Glucose Metabolism 1- Metabolism And Energy

Front 1

What is our only source for energy for moving, breathing and cardiac cycle

Back 1

Diet

Front 2

Nutrients obtained from diet have one of three possible fates, what are they?

Back 2

-Supply energy
- serve as building blocks ( proteins, hormones and enzymes)
-stored for future use (Glycogen, fats etc..)

Front 3

What is catabolism

Back 3

Breaking down of complex molecules

Front 4

Define anabolism

Back 4

Endergonic rxns which involve Building of complex molecules

Front 5

What's Metabolism and what organs regulate it

Back 5

- Balance between energy inputs and outputs of anabolism and catabolism

-primarily regulated by brain liver and adipose tissue

Front 6

Which molecules have a finite lifespan and why

Back 6

Anabolic molecules because they undergo catabolism

Front 7

Which rxns use ATP, which make it

Back 7

Anabolic- use it
Catabolic- make it

Front 8

What percentage of energy is used from catabolism for cellular function?
-what happens to the rest?

Back 8

-40%
-lost as heat

Front 9

Coupling catabolism by ATP

Back 9

Front 10

What is glycolysis

Back 10

The breakdown of glucose (C6H12O6) to make 2 molecules pyruvate and 2 molecules of ATP

Front 11

What are plasma glucose regulated to?

Back 11

90/100mg/ dl
2-3 grams

Front 12

Describe the first step of glycolysis

Back 12

- it's a phosphorylation rxn
- (6C molecule) glucose (C6H12O6) is phosphorylated by hexokinase (gkucokinase in liver)
-makes glucose-6-phosphate ( C6H11O6P1)
-uses 1 ATP
- make 1 ADP

Front 13

Describe the second stage of glycolysis

Back 13

-isomerisation rxn of g-6-p
-enzyme phosphoglucoisomerase
-makes fructose-6-phosphate (6 carbon sugar)

Front 14

Describe third stage of glycolysis

Back 14

Phosphorylation
F-1,6-P is phosphorylated to F-6-B ( C6H10O6P2)
Enzyme- phosphofructokinase
Uses 1 ATP
Gain ADP

Front 15

4th stage of glycolysis

Back 15

Destabilisation
-F1,6B is split into two sugars dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.
-By aldolase
-dihydroxyacetone can be converted into glyceraldehyde-3-phosphate by triosephosphate isomerase.

Front 16

5th step

Back 16

Dihydroxyacetone can be changed to by triosephosphate Isomerase into Glyceraldehyde-3-phosphate

Front 17

6th step

Back 17

G-3-P is dehydrohenated by glyceraldehyde-3-dehydrogenase into 1,3bisphosphogylcerate.
-1 NADH and H

Front 18

7th step

Back 18

-1,3 bisphosphoglycerate is changed to 3-phosphoglycerate by enzyme phosphoglycerate kinase.
-ATP gained

Front 19

8th step

Back 19

3-phosphoglycerate is changed into 2-phosphoglycerate by
phosphoglycerate mutase

Front 20

9th step

Back 20

-2-phosphoglycerate is changed into - phosphoenol pyruvate by enolase
Water is gained
-

Front 21

10 step

Back 21

Phosphoenolpyruvate is turned to pyruvate by pyruvate kinase
-2 ATP gained

Front 22

How does glucose get into the Gi tract

Back 22

-By secondary active transport

Front 23

How does glucose get into most other cells?

Back 23

Facilitated diffusion through GlutT molecules

Front 24

On which cells does insulin increase expression of GlutT

Back 24

Muscle and adipose

Front 25

which cells have GLUT1 and is it affected by insulin

Back 25

-Nerve cells and hepatocytes
-no GLUT1 is always open

Front 26

What are the gains of glycolysis

Back 26

2 molecules of pyruvic acid, 2 molecules of ATP, 2 NADH and 2H+

Front 27

What's the purpose of formation for Acytyl Co enzyme? And what's the gain

Back 27

-To prepare pyruvate for entry into the krebs cycle
-produced NADH and H and CO2

Front 28

What happens in the krebs cycle rxn

Back 28

Acytyl coenzyme A is oxidised to produce ATP, CO2, NADH, H+, and FADH2 and transfers their electrons through electron carriers

Front 29

What exactly happens in glycolysis in summary

Back 29

-Glucose is split into 2 3-carbin molecules of pyruvic acid
-consumes 4 ATPs but uses 2
-fate of pyruvic acid depends on oxygen availability
-if oxygen is lacking then it is turned to lactic acid
-if oxygen is plentiful then it is converted to Acytyl coenzyme A

Front 30

What's the key regulatory enzyme in glycolysis

Back 30

Phosphofructokinase

Front 31

What happens in steps 1-5 of glycolysis

Back 31

-energy is invested in form of ATP
-6-C glucose is split into 2 3-carbon molecules glyceraldehyde-3-phosphate
-PFK activity is high when ADP levels are elevated.

Front 32

What happens when PFK is low

Back 32

-Glucose is shunted away from glycolysis to glycogen storage pathway

Front 33

Overall what happens in steps 8-10 of glycolysis

Back 33

-2 glyceraldehyde molecules are converted to 2 molecules of pyruvic acid and ATP is gained
-NADH and H+ generated in step 6 is used to generate 4 ATPs in the electron transport chain.
Hepatocytes and cardiac muscle generate 6 ATPs. From them.

Front 34

What's Gluconeogenesis

Back 34

Formation of glucose from non-carbohydrates such as lactate, glycerol, and aas

Front 35

Glycogenesis

Back 35

Formation of Glycogen from glucose and (fructose)

Front 36

What's glycogenolysis

Back 36

Breakdown of glycogen to glucose (G-1-phosphate)

Front 37

Gluconeogenesis

Back 37

Breakdown of fats, amino acids to form glucose

Front 38

What tissues have an absolute requirement of glucose per day and what are they?

Back 38

Brain - 120g/day
Erythrocytes - 40g/day

Front 39

What are the key organs involved in carbohydrate Metabolism?

Back 39

Liver
Pancreas

Front 40

What's the role of the liver in CM

Back 40

-Acts as body's sink for glucose
-major site for glucose storage
-site for Gluconeogenesis

Front 41

What's the role of the pancreas in carbohydrate Metabolism

Back 41

-produces pancreatic amylases and bicarbonate to aid with carb digestion
-produces two key hormones:
Insulin from B-cells
Glucagon from a-cells

Front 42

What type of hormones are Glucagon, insulin and adrenaline

Back 42

Peptide hormones

Front 43

What does Glucagon do

Back 43

Increases blood glucose by stimulating glycogenolysis

Front 44

What hormone plays a supporting role in the increase of glucose

Back 44

ADRENALINE

Front 45

What is the effect of high insulin in the body on:
Gluconeogenesis
Glycolysis
Glycogenolysis
Glycogenesis

Back 45

1. Decreases Gluconeogenesis- don't need to make more glucose
2. Increases glycolysis- excess glucose needs to be broken down and stored
3. Glycogenolysis- decrease because sugar is not needed
4. Glycogenesis- increase because sugar needs to be stored

Front 46

Glucagon effect on
Glycolysis
Glycogenolysis
Glycogenesis
Gluconeogenesis

Back 46

1. Glycolysis- Decreases stop storing sugar
2. Glycogenolysis- Increases needed for glucose
3 . Glycogenesis- Decreases can't be making glycogen because sugar is needed
4 .Gluconeogenesis- increases sugar needs to be made

Front 47

-How many steps of glycolysis are irreversible
-what are they
-why

Back 47

- 3
-step 1: G to G-6-P by hexokinase
Step 3: F-6-P to F-1,6-B by PFKs
Step 10: Phosphoenolpyruvate to pyruvate
-because of input of ATP

Front 48

Key enzymes of glycolysis

Back 48

Hexokinase, PFK and pyruvate kinase

Front 49

In what ways are the key enzymes of glycolysis regulated

Back 49

1 Allosteric effects of metabolites
(build up of AMP or product)

2 Hormonal action:-
a) Enzyme modification usually phosphorylation (short term)
b) Induction/repression of enzyme synthesis
(longer term)

Front 50

PFK 1 ALLOSTERIC REGULATION

Back 50

Front 51

PEP Allosteric regulations

Back 51