Glycolysis 2

Question 1

What does there need to be a continual supply of in order for glycolysis to continue?

Answer 1

NAD+

Question 2

How are apoenzymes activated?

Answer 2

By binding of coenzyme or cofactor to enzyme

Question 3

How is a holoenzyme formed?

Answer 3

When associated cofactor/ coenzyme binds to the enzymes active site

Question 4

Does the coenzyme have to bind before or after the substrate?

Answer 4

before

Question 5

Do coenzymes bind tightly or loosly and why?

Answer 5

Relatively tightly so the particular group to be transferred is properly orientated to allow catalysis to occur

Question 6

Do coenzymes need to be regenerated?

Answer 6

Yes

Question 7

Once bound to a chemical group what happens to the coenzyme

Answer 7

The coenzymes structure changes

Question 8

What are the 3 steps to how Glyceraldehyde-3-phosphate dehydrogenase works

Answer 8

1- Formation of covalent thioester bond between substrate and enzyme

2-Oxidation of the thioester bond to form thioester bond using NAD+ to perform the oxidation

3- cleavage of the thioester bond supplies the energy to drive the endergonic phosphorylation reaction. The product, a phosphoanhydride is realised from the enzyme

Question 9

Hydrolysis of a thioester bond is exergonic or endergonic?

Answer 9

Exergonic

Question 10

What is the fate of pyruvate in aerobic conditions?

Answer 10

Continual Supply of NAD+ by oxidation of NADH by the ETC

Pyruvate can enter mitochondria and be consumed by TCA cycle to generate more NADH

Question 11

What is the fate of pyruvate in anaerobic condition?

Answer 11

NAD+ is generated by conversion of pyruvate to lactate. ALL of pyruvate needed for this

Question 12

RBC only use lactic acid pathway not O2 - why and how is this useful?

Answer 12

RBS have no mitochondria and this spares o2 they carry to deliver to other cells

Question 13

What is the equation for pyruvate to lactate?

Answer 13

2 pyruvate ( from glycolysis) -> 2 lactate with 2NADH + 2H+ to produce 2 NAD+

Question 14

What is the equation for pyruvate to alcohol?

Answer 14

2 Pyruvate-> 2CO2 + 2 Acetaldehyde with pyruvate decarboxylase

2 Acetaldehyde-> 2 ethanol via alcohol dehydrogenase and 2 NADH to 2 NAD+

Question 15

Under anaerobic conditions how many ATP are produced and why?

Answer 15

2 ATP are produced for every glucose molecule that is converted to lactate or alcohol.

NADH is recycled and not used to make more ATP.

Question 16

In both prokaryotic and eukaryotic organisms where does Glycolysis occur?

Answer 16

cytoplasm

Question 17

In both prokaryotic and eukaryotic organisms where does the TCA cycle occur?

Answer 17

Prokaryotic-cytoplasm

Eukaryotic-mitochondria

Question 18

In both prokaryotic and eukaryotic organisms where does the ETC occur?

Answer 18

Prokaryotic- cell membrane

Eukaryotic-mitochondrial membrane

Question 19

In both prokaryotic and eukaryotic organisms where does fermentation occur?

Answer 19

cytoplasm

Question 20

There is no specific mitochondrial NADH transporters

Answer 20

cool

Question 21

Name the full equation from pyruvate to Acetyl-CoA

Answer 21

Pyruvate -> Pyruvate dehydrogenase complex, NAD+ CoA-SH to NADH CO2 AcetylCo-A

Question 22

What does Coenzyme A stand for?

Answer 22

“activation of acetate“

Question 23

What are the 3 steps of pyruvate oxidation steps

Answer 23

Step 1. A carboxyl group is snipped off of pyruvate and released as a molecule of carbon dioxide, leaving behind a two-carbon molecule (acetate).
Step 2. The two-carbon molecule from step 1 is oxidized, and the electrons lost in the oxidation are picked up by NAD+ to form NADH.
Step 3. The oxidized two-carbon molecule—an acetyl group, highlighted in green—is attached to Coenzyme A (CoA), an organic molecule derived from vitamin B5, to form acetyl CoA. Acetyl CoA is sometimes called a carrier molecule, and its job here is to carry the acetyl group to the citric acid cycle.
2c into TCA

Question 24

Summarise pyruvate oxidation

Answer 24

Two molecules of pyruvate are converted into two molecules of acetyl CoA.
Two carbons are released as carbon dioxide—out of the six originally present in glucose.
2 NADH are generated from NAD+.