Metabolism

Front 1

1st law of thermodynamics

Back 1

Energy cannot be created or destroyed

Front 2

2nd law of thermodynamics

Back 2

Energy transformation is not 100% efficient, and usable energy is lost, while entropy increases

Front 3

Gibbs Free Energy Equation

Back 3

∆G=∆H-T∆S
+∆G = endergonic, anabolism
-∆G = exergonic, catabolism

Front 4

Gibbs free energy needed to reach equilibrium

Back 4

∆G = ∆G˚ +RT ln ([C][D]/[A][B])
∆G˚ = ∆G when reactants and products in 1 molar quantities

Front 5

Equilibrium Constant

Back 5

Keq = ([C][D]/[A][B])

Front 6

∆G'˚ and K'eq

Back 6

∆G˚ and Keq at pH = 7 and T = 37˚C
K'eq > 1; ∆G'˚< 0
K'eq = 1; ∆G'˚= 0
K'eq < 1; ∆G'˚> 0

Front 7

5 Characteristics of Metabolism

Back 7

1. Irreversible
2. Independent Catabolic and Anabolic pathways
3. First committed step
4. Regulated (usually through enzymes)
5. Specific cellular locations

Front 8

5 reactions in Metabolism

Back 8

1. Make or break carbon bonds
2. Internal rearrangement, isomerization, elimination
3. Free radical reaction
4. Group transfer reaction
5. Oxidation-Reduction reaction

Front 9

ATP Hydrolysis

Back 9

- H2O hydrolyzes ATP
- Phosphate group stabilized by resonance
- ATP and ADP stabilized by Mg2+

Front 10

Human's Daily ATP

Back 10

- Take in 11,700 kJ of food
- 50% efficiency, 5860 kJ to ATP
- 50 kJ/ATP = 117 moles ATP/day
- 50 g of ATP in body; so each one recycled 1300x

Front 11

ATP Generation Mechanisms

Back 11

1. Substrate-Level Phosphorylation
2. Oxidative Phosphorylation
3. Photophosphorylation

Front 12

Substrate-Level Phosphorylation

Back 12

Transfer of high energy PO4- group from compound to ADP
- Different Energy per compound
- ex: PEP, Creatine Phosphate

Front 13

Oxidative-Phosphorylation

Back 13

ATP created from proton gradient created by transfer of electrons in an electron transport chain
- Triggered by compounds

Front 14

Photophosphorylation

Back 14

ATP created from proton gradient created by transfer of electrons in an electron transport chain
- Triggered by sunlight

Front 15

Carbohydrates/Saccharides

Back 15

- Formula = (CH2O)n
- Act as Structural Elements or Energy Sources
- Can exist in many "isomeric forms"

Front 16

Monosaccharide

Back 16

- Simple sugars with 3-7 Carbon Atoms
- Many Types:
- Aldose: Contains aldehyde group
- Ketose: Contains ketose group

Front 17

Monosaccharide Cyclization

Back 17

- Occurs in pentoses and hexoses
- Carbonyl group -> Anomeric Carbon
- Carbonyl Oxygen -> hydroxyl group (determines whether the sugar is alpha or beta)
- Different side as CH2OH? alpha
- Same side? beta

Front 18

Oligosaccharides

Back 18

Typically 2-10 molecules
Bound by glycosidic bonds (dehydration)
Usually found covalently bound to proteins or lipids on cell surface to act as recognition signals

Front 19

Polysaccharides

Back 19

10-infinite number of molecules
Bound through dehydration (glycosidic bonds)
Different locations of binding lead to differences in starch, glycogen, or cellulose
- alpha cyclic sugars makes alpha glycosidic linkage
- beta sugar makes beta linkage

Front 20

Molecular Binding of Cellulose vs Starch vs Glycogen

Back 20

Cellulose -> B 1,4 linkages (linear)
Starch and Glycogen -> A 1,4 linkages
- A 1,6 linkages allow branching
- C1 = Anomeric carbon
- Glycogen is higher branched than starch

Front 21

3 Great Characteristics of Glucose

Back 21

1. complete oxidation -> ∆G'˚ = -2,840 kJ/mole
2. Can be stored as large quantities of hexose units, controlling blood sugar levels and allowing easy transition to ATP
3. Versatile Precursor to many biosynthetic reactions

Front 22

4 major fates of glucose

Back 22

1. Synthesis of complex polysaccharides (for ECM and cell wall)
2. Storage as glucose polymers (for storage)
3. Oxidation to ribose 5-phosphate (via pentose phosphate pathway, for DNA)
4. Oxidation to pyruvate via glycolysis (for ATP)

Front 23

Two Glycolitic Stages

Back 23

1. Preparatory Phase
2. Energy Conserving Stage (payout)
- Takes 10 Reactions
- Process turns Glucose -> (2) 3 carbon pyruvic acid + ATP + NADH

Front 24

Glytolitic Stage 1: Preparatory Phase

Back 24

2 ATP's are invested
Glucose -> Fructose 1,6 biphosphate (F-1,6-BP)
then F-1,6-BP -> (2) triose glcyeraldehyde 3-phosphate (GAP)

Front 25

Glytolitic Stage 2: Energy Conserving Stage

Back 25

(2) GAP -> (2) Pyruvate + 4 ATP + 2NADH

Front 26

Feeder Pathways from Storage

Back 26

Starch or Glycogen feed into glycolysis 2 steps
1. Phospholytic cleavage of terminal glucose --> glucose 1-phosphate
2. Phosphoglucomutase converts glucose 1-phosphate into glucose 6-phosphate

Front 27

Feeder Pathways from ingestion

Back 27

Ingested polysaccharides broken down by intestinal hydrolytic enzymes -> monosaccharides
- Leads to variety of D-Hexoses; which can be phosphorylated into G6P, F6P, or F1P
- Galactose 1P and Glucose 1P require nucleotide derived UDP

Front 28

3 Pyruvate Fates

Back 28

1. 2 Ethanol + CO2 (fermentation in yeast)
- Makes alchohol
2. 2 Acetyl CoA (aerobic)
3. Lactate (anerobic)
- cheese/yogurt

Front 29

Regeneration of NADH

Back 29

Glycolytic oxidation of glyceraldehyde uses NAD+ as electron acceptor. O2 takes this electron back to regenerate NAD+; but in anaerobic conditions, an organic molecule (i.e. lactate,ethanol) accepts this electron

Front 30

Metabolic Regulation Tactics

Back 30

1. Altering enzyme activity
2. Using equilibrium and mass action
3. Have tissue specific isozymes of enzymes (same enzyme, different tissue, different rate)
4. Responding to energy (ATP/ADP) ratios (most enzymes need full ATP saturation)

Front 31

AMP-Activated ATP Kinase (AMPK)

Back 31

When [ATP]/[AMP] decreases, triggers AMPK to increase ATP.
- Activated by low ratio, exercise, SNS, or hormones
- When active, phosphorylates proteins and shifts metabolism away from energy (ATP) consumption
- Ex: Makes brain hungry, increases fatty acid oxidation

Front 32

AMP Production

Back 32

AMP produced by:
1. ATP hydrolyzed to ADP
2. 2 ADP converted to 1 ATP and 1 AMP

Front 33

4 ways of regulating glycolysis and glyconeogenesis

Back 33

1. Allosteric Activation/Inhibition (intracellular)
2. Reversible Phosphorylation
3. Regulating Expression of Genes (via T-factors)
4. Signal Transduction Events

Front 34

Allosteric Regulation in PFK and FBPase

Back 34

PFK = ATP + F6P -> ADP + F1,6P -> Glycolysis
FBPase = F1,6P + H2O -> F6P + Pi -> Gluconeogenesis
F26BP activates PFK, inhibits FBPase
- Contains Kinase group and Phosphotase group
- F26BP increases glycolysis
Insulin activates PFK, glucagon activates FBPase

Front 35

Reversible Phosphorylation of Pyruvate Kinase

Back 35

Phosphorylated P-Kinase is less active
- Becomes phosphorylated in presence of ATP

Front 36

Insulin Gene Regulation

Back 36

Insulin attaches to a receptor that goes on to downregulate genes for gluconeogenic enzymes