How does cellular respiration work? Please Help!

Question

Our teacher went over some of it in class, but I'm totally lost and don't understand the 4 stages of cellular respiration at all! I also don't understand breaking down glucose! I'm very confused! Could someone explain to me how these all work? Thanks.

Answer 1

Cellular Respiration: sugar is broken down to CO2 and H2O, and in the process, ATP is made that can then be used for cellular work.

 

The overall reaction for cellular respiration: 

C6H12O6 + 6O2 -------------------> 6CO2 + 6H2O + ~38 ATP

 

Cellular respiration can be broken down into 4 stages:

 

1: Glycolysis ("splitting of sugar"): This step happens in the cytoplasm.

One Glucose (C6H12O6) is broken down to 2 molecules of pyruvic acid. Results in the production of 2 ATPs for every glucose.

 

2: Transition Reaction: Pyruvic Acid is shuttled into the mitochondria, where it is converted to a molecule called Acetyl CoA for further breakdown.

 

3: The Krebs Cycle, or Citric Acid Cycle: Occurs in the mitochondrial matrix, the liquid-y part of the mitochondria.

In the presence of Oxygen gas (O2), all the hydrogens (H2) are stripped off the Acetyl CoA, two by two, to extract the electrons for making ATP, until there are no hydrogens left - and all that is left of the sugar is CO2 - a waste product - and H2O. The Krebs cycle results in the production of only ~4 ATPs, but produces a lot of NADH, which will go on to the next step.

 

4: The Electron Transport Chain and Chemiosmosis.

 

Electrons from Hydrogen are carried by NADH and passed down an electron transport chain to result in the production of ATP. Results in the production of ~32 ATPs for every glucose.

 

 

Hope this answer helps to understand the cellular respiration. Need more clarification or any doubts let me know.

 

Thanks.