plants All plants use the Calvin cycle (C3 pathway) to make glucose C3 plants use only the Calvin cycle About 95% of plant species (peanuts, spinach, trees) Photorespiration is a problem in hot, dry conditions Rubisco uses O2 as a substrate (instead of CO2) starting a process that removes already fixed carbon If stomata kept closed to prevent water loss, O2 builds up and photorespiration increases

C4 plants Light and Dark reactions in separate cells Malate 4-carbon compound 1% of plants Sugarcane, corn, crabgrass

CAM plants Crassulacean acid metabolism Open stomata to fix carbon only at night Store malate in vacuole Fix it again in Calvin cycle during the day Stored malate moves into chloroplast in the same cell 3-4% of plants Pineapple and cacti Saves water

Photosynthesis Video

Chapter 8 Cellular Energy Chapter Assessment Questions Look at the following figure. Which part of the chloroplast is a sac-like membrane arranged in stacks? grana stroma thylakoids Golgi apparatus A B C D CAQ 1

pyruvate is broken down into what compound? Chapter 8 Cellular Energy Chapter Assessment Questions During the Krebs cycle, pyruvate is broken down into what compound? H2O O2 CO CO2 A B C D CAQ 2

Where in the plant cell does photosynthesis take place? Chapter 8 Cellular Energy 8.2 Formative Questions Where in the plant cell does photosynthesis take place? chloroplasts Golgi apparatus mitochondria vacuoles A B C D FQ 5

Which range of wavelengths is reflected by chlorophylls a and b? Chapter 8 Cellular Energy 8.2 Formative Questions Which range of wavelengths is reflected by chlorophylls a and b? 400-500 nm 500-600 nm 600-700 nm A B C FQ 6

Which mechanism of photosynthesis uses Chapter 8 Cellular Energy 8.2 Formative Questions Which mechanism of photosynthesis uses the movement of hydrogen ions (H+) across a concentration gradient to synthesize ATP? absorption chemiosmosis electron transport C2 pathway A B C D FQ 7

How are the C4 pathway and the CAM pathway Chapter 8 Cellular Energy 8.2 Formative Questions How are the C4 pathway and the CAM pathway an adaptive strategy for some plants? They accelerate photosynthesis. They release more oxygen. They help the plant conserve water. They reduce the requirement for ATP. A B C D FQ 8

A B Which metabolic process is photosynthesis? A B Chapter 8 Cellular Energy Standardized Test Practice Which metabolic process is photosynthesis? A B A B STP 1

At the beginning of photosynthesis, which Chapter 8 Cellular Energy Standardized Test Practice At the beginning of photosynthesis, which molecule is split to produce oxygen (O2) as a waste product? CO2 H2O C6H12O6 3-PGA A B C D STP 2

Which molecule helps provide the energy that drives this cycle? Chapter 8 Cellular Energy Standardized Test Practice Which molecule helps provide the energy that drives this cycle? 3-PGA CO2 NADPH rubisco A B C D STP 3

Which product of the Calvin cycle is used for Chapter 8 Cellular Energy Standardized Test Practice Which product of the Calvin cycle is used for the production of glucose and other organic compounds? ADP CO2 G3P NADP+ A B C D STP 4

Overview of Cellular Respiration Chapter 8 Cellular Energy 8.3 Cellular Respiration Overview of Cellular Respiration Organisms obtain energy in a process called cellular respiration. The equation for cellular respiration is the opposite of the equation for photosynthesis.

Cellular respiration occurs in two main parts. Glycolysis Chapter 8 Cellular Energy 8.3 Cellular Respiration Cellular respiration occurs in two main parts. Glycolysis Aerobic respiration Krebs cycle Electron transport chain

Glycolysis does not require oxygen and is therefore anaerobic. Chapter 8 Cellular Energy 8.3 Cellular Respiration Glycolysis Glucose is broken down in the cytoplasm through the process of glycolysis. Two molecules of ATP and two pyruvate are formed for each molecule of glucose that is broken down. Glycolysis does not require oxygen and is therefore anaerobic.

Glycolysis has a net result of two ATP and two pyruvate. Chapter 8 Cellular Energy 8.3 Cellular Respiration Krebs Cycle Glycolysis has a net result of two ATP and two pyruvate. Most of the energy from the glucose is still contained in the pyruvate. The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.

Chapter 8 Cellular Energy 8.3 Cellular Respiration The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.

Electron Transport Chain Chapter 8 Cellular Energy 8.3 Cellular Respiration Electron Transport Chain Final step and most important step in the breakdown of glucose Point at which ATP is produced Produces 32 ATP The Kreb cycle and ETC occur in the mitochondria of eukaryotes.

Anaerobic Respiration Chapter 8 Cellular Energy 8.3 Cellular Respiration Anaerobic Respiration The anaerobic pathway that follows glycolysis Two main types Lactic acid fermentation Alcohol fermentation Wine and Chocolate Ethanol Cellular Respiration

Cellular Respiration Video

What is the overall purpose of cellular respiration? Chapter 8 Cellular Energy 8.3 Formative Questions What is the overall purpose of cellular respiration? to make ATP to process H2O to store glucose to deliver oxygen A B C D FQ 9

Which represents the general sequence of cellular respiration? Chapter 8 Cellular Energy 8.3 Formative Questions Which represents the general sequence of cellular respiration? TCA cycle  chemiosmosis  glycolysis glycolysis  Krebs cycle  electron transport electron absorption  catalysis  phosphorylation aerobic pathway  anaerobic pathway  fermentation A B C D FQ 10

Which stage of cellular respiration is the anaerobic process? Chapter 8 Cellular Energy 8.3 Formative Questions Which stage of cellular respiration is the anaerobic process? glycolysis Krebs cycle electron transport A B C FQ 11

CoA CO2 FADH2 NADH Which molecule generated by the Krebs Chapter 8 Cellular Energy 8.3 Formative Questions Which molecule generated by the Krebs cycle is a waste product? CoA CO2 FADH2 NADH A B C D FQ 12

What is the final step of cellular respiration? Chapter 8 Cellular Energy Standardized Test Practice What is the final step of cellular respiration? O2 and H+ form H2O. Electrons and H2O generate ATP. C6H12O6 is broken down into CO2. NADH and FADH2 gain electrons. A B C D STP 5

an increased demand for ATP Chapter 8 Cellular Energy Standardized Test Practice What prevents pyruvate from entering the Krebs cycle and instead results in this pathway? a buildup of CO2 a lack of oxygen an excess of glucose an increased demand for ATP A B C D STP 6

Which is not a process that occurs in both Chapter 8 Cellular Energy Standardized Test Practice Which is not a process that occurs in both cellular respiration and glycolysis? chemiosmosis electron transport glycolysis production of G3P A B C D STP 7

Sources This PowerPoint presentation is a modified version of a presentation included in a purchased teacher edition supplemental materials packet by McGraw-Hill’s Glencoe Tennessee Biology (material used to modify the presentation was obtained from the same source): Biggs, Alton. Tennessee Biology. Teacher Ed. T.l.: Glencoe/McGraw-Hill, 2010.