Photosynthesis and Cellular Respiration

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Photosynthesis and Cellular Respiration

• AHSGE Standard II-1The students will understand
  the concepts dealing with matter. Objective
  Trace the transfer of matter and energy through
  biological systems.
• AHSGE Standard V-1 The student will understand
  concepts of cells.

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Overview

• In one way or another all of the energy that
  your body needs comes from the sun. Plants take
  in energy from the sun through the process of
  photosynthesis. Other living organism take in
  food and break it down to make energy through the
  process of cellular respiration. All of this
  energy flows through different organisms either
  through the food web or the food chain.

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Photosynthesis

• Photosynthesis is a process in which plants take
  in energy from the sun, carbon dioxide, and water
  and convert them all to make glucose (sugar), and
  oxygen.
• Photosynthesis takes place in the chloroplast of
  plant and algae cells and in the membranes of
  certain bacteria.

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3 Stages of Photosynthesis

1. Energy is captured from sunlight.
2. Light energy is converted to chemical energy,
   which is temporarily stored in ATP and the energy
   carrier molecule NADPH.
3. The chemical energy stored in ATP and NADPH
   powers the formation of organic compounds, using
   carbon dioxide (CO2).

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Photosynthesis Formula

• Reactants Products
• 6CO2 6H2O---------gt C6H12O6 6O2
• Carbon Water
  Glucose Oxygen
• Dioxide
• OR
• 3CO2 3H2O---------gt C3H6O3 3O2
• Carbon Water Glucose
  Oxygen
• Dioxide
• Note The left hand side of the formula
  represents the reactants and the right side the
  products.

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Photosynthesis Stage One

• Light Energy is Absorbed
• The chemical reactions that occur during the
  first and second stages of photosynthesis are
  sometimes referred to as light reactions or
  light dependent reactions.

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Pigment and Wavelengths of Light

• Pigments are molecules that absorbs wavelengths
  of light.
• Pigments only absorbs only certain wavelengths
  and reflects all others.
• Chlorophyll is the primary pigment that is
  involved in photosynthesis.

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Pigment and Wavelengths of Light

• Chlorophyll
• During photosynthesis the primary pigment which
  is chlorophyll, absorbs mostly the blue and the
  red light and reflects the green and yellow
  light. The reflection of the green and yellow
  light is what make plants look green.
• There two types of chlorophyll. You have
  chlorophyll A and B.

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Pigment and Wavelengths of Light

• Carotenoids
• Carotenoids are the yellow and orange plant
  pigments that aid in photosynthesis. These are
  the colors of most fruits, vegetables, and
  flowers. Carotenoids absorbs wavelengths of light
  differently than the chlorophyll. So, in
  conjunction with chlorophyll they are able to
  absorb more light. These pigments are located in
  the chloroplast of the plant cell in the
  thylakoid membranes.

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Stage II of Photosynthesis

• Light Energy is Converted to Chemical Energy
• The electron transport chain is used to pump
  hydrogen ions into the thylakoid (membrane inside
  the chloroplast). The ions will accumulate so
  much that they will diffuse back out of the
  thylakoid membrane down their concentration
  gradient through carrier proteins. (This is
  passive transport) When this happens the carrier
  proteins also serving as channels catalyzes
  (speeds up) the reaction in which a phosphate
  group is added to ADP (adenosine diphosphate)
  turning it into ATP (energy molecule). The
  movement of the hydrogen ions across the
  thylakoid membrane through the carrier proteins
  gives the energy needed for the third stage of
  photosynthesis.

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Stage II of Photosynthesis

• Light Energy is Converted to Chemical Energy
• While one electron transport chain is working to
  provide the energy needed to make ATP the second
  one is providing energy to make NADPH. NADPH is
  an electron carrier that provides the high energy
  electrons need to make carbon-hydrogen bonds in
  the third stage of photosynthesis. In this second
  chain the excited electrons along with hydrogen
  and the electron acceptor NADP to form NADPH.

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Summary of Photosynthesis
STAGES OF PHOTOSYNTHESIS STAGES OF PHOTOSYNTHESIS STAGES OF PHOTOSYNTHESIS
Used Produced
Stage 1 Light, water Oxygen, hydrogen ions
Stage 2 Electrons, hydrogen ions ATP, NADPH
Stage 3 ATP, NADPH, Carbon Dioxide Organic Compounds
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Cellular Respiration

• Most of the foods that we eat contains energy.
  Before our bodies are able to use that energy it
  has to be first broken down into a more usable
  form. That energy will be in the form of ATP. The
  process that is used to break those foods that
  are high in energy down is called cellular
  respiration. Cellular respiration takes place in
  the mitochondria (powerhouse of the cell).

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Cellular Respiration Formula

• Reactants Products
• C6H12O6 6O2 -----? 6CO2 6H20 energy
• Glucose Oxygen enzymes Carbon
  Water ATP
• Dioxide

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Stages of Cellular Respiration

• Stage 1 Glucose is converted to pyruvate helps
  in energy production and starts the krebs cycle.
  Once converted, a small amount of ATP and NADH is
  formed.
• Stage 2 When oxygen is present (aerobic) the
  NADH and pyruvate is used make a large amount of
  ATP. This is called aerobic respiration which
  occurs in the mitochondria of the cell for
  eukaryotes and in the cytoplasm (cytosol) of the
  prokaryotes. If oxygen is not present the
  pyruvate is converted to lactate or ethanol and
  carbon dioxide.

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Glycolysis

• In the first stage of cellular respiration
  glucose is broken down through a process called
  glycolysis ( a process that breaks down glucose
  into pyruvates).

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Cellular Respiration Summary

• Cellular Respiration has two stages. First
  glucose is broken down to pyruvate during
  glycolysis to make some ATP. Then a large amount
  on ATP is made during aerobic respiration.
• The Krebs Cycle is a series of reactions that
  produce energy storing molecules during aerobic
  respiration.
• During aerobic respiration, large amounts of ATP
  are made in an electron transport chain.
• When oxygen is not present, fermentation follows
  glycolysis, regarding NAD needed for glycolysis
  to continue.