Cellular Respiration

By: Katrina, Anne, Annika & Ema

IntroductionCellular respiration: The process of combining glucose

(C6H12O6) with oxygen (O2) to get carbon dioxide (CO2), water (H2O), and usable energy in the form of adenosine triphosphate

(ATP) ATP: The molecule in which energy is stored for use by all

energy-consuming activities of the cellOne molecule of glucose can make up to 38 molecules of ATP

Glycolysis● The use of enzymes to breakdown glucose, and release energy and pyruvic acid● The breaking down of glucose

o Glyco = sugaro Lysis = breaking

● Occurs in cytoplasm● Breaking down of glucoses’ six-carbon ring into two, three-carbon molecules

known as pyruvic acids or pyruvate molecules● Uses two ATP to make four ATP, two ATP profit

Glycolysis Cont.● Other products:

o Two NADH moleculeso Two pyruvate molecules

● Can take place without oxygen- an anaerobic processo Pyruvates sent to fermentationo Frees up more NAD+ molecules to continue glycolysis

NAD+

fun fact!● Fermentation creates some fun byproducts! Some organisms like yeast create

ethyl alcohol through fermentation, it’s what makes wine and that fun stuff!! Sadly enough, when our muscles lack oxygen, they don’t make ethyl alcohol, they make lactic acid- the stuff that makes you feel sore after working out! But this only happens when your muscles run out of oxygen, and glycolysis becomes an anaerobic process.

FERMENTATION

Krebs Cycle● Also called the Citric Acid Cycle● Requires oxygen- aerobic process● Results in 6 NADH, 2 FADH2, and 2 ATP● Turns pyruvate molecules into ATP and other energy storing molecules● Occurs in the inner membrane of the mitochondria

Krebs cycle Cont.● Oxidizes pyruvate molecules (combines it with oxygen)

o Takes one of the carbons off of the three carbon chain

o Bonds carbon to an oxygen molecule, leaving CO2 as a waste product

● Left is a two carbon chain- acetyl coenzyme A (Acetyl-CoA)

● NAD+ bonds with H+ ion, forms NADH

Acetyl-CoAThree-carbon chain

CO2

Krebs Cycle Cont.● Enzymes bring together a phosphate and ATP, creates two more ATP molecules

for each pyruvate

● Enzymes bond acetyl-CoA with a four-carbon molecule (Oxaloacetic acid), forms

a six-carbon molecule called citric acid

Krebs cycle cont.● Citric acid is oxidized, eventually recreates oxaloacetic acid

o Byproducts of this process are CO2 ● Citric acid creates CO2 when stripped of carbon

o Energy stored in FAD and NAD+

● NAD+ and FAD pick up H+ and electrons from each pyruvate, which then charges them like batteries

● Hydrogen turns them into NADH and FADH2

o Each pyruvate yields one FADH2 and three NADH molecules

Electron Transport Chain● Requires oxygen- aerobic process ● Where the bulk of ATP is made

o A very efficient cell can yield up to 34 ATP molecules● Electrons from NADH and FADH2 provide energy

o Works as a pump along a chain of protein channels in the inner mitochondrial membrane

● Protein channels take the electrons from NADH and FADH2

o send hydrogen protons from the matrix across the inner membrane to the outer compartment of the mitochondria- the intermembrane space

E- transport Cont.● Hydrogen protons come out of the matrix● Hydrogen protons want to go back because of high concentration of protons in the

intermembrane space (concentration● To seek equilibrium (which nature loves to do), they flock to the ATP synthase

protein channel● The protein channel combines a phosphate, and ADP to create ATP

Bibliography● http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellularRespiration.htm● https://www.youtube.com/watch?v=00jbG_cfGuQ● https://www.khanacademy.org/test-prep/mcat/biomolecules/overview-metabolism/v/atp● http://www.elmhurst.edu/~chm/vchembook/601glycolysissum.html● http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect12.htm