Home / AP Biology : 3.6 Cellular Respiration – Study Notes

AP Biology : 3.6 Cellular Respiration – Study Notes

F. Cellular Respiration
➢$ C_6H_12O_6 + 6O_2 ⟶6CO_2 + 6H_2O + ATP$
Aerobic respiration: ATP made in the presence of oxygen
Anaerobic respiration: ATP made without presence of oxygen
➢ 1. GLYCOLYSIS

  •  Glucose is split
  • Glucose 6-carbon; when it is split it makes 2 3-carbon pyruvates
  •  Creates 2 ATP (net)
  •  NADH created from the transfer of electrons to NAD+
  • Occurs in cytoplasm
  •  Glucose + 2 ATP + 2 NADh ⟶2 Pyruvate + 4 ATP + 2ND

➢ 2. FORMATION OF ACETYL CoA

  • $ 2Pyruvate + 2 Coenzyme A + 2 NAD^+ ⟶2 Acetyl-CoA + 2CO^2 + 2 NADH$
  •  Extra carbons leave cell as $CO_2$

➢ 3. CITRIC ACID CYCLE

  • Aka Krebs cycle
  •  Each acetyl coa will enter Krebs cycle on at a time, and all carbons will be turned into $CO_2$ eventually
  • Acetyl $CoA$ combines with oxaloacetate (4-carbon) to create citric acid
  •  Active transport into mitochondria via cotransport with oxygen
  •  citric eventually gets turned back into oxaloacetate

 

  •  3 types of energy produced:
    ■ $1ATP$
    ■ $3 NADH$
    ■ $1 FADH_2$
    ○ Atthis point there are 4 ATP, 10 NADH, and 2 FADH2 total

➢ 4. OXIDATIVE PHOSPHORYLATION

  •  As electrons are removed from a molecule of glucose, they carry with them as much of the energy that was originally stored within their bonds
  •  These electrons are then transferred to readied carrier molecules–NADH and $FADH_2$
  • Electron carriers shuttle electrons down to electron transport chain, and the resulting $NAD^{+}$ and FADH can be recycled to be used again
    ■ Hydrogen atoms are split
                   ● $\mathrm{H}_2-2 \mathrm{H}^{+}+2 e^{-}$
    ■ High-energy electrons are passed down a series of protein carrier molecules that are embedded in the cristae
                 ● Some proteins include NADH dehydrogenase and cytochrome C
    ■ The electrons travel down the electron transport chain until they reach the final acceptor, oxygen
                  ● Oxygen pulls the electrons through the chain due to its electronegativity and then combines with them and hydrogen to create water
                 ● Allows For a gradual release of energy rather than a sudden, explosive one
  •  Chemiosmosis
    ■ The energy released from the ETC is used to pump hydrogen ions across the inner mitochondrial membrane from the matrix into the intermembrane space
    ● Creates pH/proton gradient
    ● Potential energy created from gradient is responsible for the production of ATP
  •  Flow back in through ATP synthase and this movement provides the energy necessary to produce ATP
  •  $ADP + P_i ⟶ATP$

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