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Energy & Photosynthesis

Energy & Photosynthesis. What is energy and what is it needed for?. Energy. Energy is the ability to cause matter to move or to change The ability to do work Why do our cells require energy? Growth & repair Active transport Reproduction Synthesis of molecules.

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Energy & Photosynthesis

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  1. Energy& Photosynthesis

  2. What is energy and what is it needed for?

  3. Energy • Energyis the ability to cause matter to move or to change • The ability to do work • Why do our cells require energy? • Growth & repair • Active transport • Reproduction • Synthesis of molecules

  4. Does food, which contains sugar and other carbon-based molecules give you energy?

  5. Does food provide energy? Yes & No! • All carbon-based molecules in food STORE chemical energy in their bonds! • Remember, carbohydrates & lipids are the most important energy sources in food you eat • However, the energy in food is only usable after these molecules are broken down during digestion and a series of other chemical reactions

  6. ATP: The Energy Molecule • ATP = adenosine triphosphate • All cells use chemical energy carried by ATP! • Monomers- single building blocks: • Adenine: a nitrogenous base • Ribose: 5 Carbon sugar • 3 phosphate groups

  7. Where is Energy stored in the ATP molecule? • Energy is in the chemical bonds between the phosphates • The bond holding the third phosphate group is unstable and very easily broken • The removal of the third phosphate group releases energy

  8. ADP Molecule • Adenosine diphosphate or ADP • Has 2 phosphate groups • When a phosphate is removed, energy is released and ATP becomes ADP

  9. Phosphorylation & ATP/ADP Cycle • When a cell has energy available, it can store small amounts of it by phosphorylation (the addition of a phosphate group) to the ADP molecule, thus producing ATP • This requires a large, complex group of proteins

  10. ADP ATP Low-Energy Molecule High-energy molecule

  11. What makes these cells so important to many other organisms? • These diatoms are single-celled algae that use the process of photosynthesis to store chemical energy in sugars. • Animals eat photosynthetic organisms such as plants & algae to get this chemical energy • Photosynthetic organisms also produce the oxygen that is required to release much of the chemical energy in sugars

  12. Plants are Energy Producers • Like animals, plants need energy to live • unlike animals, plants don’t need to eat food to make that energy • Plants produce the source of chemical energy for themselves and other organisms • animals are consumers (heterotrophs) • plants are producers (autotrophs/photoautotrophs)

  13. How do autotrophs provide energy? • Plants, some bacteria, and protists are the main sources of chemical energy for most organisms • These autotrophs convert solar energy into chemical energy (sugars) • Ex. glucose, sucrose, cellulose & starch sun ATP sugars

  14. How do we perceive colors?

  15. Light energy Sunlight includes a wide range of radiant energy, such as ultraviolet radiation, microwaves, and the visible light spectrum that lets you see

  16. Wavelengths • Electromagnetic radiation – form of energy that exhibits wavelike behavior as it travels through space • Longer wavelength = lower energy • Shorter wavelength =higher energy

  17. Visible Light Spectrum •  Visible light appears white, but it is made up of several colors, or wavelengths of light • The surface of an object reflects some colors and absorbs all the others. • We perceive only the reflected colors. • An object appears white when it reflects all wavelengths and black when it absorbs them all.

  18. What role do pigments play in the process of photosynthesis?

  19. Light and Pigments • Since light is a form of energy, any compound that absorbs light also absorbs the energy from that light • Chlorophyll is a molecule in chloroplasts that absorbs some of the energy in visible light • There are two main types of chlorophyll (a & b) which, together, absorb mostly red and blue wavelengths of visible light

  20. Chlorophyll • Neither type of chlorophyll absorbs green light • The green color of plants comes from the reflection of light’s green wavelengths by chlorophyll • 2 Main Types of Chlorophyll: • Chlorophyll a – absorbs mainly blue-violet and red regions • Chlorophyll b – absorbs mainly in blue and red regions

  21. pigments

  22. What are the reactants and products of photosynthesis?

  23. Photosynthesis Reaction PHOTOSYNTHESIS:A process in which plants and cyanobacteria capture sunlight & convert water and carbon dioxide into oxygen and high energy carbohydrates- such as sugars (monosaccharides) and starches (polysaccharides) Reactants: carbon dioxide and water Products: oxygen and sugar (monosaccharide- glucose) 6CO2 + 6H20 C6H1206 + 6 O2 OR Carbon dioxide + water sugars + oxygen

  24. P H O T O S Y N T H E S I S

  25. Chloroplasts • The three main parts of chloroplasts needed for photosynthesis are the: • Grana-stacks of coin-shaped, membrane-enclosed compartments called thylakoids which contains chlorophyll • Thylakoids-inner membrane of the chloroplast • Stroma- the fluid that surrounds the grana inside a chloroplast

  26. 3 Major Parts of a Chloroplast • Grana:(singular-granum) • Stack of thylakoid membranes • Increases light absorbing efficiency (surface area) • Contains chlorophyll • Thylakoid membranes: Inner membrane • Light-dependent reactions occur here • Embedded with chlorophyll & other pigments • Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters known as photosystems • Helps produce ATP • Stroma: dense, protein-rich gel like material surrounding Grana • Calvin Cycle (Light-Independent reaction) occurs here

  27. What happens during the process of photosynthesis?

  28. Process of Photosynthesis • 2 steps: 3 stages • Step 1 occurs in 2 Stages- • Light-Dependent Reaction (Light Reaction): • occurs in the thylakoid membrane – light energy is captured and transferred here by two groups of molecules called photosystems (photosystem I and photosystem II). Stage 1. Energy is captured from sunlight (pigments absorb light) • Water (H2O) taken into chloroplast • Oxygen (O2) is produced/released(comes from the water that gets broken down) Stage 2. Light energy is converted to chemical energy (temporarily stored as ATP& NADPH) • Energy (ATP & NADPH) is produced to power the 2ndstep = Calvin Cycle

  29. Light-dependent reactions Photosystems II and I absorb energy from sunlight and transfer energy to the Calvin Cycle

  30. What are some electron carriers that play a role in photosynthesis?

  31. Electron carriers • A carrier molecule is a compound that can accept a pair of high-energy electrons and transfer them along with most of their energy to another molecule • This process is called electron transport and the electron carriers themselves are known as the electron transport chain

  32. NADP+ is a carrier molecule that accepts and holds 2 high energy electrons along with a hydrogen ion (H+) form NADPH • NADP+ + 2 electrons (2 e-) + H+ = NADPH • NADPH carries these high energy electrons to chemical reactions elsewhere in the cell

  33. Process of photosynthesis Step 2: • Stage 3 Calvin Cycle (Light-Independent Reaction) • Occurs in stroma and uses energy from the light-dependent reactions to make sugars • Carbon dioxide (CO2) is taken from atmosphere and brought into the chloroplast • CO2 is added to a cycle of chemical reactions to build larger molecules • A molecule of a simple sugar is formed (usually glucose, C6H12O6)

  34. Light-independent reactions (Calvin cycle)

  35. Compare/Contrast the light-dependent & light-independent reactions.

  36. Summary of photosynthesis Stage 1 and 2 Stage 3 aka. Light Independent Reaction

  37. Summary of photosynthesis Light-Dependent Reactions • Energy is captured from sunlight and energy is transferred to electrons that enter an electron transport chain (ETC) • Water molecules are broken down into H+ ions, electrons, and oxygen molecules. • Energized electrons provide energy for H+ ion transport and are added to NADP+ to form NADPH • The flow of H ions through a protein makes ATP • Products of this reaction are oxygen, NADPH and ATP • ATP and NADPH are used later to make sugars Light-Independent Reactions • Carbon dioxide enters the Calvin Cycle • ATP and NADPH are used from the light-dependent reaction • One high-energy 3-carbon molecule is made for every three molecules of carbon dioxide that enter the cycle • Two high-energy 3-carbon molecules are bonded together to make a sugar • Therefore, six molecules of CO2 must be added to make one 6-carbon sugar • The products are a 6-carbon sugar such as glucose, NADP+ and ADP • The NADP+ and ADP molecules return to the light-dependent reactions

  38. How are gases & water exchanged in plants?

  39. How are gases & water exchanged in plants? • Stoma (singular), stomata (plural) • Pore or opening found on plant leaves and stems used to control the exchange of gas (oxygen & carbon dioxide) • Guard cells- surround each stoma; regulate the rate of transpiration (evaporation of water) by opening and closing the stomata, help to maintain homeostasis

  40. What 3 factors affect the rate of photosynthesis?

  41. Factors Affecting the Rate of Photosynthesis • Light Intensity: • Increasing light can speed up photosynthesis • Extreme intensity can damage the chlorophyll • Availability of raw materials: (CO2, H2O) • A shortage of these can slow or even stop photosynthesis • Temperature: • 0-35ºC is ideal for enzymatic function

  42. Rates of Photosynthesis vs. Regulating Factors • What happens as you continue to increase the light intensity that the plant receives? • What happens as the temperature of the environment the plant is in continues to increase?

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