Cellular Respiration

Cellular Respiration: How we derive energy from the food we eat, specifically from glucose

  • Chemical formula for glucose: C6H12O6

  • In order to turn glucose into energy, oxygen needs to be added (6 molecules)

  • The glucose and oxygen are used to turn into 6 CO2, 6 H20 molecules, and energy

  • ATP: “Currency” of biological energy 

    • 3 phosphate groups do not like each other  ⟶ one phosphate group “shoots” off (creating ADP), and this causes energy to be released ⟶ because there are a lot of H20s around an OH group (Hydroxide) from H20 takes the place of the third phosphate group (called Hydrolosis)

  • Glycolysis: Breaking up of glucose’s 6-carbon ring into two 3-carbon molecules called Pyruvic Acids or Pyruvate

    • Needs “investment” of 2 ATPs to work and, in the end, generates 4 ATPs

    • Also produces 2 NADH: NAD+ paired with energized electrons and hydrogen to create storehouses for energy that will later be used to make ATP

    • Glycolysis is an anaerobic process (done without oxygen)

  • Fermentation: If there is no oxygen in the cell, it needs more NAD+ to keep glycolysis going, so fermentation frees up some NAD+ 

    • It creates some products, such as ethyl alcohol (from yeast), but in the body, it creates lactic acid. 

  • Krebs Cycle: Takes products of glycolysis (pyruvates) and reworks them to create 2 ATPs per glucose molecule and some energy in other forms

    • One Pyruvate is oxidized, which means that it's combined with oxygen ⟶ one of the carbons of the three-carbon chain (of pyruvate) bonds with an oxygen molecule and leaves the cell as CO2 ⟶ which is left in a two carbon compound called acetyl coenzyme A or acetyl CoA 

    • Then another NAD+ bonds with hydrogen and becomes NADH 

    • Enzymes bring a phosphate to an ADP to form an ATP molecule for each pyruvate and also help join acetyl coA and an oxaloacetic acid (a 4-carbon molecule) and together form a 6-carbon molecule, Citric Acid ⟶ citric acid oxidized, stripping carbons to eventually gets back to oxaloacetic acid; leftover carbons are exhaled by the cell as CO2 (carbon dioxide) 

    • Arerobic process

    • Occurs in the inner membrane of mitochondria

  • NAD+ and FAD are enzymes that are good at holding on to high-energy electrons and keeping that energy until it can get released in the electron transport chain

    • Picks up hydrogens and energized electrons from pyruvate, which then charges them up ⟶ addition of hydrogen turns them into NADH and FADH2

  • Electron Transport Chain: NADH and FADH electrons provide energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the Krebs Cycle occurs ⟶ the proteins will swap the electrons to send hydrogen protons from inside the center of mitochondria across its inner membrane to the outer compartment of the mitochondria ⟶ protons want to go back inside membrane and are let back in through a protein called ATP Synthase that squeezes out some ADP and phosphates together to form ATP because of energy of the proton flow makes in spin

    • Aerobic process