3.2 Cellular Respiration

3.2 Cellular Respiration

Fuel= any material that causes the release of energy to be used for work. For a body to use fuel, the energy in chemical bonds of the fuel must be RELEASED. *Chemical energy must be BROKEN for the stored energy to be RELEASED * Cellular respiration (C.R.)-  Production of ATP(RELEASED) by BREAKING down carbon-based mulecules (in this case glucose) when oxygen IS present (making it aerobic). Example of the rule for cellular respiration: The release of chemical energy from glucose and other carbon-based molecules to make ATP.(Chemical bonds must be broken for the chemical energy from glucose to be relased so ATP could be made.) *C.R. is and Exothermic Reaction since it releases more energy than absorbed. Process of C.R: BREAK down glucose and other carbon-based molecules and RELEASES stored energy in chemical bonds, which is transfered to ATP.  Energy as HEAT IS also released  

Inputs: Oxygen glucose Outputs: Carbon Dioxide Water ATP Heat Role of the fox: combine all inputs and use them into movements/ activities... and then discard as waste: Carbon dioxide and water.

Inputs and Outputs of C.R.

• Inputs and Outputs of Crllular Respiration

Q: How does the equation for C.R. represent law of conservation of matter?

C6H12O6 -> 6CO2+6H2O+ heat+ ATP   A: There are equal numbers on each side

Mitochondria

Where C.R. takes place  Release chemical energy required to make ATP

Mitochondria (binary/octet-stream)

C.R. and Photosynthesis

Most energy for organisms come form photosynthesis, either directly or indirectly. EX: Producers absorbs light energy --> energy/food. Producers ---> consumers  During photosynthesis:  absorption of sunlight production of sugars During C.R: breakdown of sugars ATP production

• Photosynthesis and C.R

Glycolysis

Input: glucose (output of photosynthesis) Glycolysis forms Pyruvate (a 2 3-carbon mol.), which startes the Krebs Cycle to produce CO2 and ATP. Needs NAD+ and ADP to form pyruvates Steps of C.R: Glycolysis Krebs Cycle Electron Transport Chain  

In Glycolysis, glucose is broken down into compounds mithochondria can use. (occurs in cytoplasm of cell) Glycolysis is anaerobic and therefore does not need oxygen.  Mitochondria uses Pyruvate to FUEL Cellular Respiration. Glycolysis can occur with or without oxygen. In the presence of oxygen, glycolysis is the first stage of cellular respiration. In the absence of oxygen, glycolysis allows cells to make small amounts of ATP through the process of fermentation. (In 6 slides)

About the Krebs Cycle

A.K.A "Citric acid cycle" Function: to complete the breakdown of glucose in glycolysis and fuel the making of ATP. Does this ^ by moving high-energy electrons (NADH and FADH2) into the electron transport chain  *CO2 = waste product released.

Energy in chemical bonds are RELEASED when bonds are BROKEN.  High-energy electrons are transferred into NADH and FADH2, which carry the high-energy electrons into the next stage of C.R (ETC)

Steps of the Krebs Cycle

 Pyruvate is broken down into a 2-carbon mol. . CoenzymeA (CoA) is added to the mol, becoming an intermediate mol. The intermediate mol. is added to a 4- carbon mol. = 6-carbon mol "citric acid." Citric acid mol is broken down by enzyme = 5-carbon mol. A molecule of NADH is made which moves out the Krebs cycle. A CO2 is released as waste. 5- carbon mol is broken down by an enzyme as well. A 4-carbon mol, a mol of NADH, and a mol of ATP are formed. CO2= waste. The 4-carbon mol is rearranged, high-energy electrons are released (NADH and FADH2). They leave the cycle and the 4- carbon molecule remains.

• Krebs Cycle

Electron Transport Chain

Electrons are removed from electron carriers like NADH and FADH2.  Energy from the electrons is used to pump hydroger ions across the inner- membrane. As ions flow through the membrane, energy is used to build ATP. The electrons leaving the ETC are combined with hydrogen and oxygen to form water molecules (as waste).

Etc (binary/octet-stream)

Caption: : Uses Proteins embedded in the inner-membrane of the mitochondrion

Steps of the Electron Transport Chain

• Steps of Kerbs cycle

Etc (binary/octet-stream)

Q: What parts of C.R. involve the BREAKING of chemical bonds and FORMATION of new bonds resulting in a net transfer of energy from food to cell?  A: Generation of ATP  Release of sugar from carbs Formation of pyruvate 

Fermentation

^How cells function without oxygen (anaerobic) to keep Cellular Respiration going. Allows glycolysis to continue  Removes electrons from NADH and recycles NAD+ for glycolysis IMPORTANT BECAUSE: Glycolysis (like C.R.) needs molecules that picks up electrons to carry into the next stage.(It needs molecules like NAD+) *So basically its role is to supply glycolysis with a steady supply of NAD+.

Once oxygen is available again, cells return to use Cellular Respiration. Lactic acid is a waste product of fermentation that build up in muscle cells = "burning" feeling. Once oxygen is available, Lactic acid is broken down and removed form cells. *Fermentation= When O2 isnt available, anaerobic respiration comes in.

Summary and resources

*Chemical energy must be BROKEN for the stored energy to be RELEASED: C.R: BREAK down glucose and other carbon-based molecules and RELEASES stored energy in chemical bonds =ATP.  Mitochondria: Where C.R takes place+ releases chemical energy to make ATP; Uses Pyruvate from Glycolysis to make ATP  Glycolysis, glucose is broken down into compounds mithochondria can use. Krebs cycle: to complete the breakdown of glucose in glycolysis and fuel the making of ATP; Uses NADH nad FADH2 as electron transporters to move on the ETC. (Last step of C.R) ETC: Uses inputs from Kreb cycle to pump hydr. ions to finally form ATP.  

• Inputs and Outputs of Crllular Respiration
• Photosynthesis and C.R
• Krebs Cycle
• Steps of Kerbs cycle