Glycolysis: An Overview video review

This is a concise video giving you a gist of the basics of glycolysis.

It starts off giving their explanation of what glycolysis is. They define it as a series of 10 reactions which break down sugars like glucose into 3C molecules called pyruvate and it also produces ATP and NADH and all of this occurs in the cytosol of the cell. They then take you through the steps of the first phase. They explain that this stage uses energy to get from step 1, which is glucose, to step 5 which is Glyceraldehyde-3-phosphate.

They then move on to phase 2 saying this phase produces 4 ATP’s 2 in step 7 and 2 in step 10. It also mentions how the steps involved with ATP production and loss are catalysed by a kinase. The video stresses that the product formed in steps 6 through 10 are formed for EACH G3P molecule generated in steps 4 and 5. This gives you an idea of how many of each product is produced seeing as the number is doubled. They finish the video by saying the net amount of product gotten is 2NADH and 2 ATP’s because 2 ATP’s were spent in the first half of the reaction.

  YouTube. “Glycolysis: An Overview.” 2014. (accessed 17 Mar 2014).

Know your Glycolytic enzymes

We all know that in glycolysis there are 10 reactions controlled by 10 enzymes. These are:

Phase 1                                                                          

  • Hexokinase: It catalyses alpha D-Glucose and ATP to Glucose-6-Phosphate (G6P) and ADP by phosphorylation.
  • Phosphoglucose isomerase: This catalyses G6P to its isomer Fructose-6-phosphate (F6P). This occurs by changing the carbonyl oxygen from the C1 position on the G6P to the C2 position on F6P
  •  Phosphofructokinase: Catalyses F6P and ATP to Fructose-1, 6-Bisphosphate (F1, 6PP) and ADP.
  • Fructose-Bisphosphate aldolase: Catalyses F1,6PP to split into  Dihydroxyacetone Phosphate (DHAP) and Glyceraldehyde-3-Phosphate (G3P)
  • Triosephosphate isomerase: This catalyses DHAP to turn into G3P because only G3P can be used in the reaction.

Phase 2

  • Glyceraldehyde-3-phosphate dehydrogenase:  Catalyses G3P, NAD and Pi to 1,3 Bisphosphoglycerate (1,3 BPG), NADH and H+
  • Phosphoglycerate kinase: Catalyses 1,3 BPG and ADP to 3-Phosphoglycerate and ATP
  • Phosphoglycerate mutase: Catalyses 3PG to 2-Phosphoglycerate (2PG)
  • Enolase: Catalyses 2PG to Phosphoenolpyruvate (PEP) and H2O.
  • Pyruvate kinase: It catalyses PEP and ADP to Pyruvate and ATP.


Diagram showing Glycolysis

Diagram showing Glycolysis

Untitled. 2014. : (accessed 17 Mar 2014).

10 Glycolysis Facts

1. Glycolysis aka the Embden-Meyerhof-Parnas pathway (EMP pathway) was discovered by Gustav Embden, Otto Meyerhof and Jakub Karol Parnas.

2. The Glycolysis process is so old that it has probably been around before oxygen made its debut in the atmosphere.

3. Glyco –glucose Lysis- splits. It basically is the conversion of one 6-carbon glucose molecule into two 3-carbon sugars called pyruvate through a series of enzymatic reactions.

4. It involves two phases, the Preparatory phase or the energy investment phase and the energy generation phase or the payoff phase.

5. In the investment phase, initially 2 ATP molecules are invested in glycolysis.  The payoff is the generation of 4 ATP molecules so a profit or net gain of 2 ATP molecules is made.

6. Glycolysis involves 10 reactions each being catalyzed by one of ten enzymes, in the following order Hexokinase, Phosphohexose Isomerase, Phospho- fructokinase -1, Aldose, Triose phosphate isomerase, Glyceraldehyde 3- phosphate, Phosphoglycerate kinase, Phosphoglycerate mutase, Enolase and finally Pyruvate kinase.

7. It occurs in plant and animal cells and the cells of microbes.

8. It occurs in the cytoplasm of prokaryotes and the cytosol of eukaryotes.

9. Under anaerobic conditions, glycolysis causes cells to produce ATP. This process is called fermentation.

10. Under aerobic conditions, glycolysis is the first phase of cellular respiration.


Mix and Match!

Try to match the enzymes in the order it is used in the glycolysis process

  1. Glucose –> glucose 6-phosphate
  2. Glucose 6-phosphate –> fructose 6-phosphate
  3. Fructose 6-phosphate –> fructose 1,6-bisphosphate
  4. Fructose 1,6-bisphosphate –> glyceraldehyde 3-phosphate + dihydroxyacetone phosphate
  5. Dihydroxyacetone phosphate –> glyceraldehydes 3-phosphate
  6. Glyceraldehydes 3-phosphate –> 1,3-bisphosphoglycerate
  7. 1,3-bisphosphoglycerate –> 3-phosphoglycerate
  8. 3-phosphoglycerate –> 2-phosphoglycerate
  9. 2-phosphoglycerate –> phosphoenolpyruvate
  10. Phosphoenolpyruvate –> pyruvate

A. Phosphoglycerate kinase

B. Aldolase

C. Glyceraldehydes 3-phosphate dehydrogenase

D. Enolase

E. Pyruvate kinase

F. Hexokinase

G. Phosphohexose isomerase

H. Phosphoglycerate mutase

I. Triose phosphate isomerise

J. Phosphofructokinase-1

multiple choice part 2…no pressure…

I.            Pyruvate decarboxylase

II.            Pyruvate dehydrogenase

III.            Transketolase

Which enzyme(s) use TPP?

a) I

b) II and III

c) III

d) I and III

e) all of the above





Anonymous. 2014. [online] Available at: http://biology, [Accessed: 16 Mar 2014]. 2014. glycolysis Facts, information, pictures | articles about glycolysis. [online] Available at: [Accessed: 16 Mar 2014].

Encyclopedia Britannica. 2013. glycolysis (biochemistry). [online] Available at: [Accessed: 16 Mar 2014].

Matthew, J. 2014. BiochemJM. [online] Available at: [Accessed: 16 Mar 2014]. 2014. Glycolysis. [online] Available at: [Accessed: 16 Mar 2014].












-nandeh and areh

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