Metabolism And Lipid Membranes Flashcards
What is Kwaashiorkor?
Condition that is characterized by protein deficiency.
Symptoms include Edema, Fatty lover, muscle wasting, skin lesions, hypoptoteinemia (obv)
What is the end process that all macronutrients enter to produce ATP?
All Become Acetyl Coa —> TCA
What are the three “hubs” of metabolic systems?
- Glucose-6-Phosphate
- Pyruvate
- Acetyl-CoA
Besides glycolysis, what other pathways use G6P?
- Converted to G1P to become glycogen
- Forms precursors for pentose phosphate pathway to form nucleotides and NADP
What is Von Gierke Disease?
Type I GSD
- Autosomal recessive
- deficiency of Glucose-6-phosphatase
- Have fasting hypoglycemia and accumulation of glycogen, siezures, hepatomegaly, hypertiglyceridemia
- Lactic Acidosis: Impairment of gluconeogenesis leads to accumulation of Pyruvate which impairs conversion of lactate
- Build up of Lactic acid competes with Uric Acid —> Gout
How is pyruvate generated from different metabolic pathways?
- Muscle cell fermentation through Cory cycle from lactate in Liver
- Deamination/transamination to/from alanine (gluconeogenesis)
- Pyruvate to Acetyl-CoA
What are the two main sources of Acetyl-CoA?
Pyruvate and Fatty Acids
What metabolic pathways are connected to acetyl-CoA?
- Ketone Bodies are converted to Acetyl-CoA in brain and Cholesterol
- Acetyl-CoA is made from amino acids produced from G6P
*** Acetyl-CoA cannot make Pyruvate!
What may be produced from FAs?
- Full Oxidized to CO2/H2O
- Serve as precursors of cholesterol and steroids
- Transformed to ketone bodies
What can happen to the Carbon skeleton after AA transamination?
- Become fully oxidized
- Used in gluconeogenesis
- Form ketone bodies or Acetyl-Coa for FA synthesis
How does stress and the CNS affect metabolism?
- Adrenaline activates Liver (similar to glucagon)
- Adrenaline activates muscle -> Glycogen production of G1P -> G6P -> ATP
What part of the brain is involved in the anorexigenic affect of acute stress?
Hypothalamic-pituitary-adrenal axis
What are the major metabolic affects of stress?
- Increase in Glucagon
- INC Cortisol -> Gluconeogenesis and FA mobilization
- INC EP/NE
- Hyperglycemia and insulin resistance
- Catabolism of skeletal muscle and inflammation
- Reliance on proteins for source of glucose
What percent of the pancreases are islets of langerhans?
1-2%
What cell make up the islets of langerhans?
Beta - Insuln Alpha - Glucagon Delta - Somatostatin Gamma - Pancreatic polypeptide Epsilon - ghrelin
What affect does glycogen have in the liver?
Inhibits glycogen synthase
What are the main affects of glucagon across the body?
- Activates glycogen phosphorylase
- Activate lipid catabolism
- activate AA catabolism
What process allows G6P to leave the Liver?
Glucose-6-phosphatase hydrolyzes it to glucose which can leave
What are the fat-soluble vitamins?
VitamiNs A K E D
How do normal capillaries differ from ones in the BBB?
- No fenestrae
- BBB capillaries are surrounded by astrocytes and pericytes
- Contain Tight junctions, so only H2O, CO2, and O2 can pass freely
What is the MCT1?
Transporter of Monocarboxylic acids
what are the main transporters in the BBB?
- GLUT1
- MCT1
- Essential AA transporters
*nonessential are blocked from transport
What are the pathways that can result in brain damage from metabolic dysfunction?
Hypoglycemia -> INC MCT1 -> Slowing of energy supply —> DEC NT synthesis —> No ATP —> Brain damage
Hypoxia —> No O2 for ETC -> anaerobic fermentation. —> Dec in pH —> Brain damage
What is the skeletal muscle’s main source of energy during rest, moderate activity, and burst of heavy activity?
At Rest: Mainly FAs through Beta oxidation.
Moderate: Uses FAs and glucose from liver
Heavy: Uses FAs, Glucose, and Phosphcreatine
What advantage is there for muscle to use glycogen?
When the source is glycogen breakdown, there is a net gain of 3 ATP due to the lack of investment needed to produce G6P from glucose
How does cardiac muscle use of energy differ from skeletal muscle?
- Mainly uses FAs all the time
- Always needs O2 (No anaerobic Respiration)
- VERY sensitive to pH
Describe McArdle Disease.
- Type V GSD
- Inability to break down glycogen in muscle
- Deficiency of Glycogen phosphorylase
- Symptoms include exercise intolerance on initial start, however will get “Second wind phenomenon”
Describe Cory/Forbes Disease
- GSD Type III
- Autosomal recessive
- Deficiency in glycogen debranching enzyme alpha-1,6-glucosidase
- Symptoms include hepatomegaly and hypoglycemia
How does cytoplasmic calcium affect skeletal muscle?
Causes fusion of GLUT4 independent of Insulin
Where is the TCA located?
Mitochondria
Where do PPP and FA synthesis occur?
Cytosol
