Samenvatting
Summary Summery lectures Medical biochemistry of BMS year 2 (23-24)
- Instelling
- Vrije Universiteit Amsterdam (VU)
Summery of all the lectures of Medical biochemistry of BMS year 2 (23-24).
[Meer zien]Voorbeeld 4 van de 67 pagina's
Voorbeeld 4 van de 67 pagina's
In winkelwagengesponsord bericht van onze partner
Verkoper
VolgenVoorbeeld van de inhoud
HC 1: Intro & Overview of human metabolismCarbohydrates à most important fuel for the body à glucose
Proteins à amino acids (long chains are called peptides or proteins)
Fat/triglycerides à composed of glycerol molecule and 3 fatty acids coupled to it
- Palmitate
- Oleate
- Stearate
Glycolysis is the central pathway in human metabolism à carbohydrates, lipids, amino acids,
DNA/RNA
Big three
- Glucose 6 phosphate: Ribose 5 phosphate (DNA), Pyruvate, Glycogen
- Pyruvate: Lactate, Alanine (amino acid), Acetyl coA, oxaloacetate (à glucose 6
phosphate à pyruvate)
- Acetyl CoA: Fatty Acids, 3 hydroxy 3 methyl glutaryl coa (cholesterol or ketone bodies)
Major fates of fuels in the fed state
- Glucose à Energy (Oxidation), glycogen/TG (storage), many compounds (synthesis)
- Amino acids à protein synthesis, energy (oxidation), synthesis of nitrogen-containing
compounds
- Fats à TG (storage), membrane lipids (synthesis), energy (oxidation)
Free energy carriers: ATP, GTP, NADPH, FADH
- ATP: major energy carrier à (hydrolysis) ADP + Pi (continuous cycle)
- TCA cycle and ATP generation à in mitochondria
o 2 carbons of Acetyl Coa released as CO2
o Hydrogens releases as H2O
- Other pathways in cytoplasm (glycolysis)
- Liver: central factory
- Many tissues have their own tissue metabolism
Regulation OXPHOS and ATPase
- ATP synthase uses energy from proton gradient to produce ATP
- When all ADP has been converted to ATP the enzyme stops
- No regeneration of NAD+
- Regulation TCA: without NAD+ this reaction and the TCA cycle cannot proceed
When OXPHOS stops recycling NADH: TCA will also stop
à NADH is a negative factor for OXPHOS
à ADP is a stimulator
When there is sufficient ATP: excess Acetyl CoA is converted to fat
Excess dietary fuel à (fed) Fuel stores: fat, glycogen, protein à (fasting) oxidation à energy
Excess glucose converted to fat: glucose à pyruvate à acetylcoa à citrate à acetylcoa à
malonyl coa à FA à palmitate
Fatty acids cannot pass the myelin sheets in the brain à brain cannot use FAs
, - Fatty acids à Acetyl CoA à Ketone bodies (brain can use this as fuel), but this will only
happen after a couple of days of starvation
Nitrogen excretion during fasting
- Urea excretion will increase when fasting à proteins are used as fuel
- After more days à ketone bodies are made and then the urea excretion will drop
again
o B-hydroxybutyrate
o Acetoacetate
,HC 2: Carbohydrate and glucose metabolism
Brain requires glucose! à first priority, most of the glucose goes to the brain (75%)
Storage as glycogen à 190 gram (liver)
During fasting all glucose stores are finished within 1 day
Brain neuronal cells have no beta cells
Stereo-isomers à different enzymes also needed for these different isomers (3D difference)
- D-glucose
o Beta-D-glucose
o Beta-L-glucose à cannot be metabolized
- D-mannose
- D-galactose
Dietary sources of carbohydrates
- Starch, plants à amylose and amylopectin
- Dairy (milk products) à lactose (galactose + glucose)
- Every processed food in Western society à sucrose (glucose + fructose)
Amylase is beginning in the mouth à as soon as possible to get as much glucose directly to
the brain
Fibers à a kind of carbohydrate that we cannot digest
- Intestines can use it to promote normal digestion
Uptake by facilitated transport
- Passive diffusion (through concentration gradient) à simple diffusion or facilitative
diffusion
- Active transport (against the concentration gradient) à energy is needed
Lactose intolerance: intestinal problems
- Lack enzyme (lactase) to break the bond between galactose and glucose
- Cannot digest the lactose sugar
- Bacteria can digest à so sugar that is not digested, will be used by bacteria à diarrhea
- Western world less people are lactose intolerant
Galactosemia: very serious disease (no relation to lactose intolerance)
- No intestinal problems, but liver
- Galactose à galactose 1-phospase (non classical) or galactose-1-phosphate à glucose
1-phosphate cannot occur
- Traps all the phosphate in the body (galactose 1-phosphate, galactose an galactitol
increase)
- Management: elimination of galactose (milk and dairy products)
Fructosemia
- Lack enzyme fructokinase (not severe) or dihydroxyacetone-P (severe)
- Remedy à do not eat any fruits
, Glycogen: storage unit of glucose
- You can degrade it very fast, that’s why it is all bonded to each other (also takes up
less space)
- Liver: key function in glucose storage for blood glucose homeostasis in between
meals or during fasting
- Muscle: glycogen is main glucose source during exercise
- Glucose-6-phosphatase à leads to the making of glucose back to the blood
- Synthesis: glucose à glucose-6-P à glucose-1-P à glycogen
(à glycogen synthase, ß glycogen phosphorylase)
o Glucose-6-P can go to glycolysis, PPP and other pathways
- Glycogensynthese: will add branches on glycogen
- Glycogen phosphorylase: chops off at any free ends the different glucose molecules
until reached 4 …
- It is branched because it can increase the speed of synthesis, many more sites to
react
- Regulation
o Muscle: insulin (storage), epinephrine (via PKA) and activity (via CA2+)
(exercise), not responsive to glucagon!
o Liver: insulin (storage), glucagon (fasting), epinephrine (via PKA,
exercise/stress)
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper lilingho. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €7,49. Je zit daarna nergens aan vast.
Is Stuvia te vertrouwen?
4,6 sterren op Google & Trustpilot (+1000 reviews)
Afgelopen 30 dagen zijn er 75759 samenvattingen verkocht
Opgericht in 2010, al 14 jaar dé plek om samenvattingen te kopen