glyclosiss

Before coming to glycolysis,  we should understand what cell respiration is.
Cell respiration is a process which takes place in living cells, by which complex organic substances are oxidized according to a sequence of enzyme controlled reactions releasing energy.
This divides into 3 main stages.
a) Glycolysis
b) Kreb's cycle
c) Respiratory chain

Since you wanted to know only about the Glycolysis, I'll explain only that part.

During this, 1 glucose molecule is split into 2 pyruvic acid molecules. 
This is done by a series of specific reactions catalyzed by enzymes.
Glycolysis begins with phosphorylation of substrate glucose.
2 ATP molecules are used in this reactions.
In a later stage ATP is produced by substrate level phosphorylation.
Glucose is subjected to oxidation and produce 2 NADH/2H+ (2 protons)
This takes place within the cytoplasm.
The sequence of chemical reactions that take place during glycolysis can be summarized as follows.

glucose + 2pi+2ADP+2NAD+ ----lysis--------->   2 pyruvic acid+2 ATP+2NADH/2H+
                  --------------------

Post Merge: 9 years ago

The arrow that shows backwards should actually come below the lysis to indicate that this both forward/backward reaction. When I was typing, it was at the correct spot. I wonder how it went there after posting. 

First of all your question is wrong. Glycolysis is not something to be produced, it is the first  step in the Cellular respiration(whether aerobic or anaerobic).

Glycolysis occurs in the cytoplasm where glucose is present. It is the first step on anaerobic and aerobic cellular respiration. **Glycolysis doesn't require oxygen, nor it is halted in its presence!

Before talking about glycolysis, it is important to know about "Substrate-level Phosphorealtion". its a process in which ATP is PRODUCED from ADP and inorganic phosphate using the energy released by the decay of high energy phosporelated compounds.

Glycolysis:
1-Upon entry of a glucose molecule into the cytoplasm of the cell, the glucose molecule is phosphorelated to get glucose 6-phosphate(G6P). 1 ATP is used.

2-G6P is converted  thru reactions(using enzymes) into Fructose 6-phosphate. No energy used or produced.

3- F6P is then phophorelated to get 1,6-bisphosphate. 1 ATP is used.

Next, cytoplasmic enzymes carry reactions that result in Breakdown of the bisphophate into
2 pyruvate molecules, 2 NADH molecules and 4 ATP molecules. **Theses 4 ATP molecules that are produced are manufactured thru substrate level phosphorelation.


Therefore; The NET result of glycolysis is:: 2 Pyruvate molecules , 2 ATPs (4 produced - 2 used), and 2 NADHs. All from one initial glucose molecule.
 
After glycolysis, these products can enter into Kerbs cycle in the presence of Oxygen--> aerobic respiration. Or go thru different steps in the absence of oxygen anaerobic respiration.