| Question | Answer |
| Glycosis | - process that cleaves and oxidizes glucose
-ultimate goal to produce ATP, pyruvate and NHDA
-happen in cytosol of all cell
-required for production of energy from glucose(ananerobic or aerobic cell) |
| What are the starting material for glycosis | Glucose, ADP, NAD+ |
| how does glucose enter the cell? | it is mediated by a facilitated transporter (GLUT) |
| Which cell has high affinity transporter with large amount of transporters on the cell surface? | RBC and Brain |
| Which cell or tissue has low affinity transporter and large amount on cell surface? | LIVER |
| Which cell or tissue has insulin sensitive transporters and little amount on cell surface? | Muscle and adipose tissue |
| which enzyme catalyze the process of converting glucose to glucose-6-phosphate | Hexokinase
different isoform (Liver ==> Glucokinase , hexokinase IV)
brain: hexokinase I |
| how does a cell trap glucose? | Glucose --> glucose - 6- phosphate
the phosphorylation of glucose result in product that is not able to cross the membrane |
| What is the name of hexokinase used by Liver | Glucokinase
we don't call it Hexokinase |
| Which tissue-specific hexokinase is upregulated by insulin? | Liver and muscle
brain hexokinase is not regulated by insulinas brain is highly depend on glucose |
| why liver hexokinase cant be inhibited by glucagon, but muscle hexokinase is not affected? | Muscle has no receptor for glucagon |
| 3 pathway that glucose-6-phosphate can proceed to | 1) glycolysis
2) glycogenesis
3) pentose phosphate pathyway |
| which enzyme catalyze following process
fructose 6-phosphate ==> fructose 1,6-biphosphate | Phosphofructokinase -1 (PFK --1) |
| activation and inhibition factor of PFK-1 | Activation factor: AMP
Inhibition factor: ATP |
| Which two products does fructose 1,6-biphosphate split into? | Dihydroxyacetone phosphate (DHAP)
Glyceraldehyde 3-phosphate |
| What enzyme catalyze the formation of pyruvate and from which molecules? | Phosphoenolpyruvate => pyruvate
enzyme: pyruvate kinase |
| Pyruvate kinase has tissue specific isoform. What upregulate and down regulate its function in liver and muscle | upregulated by Insulin (liver and muscle)
downregulated by Glucagon (Liver only) |
| what are the two product formed from Pyruvate | 1) Acetyl-coA (catalyzed by pyruvate dehydrogenase)
2) Lacate (catalyzed by Lactate dehydrogenase) |
| can NADH cross from cytoplasm to mitochondrion? | NO |
| What are the two ways to regenerate NAD+ | 1) donation of NADH e- to the electron transport chain with help of shuttle system (shift an H atom across the mitochondrial membrane)
2) Lactate dehydrogenase reaction : important to glycolysis in anaerobic tissue |
| where does the conversion of pyruvate to acetyl coA happen in cell?
is it a reversible or irreversible process? | It occurs in mitochondria and is irreversible process |
| What enzyme catalyze process of conversion of pyruvate to acetyl coA? | pyruvate dehydrogenase complex
(multisubunit enzyme complex) |
| What activate the activity of PDC? | Elevation of ADP and substrate(Pyruvate) and Calcium (exercising muscle)with sufficient O2 supply |
| What inhibit the activity of PDC? | elevation of ATP, CoA-acetyl, NADH and absence of O2 |
| what is the key rate limiting enzyme in TCA cycle? | Isocitrate dehydrogenase
activated by increasing ADP and Calcium
inihibited by increasing NADH |
| TCA Cycle | -required for all aerobic production of ATP form glucose
-required to generate ATP form ketons, fatty acid, alcohol and amino acid
-generate other intermediates for other pathway
-required vitamin derived cofactor |
| What vitamin derived cofactor is required by TCA cycle and PDC activity? | -) pantothenate
- biotin
-niacin
-thiamine
-ribioglavin |
| List the factors which will reduce aerobic metabolism | -nutritional deficiencies
-Ischemia/hypoxia |
| How can delpeted oxaloacetate be replenished? | It can replenish from Pyruvate with the help of pyruvate carboxylase. |
| What molecules can be broken down to acetyl-coA? | fatty acid, ketones, amino acid, alcohol
TCA cycle is a must to generate ATP from them |
| Pathway of TCA cycle | Pyruvate ==> Oxaloacetate=> citrate => isocitrate => alpha-ketoglutarote => succinyl coA => succinate => fumarate => malate => oxaloacetate |
| What kind of synthesis is associate with citrate | fatty acid syntheis |
| What kind of synthesis is associated with succinly CoA? | heme synthesis |
| What is the rate limiting process in TCA cycle? | citrate ==> alpha-ketoglutarate
(citrate dehydrogenase) |
| product of TCA Cycle | NADH, FADH2, CO2
(NADH and FADH2 are reoxidized through oxidative phosphorylation process) |
| where do we find acetyl CoA? | Mitochondrion
It is synthesized in mitochondrion but it cannot across the Mitochondrial membrane |
| What is the intermediate product if we want to convert acetyl CoA to fatty acid? | Citrate, so it can move out into cytosol where fatty acid synthesis occurs |
| list the 3 irreversible enzymes of glycolysis | 1) Hexokinase (glucokinase in liver)
2) Phosphofructokinase
3) Pyruvate kinase |
| Phosphofructokinase -2 (PFK-2) | It catalyze the conversion of frctose-6-phosphate to fructose-2,6-biphsophate which will activate the activity of PFK-1
(ENSURE ALL EXCESS FUEL GET STORED) |
| which enzyme promote the synthesis of glycagon | Glucagon synthase + branching enzyme |
| Which enzyme promote the degradation of glycagon | Glucogen phosphorylase + debranching enzyme |
| Glucose 6- phosphatase | -ONLY in Liver
-convert glucose 6-phosphate to glucose and export out of cell
muscle lack of this enzyme and cant transport glucose out of cell |
| Which transduction pathway does insulin associate with? | Tyrosine kinase receptor |
| Which transduction pathway does Glucagon and epinephrine associate with? | GPCR (G-protein coupled receptor) |
| pathway of glycagon synthesis from glucose 1-phosphate | glucose-1-phosphate ==> UDP-glucose ==> Glycogen
enzyme: glycogen synthase, branching enzyme) |
| Pathway of glycagon degradation in all cell | glycagon ==> glucose-1-phosphate
enzyme: glycogen phosphorylase, debranching enzyme |
| What activate glucogen synthase activity? | insulin |
| What inihibit glucogen synthase activity? | Glucagon (exception muscle)
epinephrine |
| What activate glucogen phosphorylase activity? | liver: Glucagon and epinephrine
muscle: epinephrine, AMP, Ca2+ |
| What inhibit glucogen phosphorylase activity? | Insulin |
| what factor determine glycogen degradation in muslce cell | 1) the need for ATP
2) whether or not the muscle is exercising (level of calcium) |
| slow twitch fiber vs fast twitch fiber | Slow twitch fiber has
-higher capacity for aerobic metabolism
-lots of mitochondrion and myoglobin
-resistant to fatigue
-more glycogen
-slower contraction speed
than fast twitch fiber |
| Myoglobin | one subunit, bind one oxygem molecules and help transport of oxygen in muscle cell
-it also serves as small O2 store |
| what type of muscle fiber does muscle involve in posture usually have? | Slow twitch fiber |
| What type of muscle fiber does muscle in leg has? | Fast twitch fiber |
| Cardiac muscle | higher aerobic metabolism and DOES NOT store much glycogen |
| What factor determine the degree of glycogenolysis in skeletal muscle? | The length of fast |
| the effect of ephinephrine and cortisol on skeletal muscle during prolonged fasting? | it increases skeletal muscle break down and conversion of amino acid to glucose |
| Creatine | -synthesized in kidney, complete in liver, take up by skeletal and cardiac muscle cell
-store energy in creatine phosphate form
-provide rapid energy supply to muscle |
| Myokinase | -enzyme express in muscle cell
-2ADP==> 1 ATP + 1 AMP |
| Which pathway is the primary way that skeletal muscle obtains its ATP at the onset of exercise | Anaerobic glycolysis |
| Anaerobic glycolysis | -generate ATP rapidly at the onset of exercise
-increase production of lactate
=a means of regnerating NAD+
= production of lactic acid contribute to muscle pain
=use as fuel source for other tissue |
| Cori Cycle | the cycling of lactate between anaerbic tissue and liver) when anaerobic glycolysis and gluconeogeneiss occur simultaneously |
| AST | -present high amount in skeltal and cardiac muscle
increase AST ==> Tissue damage |
| List isoform of Creatine kinase in brain, muscle and cardiac muscle | Brain; 2 B subunit (CK-BB_
Muslce; 2 M subunit (CK-MM)
Cardiac muscle: 1 M and 1 B subunit (CK-MB) |
| Rhabdomyolysis | -breakdow product of damaged muscle tissue release into blood stream
-increase in creatinine level |
| Myositis | inflammatrion of cell |
| what happen to the level of creatinine in a person with loss of muscle | Decrease level of creatinine |
