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Cell Energy & Photosynthesis

Cell Energy & Photosynthesis. Cell Energy. Source of Energy In most living organisms the energy in most food comes from? the sun autotroph – ‘auto’ – self, ‘troph’ – food. organisms which are able to make their own food examples?. Cell Energy. Source of Energy

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Cell Energy & Photosynthesis

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  1. CellEnergy & Photosynthesis

  2. Cell Energy Source of Energy In most living organisms the energy in most food comes from? • the sun • autotroph – ‘auto’ – self, ‘troph’ – food. organisms which are able to make their own food • examples?

  3. Cell Energy Source of Energy • heterotroph –‘heteros’– other,‘troph’– food. obtain energy from the foods they eat. • Impalas ? • Leopards ? • Mushrooms ? • to live, all organisms must release the energy stored in sugars and other compounds

  4. Cell Energy Source of Energy In nature there are many forms that energy can take • examples? • heat • light • nuclear • kinetic – motion • electrical • and chemical

  5. Cell Energy Stored Energy One of the principal chemical compounds that living things use to store energy is? • adenosine triphosphate (ATP) • an ATP molecule consists of the following • a nitrogen-containing compound - adenine

  6. Cell Energy adenosine tri-phosphate (ATP) Adenine

  7. Cell Energy Stored Energy One of the principal chemical compounds that living things use to store energy is? • adenosine triphosphate (ATP) • an ATP molecule consists of the following • a nitrogen-containing compound – adenine • a 5-carbon sugar - ribose

  8. Cell Energy adenosine tri-phosphate (ATP) Adenine Ribose

  9. Cell Energy Stored Energy One of the principal chemical compounds that living things use to store energy is? • adenosine triphosphate (ATP) • an ATP molecule consists of the following • a nitrogen-containing compound – adenine • a 5-carbon sugar – ribose • and 3 phosphate groups

  10. Cell Energy adenosine tri-phosphate (ATP) Adenine Ribose 3 Phosphate groups

  11. Cell Energy Stored Energy adenosine diphosphate (ADP) • has a structure similar to ATP but with one important difference • ADP has 2 phosphate groups instead of 3 • the addition of that 3rd phosphate group allows the cell to store small amounts of energy • similar to a battery storing energy

  12. Cell Energy ATP – stored energy Adenosine Diphosphate (ADP) + phosphate

  13. Cell Energy ATP – stored energy Adenosine Diphosphate (ADP) + phosphate Partially charged battery

  14. Cell Energy ATP – stored energy energy Adenosine Diphosphate (ADP) + phosphate Partially charged battery

  15. Cell Energy ATP – stored energy energy Adenosine Diphosphate (ADP) + phosphate Adenosine triphosphate (ATP) Partially charged battery

  16. Cell Energy ATP – stored energy energy Adenosine Diphosphate (ADP) + phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

  17. Cell Energy Releasing energy from ATP • the energy stored in ATP is released when ATP is converted to ADP and a phosphate group. • this adding and subtracting of a third phosphate group is a way of a cell storing and releasing energy as needed

  18. Cell Energy Is there another molecule similar to ATP & ADP? AMP

  19. Cell Energy Releasing energy from ATP the ATP molecule carries just enough energy to power a variety of cellular activities • active transport – sodium-potassium pump. enough energy to transport 3 sodium ions and 2 potassium ions • move organelles along microtubules inside cell

  20. Cell Energy ATP-ADP cycle

  21. Cell Energy ATP and Glucose most cells have only a small amount of ATP – enough to last for a few seconds of activity. • why? • ATP is very efficient at transferring energy but not very good at storing large amounts of energy • what can store lots of energy for a cell?

  22. Cell Energy ATP and Glucose • glucose – stores more than 90 times the chemical energy of a molecule of ATP • cells can therefore use carbohydrates like glucose to regenerate ATP from ADP

  23. Cell Energy Photosynthesis Equation light 6CO2 + 6H2O C6H12O6 + 6O2 carbon dioxide + water sugar + oxygen

  24. Cell Energy Light and Pigments In addition to water and carbon dioxide, photosynthesis requires? • light &? • chlorophyll, a molecule in chloroplasts

  25. Cell Energy Light and Pigments energy from the sun travels to the Earth in many forms. • one of these forms is light (sunlight) which your eyes perceive as ‘white light’ • it is actually a mixture of different wavelengths of light • many of these wavelengths are visible to your eyes and are referred to as the visible spectrum • R O Y G B I V

  26. Cell Energy Light and Pigments • plants gather the sun’s energy with light-absorbing molecules called pigments • the plants principal pigment is chlorophyll • there are 2 main types of chlorophyll • chlorophyll a and chlorophyll b

  27. Absorption of light by chlorophyll a and chlorophyll b Cell Energy chlorophyll b chlorophyll a chlorophyll absorbs light very well in the blue and red regions however, it does not absorb it very well in the green and yellow regions

  28. Cell Energy Light and Pigments • light is a form of energy, any compound that absorbs light also absorbs the energy from that light. • when chlorophyll absorbs light much of the energy is transferred directly to electrons in the chlorophyll molecules, raising the energy levels of these electrons • these high energy electrons make photosynthesis work

  29. Cell Energy Inside a Chloroplast • thylakoid membranes • saclike photosynthetic membranes • contain clusters of chlorophyll and other pigments and proteins known as photosystems • able to capture the energy of sunlight • grana – (singular: granum) stacks of thylakoids • stroma – fluid region outside the thylakoid membranes

  30. Cell Energy Photosynthesis • light-dependent reactions • occurs in the __________ _________

  31. Cell Energy Photosynthesis • light-dependent reactions • occurs in the thylakoid membranes

  32. Cell Energy Photosynthesis light- dependent reactions Chloroplast

  33. Cell Energy Photosynthesis • light-dependent reactions • occurs in the thylakoid membranes • requires – ?

  34. Cell Energy Photosynthesis • light-dependent reactions • occurs in the thylakoid membranes • requires – light energy, water & raw materials

  35. Cell Energy Photosynthesis H2O light raw materials light- dependent reactions Chloroplast

  36. Cell Energy Photosynthesis • light-dependent reactions • occurs in the thylakoid membranes • requires – light energy, water & raw materials • produces – ?

  37. Cell Energy Photosynthesis • light-dependent reactions • occurs in the thylakoid membranes • requires – light energy, water & raw materials • produces – oxygen, ATP & NADPH

  38. Cell Energy Photosynthesis H2O light light- dependent reactions ATP NADPH Chloroplast O2

  39. Cell Energy Photosynthesis • light-independent reactions • also referred to as the ? • Calvin cycle • occurs in the ? • stroma

  40. Cell Energy Photosynthesis H2O light light- dependent reactions Calvin Cycle ATP NADPH Chloroplast O2

  41. Cell Energy Photosynthesis • light-independent reactions • also referred to as the ? • Calvin cycle • occurs in the ? • stroma • requires? • carbon dioxide, ATP & NADPH

  42. Cell Energy Photosynthesis CO2 H2O light light- dependent reactions Calvin Cycle ATP NADPH Chloroplast O2

  43. Cell Energy Photosynthesis • light-independent reactions • also referred to as the ? • Calvin cycle • occurs in the ? • stroma • requires? • carbon dioxide, ATP & NADPH • produces? • sugars, NADP+, & ADP + P

  44. Cell Energy Photosynthesis CO2 H2O light NADP+ ADP + P light- dependent reactions Calvin Cycle ATP NADPH sugars Chloroplast O2

  45. Cell Energy NADPH • when sunlight excites electrons in chlorophyll, the electrons gain a great deal of energy • a special carrier is needed to move these high-energy electrons • similar to hot coals of a fire

  46. Cell Energy NADPH • carrier molecule • compound that can accept a pair of high-energy electrons and transfer them along with most of their energy to another molecule

  47. Cell Energy NADPH • NADP+ - carrier molecule that accepts and holds 2 high-energy electrons along with a hydrogen ion (H+) • results in the production of NADPH • this conversion to NADPH allows some energy of light to be trapped in a chemical form • chemical energy can then be used by cell for chemical reactions elsewhere in cell

  48. Cell Energy Light-Dependent Reactions • Step A – Photosystem II • pigments in photosystem II absorb light via antenna complexes • energy from light is absorbed by electrons – increasing their energy level • energy is then passed on to the electron transport chain • enzymes break up water molecules into electrons, hydrogen ions (H+), and oxygen

  49. Cell Energy Light-Dependent Reactions inner thylakoid membrane thylakoid membrane Stroma

  50. Cell Energy Light-Dependent Reactions • Step B – Electron transport chain (ETC) • high-energy electrons move through electron transport chain • energy from electrons is used by molecules to transport H+ ions from stroma to the inner thylakoid

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