Cellular Respiration and Photos Pigments Cont. Chlorophyll is a green pigment in chloroplasts that absorbs

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  • Cellular Respiration and Photosynthesis

  •  Imagine an abandoned house that is falling apart. Restoring order to the house will require an input of energy (for example: hammering nails, applying paint). Living things also need energy in order to stay in good repair, or maintain HOMEOSTASIS. Every organism must maintain HOMEOSTASIS as long as it lives. Therefore, all organisms require a constant source of energy!

  • Chemical Energy  Energy in organic compounds (like carbohydrates)

    comes from the sun.

     SOLAR energy (energy from our sun) enters living systems when plants make organic compounds from carbon dioxide and water through the process of PHOTOSYNTHESIS.

     We cannot (and other animals) cannot perform photosynthesis, so why does this matter to us?

     We eat plants! So we are getting our energy from the sun!

  • Chemical Energy Continued…  Food molecules that are made or consumed by an

    organism are the fuel for its cells.

     Cells use these molecules to release the energy stored in the molecules bonds.

     What organelle in the cell is responsible for releasing this energy?

     Mitochondria

  • So what is happening when photosynthesis takes place????  Energy enters an ecosystem when organisms use

    sunlight during photosynthesis to convert carbon dioxide molecules (stable) into glucose (less stable).

     In which organelle of a plant cell does photosynthesis take place?

     Chloroplast

  • So what is happening when photosynthesis takes place????  Once a plant has made that GLUCOSE, energy can be

    extracted through the process of CELLULAR RESPIRATION.

  •  What percent of the energy in sunlight is used for photosynthesis?

     Only 1%!

  • Harvesting Light Energy  Chloroplast organelles convert light energy into

    chemical energy.

     Chloroplasts have a membrane much like the plasma membrane on the outside of the cell.

     The space inside the membrane is called the STROMA.

     Within the stroma is a membrane called the THYLAKOID MEMBRANE.

     This membrane is folded in a way that produces flat, disc-like sacs called THYLAKOIDS.

     Stacks of THYLAKOIDS are called GRANUM

  • Harvesting Light Energy  The THYLAKOIDS contain molecules that absorb light

    energy for photosynthesis.

     The first stage of photosynthesis begins when light waves hit these stacks.

  • Light  Light travels in waves.

     Sunlight contains all of the wavelengths of visible light. We see these different wavelengths as different colors.

     For Example: The wavelength of purple light is from 400-425 nm. Green: 475-500 nm.

  • Pigments  Why can you see light?

     Cells in the back of the eye contain pigments!

     A pigment is a substance that absorbs certain wavelengths (colors) of light and reflects all of the others.

     In plants, light energy is harvested by pigments that are located in the thylakoid membrane of chloroplasts.

     What is the pigment in chloroplasts that absorbs light energy?

     Chlorophyll

  • Pigments Cont.  Chlorophyll is a green pigment in chloroplasts that absorbs

    light energy to start photosynthesis.  Chlorophyll absorbs mostly blue and red light and reflects

    green and yellow light.  ***look at your classmates. The pigments in their shirts are

    reflecting colors back at your eye.  Plants have two types of chlorophyll:

     Chlorophyll a  Chlorophyll b

     Plants also have pigments called carotenoids that absorb blue and green light and reflect yellow, orange, and red.

     Why do leaves turn redish orange in the fall?  Chlorophyll regresses and carotenoids are exposed.

  • The organelle in which photosynthesis occurs: A. Mitochondria

    B. Nucleus

    C. Endoplasmic Reticulum

    D. Chloroplast

    E. Golgi Apparatus

  • While performing an experiment using green spinach leaves, Jamie identifies Chlorophyll and other pigments of several colors. What is the most accurate conclussion Jamie can make about pigments in spinach leaves.

    A. Chlorophyll decomposes to reveal other pigments

    B. Chlorophyll absorbs light while other pigments reflect light

    C. Chlorophyll passes light energy to other pigments in leaves

    D. Chlorophyll appears in higher concentrations than other pigments

  • Photosynthesis converts light energy into energy A. mechanical

    B. kinetic

    C. chemical

    D. fast

  • The chemical energy produced from photosynthesis is found in the bonds of: A. Glucose

    B. Enzyme

    C. Lipid

    D. Water

  • Which of the following pigments is most soluble in solvent? A. Chlorophyll b

    B. Chlorophyll a

    C. Xanthophylls

    D. Carotene

  • Which of the following pigments has the greatest affinity for chromatography paper?

    A. Chlorophyll b

    B. Chlorophyll a

    C. Xanthophyll

    D. Carotene

  • Pop Quiz hot shot…  Where are these pigments found?

     Thylakoid (inside the Chloroplast)

  • The Reactions of Photosynthesis  Scientists describe the reactions of photosynthesis in

    two parts:

     Light Dependent

     Light Independent

     The light dependent reaction takes place within the thylakoid membrane.

     Where are the thylakoids found?

     Inside the chloroplasts

  • The Reactions of Photosynthesis  The light independent reaction (aka: the calvin cycle)

    takes place in the stroma.

     Where is the stroma?

     Space inside the membranes of the chloroplasts.

  • The Reactions of Photosynthesis  When sunlight is captured by pigments, electrons gain

    a great deal of energy.

     The electrons come from water!

     What are the pigments found in the leaf?  Chlorophyll A

     Chlorophyll B

     Carotein

     Xanthophylls

     These high-energy electrons require a special carrier.  These carriers are called electron carriers!

  • The Reactions of Photosynthesis  Electron Carriers

     One of these carrier molecules is a compound known as NADP+. (Nicotinamide adenine dinucleotide phosphate)

     The name is complicated, but its job is simple!

     Accepts and holds 2 electrons that were excited from the pigments.

     NADP+ is converted into NADPH when it holds the electrons

     NADPH then carries electrons to other parts of the chloroplast

  • The Reactions of Photosynthesis  ATP (energy) is also produced during the light

    dependent reaction.  When water is broke down to remove electrons used to

    attach to NADP+, hydrogen ions are left behind in the cytoplasm.

     These ions move through a protein channel to the outside of the cell. This protein is called ATP synthase.

     As Hydrogen ions pass through ATP synthase, ADP is convernted to ATP

     What is ATP?  Energy!

  • ATP Synthase

  • The Reactions of Photosynthesis  The light independent Reaction (aka Calvin Cycle)

     The ATP and NADPH formed by the light-dependent reactions contain an abundance of chemical energy, but they are not stable enough to store that energy for any more than a few minutes.

     During the Calvin Cycle, plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time.  Sugar

  • Steps to the Calvin Cycle  1. Six carbon dioxide molecules enter the cycle.

     Where does the plant get the carbon dioxide?

     From the atmosphere!

     Through a series of reactions, ATP and NADPH provide the energy to convert Carbon dioxide into Glucose.

     Where did the ATP and NADPH come from?

     The light dependent cycle

  • The light independent reaction takes place within the _________. A. Thylakoid

    B. Mitochondria

    C. Nucleus

    D. Stroma

  • Energized electrons that initiate photosynthesis come from _____. A. Pigments

    B. Carbon Dioxide

    C. Water

    D. Oxygen

  • How many electrons can NADP+ capture and hold? A. 1

    B. 2

    C. 3

    D. 4

  • As Hydrogen ions move through ATP synthase, ADP is converted into____. A. ATP

    B. Oxygen

    C. Water

    D. ASP

  • The reaction of photosynthesis that DOES NOT require light is known as the: A. Dark Reaction

    B. Calvin Cycle

    C. Light Independent Reaction

    D. All of the above

  • Chemical Energy and Food  Food provides living things with the chemical building

    blocks they need to grow and reproduce.

     Food serves as energy to the cells of the body.