Cellular Respiration

Cellular Respiration Process that makes energy for all life on earth It is the transfer of chemical bond energy of organic molecules to the chemical bond energy of ATP Remember: Making chemical bonds stores energy Breaking chemical bonds releases energy Respiration breaks the bonds of glucose, so it releases energy

Harvesting energy stored in food Cellular respiration breaking down food to produce ATP in mitochondria Oxygen is needed for these reactions “aerobic” respiration usually digesting glucose but could be other sugars, fats, or proteins ATP food O2 Movement of hydrogen atoms from glucose to water glucose + oxygen  energy + carbon + water dioxide C6H12O6 6O2 ATP 6CO2 6H2O  +

Both plant and animal cells carry out the final stages of cellular respiration in the mitochondria. Outer membrane Intermembrane space Mitochondrion Plantl Cells Inner membrane Animal Cells Matrix

Using ATP to do work? ATP facts: Can’t store ATP too unstable only used in the cell that produces it only short term energy storage carbohydrates & fats are long term energy storage ATP Adenosine TriPhosphate work Adenosine DiPhosphate ADP A working muscle recycles over 10 million ATPs per second

ATP Factoid On average, the human body contains 250 grams of ATP The amount of ATP used by the human body in a day equals the body weight of the individual.

ADP vs. ATP

{ { { A Body’s Energy Budget ATP make energy eat food synthesis 1 make energy • energy needed even at rest • activity • temperature control { eat food ATP • growth • reproduction • repair { 2 synthesis (building) • glycogen (animal starch) • fat { 3 storage

Other Energy Molecules… NAD+ and FAD Hydrogen and electron carriers Bring hydrogen/electrons to the electron transport chain where they are used to make more ATP Hydrogen and Electrons are sources of potential energy Energy can be released from these molecules later on to make ATP Low High NAD+  NADH FAD  FADH2

Cellular Respiration Occurs in 3 Distinct Phases The first stage, glycolysis, is anaerobic—no oxygen is required. The last two stages are aerobic and require oxygen to be completed. SUMMARY EQUATION:

STAGES OF CELLULAR RESPIRATION Respiration occurs in three main stages High-energy electrons carried by NADH GLYCOLYSIS ELECTRON TRANSPORT CHAIN KREBS CYCLE Cytoplasmic fluid Mitochondrion

Glycolysis Glyco=sweet, sugar lysis = to split Glycolysis: a series of chemical reactions in the cytoplasm of a cell that break down glucose, a six-carbon compound, into two molecules of pyruvic acid, a three-carbon compound Pyruvic acid: a 3 carbon compound made during glycolysis by splitting a glucose molecule. produces two ATP molecules for each glucose molecule broken down. 2 molecules of NADH are formed

Detailed View

Glycolysis Summary Produces 2 ATP Creates 2 NADH molecules 2 ATP were needed for the reaction 4 ATP were made in the reaction Creates 2 NADH molecules Passed to Electron Transport Chain Glucose (6 C’s) has been broken down to form 2 molecules of pyruvic acid (3 C’s) Will be converted into Acetyl CoA

The Transition Phase *(we’ll include this as part of Kreb’s) Before Krebs Cycle and electron transport chain can begin, pyruvic acid undergoes a series of reactions in which it gives off a molecule of CO2 and combines with a molecule called coenzyme A to form acetyl-CoA. (a molecule made from pyruvic acid ) Acetyl CoA (acetyl coenzyme A) Pyruvic acid CO2

The Krebs Cycle Series of reactions that occurs in mitochondrial matrix Breaks pyruvic acid down into CO2, releasing energy For every one turn of the cycle, one molecule of ATP, two molecules of carbon dioxide, 4 NADH, 1 FADH2 are produced. Per molecule of glucose, Kreb’s creates: 2 ATP 8 NADH 2 FADH2 4 CO2 CO2

The electron transport chain (ETC) Set of reactions taking place in the inner mitochondrial membrane that convert the NADH and FADH2from glycolysis and the krebs cycle to convert ADP into ATP. In the electron transport chain, the carrier molecules NADH and FADH2 give up electrons that pass through a series of reactions. Oxygen is the final electron acceptor forming water. This sets up a H+ (proton) gradient Allow the protons to flow through ATP synthase which synthesizes ATP (ADP + Pi = ATP)

ETC continued… The electron transport chain adds 32 ATP molecules to the four already produced during glycolysis & Krebs cycle Occurs in the inner mitochondrial membrane

ETC Located in the inner Mitochondrial membrane Produces 32 ATP For each pair of Hydrogen atoms brought in by: NADH: 3 ATP molecules are made FADH2: 2 ATP molecules are made

In summary, what do we need to make energy? The “Furnace” for making energy mitochondria Fuel food: carbohydrates, fats, proteins Helpers oxygen enzymes Product ATP Waste products carbon dioxide then used by plants water food ATP enzymes CO2 H2O O2

Summary Facts : Cellular Respiration Reactants/Raw materials : oxygen + sugar (glucose, starch, food, fats)   Energy Source: chemical bond energy of organic comp’ds   Products Made : carbon dioxide, water, ATP (energy)   When does it occur?: all the time, constantly, 24/7   Location in the Cell: mitochondria   Organisms that use it: all living things