📑 Medical Biochemistry: The Master Index
I. Energy Metabolism & The "Engine"
The Big Picture: Fed vs. Starved States (The Metabolic
Timeline)
Glycolysis & Gluconeogenesis: The PFK-1/PFK-2 "Tug-of-
War"
Glycogen Dynamics: Storage (Insulin) vs. Release
(Glucagon)
The TCA Cycle & ETC: Proton Gradients, ATP Synthase, and
Cyanide Toxicity
The Uncouplers: Thermogenesis and the 2,4-DNP
Mechanism
II. The "Fuel" Shuttles & Specialized Pathways
Fatty Acid Metabolism: $\beta$-Oxidation vs. Synthesis
(Carnitine vs. Citrate Shuttles)
Ketogenesis: The Brain’s Famine Fuel
Pentose Phosphate Pathway (PPP): NADPH, Ribose-5-P,
and G6PD Armor
The Cori Cycle & Alanine Cycle: Muscle-Liver Teamwork
III. Protein, Nitrogen & Waste Management
The Urea Cycle: Ammonia Detoxification and CPS-1
Amino Acid Breakdown: Ketogenic vs. Glucogenic logic
Heme Metabolism: Synthesis (ALA-S), Lead Poisoning, and
Bilirubin (Jaundice)
Purine/Pyrimidine Metabolism: Salvage Pathways and Gout
(Uric Acid)
IV. Quality Control & Genetics
The Genetic Blueprint: Heterochromatin vs. Euchromatin
DNA Repair: NER (UV damage) and Mismatch Repair
Protein Folding: Chaperones vs. The Ubiquitin-Proteasome
"Shredder"
Apoptosis: The Mitochondrial "Self-Destruct" (Cytochrome
C & Caspases)
Enzyme Kinetics: Michaelis-Menten ($V_{max}$ and
$K_m$) and Inhibition Logic
,V. Clinical Correlates & Nutrition
The Vitamin Spark Plugs: $B_1$ (Thiamine), $B_3$
(Niacin), $B_{12}$/Folate, and Vitamin C
Metabolic Diseases: PKU, Tay-Sachs, Wilson’s, and Maple
Syrup Urine Disease
Connective Tissue: Collagen Synthesis and the Vitamin
C/Copper Connection
1. Lipid Transport & Lipoproteins
Lipoproteins are essentially the "taxicabs" of the blood. Their function is defined by their density
(lipid-to-protein ratio) and their Apolipoprotein "ID tags."
,
, Lipoprotein Primary Lipid Key Apolipoproteins Function
Transports dietary lipids from
Chylomicron Dietary TG B-48, C-II, E
intestines to tissues.
Transports liver-synthesized
VLDL Endogenous TG B-100, C-II, E
TG to peripheral tissues.
Delivers cholesterol to
LDL Cholesterol B-100
peripheral tissues ("Bad").
Reverse cholesterol transport
HDL Phospholipids A-I, C-II, E
(periphery $\rightarrow$ liver).
Clinical Pearl: Apo C-II activates Lipoprotein Lipase (LPL), allowing tissues to "snip" fatty acids
off the passing "cab."
2. Specialized Amino Acid Derivatives
Amino acids aren't just for building muscle; they are the precursors to your brain's chemistry and
hormonal signals.
Tyrosine: Converts to DOPA $\rightarrow$ Dopamine $\rightarrow$ Norepinephrine
$\rightarrow$ Epinephrine. Also the precursor for Melanin (pigment) and Thyroxine ($T_4$).
Tryptophan: Uses Vitamin $B_6$ to become Serotonin (mood) and Melatonin (sleep). It can
also be used to synthesize Niacin ($B_3$).
Histidine: Decarboxylated to Histamine (allergic response/gastric acid).
Arginine: The sole source of Nitric Oxide (vasodilator) and a key player in Creatine synthesis.
3. Signal Transduction Pathways
Hormones are the mail; signaling pathways are the person opening the envelope.
G-Protein Coupled Receptors (GPCR)
1. cAMP Pathway: Glucagon or $\beta$-Adrenergics activate Adenylate Cyclase $\rightarrow$
$\uparrow$ cAMP $\rightarrow$ Protein Kinase A (PKA).
2. $IP_3$/DAG Pathway: $\alpha_1$-Adrenergics activate Phospholipase C $\rightarrow$
cleaves $PIP_2$ into $IP_3$ (releases $Ca^{2+}$) and DAG (activates PKC).
Enzyme-Linked Receptors
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I. Energy Metabolism & The "Engine"
The Big Picture: Fed vs. Starved States (The Metabolic
Timeline)
Glycolysis & Gluconeogenesis: The PFK-1/PFK-2 "Tug-of-
War"
Glycogen Dynamics: Storage (Insulin) vs. Release
(Glucagon)
The TCA Cycle & ETC: Proton Gradients, ATP Synthase, and
Cyanide Toxicity
The Uncouplers: Thermogenesis and the 2,4-DNP
Mechanism
II. The "Fuel" Shuttles & Specialized Pathways
Fatty Acid Metabolism: $\beta$-Oxidation vs. Synthesis
(Carnitine vs. Citrate Shuttles)
Ketogenesis: The Brain’s Famine Fuel
Pentose Phosphate Pathway (PPP): NADPH, Ribose-5-P,
and G6PD Armor
The Cori Cycle & Alanine Cycle: Muscle-Liver Teamwork
III. Protein, Nitrogen & Waste Management
The Urea Cycle: Ammonia Detoxification and CPS-1
Amino Acid Breakdown: Ketogenic vs. Glucogenic logic
Heme Metabolism: Synthesis (ALA-S), Lead Poisoning, and
Bilirubin (Jaundice)
Purine/Pyrimidine Metabolism: Salvage Pathways and Gout
(Uric Acid)
IV. Quality Control & Genetics
The Genetic Blueprint: Heterochromatin vs. Euchromatin
DNA Repair: NER (UV damage) and Mismatch Repair
Protein Folding: Chaperones vs. The Ubiquitin-Proteasome
"Shredder"
Apoptosis: The Mitochondrial "Self-Destruct" (Cytochrome
C & Caspases)
Enzyme Kinetics: Michaelis-Menten ($V_{max}$ and
$K_m$) and Inhibition Logic
,V. Clinical Correlates & Nutrition
The Vitamin Spark Plugs: $B_1$ (Thiamine), $B_3$
(Niacin), $B_{12}$/Folate, and Vitamin C
Metabolic Diseases: PKU, Tay-Sachs, Wilson’s, and Maple
Syrup Urine Disease
Connective Tissue: Collagen Synthesis and the Vitamin
C/Copper Connection
1. Lipid Transport & Lipoproteins
Lipoproteins are essentially the "taxicabs" of the blood. Their function is defined by their density
(lipid-to-protein ratio) and their Apolipoprotein "ID tags."
,
, Lipoprotein Primary Lipid Key Apolipoproteins Function
Transports dietary lipids from
Chylomicron Dietary TG B-48, C-II, E
intestines to tissues.
Transports liver-synthesized
VLDL Endogenous TG B-100, C-II, E
TG to peripheral tissues.
Delivers cholesterol to
LDL Cholesterol B-100
peripheral tissues ("Bad").
Reverse cholesterol transport
HDL Phospholipids A-I, C-II, E
(periphery $\rightarrow$ liver).
Clinical Pearl: Apo C-II activates Lipoprotein Lipase (LPL), allowing tissues to "snip" fatty acids
off the passing "cab."
2. Specialized Amino Acid Derivatives
Amino acids aren't just for building muscle; they are the precursors to your brain's chemistry and
hormonal signals.
Tyrosine: Converts to DOPA $\rightarrow$ Dopamine $\rightarrow$ Norepinephrine
$\rightarrow$ Epinephrine. Also the precursor for Melanin (pigment) and Thyroxine ($T_4$).
Tryptophan: Uses Vitamin $B_6$ to become Serotonin (mood) and Melatonin (sleep). It can
also be used to synthesize Niacin ($B_3$).
Histidine: Decarboxylated to Histamine (allergic response/gastric acid).
Arginine: The sole source of Nitric Oxide (vasodilator) and a key player in Creatine synthesis.
3. Signal Transduction Pathways
Hormones are the mail; signaling pathways are the person opening the envelope.
G-Protein Coupled Receptors (GPCR)
1. cAMP Pathway: Glucagon or $\beta$-Adrenergics activate Adenylate Cyclase $\rightarrow$
$\uparrow$ cAMP $\rightarrow$ Protein Kinase A (PKA).
2. $IP_3$/DAG Pathway: $\alpha_1$-Adrenergics activate Phospholipase C $\rightarrow$
cleaves $PIP_2$ into $IP_3$ (releases $Ca^{2+}$) and DAG (activates PKC).
Enzyme-Linked Receptors
( ) db l d h d
