Glycolysis Quiz

Its quiz time once put on your thinking caps and make me proud biochemists!


1) What is the most regulated enzyme?

a)      Adolase

b)      Phosphofructokinase-1

c)       Phosphohexoseisomerase

d)      Enolase

e)      Pyruvate Kinase

2) What co-factor is needed for the conversion of Pyruvate to Acetyl-CoA?

a)      Mg2+

b)      TPP

c)       Cu2+

d)      Vitamin C

e)      All the above

3) What is the co-factor that all kinase enzyme require?

a)      Fe2+

b)      Cu2+

c)       Vitamin A

d)      TPP

e)      Mg2+

4) Which reaction is the only oxidation phase in glycolysis?

a)      Fructose-6-phosphate to Fructose-1,6-bisphosphate

b)      1,3-BPG to 3-Phosphoglycerate

c)       G3P to 1,3-BPG

d)      Phosphoenolpyruvate to Pyruvate

e)      Glucose to Glucose-6-Phosphate

5) In which reactions are ATP produced?

a)      1st and 10th reactions

b)      All reactions of the Energy Generation phase

c)       7th and 10th reactions

d)      Reactions vary according to cell

e)      ATP is produced in the Citric cycle and consumed in Glycolysis

6) In which reactions are ATP consumed?

a)      1st and 3rd reactions

b)      All reactions of the Energy Investment Phase

c)       2nd and 5th reactions

d)      ATP is only produced not consumed

e)      Glucose to Glucose-6-phosphate ONLY

7) Where does glycolysis occur in the cell?

a)      Cytosol

b)      Cytoplasm

c)       Mitochondria

d)      Nucleus

e)      Directly outside the cell

8) Multiple Answer MCQ:

Select the correct multiple choice answer using ONE of the keys A,B,C,D or E below:

a)      1 and 4 are correct

b)      2 and 3 are correct

c)       Only 4 is correct

d)      1 and 3 and 4 are correct

e)      2 and 4 are correct

8) Which reactions are irreversible?

1)      Glucose-6-Phosphate to Fructose-6-Phosphate

2)      Glucose to Glucose-6-phosphate

3)      DHAP to G3P

4)      Phosphoenolpyruvate to Pyruvate

9) Why is/are this/these reaction(s) irreversible?

a)      Backward reaction is not energetically feasible

b)      Not enough product is made for a reverse reaction

c)       Backward reaction produces too much heat

d)      Change in structure of product prevents reactants from being made.

e)      All of the above

10) What enzyme is used to convert Glucose-6-Phosphate to Fructose-6-Phosphate?

a)      Aldolase

b)      Enolase

c)       Phosphohexose isomerase

d)      Phosphofructokinase-1

e)      Glucose-6-Phosphase

11) What is the by-product when Enolase converts Phosphoglycerate to Phosphoenolpyruvate?

a)      NADH

b)      H2O

c)       ATP

d)      DHAP

e)      TPP

12) What happens to pyruvate when oxygen is unavailable?

a)      It is converted to L-Lactate

b)      It is converted to Ethanol and enters Citric cycle

c)       It is converted to Acetaldehyde and enters Citric cycle

d)      It is converted to Acetyl-CoA and enters Citric cycle

e)      All the reactions of Glycolysis are reversed

Glycolysis…this is friggen awesomeeeeee


Stop whatever you are doing and watch this AMAZING video!!!

Now tell me that song isnt stuck in your head and you’ve already learnt and memorized BOTH glycolysis and TCA!!!

Regardless of that vid, in case you’re not a huge rap fan..allow me to break it down for you!

Glycolysis is the process that breaks down Glucose into Pyruvate and produces ATP along the way. ATP is used for energy. ATP is like money to cells, if you aint got no ATP, you aint got no game. And guess what? Glycolysis is going on in your body RIGHT NOW! As you read this, 10 different enzymes are working hard to convert that sandwich you ate into pyruvate. How you ask? This picture should give you a good explanation:


In the first reaction, glucose is converted to glucos-6-phosphate because the phosphate group makes it more reactive as well as prevents it from passing through the glucose transporter.

All kinases enzyme require Mg2+ as a cofactor. All these enzymes are induced-fit.

Also, wherever a Kinase is involved, ATP is either being broken or formed.

The enzyme in the third reaction; Phosphofructokinase-1 is the most regulated enzyme, and the this reaction is also the second priming reaction.

The sixth reaction is the only oxidation reaction in glycolysis by the enzyme Glyceraldehyde-3-phosphate dehydrogenase, and hence forth, 2molecules of everything is produced in each reaction.

There are 3 irreversible reactions in glycolysis and this is because the forward reaction has a high negative deltaG value and hence a high positive deltaG value will be needed to overcome for a backward reaction to occur.

The 3 irreversible reactions are:

1st reaction: Glucose –> Glucose-6-phosphate

3rd reaction: Fructose-6-phosphate –> Fructose-1,6-bisphosphate

10th reaction: Phosphoenolpyruvate (2) –> Pyruvate (2)

The 2 enzymes involved in sub-level-phosphorylation are;  Phosphoglycerate kinase and Pyruvate kinase.

Fate Of Pyruvate:

After pyruvate has been made, 3 things can happen depending on if oxygen is available or not.

If oxygen is available:  Pyruvate is converted to Acetyl-CoA by enzyme Pyruvate dehydrogenase complex and NADH is produced as a by-product. Acetyl-CoA then enters the TCA cycle.

If oxygen is unavailable:

Pyruvate is converted to L-Lactate by the enzyme Lactate dehydrogenase and NAD+ is produced as a byproduct.

Fermentation can also occur: Pyruvate is converted to Acetaldehyde which is then converted to Ethanol by enzyme Pyruvate decarboxylase and alcohol dehydrogenase respectively. For the enzyme Pyruvate decarboxylase; co-factors include Mg2+ and TPP (thiamine pyrophosphate) and CO2 is produced as a by product. Conversion of Acetaldehyde to ethanol produces NAD+ as a by-product.


And that folks, is Glycolysis! Hope you learnt a thing or two! catch ya next time.