PHOTOSYNTHESIS AND CELLULAR RESPIRATION

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PHOTOSYNTHESIS AND CELLULAR RESPIRATION

• CHAPTER 8 9

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ENERGY ATP

• Compounds that store energy
• ATP NADH
• NADPH FADH2

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• ATP
• chief energy storing molecule composed of
• adenine
• Phosphates
• Ribose (5 carbon
  sugar)

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High energy bonds
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• ATP does three types of work
• mechanical functions for cell
• active transport for movement of molecules across
  membrane
• breakdown and synthesis of large molecules

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• ATP releases energy when a bond between 2
  phosphates (P) is broken
• Becomes ADP phosphate
• A P P P A P P P energy
• (releasing P energy)

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• ATP can be regenerated by bonding a phosphate
  back to ADP

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SOURCES OF ENERGY

• Autotrophs -- organisms that make food from
  carbon dioxide and energy like sunlight
  organisms that make their own food

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• Heterotrophs -- organisms that depend on
  autotrophs or other heterotrophs for food
  organisms that cannot make their own food

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PHOTOSYNTHESIS

• Energy from sunlight
• Introduction to Photosynthesis
• Process in which autotrophs convert light energy
  into chemical bond energy of carbohydrates (sugar
  and starch)

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• Pigment -- molecule that absorbs certain
  wavelengths of light
• chlorophyll -- absorbs violet, blue, and red light

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Reflected wavelengths determine what color you
perceive an object to be Absorbed wavelengths
provide energy for photosynthesis
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• History
• Van Helmonts studies of mass accounted for
  contribution of water to plant growth.

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• Priestleys candle experiments showed oxygen
  needed for burning and that
  plants produced
  oxygen.

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• Ingenhousz effect shown by Priestley only
  occurs when the plant is exposed to light

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• Conclusion of all 3
• in light, plants transform CO2 and water into
  carbohydrates and oxygen

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• Chloroplasts
• organelle that performs photosynthesis
• thylakoid
• grana

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LEAF
PLANT CELLS
CHLOROPLAST
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• Thylakoid - sacs of membrane, chlorophyll
  containing structure in the chloroplast
• Grana - stacks of thylakoid, light collecting
  photosystems
• Stroma - gel-like material

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stroma
thylakoid
grana
Chloroplast
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• Overview of Photosynthesis
• 6CO2 6 H2O ---------gt C6H12O6 6O2
• Occurs in the chloroplast
• Produces glucose

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• -Requires light energy to start
• Uses ATP NADPH
• Divided into 2 main parts
• Light Dependent Reactions
• Light Independent Reactions (Calvin Cycle)

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• Light Dependent Reactions
• first stage of photosynthesis requires light and
  water
• Takes place on thylakoid membrane
• water is split
• O2 is released
• Electrons are harvested and used to make ATP and
  NADPH

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• Light-Independent Reactions or The Calvin Cycle
• Takes place in the stroma
• requires the products of the light-dependent
  reactions
• CO2 is used to build carbohydrates (glucose)

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Visit Virtual Chloroplast

• www.scale.uiuc.edu/pb102/07/virtchlor.html

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Cellular Respiration

• Energy-Yielding Processes in Cells
• Involves Breaking Down Food
• Series of Chemical Reactions that Produce ATP

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Two Main Types

• Cellular Respiration
• Fermentation

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• Cellular Respiration
• process by which glucose molecules are broken
  down to release energy

C6H12O6 O2
6CO2 6H2O ATP
(Energy)
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• Fats, carbohydrates, and proteins may be broken
  down

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• Cellular Respiration (continued)
• requires oxygen aerobic process
• produces 36 ATP molecules for each glucose
  molecule
• reverse equation of photosynthesis

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• Overall Chemical Reaction
• Glucose Oxygen --gtCarbon dioxide Water
  Energy (ATP Heat)
• C6H12O6 6O2 -----gt 6CO2 6H2O Energy
  (ATP Heat)

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• Complete Cellular Respiration has Three Parts
• Glycolysis
• Krebs Cycle
• Electron Transport Chain

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• Glycolysis
• process by which glucose is converted to pyruvate
  and energy is released
• occurs in the cytoplasm

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• During the process, glucose yields 2ATP and
  pyruvates

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Krebs Cycle

• Pyruvates used
• Occurs in mitochondria
• two ATP formed for each glucose

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Electron Transport

• Energy from Krebs powers ETC
• requires oxygen
• occurs in the mitochondria (powerhouse)
• produces 32 molecules of ATP

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• Iworx.com/shocktest/overview

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Fermentation

• extraction of energy from food
• does not require oxygen

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• includes steps of glycolysis
• produces 2 ATP molecules

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Fermentation (continued)

• two important types include
• Alcoholic Fermentation
• Lactic Acid Fermentation

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• Alcoholic Fermentation
• pyruvate converted to ethanol and carbon dioxide
• carried out by yeast and bacteria

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• Lactic Acid Fermentation
• pyruvate converted to lactic acid
• carried out by fungi and bacteria in making
  cheese and yogurt

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• carried out by animals in muscle cells during
  early stages of strenuous exercise (blood cannot
  supply oxygen fast enough) makes your muscles
  sore!

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Anaerobic Respiration

• Some organisms do not ever use oxygen in the
  process of respiration
• use sulfur, nitrogen, or carbon

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Energy Flow in the Biosphere

• Making Food
• most photosynthetic organisms produce more sugars
  than they need

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• animals eat photosynthetic and heterotrophic
  organisms
• when plants or animals die, their energy stores
  are released to the environment