2.1 Cell Metabolism 1

Question 1

What are the 6 reaction types?

Answer 1

1- Group transfer
2- Redox
3- isomerisation
4- group removal/addition
5- hydrolytic
6- ligation requiring ATP cleavage

Question 2

What is ligation requiring ATP cleavage?

Answer 2

Formation of covalent bonds using ATP

Question 3

Glycolysis- step 1

Answer 3

Glucose -——> glucose-6-phosphate + H+
enzyme = hexokinase
Using energy from ATP

Question 4

What type of reaction is step 1 of glycolysis?

Answer 4

Group transfer

Question 5

Why is step 1 of glycolysis irreversible?

Answer 5

Glucose-6-phosphate is charged and cannot leave cell through transporters.

Question 6

What are the 2 halves of glycolysis?

Answer 6

1) formation of high energy compounds (using ATP)
2) splitting of high energy compounds (producing ATP)

Question 7

Where does glycolysis occur?

Answer 7

In the cytoplasm
/cytosol

Question 8

Step 2 of glycolysis

Answer 8

Glucose-6-phosphate ——> fructose-6-phosphate

Enzyme = phosphoglucose isomerAse

Question 9

What type of reaction is step 2 of glycolysis?

Answer 9

Isomerisation reaction

Question 10

Glycolysis- step 3

Answer 10

Fructose-6-phosphate ——> fructose-1,6-bisphosphate

Enzyme =phosphofructokinase

Question 11

What type of reaction is step 3 of glycolysis?

Answer 11

Group transfer
(Since atp -> adp + pi)

Question 12

Glycolysis - step 4

Answer 12

Fructose-1,6-bisphosphate ——> glyceraldehyde 3- phosphate + dihydroxyacetone phosphate

Question 13

What type of reaction is step 4?

Answer 13

Hydrolytic

Question 14

Glycolysis- step 5

Answer 14

Dihydroxyacetone phosphate ——> glyceraldehyde 3 phosphate

Enzyme = TPI (trios phosphate isomerase)

Question 15

What if you are TPI (see glycolysis step 5) deficient?

Answer 15

It’s fatal most people die within 6 years of life

Question 16

What type of reaction is step 5?

Answer 16

Isomerisation

Question 17

Glycolysis - step 6

Answer 17

Glyceraldehyde-3- phosphate ——> 1,3 - bisphosphoglcerate

NAD -> NADH

Question 18

What kind of reaction is step 6?

Answer 18

REDOX and group transfer

Question 19

Glycolysis - step 7

Answer 19

1,3 - bisphosphoglycerate ——> 3- Phosphoglycerate

enzyme = phosphoglycerate kinase

ADP -> ATP

Question 20

What type of reaction is step 7?,

Answer 20

Group transfer

Question 21

Glycolysis - step 8

Answer 21

3 - phosphoglycerate ——> 2 phosphoglycerate

enzyme = phosphoglycerate mutase

Question 22

What type of reaction is step 8?

Answer 22

Isomerising

Question 23

Glycolysis- step 9

Answer 23

2 - phosphoglycerate ——> phosphoenolpyruvate + h2o

enzyme = enolase

Question 24

What type of reaction is step 9 of glycolysis?

Answer 24

Group removal

Question 25

Glycolysis - step 10

Answer 25

Phosphoenolpyruvate ——> pyruvate enzyme = pyruvate kinase ADP -> ATP

Question 26

What type of reaction is step 10?

Answer 26

Group transfer

Question 27

Net result of glycolysis

Answer 27

2 pyruvate, 2 ATP, 2 NADH

Question 28

What types of reactions do dehydrogenases catalyse?

Answer 28

Redox

Question 29

What type of reactions do kinase enzymes catalyse?

Answer 29

Phosphorylation

Question 30

What 3 amino acids can be substrates of kinases?

Answer 30

Serine Threonine Tyrosine (Only 3 that contain a hydroxyl group)

Question 31

Why is NADH production important?

Answer 31

NADH used in oxidative phosphorylation in mitochondria to produce ATP

Question 32

3 fates of pyruvate

Answer 32

- alcoholic fermentation - lactate production - acetyl co A production

Question 33

What is alcoholic fermentation?

Answer 33

Pyruvate —> acetaldehyde + co2 Acetaldehyde —> ethanol NADH -> NAD+

Question 34

What is lactate production?

Answer 34

Pyruvate —> lactate NADH -> NAD+ enzyme = lactate dehydrogenase (LDH)

Question 35

What can elevated LDH levels mean? (LDH = lactate dehydrogenase)

Answer 35

Can be used to diagnose several disorders eg stroke and myocardial infarction

Question 36

What does Creatine phosphate do?

Answer 36

Buffer demands for phosphate when ATP is used up by cell. Creatine kinase breaks down Creatine phosphate into Creatine + ATP

Question 37

What is Acetyl Co-A production? (And where)

Answer 37

(In mitochondria) Pyruvate + HS-CoA ——> acetyl co A + CO2 NAD+ -> NADH

Question 38

What is Beri Beri?

Answer 38

A deficiency of thiamine (needed for thiamine pyrophosphate, a cofactor of the PDH complex which readily loses a proton and the resulting carbanion attacks pyruvate)