INTRODUCTION TO INTEGRATIVE METABOLISM Flashcards
3 MAIN FUEL MOLECULES?
FATS, PROTEINS AND CARBOHYDRATES
HOW DO AMINO ACIDS PRODUCE ATP?
BY ENTERING THE CITRIC ACID CYCLE AT VARIOUS ENTRY POINTS OR BY BEING CONVERTED INTO PYRUVATE BEFOREHAND
WHAT MOLECULE IS AT THE CROSSROADS OF ALL PATHWAYS?
ACETYL CoA
WHAT IS THE NAME OF THE PROCESS THAT CREATES ATP AND WHAT DRIVES IT?
OXIDATIVE PHOSPHORYLATION
DRIVEN BY A PROTON GRADIENT THAT HAS BEEN CREATED BY THE OXIDATION OF NADH AND FADH2
WHAT ARE THE END PRODUCTS OF GLYCOLYSIS?
2 PYRUVATE MOLECULES, 2 NADH MOLECULES, 2 ATP MOLECULES
WHAT IS THE PDH COMPLEX?
PYRUVATE DEHYDROGENASE COMPLEX WHICH CONVERTS THE 2 PYRUVATE MOLECULES WHICH ARE PRODUCTS OF GLYCOLYSIS INTO 2 ACETYL CoA MOLECULES
WHAT PROVIDES THE FORCE FOR THE ATP SYNTHASE TO MAKE ATP FROM ADP?
THE PROTON GRADIENT WHICH RESULTED FROM OXIDATION OF NADH AND FADH2
WHERE DOES OXIDATIVE PHOSPHORYLATION TAKE PLACE?
INNER MITOCHONDRIAL MEMBRANE
NUMBER OF STEPS IN BETA OXIDATION?
4
WHY DON’T ALL CELLS USE LIPIDS AS FUEL?
- BECAUSE SOME LACK MITOCHONDRIA (ERYTHROCYTES, TISSUES OF THE EYE)
- LACK OF AVAILABILITY OR ACCESS (E.G. THE BLOOD-BRAIN BARRIER PREVENTS ACCESS OF LIPIDS TO CNS)
SOME CELLS OF WHICH ORGAN TISSUE LACK MITOCHONDRIA (APART FROM RBCs)?
EYES
HOW MUCH GLUCOSE DOES THE BRAIN CONSUME DAILY (g and kcals)?
120g, 420kcal
WHAT PERCENTAGE OF GLUCOSE UTILIZATION BY THE BODY IN RESTING STATE IS ACCOUNTED FOR BY THE BRAIN?
60%
WHAT PERCENTAGE OF TOTAL ENERGY EXPENDITURE IS DONE BY THE BRAIN?
20%
CAN MUSCLES USE ANYTHING APART FOR FATTY ACIDS AND GLUCOSE AS A FUEL?
KETONE BODIES
WHAT PERCENTAGE OF MUSCLE MASS IS ITS GLYCOGEN STORAGE?
1%
WHAT PERCENTAGE OF LIVER MASS IS ITS GLYCOGEN STORAGE?
6%
HOW MUCH OF ALL GLYCOGEN IN THE BODY IS STORED IN THE MUSCLE?
3/4
WHAT IS THE MAJOR FUEL USED BY SKELETAL MUSCLE AT REST?
FATTY ACIDS
MAJOR FUEL FOR SKELETAL MUSCLE RIGHT AFTER A MEAL?
GLUCOSE
PREFERRED SUBSTRATE IN ACTIVELY CONTRACTING SKELETAL MUSCLE?
GLUCOSE
CONSEQUENCES OF USING GLUCOSE AS A PREFERRED SUBSTRATE DURING MUSCLE CONTRACTION?
GLYCOLYSIS IS VERY RAPID AND WILL RAPIDLY OVERLOAD THE CAPACITY OF THE CITRIC ACID CYCLE TO DEAL WITH ACETYL CoA; TO DECREASE THE ACETYL CoA PRODUCTION, A LOT OF PYRUVATE FORMED FROM GLYCOLYSIS IS REDUCED TO LACTATE WHICH LEADS TO MUSCLE CRAMPS (BUT PART OF THE LACTATE WILL ALSO BE SENT TO THE LIVER FOR GLUCONEOGENESIS TO FURTHER SUSTAIN EXERCISE)
WHICH PRODUCT OF GLYCOLYSIS WILL CAUSE CRAMPS IN MUSCLES DURING EXERCISE?
LACTATE
DOES HEART MUSCLE HAVE GLYCOGEN RESERVES?
ESSENTIALLY NONE
WHAT IS THE MAIN SOURCE OF FUEL FOR THE HEART?
FATTY ACIDS
WHAT ARE POSSIBLE FUELS FOR THE HEART EXCEPT FOR FATTY ACIDS?
KETONE BODIES AND LACTATE
TYPICAL AMOUNT OF CALORIES STORED IN ADIPOSE TISSUE?
15 KG OF TRIGLYCERIDES; 135 000 kcal
OTHER NAME FOR TRIGLYCERIDES?
TRIACYLGLYCEROLS
DOES ADIPOSE TISSUE NEED GLUCOSE TO MAKE TRIGLYCERIDES AND WHY?
YES.
GLYCEROL IS NEEDED FOR THE PRODUCTION OF TRIGLYCERIDES AND GLYCEROL COMES FROM CONVERSION OF DHAP, ONE OF THE 2 TRIOSES FORMED DURING GLYCOLYSIS, SO THE ADIPOSE TISSUE DOES NEED GLUCOSE
WHICH FUEL IS LIVER’S MAIN SOURCE OF ENERGY?
FATTY ACIDS
ARE ALL CELLS ABLE TO TAKE UP AND UTILIZE GLUCOSE?
YES
WHICH GLUT IS PRESENT IN THE BRAIN AND RBCs?
GLUT 1
WHICH GLUT IS EXPRESSED IN NEURONS AND HOW DOES ITS AFFINITY TO GLUCOSE COMPARE TO THAT OF GLUT1?
GLUT 3, HAS EVEN HIGHER AFFINITY THAN GLUT 1
WHICH GLUT IS EXPRESSED IN THE LIVER?
GLUT2
WHERE IS GLUT 4 EXPRESSED?
INSULIN RESPONSIVE TISSUES LIKE ADIPOSE AND MUSCLE
CHARACTERISTICS OF GLUT FAMILY PROTEINS?
- PROTEIN CARRIERS THAT TRANSPORT GLUCOSE USING FACILITATED DIFFUSION
- DOESN’T REQUIRE ATP (ATP INDEPENDENT)
- UNIPORTS (ONLY TRANSPORT ONE KIND OF MOLECULE)
HOW MANY MEMBERS OF GLUTs ARE THERE?
18
CHARACTERISTICS OF SGLT FAMILY PROTEINS?
- SODIUM DEPENDENT
- SYMPORTS
- TRANSPORT GLUCOSE WITH SODIUM IN THE SAME DIRECTION
- SECONDARY ACTIVE TRANSPORT: REQUIRES Na/K GRADIENTS REQUIRE ATP TO BE GENERATED
HOW IS GLUT4 REGULATED BY INSULIN AND WHEN IS THIS IMPAIRED?
INSULIN INCREASES EXPRESSION OF GLUT 4 AND THUS INCREASES GLUCOSE UPTAKE, WHICH IS DEREGULATED IN INSULIN RESISTANCE LEADING TO HIGH BLOOD GLUCOSE LEVELS (HALLMARK OF T2D)
WHAT ARE THE PERIPHERAL TISSUES THAT ARE THE MOST INVOLVED IN METABOLISM REGULATION?
LIVER, ADIPOSE TISSUE, SKELETAL MUSCLE AND THE KIDNEYS
WHEN DOES SKELETAL MUSCLE PROVIDE GLUCOSE FOR OTHER ORGANS?
NEVER, THERE IS NO GLUCONEOGENESIS IN THE MUSCLE, THE GLUCOSE RELEASED IS ONLY USED BY THE MUSCLE
CAN GLUCEONEOGENESIS OCCUR IN MUSCLES?
NO
CAN MUSCLE STORE TRIGLYCERIDES AND WHEN?
YES, BUT INTRAMUSCULAR LIPIDS ARE HALLMARKS OF T2D AND NOT NORMAL AS THEY IMPAIR MUSCLE INSULIN RESPONSIVENESS
WHAT DOES ADIPOSE TISSUE USE GLUCOSE FOR?
- FOR ITS ATP PRODUCTION VIA GLYCOLYSIS
- TO MAKE TRIGLYCERIDES (BY UTILIZING DHAP WHICH IS CREATED DURING GLYCOLYSIS)
IS THERE ANY PLACE IN THE BODY WHERE TRIGLYCERIDES SHOULD BE STORED APART FROM THE ADIPOSE TISSUE?
NO
WHY IS GLUCONEOGENESIS ALSO REFERRED TO AS ‘DE NOVO SYNTHESIS OF GLUCOSE’?
BECAUSE IT USES ENDOGENOUS MOLECULES (NOT FROM DIET)
GLUCONEOGENESIS CAN OCCUR IN THE LIVER AND?
KIDNEYS
SUBSTRATES FOR GLUCONEOGENESIS:
GLYCEROL, AMINO ACIDS, PYRUVATE AND LACTATE
CAN LIVER SYNTHESISE TRIGLYCERIDES AND DO LIPOGENESIS?
YES
CAN SKELETAL MUSCLE DO LIPOGENESIS?
YES
WHAT ARE TRIGLYCERIDES INCORPORATED INTO IN LIVER LIPOGENESIS BEFORE BEING SECRETED TO AND MOVED TO ADIPOSE TISSUE?
VLDL
IS INSULIN ANABOLIC OR CATABOLIC HORMONE?
ANABOLIC
HOW DO LEVELS OF FATTY ACIDS IN THE BLOOD CHANGE DURING FASTING?
THEY ARE ELEVATED
MAX AMOUNT OF HRS HEAPTIC GLYCOGEN STORES WILL LAST?
18 HRS
