The Catabolism of Glucose - Glycolysis

Question 2

What is Metabolism

Answer 2

all chemical reactions that maintain the living state of cells and organisms

Question 3

What 2 things make up metabolism

Answer 3

Anabolism and Catabolism

Question 4

What is Anabolism

Answer 4

Assembly of molecules and complex structures from the building blocks of life

• Requires ATP

Question 5

What is Catabolism

Answer 5

Breakdown of complex molecules to obtain the anabolic building blocks of life and substrats for energy

• Produces ATP

Question 6

Explain metabolic redox reactions

Answer 6

Question 7

Glucose is our primary energy source what is it oxidised to

Answer 7

H₂O and CO₂

Question 8

What cells use glucose as an energy source

Answer 8

• Red blood cells
• Brain cells
• Renal medulla
• Retina
• All cancer cells

Enzyme: Hexokinase

Question 9

What is the Structure of glucose

Answer 9

• C6H12O6
• Breaking bones of glucose release energy
• Shape allows energy storage

Question 10

Name some Disaccharides

Answer 10

• Maltose
• Lactose
• Sucrose

Question 11

Name some polysaccharides

Answer 11

• Cellulose
• Glycogen

Question 12

What is Glucose used for

Answer 12

• Oxidation through aerobic glycolysis à pyruvate.

(in presence of O2)

• Fermentation through anaerobic glycolysis à lactate.

(in absence of o2, end chain is lactate. it has negative charge)

Question 13

How is Glucose transported into the cell

Answer 13

• Through Na/Glucose sympoters
• Through Facillitated Diffusion Transporters - Glut 2 in liver - insuline dependent

Question 14

What is the Mechanism of Glut 1

Answer 14

• Found in brain
• Bind of glucose to the receptor triggers a conformation change
• Brings the glocuse form the outside into insdie
• Glucose is relased into the cells
• Conformation change is Regenerated and binding site again faces the outside

Question 15

What is that is Glycolysis

Answer 15

Conversion of glucose into pyruvate

Question 16

What is the overall reaction for glycolysis

Answer 16

glucose + 2 ADP + 2 Pi + 2 NAD+ ->2 pyruvate + 4 ATP +2 H2O + 2 NADH + 2 H+

Question 17

What are the Steps of glycolysis

Answer 17

Glucose is split into fructuose-1,6-bisphosphate

1. This step is carried out by breaking down 2ATP into 2ADP and 2PI
2. Fructose-1,6-bisphosphate turns into 2 Triose phosphates
3. Which then turns into Pyruvate

• ​^ step produces 4 ATP from 4ADP and 4PI and by reducing 2NAD+ into 2NADH and 2 H+

Question 18

Glycosis in more detail

Answer 18

• Stage 1: glucose is trapped and destabilised
• Stage 2: two interconvertible three-carbon molecules are formed
• Stage 3: generation of ATP

Question 19

What are the 3 controle points in Glycolysis

Answer 19

Enzymes catalysing Irreversible reactions

1. Hexokinase- Substrate entry
2. Phophofrutokinase- Rate of flow
3. Pyruvate kinase - product exit

Question 20

What is phosphofructokinase

Answer 20

Key enzyme controlling rate of substrate movement along glycolytic pathway

Question 21

What are the activators of Phophofructokinase-PFK and what is their effect

Answer 21

• AMP
• Fructose-2,6-bisphosphate

Function: Increase glycolysis if energy is needed

Question 22

What are the inhibitors of PFK and whats their function

Answer 22

• ATP - will slpw glycolysis if energy is abundant
• Citrate - TCA cycle intermediate - Slows downstream Pyruvate entry into TCA cycle if energy is abdundant
• H+ Protons - in case of Anaerobic glycolysis will slow glycolysis if too much lactic acid is being produced

Question 23

What is the Energy charge

Answer 23

the ratio of ATP/AMP

• This controles PFK activity

Question 24

When is the celly fully charged

Answer 24

If all Adenylate Nucleotides are in shape of ATP

Question 25

When is the cell **Discharged**

Answer 25

When cell only contains **AMP** and **PI**

Question 26

What is **AMP** is positive regulator but **ADP** is not

Answer 26

AMP. Adenosine monophosphate (AMP) is a positive regulator of PFK. When a cell is very low on ATP, it will start squeezing more ATP out of ADP molecules by converting them to ATP and AMP (ADP + ADP →right arrow ATP + AMP). High levels of AMP mean that the cell is starved for energy, and that glycolysis must run quickly to replenish ATP22

Question 27

Summary of ATP and NADH yeild

Answer 27

Question 28

what happens to glycolysis when there is a lack of oxygen

Answer 28

* **NADH is used to ferment pyruvate into lactic acid - Lactate** * **NADH** is regenerated at begining of stage 3

Question 29

What is the **Warburg Effect**

Answer 29

Up-regulation of **anaerobic glycolysis** in cancer cells * Cancer cells have **Low k_m Hexokinase**

Question 30

What are advantages of the **Warburg effect**

Answer 30

* Rapid energy production * Supports other pathways for nucleotide sunthesis - need for growth * Supports rapid cell growth

Question 31

What are the **Disadvantages of the wurburg effect**

Answer 31

* Produces H+ and lactate as end products * Innefficient ATP synthesis * High glucose consumption * **Cancer patients loss weight**

Question 32

How cancer treated by targetting glycolysis

Answer 32

1. **2,Deoxy-glucose** - competitive inhibitor blocks further metabolism of glucose-6-phosphate 2. **3-bromopyruvate -** also CI - blocks production of 1,3-bisphosphoglycerate 3. **Dichloroacetate -** promotes conversion of lactic acid into pyruvate - Slow glycolytic rate - prevent cell growth

Question 33

Questions

Answer 33