MODULE 5: Ecosystem: Life Energy (Part 2)

• Cellular respiration - the process of extracting energy in the form of ATP from the glucose in the food you eat
• Equation Form of Cellular respiration:

  A) C6H12O6

  B) 6O2

  C) 6CO2

  D) 6H2O

  
• Process of cellular respiration - May produce ATP with or without the presence of oxygen.
• Most eukaryotes perform aerobic respiration - Which depends on oxygen to produce ATP.
• Three Stages of Aerobic Cellular Respiration:

  • Glycolysis
  • Krebs Cycle
  • Electron Transport chain
• Glycolysis - Means "splitting of sugar". It occurs in the cytoplasm of the cells which includes series of chemical reactions catalysed by a specific enzyme.
• Glucose - A six-carbon sugar
• Pyruvate - It is split into two three-carbon sugar molecules to produce two ATPs to start the activation process.
• Outer membrane - Contains proteins known as porins.
• Porins - Allow movement of ions into and out of the mitochondrion.
• Matrix - The area inside the inner membrane which contains proteins, cytosol and mitochondrial DNA.
• Inner membrane - It contains enzymes essential for cell respiration.
• Cristae - Folded section of the inner membrane which increases the surface area available for energy production via oxidative phosphorylation.
• Mitochondria:

  A) intermembrane space

  B) matrix

  C) cristae

  D) inner membrane

  E) ATP synthesis

  F) outer membrane

  G) DNA

  H) polin

  I) ribosome

  J) granule

  
• Krebs cycle - The second stage in cellular respiration that occurs in mitochondrial matrix.
• CoA - Stands for coenzyme A
• Acetyl-CoA - A two-carbon molecule (product of the pyruvate and coenzyme A)
• Step 1 : (Krebs Cycle)

  • Acetyl-CoA combines with four-carbon compound (oxaloacetate) to form citric acid, which has six carbon atoms.
• Step 2 : (Krebs Cycle)

  • Series of reactions that release energy goes after the six-carbon acids formed. This release energy is captured in molecules of NADH, ATP, and FADH2, another energy carrying compound.
• Step 3 : (Krebs Cycle)

  • The four carbon molecule regenerates, this molecule is needed for the next turn of the cycle. Two turns are required because glycolysis produces two pyruvate molecules when it splits glucose.
• After the Krebs cycle is completed, the original glucose molecule has been broken down completely into six of its carbon atoms that have combined with oxygen to form?

  Carbon dioxide
• After the Krebs Cycle, the energy from its chemical bonds has been stored in a total of 16 energy-carrier molecules. These molecules are?

  4 ATPs, 10 NADH and 2 FADH2
• Electron transport chain (ETC) - The final stage of aerobic respiration. It is located on the inner mitochondrial membrane.
• Oxidative phosphorylation - The process where energy stored in it release within to reduce hydrogen carriers in order to synthesize ATP.
• The ETC proteins in a general order:

  • Complex I
  • Complex II
  • Coenzyme Q
  • Complex III
  • Cytochrome C
  • Complex IV
• ATP synthase action - Pumps protons from inter-membrane space to matrix, produces ATP from ADP + Pi + energy
• Electron transport chain - a series of protein complexes located at the inner membrane of the mitochondria.
• Before the transitional stage begins in Krebs Cycle , pyruvate, which has three carbon atoms, is split apart and combined with an enzyme known as?

  CoA