Cellular Respiration

ATP: Universal Energy Source Autotrophs get their energy from the sun Heterotrophs get their energy from plants or other organisms Regardless, the energy is converted to the chemical energy of ATP

Making ATP Plants make ATP during photosynthesis Cells of all organisms make ATP by breaking down Carbohydrates Fats Proteins

2 Main Types of Energy-Releasing Pathways Anaerobic pathways Evolved first Don’t require oxygen Start with glycolysis in cytoplasm Completed in cytoplasm Aerobic pathways Evolved later Require oxygen Start with glycolysis in cytoplasm Completed in mitochondria

Summary Equation for Aerobic Respiration C6H1206 + 6O2 6CO2 + 6H20 The equation is the opposite of the equation for photosynthesis. Respiration Summary Aerobic Respiration 3 stages 1.) Glycolysis 2.) Citric Acid Cycle (Krebs Cycle) 3.) Electron Transport Chain

Glycolysis Occurs in the cytoplasm Glucose is broken down (sugar breaking) Hydrolysis reaction Catabolic reaction Exothermic

Glycolysis 2 Stages Energy Requiring Chapter 8 Cellular Energy Glycolysis 2 Stages Energy Requiring ATP Needed to break apart the bonds of glucose Energy Releasing Needed to split glucose into 2 three-carbon pyruvate molecules Most of the energy from the glucose is still contained in the pyruvate. ATP and NADH (electron carrier) form as a result of the breakdown of glucose

Glycolysis: Net Energy Yield Input Glucose 2 NAD+ 2ATP (energy requiring) 4ADP Output 2 pyruvate 2 NADH (electron carrier) 2ADP 4 ATP (energy releasing) (net gain of 2 ATP)

Krebs Cycle (Citric Acid Cycle) - video Chapter 8 Cellular Energy Krebs Cycle (Citric Acid Cycle) - video Also known as Citric Acid Cycle Occurs when oxygen is present Occurs in the mitochondria Pyruvate is further broken down The net yield from the Krebs cycle is: 6 CO2 molecules (we exhale) 2 ATP 8 NADH (important electron carrier) 2 FADH2 (important electron carrier)

Krebb Cycle: Net Energy Yield Input Pyruvate (3 carbon sugar) 8 NAD+ 2 FAD 2 ADP Output 6 CO2 8 NADH (electron carrier) 2 FADH2 (electron carrier) 2ATP

Electron Transport Chain Occurs in the mitochondria Requires the presence of oxygen will combine with the H ions to form water Final step in the breakdown of glucose Uses the NADH and FADH2 to convert ADP to ATP Produces 32 ATP

Electron Transfer Chain Electron Transport Chain OUTER COMPARTMENT H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ e- e- e- H+ H+ H+ ADP + Pi ATP NADH + H+ NAD+ + 2H+ FADH2 FAD + 2H+ 2H+ + 1/2 02 H2O Electron Transfer Chain ATP Synthase H+ INNER COMPARTMENT

Electron Transport Chain glucose Electron Transport Chain ATP 2 PGAL ATP 2 NADH 2 pyruvate glycolysis 2 FADH2 2 CO2 e– 2 acetyl-CoA 2 NADH H+ H+ 2 6 NADH KREBS CYCLE ATP Krebs Cycle ATP H+ 2 FADH2 ATP H+ 4 CO2 36 ATP H+ H+ ADP + Pi electron transfer chain H+ H+ H+

Electron Transport: Net Energy Yield Input 8 NADH (from krebs cycle) 2 FADH2 (from krebs cycle) Oxygen Output 8 NAD+ 2 FAD+ Water 32 ATP

ATP Production (per molecule of glucose) Glycolysis ____ATP Kreb Cycle ____ATP ETC ____ATP Total ____ATP

Linked Processes Photosynthesis Aerobic Respiration Energy-storing pathway Dehydration synthesis Anabolic reaction bonds are formed endothermic Releases oxygen Requires carbon dioxide Aerobic Respiration Energy-releasing pathway Hydrolysis reaction Catabolic reaction bonds are broken exothermic Releases carbon dioxide Requires oxygen Metabolism (Metabolic Rate) = Catabolic rate + Anabolic rate

Anaerobic Respiration Chapter 8 Cellular Energy Anaerobic Respiration The anaerobic pathway that follows glycolysis No oxygen is required Two main types Lactic acid fermentation Alcohol fermentation

Lactic Acid Fermentation Occurs in the cytoplasm Occurs during exercise when there isn’t enough oxygen present for respiration to occur Cells turn to fermentation to produce energy only a net of 2 ATP another product of the reaction is lactic acid inhibits muscle function causes muscles to become fatigued causes cramps causes soreness after exercise

Lactic Acid Fermentation

Lactic Acid Fermentation Lactic acid is used by microorganisms to produce food, such as yogurt cheese pickled foods even chocolate

Alcohol Fermentation Occurs with yeast, no oxygen present carbon dioxide causes bread to rise

Alcohol Fermentation Yeast’s ferment the carbohydrates in fruits and grains This process forms ethanol Source of bubbles in Beer Sparkling wines

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

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

At the end of the Calvin cycle, where is energy stored? Chapter 8 Cellular Energy At the end of the Calvin cycle, where is energy stored? NADPH ATP chloroplast glucose A B C D CDQ 3

Chapter 8 Cellular Energy 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

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

Why is cellular respiration a catabolic pathway? Chapter 8 Cellular Energy 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 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

Where in the plant cell does photosynthesis take place? Chapter 8 Cellular Energy 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 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 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

What is the overall purpose of cellular respiration? Chapter 8 Cellular Energy 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 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 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 Which molecule generated by the Krebs cycle is a waste product? CoA CO2 FADH2 NADH A B C D FQ 12

Chapter 8 Cellular Energy 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

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

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

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

At the beginning of photosynthesis, which Chapter 8 Cellular Energy 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

What is the final step of cellular respiration? Chapter 8 Cellular Energy 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 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