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Energy in cells

Energy in cells. (Photosynthesis and Respiration). Photosynthesis. Chemical process that captures light energy and stores it as Chemical Potential Energy, only occurs in autotrophs Is a series of reactions controlled by enzymes Occurs in the … 2 Stages Light phase 1 Dark phase 2.

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Energy in cells

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  1. Energy in cells (Photosynthesis and Respiration)

  2. Photosynthesis • Chemical process that captures light energy and stores it as Chemical Potential Energy, only occurs in autotrophs • Is a series of reactions controlled by enzymes • Occurs in the … • 2 Stages • Light phase 1 • Dark phase 2

  3. Structure of a chloroplast Granum – stacked thylakoids containing chlorophyll. Stroma – clear liquid interior How can you tell which phase occurs where? How has surface area been maximised? What is the green colour from?

  4. Photosynthesis The purpose is to capture light energy from the sun and store it as chemical energy in glucose molecules for use inside the plants. It also: • Removes carbon dioxide from the air • Needs water, gained by osmosis from the soil into the root hair cells and up the xylem vessels • Makes oxygen gas for use in respiration in all living organisms Photosynthesis reaction summary: Carbon dioxide + water glucose + oxygen + water CO2 + H2O C6H12O6 + O2 + H20

  5. Stages in Photosynthesis

  6. Stages in Photosynthesis

  7. Carrier molecules in Photosynthesis • ATP – the energy carrier • ADP (empty) • Transports energy from light phase to dark phase • NADP – the hydrogen carrier • NADPH2 (full) • Transports hydrogen from light phase to dark phase

  8. How plants maximise the rate of photosynthesis See handout and discuss this concept in relation to the leaf model and the chloroplast diagram

  9. Factors affecting photosynthesis reaction rate: Photosynthesis is controlled by enzymes so anything that affects enzymes also affects photosynthesis, including; • Light intensity (can differ for different plants, canopy verses forest floor plants), no photosynthesis in the dark! • Temperature (most plants have an optimum range) • CO2 concentration (substrate concentration) • Low water availability causes the stomata to close and CO2 diffusion to stop so photosynthesis stops as well.

  10. Respiration All living cells must carry out cellular respiration and the purpose is too release the energy stored in food (glucose) and make it available to power all other metabolic reactions (in both autotrophs and heterotrophs) • Occurs in the (name organelle here?) • There are two types (aerobic and anaerobic)

  11. Structure of a mitochondria Cristae are the folded inner membranes. Why are they folded? The matrix is the liquid inside . What stages take place here? Mitochrondria are found in all living cells but in general animals cells have more than plants and any cells that need more energy have more e.g. muscle and liver cells have high energy demands so have more….

  12. Aerobic Respiration (with O2) • Cellular respiration with oxygen • Also a series of reactions controlled by enzymes • Glucose (food) and oxygen convert to lots of energy (ATP) with waste products of CO2 and H2O C6H12O6 + 6O2  6CO2 + 6H2O + ATP glucose oxygen carbon dioxide water energy

  13. 4 stages of aerobic respiration

  14. 4 Stages of aerobic respiration (with oxygen) • Glycolysis, • Link reaction , • Krebs cycle, • Electron transport chain These stages are linked by carrier molecules in a similar way to photosynthesis reactions…

  15. 4 stages of aerobic respiration

  16. Carrier molecules in respiration (molecules that link stages of aerobic respiration) • Co-enzyme A – an acetyl carrier • Acetyl co-enzyme A (full) • Transports acetyl group from glycolysis to Krebs cycle • NAD – the hydrogen carrier • NADH2(full) • Transports hydrogen from Krebs cycle to Electron transport chain

  17. Anaerobic respiration (no O2) • Respiration without oxygen • Another series of reactions controlled by enzymes • Stops after glycolysis (stage 1) • Much less energy (ATP) produced • Different waste or by-products produced • Plants Glucose  carbon dioxide + ethanol + 2ATP • Animals Glucose  lactic acid + 2ATP

  18. Factors affecting respiration All respiration reactions are controlled by enzymes …so again all things that effect enzymes affect both types of respiration, plus: • Too much toxic product. Too much carbon dioxide (aerobic respiration) and too much ethanol or lactic acid (anaerobic respiration) is toxic. Toxic products must be removed during respiration for it to continue efficiently.

  19. See Factors Affecting Enzymes… • Temperature, • pH, • Surface Area, • Substrate (reactant) concentration, • Enzyme concentration, • Co-Factors (enzyme helpers), • Inhibitors (heavy metals, poisons).

  20. P P P P P P ATP • Adenosine triphosphate (ATP) is the universal energy carrier in all cells • Cellular respiration is the process of recharging ADP (Adenosine diphosphate) to ATP

  21. -P Role of ATP (Energy carrier molecule) Energy released from breaking off one phosphate (-P) from ATP. Where? ATP ADP Respiration recharges ADP to ATP using energy and adding one phosphate (+P). Where? +P

  22. Energy in cells summary Photosynthetic Autotroph cells All Autotroph and Heterotroph cells Light Energy O2 CO2 and H2O P/S Glucose ADP Respiration O2 kJ ATP H2O Heat Energy CO2

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