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Cellular respiration

Cellular respiration. Understanding Energy Transformations. Overview of Cellular Respiration. All the chemical reactions that take place inside cells are metabolic processes How slowly or quickly these reactions take place is called the metabolic rate

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Cellular respiration

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  1. Cellular respiration Understanding Energy Transformations

  2. Overview of Cellular Respiration • All the chemical reactions that take place inside cells are metabolic processes • How slowly or quickly these reactions take place is called the metabolic rate • Metabolism is one of the eight characteristics of all living things and requires a steady supply of energy

  3. Overview of Cellular Respiration • The potential energy held in the bonds of food molecules cannot be used directly by the cell • Energy from food must be converted to the only energy source that any cell can use… • ATP!

  4. Review of ATP • Adenosine Triphosphate • Result of the bonding of a free phosphate molecule w/free ADP molecule • The bond between the phosphates is where the actual energy is stored.

  5. Review of ATP • When the bond between two phosphate molecules is broken, energy is released

  6. Cellular Respiration Defined • Respiration is the process by which the energy in the bonds of nutrients are used to synthesize ATP in the presence of oxygen • Respiration occurs continuously in all cells of most organisms • The energy needed to synthesize ATP comes from an organism’s food

  7. Summary of Cellular Respiration +P Cellular Respiration Energy (in) Energy (out) Cellular Activities ADP ATP -P The entire process is an enzyme-controlled set of reactions

  8. The Metabolic Processes of Cellular Respiration

  9. Chemical Equation for Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP (reactants) (products) How does this compare to the equation for photosynthesis?

  10. Pathways of ATP Production Pathway #1: • Requires oxygen and is referred to as aerobic respiration • Occurs in mitochondria of cells Pathway #2: • Does not require oxygen and is referred to as anaerobic respiration • Occurs in cytoplasm of cells

  11. The Role of the Mitochondria • Organelles that transform energy from food into large numbers of ATP molecules • Often called the “powerhouses” of the cell • Number of mitochondria a cell has depends on the amount of energy used by that cell • Example: muscles-many hair-few

  12. Comparison of Chloroplasts and Mitochondria

  13. Glycolysis “glyco – sweet” “lysis – letting loose” • Defined: a chemical reaction that breaks apart glucose into 2 3-carbon molecules called pyruvate to produce 4 ATP • Requires input of 2 ATP molecules for activation energy • Does not require O2 – anaerobic • Rest of energy stays in pyruvate

  14. Aerobic Respiration Defined: If O2 is present, pyruvate continues to break down in a series of energy-releasing chemical reactions Pyruvic acid Series of enzyme- controlled reactions Enough energy to make 34 ATP molecules Carbon dioxide and water

  15. Summary of ATP Production glucose 2 ADP + 2 P = 2 ATP pyruvic acid 34 ADP + 34 P = 34 ATP Enough energy to make 56 ATP lost as heat carbon dioxide and water

  16. Anaerobic Respiration • Also called fermentation • Happens in low/no oxygen conditions • 1 glucose only partially broken down to form waste products and 2 ATP

  17. Anaerobic Pathways • Pathway #1 – Lactic Acid Fermentation • Glucose 2 lactic acid + 2 ATP • Happens in muscle cells when they run out of oxygen • Happens in bacteria that make yogurt, cheese & dill pickles

  18. Anaerobic Pathways • A build up of lactic acid produces muscle fatigue • This makes the muscles ache and contract with less power • A recovery period is needed; during this time more O2 is taken in which allows the energy in lactic acid to be converted into ATP • The volume of O2 needed is called oxygen debt

  19. Anaerobic Pathways • Pathway #2 – Alcoholic Fermentation • Glucose 2 ethanol + 2 CO2 + 2 ATP • Process in which sugars are converted into alcohol and carbon dioxide by the action of yeasts, molds or bacteria • This process is irreversible – O2 cannot be added to release more energy

  20. Adaptations for Respiration • Bacteria, protists and fungi • Respiratory gases are exchanged by diffusion • Plants • Respiratory gases are exchanged though leaves (stomata), stems and roots • Moves in/out of cells by diffusion

  21. Adaptations for Respiration in Animals

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