Photosynthesis and Cellular Respiration

1
Photosynthesis and Cellular Respiration

• Chapter 5

2
Chapter objectives

• To examine how energy is use to power cell
  metabolism
• How autotrophs capture store sunlight as energy
  molecules
• How all organisms use cellular respiration to
  release stored energy

3
Energy Living Things

• Chapter 5 Section1

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Energy in Living System

• almost all energy in living systems needed for
  metabolism from sun
• Directly or indirectly,

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Energy in Living System

• Sun light absorbed by living systems
• ex. Algae, plants, and some prokaryotes

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Energy in Living System

• Can store energy in organic compounds
• Sugars, Fats

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Building Molecules That Store Energy

• Metabolism involves either using energy to build
  molecules or breaking down molecules in which
  energy is stored

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Building Molecules That Store Energy

• Autotroph-organism that uses energy from sunlight
  or chemical energy to make organic compounds
• Photosynthesis-process by which light energy is
  converted to chemical energy

9
Breaking Down Food for Energy

• Heterotroph-organisms that must get energy from
  food not of directly from sunlight or inorganic
  substances 

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Breaking Down Food for Energy

• Cellular Respiration-metabolic process in which
  organisms get energy from food
• make ATP (energy molecule) 

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Transfer of Energy to ATP

• In cells, chemical energy stored in food
  molecules is released gradually in a series of
  enzyme-assisted chemical reactions
• When cells break down food, some energy is
  released as heat

12
Transfer of Energy to ATP

• Remaining energy stored temporarily in ATP
• delivers energy wherever needed in cell
• Enough energy released from ATP to drive most
  cell activities

13
ATP

• ATP-adenosine triphosphate-nucleotide with 2
  extra energy storing phosphate groups (3
  phosphates, ribose, adenine base)

14
ATP

• phosphate tail unstable because each group is
  negatively charged so repel each other-energy is
  released when bonds broken

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ATP

• when release phosphate (which requires a little
  energy) get ADP (adenosine diphosphate), a
  phosphate and energy
• use energy from release to power metabolism