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3
enzyme definition
intracellular
plasma membrane
complex enzyme = holoenyme with PROTEIN: APOENZYME and non portien component: COFACTOR
prosthetic group:
A type of cofactor (can be organic or metal) that is tightly or covalently bound to the enzyme.
Unlike coenzymes, it does not dissociate easily.
Example:
FAD in succinate dehydrogenase
Co enzyme = small organic molecule that is loosely bound to enzyme during reaction eg NAD or biotin
COFACTOR: non protein compound or metal ion that is required for an enzyme’s role as a catalyst
for exmaple:
mention cofactors for PDH complex
for heme: porphoyrins (swap) (heme is tightly bound so its a prosthetic group)
-quinones: upiquinone
and a bunch of metal ions: zn,mg,cu
ENYZME CLASSIFICATIONS:
Name | Simple Role | |
---|---|---|
1 | Oxidoreductases | Catalyze redox reactions (electron transfer) |
2 | Transferases | Transfer functional groups between molecules |
3 | Hydrolases | Break bonds using water (hydrolysis) |
4 | Lyases | Add or remove groups to form double bonds |
5 | Isomerases | Rearrange atoms within a molecule (isomerization) |
6 | Ligases | Join two molecules using energy (e.g., ATP) |
ACTIVE SITE:
- complimentary
binds to substrate via covalent. bonds
active site formed during folding of tertiary and quaternary structure
in cmplex enzymes cofactors are also part of it
amino acid residues are found
ENZYME SPECIFICITY:
REACTION SPECIFICITY:
- enzymes catalYSE CERTAIN REACTIONS, DETERMINED BY THEIR PROTEIN CONTENT
substrate specificuty:
- fisger’s lock and key” associate correspondence between active site and substrate
koshland’s induced fit: activve site and substrate dont fit compeelt,y binding leads to conformational changes in bidning sit re
1
✅ Key Features:
Tetrameric protein: LDH consists of four subunits.
Two types of subunits:
H (Heart) type
M (Muscle) type
and then state 5 LDH isoenzymes
heme: 4 subunits, 2a, 2b polypeptide chains
2 -
A chromosome is made of DNA tightly wrapped around histone proteins, forming nucleosomes.
A nucleosome is DNA wrapped around a histone octamer (8 histone proteins).
These nucleosomes coil and fold to form a chromatin fiber (about 30 nm thick).
The chromatin fiber further loops and condenses to form the highly compact chromosome structure visible during cell division.
mRNA = carries genetic info from dna to rna for protein synth
tRNA → brinds AA to ribosome during translaation
rRNA → structure and fucntional unit of ribosomes
miRNA = regulates gene expression
enzyme:
as enzyme inc, velocity increaess, until substrate is lmiiting factor
as substrate increases, so does rate (hyperbolic curve) until vMax is reached (Max velocity) → because enzyme is saturated
same for ph, temp
5
🔹 1. Gene Expression (Enzyme Synthesis ↑ or ↓)
The cell controls how much enzyme is made by regulating the expression of the gene that encodes the enzyme.
If more enzyme is needed:
Transcription of the gene is increased → more mRNA → more enzyme produced.
If less enzyme is needed:
Transcription is decreased → less mRNA → less enzyme made.
Example:
In fasting, the gene for gluconeogenic enzymes is upregulated in the liver.
🔹 2. Protein Degradation (Enzyme Breakdown ↑ or ↓)
Enzymes can be actively degraded by the cell when they are no longer needed.
This is done through:
Proteasomes (for cytosolic proteins).
Lysosomes (for membrane/secreted proteins).
By increasing or decreasing the rate of enzyme degradation, the cell adjusts how much enzyme is available.
Example:
Misfolded or damaged enzymes are rapidly degraded.
6 -
enzymes in diagnosis = used to find conc of x y z, (urine, plasma, gastric juice) and compare to normal value
8
vit D:
🦴 Vitamin D and Bone Remineralization
Vitamin D (specifically calcitriol, the active form) increases calcium and phosphate absorption from the intestine.
These minerals are essential for forming hydroxyapatite, the crystal that strengthens bone.
🧬 Role of Osteoblasts
Osteoblasts are bone-forming cells that:
Lay down new bone matrix (mainly collagen).
Promote mineralization by depositing calcium and phosphate into this matrix.
Vitamin D stimulates osteoblasts to:
Express proteins like osteocalcin and alkaline phosphatase, which support mineral deposition.
9
maroergic bonds:
- ENOL PHOSPHATE = IN PEP
PHOSPHESTER = in creatine hosphate
phosphoANHYDRIDE between 2nd and 3rd phosphate in ATP
ATP’S ENERGY IS REVERSIBLE!!!!!!!
atp hydrolised to adp + pi, energy can be used for x y z
BECAUSE adp to atp =
oxidative phsopyrlation (in mitoondria)
and substrate level phosphorylation (gluyolis)
COUPLING:
ATP → ADP + Pi (ΔG ≈ –30.5 kJ/mol)
This is coupled with various endergonic reactions, such as:
🧬 Example: Glucose phosphorylation
Glucose + Pi → Glucose-6-phosphate (ΔG > 0)
Coupled with:
ATP → ADP + Pi
→ Net reaction:
Glucose + ATP → Glucose-6-phosphate + ADP (ΔG < 0)
Biological oxidation refers to the transfer of electrons (or hydrogen) from one molecule to another during metabolic reactions.
It’s essential for energy production, especially in the form of ATP via the electron transport chain (ETC).
Oxidation is always paired with reduction: one molecule loses electrons (oxidized), another gains them (reduced).
oxidoreductase: CATALYSE REDOX REACTIONS WHERE ELCTRONS, IN THE FORMOF H IS TRANSFERRED
📚 Subclasses of Oxidoreductases:
Dehydrogenases
Remove hydrogen atoms from substrates.
Often use NAD⁺/NADP⁺ or FAD as coenzymes.
Example: Lactate dehydrogenase
Oxidases
Transfer electrons to oxygen (O₂).
Example: Cytochrome oxidase (ETC complex IV)
🔋 Key Redox Systems & Their Roles
NAD⁺ / NADH
Catabolic reactions (e.g. glycolysis, TCA).
NAD⁺ → NADH carries electrons to ETC → ATP.
NADP⁺ / NADPH
Anabolic reactions (e.g. fatty acid synthesis).
NADPH used in biosynthesis & antioxidant defense.
FMN / FMNH₂
Part of ETC Complex I.
Accepts electrons from NADH.
FAD / FADH₂
In TCA cycle, β-oxidation, and ETC Complex II.
Electron carrier bound to enzymes.
Ubiquinone / Ubiquinol (CoQ)
Lipid-soluble ETC carrier.
Transfers electrons from Complex I/II → III.
Cytochromes (heme proteins)
In ETC Complex III & IV.
Transfer electrons via Fe³⁺ ↔ Fe²⁺.
Lipoate
Coenzyme in PDH & α-KGDH complexes.
Transfers acyl groups & electrons.
Ascorbate (Vitamin C)
Antioxidant, donates electrons.
Regenerates other antioxidants (e.g., vitamin E).
11 -
OXIDATIVE PHOSPH:
Oxidative Phosphorylation
Occurs in mitochondria.
Electrons from NADH/FADH₂ pass through the electron transport chain (ETC).
Proton gradient drives ATP synthase → forms ATP.
O₂ is the final electron acceptor.
Substrate-Level Phosphorylation
Occurs in glycolysis and TCA cycle.
ATP formed directly from high-energy intermediates.
Does not require oxygen or ETC.
15 -
citrate cycle - connection w carbs: CARBS BREAK DOWN TO FORM GLUCOSE, which forms pyruvate via glycolysis, which goes into the citrate cucle
DRAW CITRATE CYCLE AGAIN +
ENERGY BALANCE - 12 ATP (3 X 3NADH, 1 X FADH2, 1 ATP AT SUBSTRATE LEVEL)
REGULATION - ATP AND NADH INHIBIT!!!!! ADP AND NAD ACTIVATE
12
flashcards suffice
13 -
thermogenesis = heat production in thermoregulation of warm blooded animals
regulated by:
CENTRAL/PERIPHERAL THERMORECEPTORS - detect blood temp changes
hypothalmus - acts as a thermostat
ways of thermogenesis
ways that heat can be lost:
radiation, convection, condction, evaporation, lsotr htrough urine and feces
sympathetic reponse to cold:
shivering
ALSO, due to cold exposure:
TRH, TSH, T3 IS RELEASED, increases adrenergic recprtor sensitivy
THERMOGENIN ROLE:
MEMBRANE PROTEIN IN BAT, bypasses ATP synthase, absorbs protons so can be converted to heat not stored as energy
Plays a key role in non-shivering thermogenesis, especially in newborns and hibernating mammals.
brown adipocutes:
polygonal, small structure with LIPID VACUOLE AND MANY MITCONDRIA WITH LOTS OF CRISTAE → with integral protein thermogenin.
OXIDASE:
o2 = electron acceptor, but not incorporated as substrate eg cytochrome oxidase
PERIOXDASE:
- happen in peroxisomes, contain catalase and oxidase, used for BETA OX OF VERY LONG CHAIN FA
MICROSOMAL:
occirs in ER, has cytochrome p450, requires NADPH
SHORT ELECTRON TRANSPORT;
The endoplasmic reticulum (ER) contains electron transport chains involved mainly in detoxification and biosynthesis, unlike the long ETC in mitochondria for ATP production.
These ER chains use cytochrome P450 enzymes,
14
metabolism:
anabolism
catabolism
pyruvate = 1 glucose, 2 pyruvate-
anabolic synth of FA AND AA
transferred to mitoondria for krebs
in asbence of o2 forms lactate → can regenerate flucose
acteyl coa:
product of beta ox of fatty acids, trasnproted by citrate shuttle to cytosol for fatty acid synth
also used for krebs
AVTICAES purivate dehydrogenase kinase
PHASES OF AEROBIC METABOLISM:
DEG OF BIOPOLYMERS to monomores
all momers are converted to acetyl coa
- acteyl coa into krebs cycle to produce CO2 and H+
H used for resp chain → (ETC)
citriate cycle: connection
GNERATING ENERGY THROUGH OXIDATION OF ACETYL COA
TAKES PLACE IN MITOCONDRIA FOR EUKAROYTES, CYTOLPLAMS FOR PROKATYOTES.
PRODUCES NADH AND AMINO ACIDS
REGULATION OF CITRATE CYCLE:
ALLOSTERIC INHIBITOR: ADP, NADH, ACGIVATOR = ADP.NAD
CONNECTION W LIPID METABOLSIM:
acetyl coa trasnfered via citrate shuttle to CYTOSOL FOR FATTY ACID SYNTH
CARB:
GLYCOLYSIS, PYRUVATE TO ACETYL COA
16
SALIVARY A AMYLASE:
1 4 GLYCOSIDIC BOND BROKEN
POLYSACC TO DISACC
ACINAR CELLS SECRETE PANCREATIC AMYLASE, BREAK DOWN DISACC TO MONO SACC
GLUCOSE ABSORPTION IN ALL THE BODY PARTS DONT FORGET:
IN LIVER: SITE OF GLYCOLISS + GNG, HAS GLYCOGEN STORES. ACTIVE PPP FOR SUPPLYING NADPH
ERYTHROCYTES - NO ORGANELLES SO ANAEROBIC GLYCOLYSIS
IN MUSCLES, can degrade carbs aeobically and anaerobically
BRAIN ENTERS BRAIN VIA GLUC 1 + 3 → no PPP or GNG
kindeys = GNG HAPPENS
lactase deficiency = lack of enzyme activity in kids
adults: change in control of gene expression
17 - glycolysis
do scheme again
anaerobic + aerobic
✅ Aerobic Glycolysis
Occurs in the cytoplasm, not mitochondria.
Glucose → Pyruvate (via glycolysis)
Pyruvate enters mitochondria → converted to Acetyl-CoA
Acetyl-CoA enters the citric acid cycle (TCA/Krebs cycle) → produces CO₂, NADH, and FADH₂
These go to the electron transport chain, which produces H₂O and lots of ATP
👉 Yes, aerobic metabolism produces much more ATP (~30–32 ATP per glucose)
✅ Anaerobic Glycolysis
Happens in low oxygen conditions (e.g., active muscles)
Glucose → Pyruvate → Lactic acid
Occurs entirely in the cytoplasm
Produces only 2 ATP per glucose
SHUTTLES: MALATE ASP/GLYCEROL 3 PHOSPH AGAIN
PYRUVATE DEHYDROGENASE REACTION -
Regulated by phosphorylation:
PDH kinase phosphorylates (inactivates) PDH
PDH phosphatase dephosphorylates (activates) PDH
PDH CONVERTS PYRUVATE TO ACETYL COA
tissue specificity:
hexokinase - ALL CELLS
glycolysis happens in - skeletal muscle and blood cells
18 - GNG
scheme again
tissue specificity: FIRST ENZYME: PEP CARBOXYLASE = IN MITOCONDIRA, LAST ENZYME: GLUCOSE 6 POHSPHATSE IS IN ER, rest are cytoplasmic
regulation: insulin, glucagon + what hormones increase or decrease it
tissue localisation: TISSUE = 80, kidnye = 20
19 - ppp
scheme
GLUCOSE 6 PHOSPHATE DEHYDROGENASE DEFICIENCY: LEADS TO IMPRAIRMENT OF NADPH PRODUCTION, therefore h202 is not detoxified, so hemolytic damage happens
lipid peroxidation happens: erythrocyte membrane breaks down and hemolytic anemia occurs
20 -
FRUCTOSE = HEXOSE SUGAR, MONOSACCARIDE
ABSORPTION:
ACTIVATION BY PHOSPHORYLATION BY
hekokinase, glucokinase, fructokinase, galactokinase
furthered by glyc, glyc, aldolase, galactose metabolism
L + M
L + K
L
L
fructosuria = DEFICIENCY OF FRUCTOKINASE THEREFORE INCREASED FRUCTOSE IN BLOOD AND URINE
FRUCTOSE INTOLERANCE:
due to aldolase b AFFECTING KINDEY
DEPOSITION OF FRUCTOSE 1 PHOSPHATE IN LIVER, INHIBITS FRUCTOKINASE - CAN CAUSE SLIGHT INCREASE IN BLOOD SUGAR
GALACTOSEMIA 1
Galactosemia Type I (Classic Galactosemia)
Enzyme deficiency: Galactose-1-phosphate uridyltransferase (GALT)
Accumulated substance: Galactose-1-phosphate
Symptoms (after milk ingestion):
Vomiting
GALACOSEMIA 2:
Galactosemia Type II
Enzyme deficiency: Galactokinase (GALK)
Accumulated substance: Galactose
(gets converted to galactitol, especially in the lens)
Main symptom: Cataracts
GALACTOSE TRANSPORT: Galactose is absorbed across the apical membrane of enterocytes via sodium-dependent cotransport (SGLT-1), and then transported across the basolateral membrane into the bloodstream via GLUT2.
21 - glycogen metabolsim
STRUCTURE:
- POLYMER OF GLUCOSE
A-14, 1-6 GLYCOSIDIC BONDS
BRANCHED OR UNBRANCHED
sphere shape
degradation:
glyc phosph - breaks 1-4 bond
glucose 1 phosphate is released
glygoen remodelled
gluc 1 phoph to gluc 6 phohsp for further metabolsim
REG ENZYMES: AS YOU EXPECT glucogen synthase, phpsphorylase
INCLUDE INSULIN AND GLUCAON
STORAGE DISEASE:
von gierke - hypoglycemia
ANDERSONS - liver dysfunction
MC,CARDLES - muscle cramps
MUSCLE defic of PFK - inab to excersie
22
just like evrything abt glucose
hypoglycemia:
- fasting, skipping meals, excess insulin, alcohol intake/adrenal insufficiency
hyperglycemia: type ½ diabetes mellitus
lipids:
Sphingosine + fatty acid = Ceramide (the core of all sphingolipids)
Ceramide + head group = Sphingolipid (e.g., sphingomyelin, cerebrosides, gangliosides)
lipoprotein = non polar lipid core with APOLIPOPROTEIN ON SURFACE
VLDL/LDL/HDL/IDL/CHYLOMICRON
GLYCEROL METABOLISM: FIRST ENZYME???
(ADIPOSE TRYGLYCERIDE LIPASE)
24 - TAG
schemes (DHAP and glycerol)
fate of fatty acids
regulation: insulin/glycagon
insulin:
increased Pyruvate dehydrog - > inc acetyl coa - > citrate shuttle: INC SUBSTRATE FOR FATTY ACID SYNTH
glucagon:
lipolysis: acetyl coa carboxylase inactive
25 -
fa to acyl coa
carnitine shuttle
even synth (acyl coa to acetyl coa + acyl coa)
odd:
propinoyl + POLYUNSATURATED FAT
-r egulation = cpt high = starving and vice versa
energy balance (Mol atp_
and number of atp produced per cycle
7 BETA OX. 7 NAD/FAD AND 8 ACTEYL COA. actetyl coa = 10, nad = 3, fad = 2
REGULATION: INSULIN REDUCES CPT1 REMEMBER
ALLOSTERIC INHIBITO: MALONYL COA FFA SYNTHASE
26
REGULATION:
Insulin:It promotes fat storage (lipogenesis) and inhibits lipolysis, so fewer free fatty acids are released from adipose tissue.
→ Result: Less substrate (acetyl-CoA) available for ketone body production in the liver.
→ Correction: HMG-CoA synthase is the key step insulin inhibits to reduce ketone production.
Glucagon: Glucagon promotes ketogenesis by stimulating the release of fatty acids from adipose tissue and increasing causing their BETA OX TO FORM ACETYL COA.Glucagon also activates the enzyme HMG-CoA synthase, which is crucial for ketone body production.
Ketosis: A metabolic state where the body uses fat instead of carbohydrates for energy, producing ketone bodies. Occurs during prolonged fasting, low-carb diets, or uncontrolled diabetes.
Ketonuria: Presence of ketone bodies in the urine. It's a sign the body is in ketosis and can be detected using urine dipsticks.
Ketoacidosis: A serious complication (most common in uncontrolled Type 1 diabetes) where excessive ketones make the blood acidic. It can be life-threatening and requires urgent treatment.
Ask ChatGPT
27 - my bday so fatty
MAAA (CALLING MA WHATS FOR DINNER = MALONYL COA + ACYL COA)
Adipose | Stores FAs as TAGs; releases FAs during fasting. |
Muscle | Oxidizes FAs for energy (esp. during fasting). |
Stearate (C18:0) → Oleate (C18:1, Δ⁹) via Δ⁹-desaturase
fatty acid bio ox = IN MITOCOHONDRIA
fatty acid sunth = IN CYTOPLASM
Elongated → using elongase enzymes (adds 2C units)
Desaturated → using desaturase enzymes to insert cis double bonds at specific positions (like Δ⁹, Δ⁶, Δ⁵)
INSULIN AND GLUCAGON REGULATE
28 - PHOSPHOLIPIDS
DE NOVO SYNTH: STARTS WITH DHAP ALMOST IDENTAICAL TILL DAG 3P
P1 = GLYC AND FA IN 1ST PLACE
G AND FA IN 2ND PLACE
C = GLYCEROL AND PHOSPHORIC ACID
ALCOHOL AND PHOSPHORIC ACID
Sphingolipidoses
LYSOSOME STORAGE DISORDER, DEFECTS IN ENZYMES,CUSES ACUCULATION
eg niemman pick → built up o sphynigomyelin, bc of def of sph = myelinase. CHERRY RED SPOT AND FOAM CELLS
29 =
nsaid = ncs = N and c
NSAID = CYCLO OX (COX 1 AND 2)= INHIBITED. THEREFORE JUST PROSTAGLANDINS DECREASE
said = lipox
inhibits phospholipase 2, reduces prostaglandins and leukortienes
BLOOD PRESSURE REGULATION:
Prostacyclin (PGI₂) → vasodilation, inhibits platelets
Thromboxane A₂ (TXA₂) → vasoconstriction, promotes platelets
MAIN REGULATION:
PLIPASE 2 = key ENZYME FOR BOTH, BUT COX IS MAIN ENZYME FOR COX, LOX IS MAIN ENZYME FOR LOX (they convert arachidonic acid into each of the enzyme)
ADRENALINE ACTIVTOR FOR PLIPASE A2
CORITOSTEROIDS = INHIBITOR FOR PLIPASE 2
but inhibitor for COX = nsaid
Feature | SAIDs (Steroids) | NSAIDs |
---|---|---|
Inhibit | Phospholipase A2 | COX-1 and COX-2 |
Effect | ↓ Prostaglandins & leukotrienes | ↓ Prostaglandins |
Examples | Cortisol, Prednisone | Ibuprofen, Aspirin, Naproxen |
Action Level | Upstream (broad anti-inflammatory) | Downstream (specific to prostaglandins) |
30 - cholesterol
HMG COA REDUCTASE!!!!! IS REG ENZYME
reverse compettive inhibition through statins
long term an short term inhibitors:
include cholesterol moving stuff
REVERSIBLE COVALENT MODIFICATION = ACTIVE IN DEPHOSPH FORM
reversible competitive inhibition = statsin
include transport;!!!!!!!
31 - chol derivatives
FORGOT:
LOCALISATION OF EACH
bile acids = primary in liver, seconary in intestine
7a hydroxylase = main enzyme
function: INHIBIT CHOL SYNTH VIA INHIB O HMG COA REDUCTASAE
inhib: bile acids
activators: cholesterol
steoird hormone:
4 fused rings, cyclophenthanjsfgsd nucelus
REGULATION: DESMOLASE P450
vit d3:
skin, liver, kidney
substrate = 7dehydrocholesterol
32
transaminase =transamination is when an amine group is transferred from an amino acid to a keto acid forming a new keto acid and new amino acid
oxidative deamination: It is the removal of an amino (–NH₂) group from an amino acid, usually glutamate,
The amino group is replaced with a keto group, forming α-ketoglutarate.
The released ammonia (NH₃) enters the urea cycle for excretion.
Catalyzed by glutamate dehydrogenase
Occurs mainly in the liver mitochondria
decarboxylation: removal of carboxyl group, released as co2
biogenic amines: hisitidine, forms histamine → allergic
TRANSDEAMINAITON:
Transamination
Amino group from an amino acid is transferred to α-ketoglutarate, forming glutamate
Catalyzed by aminotransferases
Oxidative Deamination
Glutamate is then deaminated by glutamate dehydrogenase
Produces ammonia (NH₃) and α-ketoglutarate (which can be reused
33 -
REDUCTIVE AMINATION OF AKG:
AKG + NH2 + NADPH → GLUTAMATE
emzyme = glutamate dehyrogenase
adds ammonia to a keto acid forming amino acid
important for amino acid biosynth
GLUTAMINE SYNTH:
glutamate + nh2 + atp =. glutamate
glutamine synthetase
glutamine =non toxic ammonica carrier, carries it to kidneys to be extreted
AMMONIOGENESIS IN KIDNEYS:
GLUTAMINE in prox tubules is borken down to give nh3
binds w h+ in urine, forms ammonia HWIHCH IS EXCRETED
MAINTAINS ACID BASE BALANCE
urea cycle:
Ammonia + CO₂ → Carbamoyl phosphate
Citrulline → Argininosuccinate → Arginine → Urea + Ornithine
REGULATION: CP1 = RATE LIMITING, NAG activates
deficinecy:
CP1, REDICED C PHOSPH SNTHETASE 1, LEADS TO HYPERAMMONIA TYP1 , AND VOMITING, CEREBREAL EDEMA
GLUCOSE ALANINE: exetes nitrogen from muscles, presents c skeleton of muscles to liver for glucose prof
35
ONE CARBON RESIDUES ARE:
eg co2 for carboxylation
or formyl for purine ring forming
used for synthesis of serine and methionine
synthesis of TMP from dUMP - further in DNA synth
synthesis of pruine nucleotides - further in DNA and DNA synthesis
SAM:
PHOSPHLIPD METABOLISM
dna/rna methylation
neurotransmitter sunthsesis
FOLIC ACID:
ACTIVE FORM, amino acid metab, carries one carbon unit, METHYLATES VIT 12
PURINE AND THYMIDINE SYNTHESIS
VIT B12:
ACCEPTS VIT B12
remethylates homocysteine forming METHINONINE
convert methyl malonul coa to succinyl coa
36 -
creatnie phosphate:
ARGININE, GLYCINE, SAM
L- ARGININE = precursor for polyaminesL spremidine and spermine = for ribosome formataion
cationic compound used to bind RNA AND DNA
phospholipids:
1. Ethanolamine & Choline (from serine):
Serine → Ethanolamine (via decarboxylation)
Ethanolamine → Choline (after methylation by SAM)
SPINGOLOPIDS:
SERINE + PALTMIOYL COA = soinhgosine
spingospine + FA = ceramide etc (head fgroup_
MELATONIN:
OBTAINED BY METHYLATION OF SEROTIN (also serotinin = PLATELET AGGREGATION + SMOOTH MUSCLE CONTRCT)
glutamate: OX DEAM:
removal of amine group, replaced with keto group, ammonia recycled into urea cycle
glutathione:
antioxidant, detoxifies xenobiotics, donor of H+ in reductive reactions, transport amino acids
creatine phosphate:
made by
Arginine
Glycine
S-adenosylmethionine (SAM)
using creatine kinasae.
role = energy reserve in muscles
citruline: (used for) nitrogen metabolism, especially in the urea cycle
arginine + NO synthase is required
NO is byproduct of the reaction + seconary messenger
leads to vasodilation of BV
a gas that diffuses through the membranes and reaches the smooth muscle
42 -
✅ Connection Between Lipid and Carbohydrate Metabolism – Corrected Explanation
β-Oxidation of Fatty Acids
Fatty acids are broken down via β-oxidation in the mitochondria.
This produces acetyl-CoA, NADH, and FADH₂.
Acetyl-CoA enters the Krebs cycle, generating ATP.
The ATP and NADH produced support gluconeogenesis (even though acetyl-CoA itself can’t become glucose).
Acetyl-CoA does not contribute carbon to gluconeogenesis
Instead, it activates pyruvate carboxylase, promoting gluconeogenesis from pyruvate, lactate, glycerol, or amino acids.
Excess Carbohydrate → Lipid Synthesis
Glucose → pyruvate (via glycolysis)
Pyruvate → acetyl-CoA (via pyruvate dehydrogenase in mitochondria)
Acetyl-CoA can’t cross the mitochondrial membrane directly, so:
Citrate Shuttle (not "saturated shuttle")
Acetyl-CoA combines with oxaloacetate → citrate
Citrate is transported to the cytosol
In the cytosol, ATP-citrate lyase converts citrate → acetyl-CoA + oxaloacetate
Now, cytosolic acetyl-CoA is used for fatty acid synthesis
beta ox of fatty acids: D,H,D,T ( AH, THE KILLER) (fadh2, h20, nadh2, thiolase)
(My kangaroo has three arms = FA SYNTH)
COASH + H20, NADHPH TO NADP, H20, NADPH + NADP
proteins: metabolism to amino acids
amine groups are removed from glutamate, replaced with ketone, forming ammonia to be recycled into urea cycle
47 - signal transduction
intracellular signalling = simple (ligand binds to receptor) etc
intercellular = chemical synapse thingy.\
RECEPTORS:
warer so;uble/lipid soluble
A lipid-soluble hormone (e.g., steroid or thyroid hormone) diffuses across the cell membrane.
It binds to an intracellular receptor, forming a hormone-receptor complex.
This complex enters the nucleus and binds to specific DNA sequences (hormone response elements).
It acts as a transcription factor, modifying gene expression.
This leads to the production of new proteins, which bring about specific cellular responses.
✅ Protein Kinases
Enzymes that add phosphate groups (phosphorylate) to proteins, usually on serine, threonine, or tyrosine residues.
This often activates or deactivates the target protein, altering its function or activity.
Example: Protein kinase A (PKA) activated by cAMP.
✅ Protein Phosphatases
Enzymes that remove phosphate groups (dephosphorylate) from proteins.
Oppose the action of kinases; help turn off signals or return proteins to baseline activity.
Example: Protein phosphatase 1 in glycogen metabolism.
✅ G-binding Proteins (G-proteins)
Act as molecular switches in signal transduction.
Bind GTP (active) and GDP (inactive) forms.
Involved in transmitting signals from GPCRs (G-protein-coupled receptors) to enzymes like adenylyl cyclase or phospholipase C.
🧠 In summary:
Kinases = add phosphate → modify activity
Phosphatases = remove phosphate → reverse effect
G-proteins = switch proteins that relay signals inside the cell
__________
Amplification: One signal activates many downstream molecules → bigger response.
Convergence: Different signals activate the same pathway or target.
Divergence: One signal activates multiple pathways or targets.
Integration: Multiple signals are combined and processed into a single response.
Crosstalk: One signaling pathway affects or interferes with another.
48 -
synapses
g protein coupled receptors yk (Used by water-soluble molecules (e.g., adrenaline, glucagon), which cannot cross the membrane.
The ligand binds to an extracellular domain of the GPCR, causing a conformational change.
This activates the G-protein, which transmits the signal to effectors like adenylyl cyclase.
Adenylyl cyclase converts ATP to cAMP → cAMP activates protein kinase A (PKA).
PKA phosphorylates target proteins (often on serine or threonine residues), leading to specific cellular responses.)
enzyme linked with activity:
3. Enzyme-Linked Receptors / Receptors with Intrinsic or Associated Enzyme Activity
Ligand binding directly activates enzyme activity of the receptor (e.g., receptor tyrosine kinases) or of an associated protein.
Leads to phosphorylation cascades, commonly involved in growth, metabolism, and cell division.
Example: Insulin receptor (has intrinsic tyrosine kinase activity).
ALL THE SECONDARY MESSENGERS:
ypes of Second Messengers (Mediators)
cAMP (cyclic AMP)
Activates protein kinase A (PKA).
PKA phosphorylates various proteins, leading to diverse cellular responses like metabolism regulation.
Nitric Oxide (NO)
A gaseous signaling molecule.
Causes vasodilation by relaxing smooth muscle.
Activates guanylyl cyclase, increasing cGMP levels inside cells.
cGMP (cyclic GMP)
Generated by guanylyl cyclase activation (often by NO).
Activates protein kinase G (PKG).
Involved in smooth muscle relaxation and other signaling pathways.
IP3 (Inositol Triphosphate)
Produced by cleavage of PIP2 by phospholipase C.
Releases Ca²⁺ from intracellular stores (endoplasmic reticulum).
DAG (Diacylglycerol)
Also produced from PIP2 cleavage by phospholipase C.
Activates protein kinase C (PKC), which phosphorylates target proteins.
Calcium (Ca²⁺)
Acts as a universal second messenger.
Binds to calmodulin, forming a complex that activates enzymes like myosin light chain kinase (MLCK).
Important in smooth muscle contraction and many other processes.
Calmodulin
A calcium-binding protein that transduces the calcium signal by activating target enzymes.
PIP3 (Phosphatidylinositol Triphosphate)
Generated by phosphorylation of PIP2 by PI3 kinase.
Recruits and activates signaling proteins like AKT (protein kinase B), involved in cell growth and survival.
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49 -
put your classification
mechanism of action
regulation
Mediators are substances that act locally (usually near where they are produced
Common Types of Mediators
Eicosanoids: (also a lipid-soluble hormone type)
Prostaglandins
Leukotrienes
Thromboxanes
They are involved in inflammation, pain, fever, and blood clotting.
Cytokines:
Small proteins involved in immune responses.
Examples: Interleukins, interferons, tumor necrosis factors.
Nitric Oxide (NO):
A gaseous mediator.
Acts as a vasodilator and neurotransmitter.
SYNTHEISS AND DEGRADATION:
Catecholamines (like adrenaline) are synthesized from amino acid precursors (like tyrosine).
Degradation:
Water-soluble hormones are usually degraded by enzymes in blood or target tissues and cleared by kidneys/liver.
Lipid-soluble hormones are metabolized primarily in the liver and excreted in bile or urine.
50 - hormones of hypothalamus and pituitry
you know EVERYTHING:
only thing is mechanism of action: ANTERIOR:
CRH → binds pituitary corticotrophs → stimulates ACTH release → ACTH binds adrenal cortex receptors → activates cAMP → cortisol synthesis.
Mechanism of Action: oF POSTERIOR PITUARITRY GLAND
Both hormones bind to GPCRs on target cells.
Oxytocin → increases intracellular Ca²⁺ in uterine muscle cells → contraction.
ADH → activates cAMP → insertion of aquaporin channels in kidney → water retention.
51 -
everything you know
steroids = androstene/dhap from zona reticularis
testosterone/esterogen from ovarys
mechanism of action = just lipid soluble ones
52 - water
Renin release:
Juxtaglomerular cells in the kidney secrete renin into the bloodstream.
Angiotensinogen conversion:
Renin cleaves angiotensinogen (produced by the liver) → angiotensin I.
Formation of angiotensin II:
Angiotensin I is converted to angiotensin II by angiotensin-converting enzyme (ACE), primarily in the lungs (not hypothalamus).
Effects of angiotensin II:
Potent vasoconstrictor, increasing blood pressure.
Stimulates secretion of aldosterone from the adrenal cortex (zona glomerulosa).
Stimulates release of ADH (vasopressin) from the posterior pituitary.
Stimulates thirst center in the hypothalamus.
Aldosterone action:
Acts on the distal convoluted tubule and collecting duct in the kidney.
Increases sodium reabsorption (and water follows osmotically).
NAP:
Produced by the heart (atrial natriuretic peptide - ANP) and ventricles (brain natriuretic peptide - BNP).
Released in response to increased atrial stretch (high blood volume).
Actions:
Promote vasodilation.
Inhibit renin, aldosterone, and ADH secretion.
Increase sodium and water excretion by kidneys (natriuresis and diuresis).
Overall effect: reduce blood volume and pressure.
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INSULIN:
GLUCOSE UPTAKE INC VIA GLUT 4
stimulates lipgenesis and tag formation (draw tag synth)
acetyl coa carboxylase is ACTIVATEDM forming more malonyl coa, which inhibits beta ox, meaning less acetyl coa SO KETOGENESIS IS INHIBITED (provides alternative fuel for brian via degredation of acetyl coa, stimulated when glucose is LOW)
less krebs cycle = less atp for GNG
stimualtes glycogenesis (formation of glycogen) -
INHIBTIS GNG
stimulates glycolysis
opposite for glucagon:
Glucagon promotes lipolysis → increases free fatty acids.
Inhibits acetyl-CoA carboxylase → lowers malonyl-CoA → enhances β-oxidation.
Increased acetyl-CoA → supports ATP production and ketone body synthesis.
These processes provide energy during fasting/low glucose and help maintain glucose homeostasis.
somatostatin:
🧠 Hypothalamus
Secreted by hypothalamic neurons.
Inhibits growth hormone (GH) release from the anterior pituitary.
Also inhibits TSH to some extent.
and pancreatic polypeptide
mechanism of action:
GLUCAGON:
binds to GPCR, G PROTEIN ACTIVATED, ACTIVATEDS ADNELYL CYCLASE, THEREFORE CAMP, THEREFORE PKA, ACTIVATES GLYCOGEN PHOPSHYRLASE AND INHIBTS GLYCOGEN SYNTHASE
insulin:
Insulin binds to its extracellular receptor, activating the receptor’s intrinsic tyrosine kinase activity. This leads to autophosphorylation of the receptor and phosphorylation of insulin receptor substrates (IRS). The activated IRS triggers downstream signaling pathways that stimulate glycogen synthesis (glycogenesis), glucose uptake, protein synthesis, and lipid synthesis.
54
pre cholinergic symp fibres
55 -
Types of Diabetes Mellitus
Type I Diabetes Mellitus (T1DM)
Autoimmune destruction of pancreatic β-cells → absolute insulin deficiency.
Onset usually in childhood/adolescence.
Requires lifelong insulin therapy.
Type II Diabetes Mellitus (T2DM)
Combination of insulin resistance and relative insulin deficiency.
Strong link to obesity, sedentary lifestyle, and genetics.
Managed by lifestyle, oral hypoglycemics, sometimes insulin.
🔬 Metabolic Disorders in Diabetes
Carbohydrate metabolism:
↓ Glucose uptake in tissues → hyperglycemia
↑ Gluconeogenesis and glycogenolysis (especially in T1DM)
Lipid metabolism:
↑ Lipolysis → ↑ free fatty acids → ketogenesis (especially in T1DM)
Risk of diabetic ketoacidosis (DKA)
Protein metabolism:
↑ Proteolysis → muscle wasting
Impaired protein synthesis
🚨 Symptoms of Diabetes
Classic triad:
Polyuria (frequent urination)
Polydipsia (increased thirst)
Polyphagia (increased hunger)
Weight loss (T1DM), fatigue, blurred vision
⚠ Complications of Chronic Hyperglycemia 1. Oxidative Stress
High glucose → overproduction of reactive oxygen species (ROS) in mitochondria.
Leads to cellular damage, inflammation, endothelial dysfunction.
Central in the development of complications (neuropathy, nephropathy, retinopathy).
2. Sorbitol Pathway
Excess glucose converted to sorbitol by aldose reductase.
Sorbitol accumulates in cells (esp. lens, nerves) → osmotic stress → cataracts, neuropathy.
3. Non-enzymatic Glycation – AGE & RAGE
Chronic hyperglycemia → spontaneous glycation of proteins → Advanced Glycation End-products (AGEs).
AGEs bind to RAGE receptors on cells → trigger inflammation, fibrosis, and vascular damage.
Key in microvascular and macrovascular complications.
4. DAG/PKC Pathway
High glucose increases diacylglycerol (DAG) → activates protein kinase C (PKC).
PKC affects blood flow, increases vascular permeability, inflammation, and thrombosis.
Promotes retinopathy, nephropathy, atherosclerosis.
🔬 1. Connective Tissue: Overview
Connective tissue supports and connects other tissues and organs. It consists of:
Cells
Extracellular matrix (ECM): made of fibers (proteins) and ground substance (GAGs + proteoglycans)
🧫 2. Cell Types in Connective Tissue
Fibroblasts: Main ECM-producing cells; synthesize collagen, elastin, GAGs, proteoglycans.
Macrophages: Phagocytic immune cells.
Mast cells: Release histamine and play a role in inflammation.
Adipocytes: Store fat.
Plasma cells and leukocytes: Immune defense.
🧱 3. Extracellular Matrix (ECM)
The ECM provides structural support, biochemical signals, and regulates cell behavior.
Components:
Fibrous proteins: Collagen, elastin, fibronectin, fibrillin
Ground substance: GAGs and proteoglycans
🧬 4. ECM Proteins: Structure & Function ✅ Collagen
Function: Provides tensile strength
Structure: Triple helix of three α-chains
Synthesis: In fibroblasts → pro-collagen → secretion → extracellular modification (cross-linking)
Types:
Type I: Bone, skin, tendon
Type II: Cartilage
Type III: Reticular fibers (skin, blood vessels)
Type IV: Basement membrane
✅ Elastin
Function: Elasticity to tissues (skin, lungs, arteries)
Structure: Hydrophobic, random coil protein; cross-linked via desmosine
Synthesized as tropoelastin, then cross-linked extracellularly.
✅ Fibronectin
Function: Cell adhesion, migration, wound healing
Structure: Dimer linked by disulfide bonds; contains RGD (Arg-Gly-Asp) sequence for integrin binding
✅ Fibrillin
Function: Forms microfibrils for elastin deposition; structural support
Important in Marfan syndrome (mutation in FBN1 gene)
🧪 5. Glycosaminoglycans (GAGs) Structure:
Long, unbranched polysaccharides
Composed of repeating disaccharide units (amino sugar + uronic sugar)
Highly negatively charged → attract water
Types and Functions:
GAG | Location | Function |
---|---|---|
Hyaluronic acid | Synovial fluid, ECM | Lubrication, space filler |
🧬 6. Proteoglycans Structure:
Core protein + covalently attached GAG chains
Highly hydrated → gel-like matrix
Functions:
ECM structure
Regulate molecule diffusion
Bind growth factors
Signal transduction
Examples:
Aggrecan (in cartilage)
Perlecan (in basement membranes)
🦴 1. Biochemical Composition of Bone
Bone is a specialized connective tissue composed of:
a) Organic Matrix (~30%)
Type I collagen (~90% of organic content): provides tensile strength
Non-collagen proteins: osteocalcin, osteonectin, osteopontin – involved in mineralization and cell signaling
b) Inorganic Matrix (~70%)
Hydroxyapatite crystals:₂
Provides rigidity and hardness
Contains calcium, phosphate, magnesium, fluoride
🔬 2. Molecular Organization
Osteoblasts: Build bone; secrete osteoid (unmineralized matrix)
Osteocytes: Mature bone cells; maintain bone matrix
Osteoclasts: Resorb bone; multinucleated cells that secrete acids and enzymes
🔁 3. Bone Metabolism
Bone is constantly remodeled through:
Bone formation by osteoblasts
Bone resorption by osteoclasts
Key processes:
Collagen synthesis (procollagen → tropocollagen → fibrils)
Mineral deposition into the collagen matrix
Matrix degradation during bone resorption (enzymatic and acidic)
🧪 4. Bone Mineralization – Main Mechanisms
Initiated by osteoblasts
Secretion of alkaline phosphatase (ALP) → increases local phosphate levels
Calcium and phosphate ions crystallize to form hydroxyapatite
Matrix vesicles serve as initial sites for crystal nucleation
58 -
1. Biochemistry of Blood
Blood is a specialized connective tissue composed of:
Plasma (fluid matrix): ~55% of blood volume, containing proteins (albumin, globulins, fibrinogen), electrolytes, nutrients, hormones, and waste products.
Formed elements (~45%): Red blood cells (RBCs), white blood cells (WBCs), and platelets.
2. Types of Blood Cells
Red Blood Cells (Erythrocytes)
White Blood Cells (Leukocytes):
Granulocytes: Neutrophils, Eosinophils, Basophils
Agranulocytes: Lymphocytes, Monocytes
Platelets (Thrombocytes)
3. Red Blood Cells (RBCs / Erythrocytes) Characteristic Features
Biconcave, anucleate cells specialized for oxygen transport via hemoglobin (Hb).
Lifespan: ~120 days.
Lack mitochondria: rely entirely on anaerobic glycolysis for ATP production.
"CO₂ is transported in the blood mainly as bicarbonate (via carbonic anhydrase), and some CO₂ also binds directly to hemoglobin to form carbaminohemoglobin."
Metabolic Pathways in RBCs
Glycolysis (Embden-Meyerhof pathway) – main ATP source.
Pentose Phosphate Pathway (PPP) – produces NADPH, essential for reducing glutathione, protecting RBCs from oxidative damage.
Enzymopathies
Inherited enzyme deficiencies affecting RBC metabolism:
G6PD deficiency (PPP): ↓NADPH → oxidative stress → hemolysis.
Hexokinase deficiency: rare, affects glycolysis initiation.
Anemias
Hemolytic anemia: due to RBC destruction (e.g., enzymopathies, sickle cell anemia).
Iron-deficiency anemia: ↓Hb synthesis.
Megaloblastic anemia: due to folate/B12 deficiency.
4. White Blood Cells (Leukocytes) Types & Roles
Type | Category | Function |
---|---|---|
Neutrophils | Granulocyte | Phagocytosis, first responders to infection |
Eosinophils | Granulocyte | Defense against parasites, allergy mediator |
Basophils | Granulocyte | Release histamine in allergic reactions |
Lymphocytes | Agranulocyte | T cells (cell-mediated immunity), B cells (antibody production) |
Monocytes | Agranulocyte | Become macrophages; phagocytosis, antigen presentation |
Metabolic Features
Unlike RBCs, WBCs have nuclei and mitochondria.
Use both aerobic and anaerobic metabolism.
Neutrophils rely more on glycolysis and PPP for ROS generation (via NADPH oxidase).
Lymphocytes show increased metabolic activity upon activation (e.g., glycolysis and oxidative phosphorylation).
5. Phagocytosis (Brief)
A key immune process primarily carried out by:
Neutrophils
Monocytes/macrophages
Steps in Phagocytosis
Recognition of pathogens via surface receptors (e.g., Fc, complement receptors).
Engulfment forming a phagosome.
Fusion with lysosome → phagolysosome.
Killing and digestion via:
Reactive oxygen species (ROS) – generated by NADPH oxidase (respiratory burst).
Hydrolytic enzymes – degrade engulfed particles.
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whole cascade + plasma proteins + firbonylyisis
Vitamin K is essential for the γ-carboxylation of glutamate residues in clotting factors II, VII, IX, X, and proteins C and S. This modification allows these proteins to bind calcium ions, which is necessary for their activation and function in the coagulation cascade.
61-
GNG - carb
fatty synth - lipid
proteins: deamination
extretory function:
bile - functiosn
specific products:
albumin, clotting factors
ketone
✅ Corrected Brief Definition:
Oxidative deamination is the process by which the amine group (-NH₂) is removed from glutamate, forming a keto acid (α-ketoglutarate) and free ammonia (NH₃). This reaction is catalyzed by the enzyme glutamate dehydrogenase, primarily in the liver.
. Biotransformation of Xenobiotics
Phase I: Modification (oxidation, reduction, hydrolysis) mainly by cytochrome P450 enzymes.
Phase II: Conjugation (glucuronidation, sulfation, etc.) to increase solubility for excretion.
5. Ethanol Metabolism
Occurs mainly in the liver:
Alcohol dehydrogenase: Ethanol → Acetaldehyde
Aldehyde dehydrogenase: Acetaldehyde → Acetate
Produces NADH, which can disrupt normal metabolism (e.g., fatty liver, lactic acidosis).