Chapter 8 Cellular Energy Section 1 How Organisms

Chapter 8 Cellular Energy Section 1: How Organisms Obtain Energy Section 2: Photosynthesis Section 3: Cellular Respiration Click on a lesson name to select.

• Big Idea – Photosynthesis converts the Sun’s energy into chemical energy, while cellular respiration uses chemical energy to carry out life function. Click on a lesson name to select.

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy All living organisms use energy to carry out all biological processes Macromolecules are assembled and broken down, substances are transported across cell membranes, and genetic instructions are transmitted. All of these cellular activities require 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.

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Laws of Thermodynamics § First law— (Law of conservation of energy) §energy can be converted from one form to another, but it cannot be created nor destroyed. § Examples: §Food is converted to chemical energy when you eat §Mechanical energy when you run or kick a ball

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Laws of Thermodynamics § Second law—energy cannot be converted without the loss of usable energy. §“loss” energy is generally converted to thermal energy §Increases Entropy

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Laws of Thermodynamics § Entropy – §The measure of disorder (or unusable energy) in a system

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Autotrophs and Heterotrophs § Nearly all the energy for life comes from the Sun

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Autotrophs and Heterotrophs § Autotrophs are organisms that make their own food.

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Autotrophs and Heterotrophs § Autotrophs are organisms that make their own food. § Examples: §Chemoautotrophs use inorganic substances such as hydrogen sulfide as a source of energy §Photoautotrophs (like plants) convert light energy from the Sun into chemical energy.

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Autotrophs and Heterotrophs § Heterotrophs are organisms that need to ingest food to obtain energy. § Examples: §Aphid §Lady bug

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

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Metabolism § Metabolic Pathway – §Series of chemical reactions in which the product of one reaction is the substrate for the next reaction §Examples: §Catabolic pathways §Anabolic pathways

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Metabolism § Metabolic Pathway – §Examples: §Catabolic pathways §Release energy by breaking down larger molecules into smaller molecules

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Metabolism § Metabolic Pathway – §Examples: §Anabolic pathways §Use the energy released by catabolic pathways to build larger molecules from smaller molecules

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Photosynthesis § Photosynthesis is the anabolic pathway in which light energy from the Sun is converted to chemical energy for use by the cell. §Autotrophs use light energy, carbon dioxide, and water to form glucose and oxygen

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy Cellular Respiration § Cellular Respiration is the catabolic pathway in which organic molecules are broken down to release energy for use by the cell. §Oxygen is used to break down organic molecules, resulting in the production of carbon dioxide and water

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy ATP: The Unit of Cellular Energy § ATP (Adenosine Triphosphate) 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.

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy ATP: The Unit of Cellular Energy § ATP structure §A nucleotide made of an adenine base, a ribose sugar, and three phosphate group

Chapter 8 Cellular Energy 8. 1 How Organisms Obtain Energy ATP: The Unit of Cellular Energy § ATP function §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

Chapter 8 Cellular Energy 8. 2 Photosynthesis Main Idea: light energy is trapped and converted into chemical energy during photosynthesis • Photo – means “light” • Synthesis – means “to create”

Chapter 8 Cellular Energy 8. 2 Photosynthesis Most autotrophs – including plants – make organic compounds, such as sugars, by a process called photosynthesis

Chapter 8 Cellular Energy 8. 2 Photosynthesis Overview of Photosynthesis § Photosynthesis occurs in two phases. § Light-dependent reactions § Light-independent reactions

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § The absorption of light is the first step in photosynthesis. § Light energy is absorbed and then transformed into chemical energy in the form of ATP and NADPH

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Chloroplasts large organelles that capture light energy.

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Chloroplasts are mainly found in the cells of leaves in plants.

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Thylakoids are flattened saclike membranes that arranged in stacks called grana.

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Stroma is the fluid- filled space outside the grana

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Pigments are light-absorbing molecules found in the thylakoid membranes of chloroplasts

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase One: Light Reactions (Light – Dependent Reaction) § Chlorophyll is the major light – absorbing pigment in plants. § Two types of chlorophyll: §Chlorophyll a §Chlorophyll b § Accessory pigments called carotenoids produce the color of carrots and sweet potatoes

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 O 2 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.

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 energystoring molecule NADPH.

The Light Reaction

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Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase Two: The Calvin Cycle (Light – Independent Reaction) § In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase Two: The Calvin Cycle (Light – Independent Reaction) § The ATP and NADPH that were formed in phase one are used to make glucose

Chapter 8 Cellular Energy 8. 2 Photosynthesis Phase Two: The Calvin Cycle (Light – Independent Reaction)

Chapter 8 Cellular Energy 8. 2 Photosynthesis § 1 st Step (Carbon Fixation) - Six CO 2 molecules combine with six 5 -carbon compounds to form twelve 3 -carbon molecules called 3 -PGA. § 2 nd Step (Reduction) - The chemical energy stored in ATP and NADPH is transferred to the 3 -PGA molecules to form high-energy molecules called (glyceraldehyde 3 phosphate) G 3 P.

Chapter 8 Cellular Energy 8. 2 Photosynthesis § 3 rd Step - Two G 3 P molecules leave the cycle to be used for the production of glucose and other organic compounds. § Final Step (Regeneration of Ru. BP)- An enzyme called rubisco converts the remaining ten G 3 P molecules into 5 -carbon molecules called Ru. BP. These molecules combine with new carbon dioxide molecules to continue the cycle.

Chapter 8 Cellular Energy 8. 2 Photosynthesis Alternative Pathways § C 4 plants § CAM plants

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.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration § Cellular respiration occurs in two main parts. § Glycolysis § Aerobic respiration

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Glycolysis § Glucose is broken down in the cytoplasm through the process of glycolysis.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Glycolysis § Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down. § Two molecules of ATP are required to start the reactions that will produce energy for the cell

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Glycolysis • 2 phosphate groups are joined to glucose (the 2 Phosphate groups are derived from 2 molecules of ATP) • The 6 -Carbon molecule of Glucose is broken into two 3 -Carbon compounds • Two Phosphate groups are added and electrons and hydrogen ions (H+) combine with two NAD+ molecules to form NADH molecules • Keep in mind that NAD+ is an electron carrier that is similar to NADP (an electron carrier used during photosynthesis) • The two 3 -Carbon compounds are converted into two molecules of pyruvate • At the same time 4 molecules of ATP are produced

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Glycolysis § Glycolysis has a net result of two ATP and two pyruvate.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Krebs Cycle § Also known as the tricarboxylic acid (TCA) cycle § Also known as the citric acid cycle

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Krebs Cycle § 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. § When oxygen is present, pyruvate is transported into the mitochondrial matrix

Chapter 8 Cellular Energy 8. 3 Cellular Respiration • Begins with acetyl Co. A combining with a 4 -Carbon compound to form a 6 – Carbon compound known as citric acid • Citric acid is then broken down in the next series of steps, releasing 2 molecules of carbon dioxide and generating one ATP, three NADH, and one FADH 2. FAD is another electron carrier similar to NAD+ and NADP+ • Acetyl Co. A and citric acid are generated and the cycle continues.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Before the Krebs Cycle § Pyruvate first reacts with coenzyme A (Co. A) to form a 2 -Carbon intermediate called acetyl Co. A. § At the same time NAD+ is converted to NADH and carbon dioxide is released. § Acetyl Co. A then moves to the mitochondria matrix. 2 CO 2 and 2 NADH are produced.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration § Two molecules of pyruvate are formed during glycolysis. This means that there are two “turns” of the Krebs Cycle for each glucose molecule.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration § The net yield from the Krebs cycle is six CO 2 molecules, two ATP, eight NADH, and two FADH 2.

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Electron Transport § Final step in the breakdown of glucose § Point at which ATP is produced § Produces 24 ATP

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Electron Transport • The final step in the breakdown of glucose. • Point where most ATP is produced • Electrons and hydrogen ions from NADH and FADH 2 produced in Krebs Cycle are used to convert ADP to ATP. • Electrons move along mitochondrial membrane from one protein to another. • H+ ions are pumped into the mitochondrial matrix across the inner mitochondrial membrane. • Those H+ ions then diffuse through ATP synthase into the mitochondrial matrix. This process converts ADP to ATP in a process called chemiosmosis

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Electron Transport • Similarities and Differences in Electron Transport in Photosynthesis and Cellular Respiration Photosynthesis Cellular Respiration

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Some Prokaryotes • Aerobic organisms that undergo aerobic respiration, but because they do not have mitochondria, they use the plasma membrane as the location of the electron transport. • Anaerobic organism that grow and reproduce without oxygen. • ATP is produced through glycolysis

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Anaerobic Respiration § The anaerobic pathway that follows glycolysis § One type is fermentation § Two main types § Lactic acid fermentation § Alcohol fermentation Cellular Respiration

Chapter 8 Cellular Energy 8. 3 Cellular Respiration Fermentation § Two main types § Lactic acid fermentation – enzymes convert the pyruvate in glycolysis to lactic acid § Alcohol fermentation – type of fermentation in which pyruvate is converted to ethyl alcohol and carbon dioxide Cellular Respiration

Chapter 8 Cellular Energy 8. 3 Cellular Respiration How are photosynthesis and cellular respiration related? Cellular Respiration

Chapter 8 Cellular Energy Chapter Diagnostic Questions Which statement describes the law of conservation of energy? A. Energy cannot be converted or destroyed. B. Energy can be converted and destroyed. C. Energy can be converted but not destroyed. D. Energy can be destroyed but not converted. 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Chapter Diagnostic Questions In which metabolic process are molecules broken down to produce carbon dioxide and water? A. photosynthesis B. cellular respiration C. homeostasis D. fermentation 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Chapter Diagnostic Questions At the end of the Calvin cycle, where is energy stored? A. NADPH B. ATP C. chloroplast D. glucose 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 1 Formative Questions Which law of thermodynamics explains why the ladybug receives the least amount of usable energy? A. the first law of thermodynamics B. the second law of thermodynamics 1. 2. A B

Chapter 8 Cellular Energy 8. 1 Formative Questions All of the energy from the food you eat comes from the sun. A. true B. false 1. 2. A B

Chapter 8 Cellular Energy 8. 1 Formative Questions Why is cellular respiration a catabolic pathway? A. Energy is used to form glucose and oxygen. B. Energy is converted from water to carbon dioxide. C. Energy that is lost is converted to thermal energy. D. Energy is released by the breakdown of molecules. 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 1 Formative Questions Why is adenosine triphosphate (ATP) such an important biological molecule? A. It captures light energy from the sun. B. It is produced in anabolic pathways. C. It stores and releases chemical energy. D. It converts mechanical energy to thermal energy. 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 2 Formative Questions Where in the plant cell does photosynthesis take place? A. chloroplasts B. Golgi apparatus C. mitochondria D. vacuoles 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 2 Formative Questions Which range of wavelengths is reflected by chlorophylls a and b? A. 400 -500 nm B. 500 -600 nm C. 600 -700 nm 1. 2. 3. A B C

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? A. absorption B. chemiosmosis C. electron transport D. C 2 pathway 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 2 Formative Questions How are the C 4 pathway and the CAM pathway an adaptive strategy for some plants? A. They accelerate photosynthesis. B. They release more oxygen. C. They help the plant conserve water. D. They reduce the requirement for ATP. 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 3 Formative Questions What is the overall purpose of cellular respiration? A. to make ATP B. to process H 2 O C. to store glucose D. to deliver oxygen 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 3 Formative Questions Which represents the general sequence of cellular respiration? A. TCA cycle chemiosmosis glycolysis B. glycolysis Krebs cycle electron transport C. electron absorption catalysis phosphorylation D. aerobic pathway anaerobic pathway fermentation 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy 8. 3 Formative Questions Which stage of cellular respiration is the anaerobic process? A. glycolysis B. Krebs cycle C. electron transport 1. 2. 3. A B C

Chapter 8 Cellular Energy 8. 3 Formative Questions Which molecule generated by the Krebs cycle is a waste product? A. Co. A B. CO 2 C. FADH 2 D. NADH 1. 2. 3. 4. A B C D

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? A. grana B. stroma C. thylakoids D. Golgi apparatus 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Chapter Assessment Questions During the Krebs cycle, pyruvate is broken down into what compound? A. H 2 O B. O 2 C. CO D. CO 2 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Chapter Assessment Questions Look at the following figure. Which molecule is released when ATP becomes ADP? A. phosphate group B. water molecule C. ribose sugar D. energy cells 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice Which metabolic process is photosynthesis? A 1. 2. B A B

Chapter 8 Cellular Energy Standardized Test Practice At the beginning of photosynthesis, which molecule is split to produce oxygen (O 2) as a waste product? A. CO 2 B. H 2 O C. C 6 H 12 O 6 D. 3 -PGA 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice Which molecule helps provide the energy that drives this cycle? A. 3 -PGA B. CO 2 C. NADPH D. rubisco 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice Which product of the Calvin cycle is used for the production of glucose and other organic compounds? A. ADP B. CO 2 C. G 3 P D. NADP+ 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice What is the final step of cellular respiration? A. O 2 and H+ form H 2 O. B. Electrons and H 2 O generate ATP. C. C 6 H 12 O 6 is broken down into CO 2. D. NADH and FADH 2 gain electrons. 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice What prevents pyruvate from entering the Krebs cycle and instead results in this pathway? A. a buildup of CO 2 B. a lack of oxygen C. an excess of glucose D. an increased demand for ATP 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Standardized Test Practice Which is not a process that occurs in both cellular respiration and glycolysis? A. chemiosmosis B. electron transport C. glycolysis D. production of G 3 P 1. 2. 3. 4. A B C D

Chapter 8 Cellular Energy Glencoe Biology Transparencies

Chapter 8 Cellular Energy Image Bank

Chapter 8 Cellular Energy Vocabulary Section 1 energy thermodynamics metabolism Photosynthesis cellular respiration adenosine triphosphate (ATP)

Chapter 8 Cellular Energy Vocabulary Section 2 thylakoid granum stroma pigment NADP+ Calvin cycle rubisco

Chapter 8 Cellular Energy Vocabulary Section 3 anaerobic process aerobic respiration aerobic process glycolysis Krebs cycle fermentation

Chapter 8 Cellular Energy Animation § ATP § The Calvin Cycle § Visualizing Electron Transport § The Krebs Cycle (Citric Acid Cycle)

Chapter 8 Cellular Energy

Chapter 8 Cellular Energy

Chapter 8 Cellular Energy