Meanings of Respiration

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Meanings of Respiration

• 1. External Respiration exchange of gasses (O2
  and CO2) in the lungs, between the air and the
  blood.
• 2. Internal Respiration - exchange of gasses (O2
  and CO2) in the capillaries, between the blood
  and the tissues.
• 3. Cellular Respiration Production of cellular
  energy by the intracellular breakdown of sugars

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Cellular Respiration

• Energy releasing process by which glucose
  molecules are chemically broken down to produce
  energy in the form of ATP
• ATP is used to do various types of cellular work
  (active transport, synthesis, maintenance,
  growth, repairing, and muscle work)

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• Glucose C6H12O6
• 6 atoms of carbon
• 12 atoms of hydrogen
• 6 atoms of oxygen
• O2 oxygen gas
• CO2 carbon dioxide gas
• H2O water

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• ATP adenosine triphosphate
• ADP adenosine diphosphate
• Pi phosphate
• ADP Pi ATP

energy
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• Aerobic requiring O2
• Anaerobic not requiring O2

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Cellular RespirationSimplified Formula

• C6H12O6 6 O2 36 ADP 36 Pi
• 6 CO2 6 H2O 36 ATP

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The Three Stages of Cellular Respiration

1. Glycolysis (does not require O2).
2. The Krebs cycle (requires O2).
3. Electron transport chain (ETC) (requires O2).

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Glycolysis

• One molecule glucose is partially broken down to
  2 molecules of pyruvic acid (3-carbon molecules).
  
• Takes place in the cytoplasm.
• Primitive and inefficient process, extracting
  only about 5 of the energy in glucose.
• Occurred first in evolution, because the
  concentration of oxygen in the air was low.

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• Fermentation is glycolysis without the later
  steps in respiration. But in fermentation, there
  is a simpler second step that does not produce
  energy pyruvic acid is converted to alcohol and
  carbon dioxide, acetic acid, or lactic acid.

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Fermentation in Different Cells

• Yeast cells Glucose ? CO2 Ethanol
• Cider Bacteria Glucose ? Acetic acid
• Sauerkraut Bacteria Glucose ? Lactic acid
• Anaerobic respiration in muscle cells
• Glucose ? Lactic acid

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The Krebs Cycle and the ETC occur inside
mitochondria
mitochondrion
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The Electron Transport Chain 1

• The first carrier donates electrons to the next
  carrier, and so on down the line. The last
  electron acceptor is O2 , and H2O is formed.
• The electron movement provides energy to move
  hydrogen ions, pushing them into the outer
  compartment of the mitochondria.

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The Electron Transport Chain 2

• Hydrogen ions flow back into the inner
  compartment through an enzyme called ATP
  synthase. This flow causes ATP synthase to
  rotate, which puts Pi onto ADP, thus making ATP.

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The Electron Transport Chain
Hydrogen flows back to inner compartment,
generating ATP
As electrons are transported, hydrogen is pumped
from the inner compartment to the outer
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ATP production from Cellular Respiration

• Glycolysis 2 ATP
• Krebs cycle 2 ATP
• ETC 32 ATP
• _____________________
• Total 36 ATP per molecule of glucose

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External Respiration (Respiratory Systems)

• Large aerobic organisms need to take in oxygen
  and get rid of CO2. Various respiratory systems
  developed in different animals, depending on
  their environment and their life style.

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Respiratory Structures

• Lungs - in all vertebrates except fish
• Gills - in fish
• Skin gills - surrounded by pincers -
  Echinoderms/Starfish
• Book gills - between belly plates - some
  Arthropods/Horseshoe crab
• Tracheae and spiracles insects (air tubes that
  branch internally)