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Cellular Energy

Cellular Energy. Overview. The purpose of this unit is to examine how energy is made available to cells to power metabolism.

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Cellular Energy

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  1. Cellular Energy

  2. Overview The purpose of this unit is to examine how energy is made available to cells to power metabolism. We will learn how energy is captured and stored during photosynthesis in autotrophs, and how energy becomes usable to both autotrophs and heterotrophs through cellular respiration.

  3. Light like the sun. Heat like from fire. Mechanical: Involves movement Ex: mechanical pencil, pencil sharpener, car, bike, etc Chemical: Energy is present in chemical bonds of compounds Ex: Sugar-each bond (line) holds a lot of energy. Forms of Energy

  4. All of the chemical reactions that go on inside a cell are known as the cell’s metabolism • Metabolism= A process that involves using energy to build or break down molecules • Photosynthesisandcellular respiration involve making and breaking energy-rich molecules

  5. Review • Autotrophs (self feeders)= organisms that can produce their own food using light or chemical energy Ex: Plants, algae, certain bacteria • Heterotrophs(different feeders)= cannot obtain energy from the sun directly so obtain their nutrients by feeding on other organisms Ex: Animals and Fungi

  6. SinceAutotrophs are self feeders, organisms capable of making their own food • then… • 1. Chemoautotrophs: are organisms that use chemicals instead of light energy to produce food. This process is called Chemosynthesis. (synthesis means “to make”) • Organsims that carry out chemosynthesis are microbes (bacteria) that live far from the sun, such as deep on the ocean floor.

  7. 2. Photoautotrophs: are organisms that capture light energy and convert it to chemical energy. This cellular process is photosynthesis. Organisms that carry out photosynthesis are Plants Photosynthetic Bacteria Some Protists • (ex. cynobacteria) (ex. Algae)

  8. Photosynthesis Overview • Happens in: autotrophs • Goal: Converting light energy into chemical energy (glucose) • Glucose: carbohydrate monomer C6H12O6

  9. Cellular Respiration Overview • Happens in: autotrophsANDheterotrophs • Goal: convert chemical energy (glucose) into usuable energy (ATP). • ATP = adenosine triphosphate • ATP provides cells with energy they need to carry out the activities of life

  10. ATP (Adenine Triphosphate) • is used by all types of cells as their basic energy source. • releases energy when the bond between the 2nd & 3rd phosphate group is broken • ATP → ADP + P + energy! • Can be used to: • Contract muscles • Move things across a cell membrane (Active Transport)

  11. hhh • Times New Roman (Body) Adenosine Triphosphate Adenosine Diphosphate • ATP – contains three phosphate groups (tri = three) • ADP – contains two phosphate groups (di = two)

  12. Photosynthesis • Needed (Reactants): • Light • Water • Carbon dioxide • Given Off (Products): • Sugars • Oxygen

  13. Photosynthesis WRITE THIS EQUATION IN YOUR NOTES

  14. Which organelle does plants use to perform photosynthesis? • Chloroplasts • Found in cells of leaves • Contains chlorophyll

  15. Chloroplast containing chlorophyll Stoma (Stomata) - small pores on the underside of leaves where gas exchange occurs

  16. Chlorophyll • Plants gather the sun's energy with light-absorbing molecules called pigments. • The plants' principal pigments are called chlorophyll. • Chlorophyll does not absorb light well in the green region of the spectrum therefore green light is reflected by leaves (this is why plants look green).

  17. Pigments • Carotenoids • Other pigments • Ex: b-carotene • Reflects red/yellow light • Gives carrots/sweet potatoes their color

  18. The Fall Season • Chlorophyll breaks down • You can see color of other pigments

  19. Chloroplast Vocabulary • Thylakoids - disc like photosynthetic membrane found in chloroplasts. • Stroma - Region outside the thylakoid membranes in chloroplasts • Granum- stack of thylakoids - Stack of thylakoids

  20. OVERVIEW OF PHOTOSYNTHESIS Photosynthesis is the process by which plants (producers) take in water and CO2 and using light energy and chlorophyl make 02and glucose

  21. Light Independent Reaction Light Dependent Reaction Photosynthesis • 2 steps: • Light Dependent reactions • Light Independent reactions (Calvin cycle) These two chemical reactions work together!

  22. Light Dependent reaction: Occurs in the thylakoid (granum) Must have light light Light Independent Reaction Light Independent Reaction LIGHT REACTION Light Reaction thylakoid (chlorophyll) Photosynthesis

  23. ENERGY H2O H H Step 1: Light Dependent Reactions How does the O2 leave the leaf? light energy reacts with the chlorophyll water is split by the light energy H is kept for the light independent reaction O2 is released O2 O2 O2 O2 O H2 O2

  24. What happens to the H+? • NADP+ picks up the H+ ions (becoming NADPH) and moves them to the stroma for the light independent reaction (Calvin cycle). • NADPH is a high energy electron carrier ( like a delivery man) provides the energy that converts CO2 to molecule of sugar

  25. Light Dependent • Occurs in the thylakoid • Water is absorbed through roots. • Sunlight (Light Energy)enters the chloroplast, causing H2O molecules to split. • O2 leaves as a waste product through the stomata.

  26. NADP+picks up the H+ ions (becoming NADPH) and moves them to the stromafor the light independent reaction (Calvin cycle) • ATP( ENERGY) helps to fuel the light independent reaction, or the Calvin Cycle

  27. Light Independent reactions (aka Calvin cycle): Occurs in the stroma Occurs in the light and dark Light Reaction LIGHT INDEPENDENT REACTION  Light Reaction Light Independent Reaction  stroma (liquid) Photosynthesis

  28. + H CO2 C6H12O6 Step 2: Light Independent Reactions • AKA: CALVIN CYCLE CO2 enters the chloroplast H from the water split in the light reaction is present the reactants H and CO2 combine glucose is the product CO2 How does CO2enter the plant? CO2 CO2 CO2 H H • Other carbohydrates besides glucose may be made in photosynthesis

  29. Light Independent Overview • Carbon dioxide from the atmosphere enters the stoma • Light Independent Reaction takes place in stroma • H+ breaks off from NADPH • NADP+ returns to the Light Dependent Reaction (Thylakoid) • Carbon dioxide becomes “fixed” with the H+ producing the glucose molecule C6H12O6. • ATP helps to fuel the light independent reaction. ATP becomes ADP and returns to the light dependent reaction.

  30. Light Independent Reaction Light Reaction Photosynthesis Review • Light reactions: H2O split into H2 + O • Light independent reactions: H + CO2 = C6H12O6 O2 H2O C6H12O6 chlorophyll H CO2

  31. How would this be written as a chemical equation? What goes in? (the reactants) What comes out? (the products) Light Dependent Reaction Light Independent Reaction O2 H2O C6H12O6 chlorophyll CO2 Photosynthesis Formula light H2O CO2 C6H12O6 O2

  32. What’s wrong with this equation? The number of atoms is not equal on both sides of the equation. Balance the equation so that the number of atoms of each element is equal on both sides. one carbon atom reactant 6 carbon atoms product H2O CO2 C6H12O6 O2 Photosynthesis Formula 6 (1) 6 6

  33. Comparing Photosynthesis and Respiration CO2 + H20 + Energy (Light)  C6H12O6 + O2 C6H12O6 + 02 Energy (ATP) + CO2 + H20 IMPORTANT COMPARISON!: the reactants of one reaction are the products of the other reaction!

  34. Factors Affecting Photosynthesis • Water • A shortage of water can slow or even stop photosynthesis. • Temperature • Photosynthesis depends on enzymes that function best between 0°C and 35°C. • Intensity of Light • Increasing light intensity increases the rate of photosynthesis...but a plant will reach a maximum rate.

  35. Light-Dependent Reactions • Takes place within the thylakoid membranes • Requires light • Requires: Water, ADP, and NADP+ • Produce: Oxygen, ATP, and NADPH

  36. Electron Carriers within the Light Dependent reaction • Inside the thylakoid, electrons within the chlorophyll become “excited” (gain energy) from the sunlight. Now that they have all this energy they require a carrier molecule : NADP+.

  37. NADP+ • NADP+ • As soon as this carrier molecule NADP+ accepts the energy (from the electrons) it converts the NADP+ into NADPH. • This transfer of electrons and energy is called the Electron Transport Chain (ETC)

  38. Light Dependent Reactions • The sunlight breaks each water molecule into : • electrons • H+ ions (released into thylakoid membrane) • Oxygen atoms (released into the air)

  39. Light Dependent Reactions • As electrons are passed from chlorophyll to NADP+, more hydrogen ions are pumped across the membrane. • Inside of the membrane fills up with positively charged hydrogen ions. • Outside of thylakoid membrane becomes negatively charged. • The difference in charges across the membrane provides the energy to make ATP. The H+ ions are important!

  40. Light Dependent Reactions • ATP Synthase - Large protein/enzyme that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP. • Spans the thylakoid membrane and allows H+ ions to pass through it. • Overall: Produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH.

  41. http://www.youtube.com/watch?v=eY1ReqiYwYs

  42. The Light-Independent Reactions (Calvin Cycle) • Takes place in the stroma • Uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars.

  43. Calvin Cycle • Uses six molecules of carbon dioxide to produce one 6-carbon glucose molecule. • Energy for this conversion comes from ATP and high-energy electrons from NADPH.

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