| Question |
Answer |
| Fructokinase is found where |
liver |
| Fructose metabolism pathway |
fructose (fructokinase) fructose-1-P (aldolase b) dihydroxyacetone-P + glyceraldehyde (triose kinase) glyceraldehyde-3-P |
| Fructokinase deficiency |
benign |
| Aldolase b defficiency |
hereditary, liver damage and failure, death, hypoglycemic; Pi is sequestered as fructose-1-P; treat by removing fructose |
| Fructose synthesis occurs where |
liver, seminal vesicles, ovaries |
| Fructose synthesis pathway |
glucose, sorbitol, fructose |
| Lactose synthesis pathway |
glucose1P, UDP-glucose, UDP-galactose, lactose |
| Galactose degradation pathway |
galactose (galactokinase) galactose1P (galactose1P uridylytransferase)glucose1P |
| Galactokinase deficiency |
galactose in blood and urine, cataracts |
| Uridyl transferase deficiency |
galactose in blood and urine, cataracts, dysfunction of liver, kidney, spleen, intestine, and brain, DEATH |
| UDP glucose is used in what |
glycogen, proteoglycans, lactose synthesis |
| Proteoglycans |
core protein attached to many long, linear chains of glycosaminoglycans |
| Glycoproteins |
proteins that contain short chains of oligosaccharides that are usually branched |
| Hurler’s syndrome |
mucopolysaccharide disease with corneal clouding |
| Hunter’s syndrome |
mucopolysaccharide disease with no corneal clouding, x-linked |
| Location of fatty acid synthesis |
liver, fat cells |
| Location of gluconeogensis |
liver, kidney |
| Location of heme synthesis |
bone marrow |
| Location of PPP |
liver, fat cells, adrenal cortex, mammary gland |
| Location of amino acid synthesis and breakdown |
liver |
| Location of urea synthesis |
liver |
| Location of cholesterol synthesis |
liver |
| Location of steroid hormone synthesis |
adrenal cortex, gonads |
| Enantiomers |
mirror images |
| Do we have D or L sugars |
D sugars |
| Epimer |
sugars that differ only in one hydroxyl group position |
| Amylose/amylopectin |
starch |
| Carbohydrate digestive enzymes in intestine |
isomaltase, glucoamylase, lactase, sucrase |
| How do most cells get glucose past the membrane |
facilitated diffusion |
| Glut1 and Glut3 |
basal transporters for the brain; high affinity, low Km |
| Glut 2 |
glucose transporter in intestine, liver, and kidney |
| Glut 4 |
glucose transporter in adipose and muscle tissue; regulated by insulin |
| Glut 5 |
transports fructose |
| SGLT1 |
glucose (or galactose) and sodium transporter into enterocyte cells |
| Lactose intolerance is cause by |
inability to make lactase |
| Difference between glucokinase and hexokinase |
glucokinase is only in the liver, has a high Km and a high Vm, and is not inhibited by glucose6P |
| Why phosphorylate glucose |
1)net negative charge traps molecule in cell 2)conserves energy 3)commits the cell to use the glucose |
| Glucose to pyruvate structure names, no enzymes |
glucose, glucose6P, fructose6P, fructose16bP, glyceraldehyde3P, dihydroxyacetoneP, 13bisphosphoglycerate, 3Pglycerate, 2Pglycerate, phosphenolpyruvate, pyruvate |
| Glucose to pyruvate enzymes |
hexokinase (glucokinase), phosphoglucose isomerase, phosphofructokinase 1, aldolase, triose phosphate isomerase, glyceraldehyde3PDH, phosphoglycerate kinase, phosphoglycero mutase, enolase, pyruvate kinase |
| Regulated steps in glycolysis (enzyme names) |
hexokinase, PFK1, pyruvate kinase |
| what is 2,3BPG used for |
lowers Hb’s affinity for O2 |
| hexokinase regulation |
-G6P, +insulin |
| PFK1 regulation |
+F26BP, +AMP, -ATP, -citrate |
| Pyruvate kinase regulation |
-alanine, +F16BP, (in liver, -phosphorylation from cAMP) |
| Pyruvate to lactate biproduct |
NADH goes to NAD+ |
| What kind of Fatty acids feed into glycolysis |
only odd number FA through succinyl CoA |
| Is inactive pyruvate kinase phosphorylated or not |
inactive pyruvate kinase is phosphorylated |
| Pyruvate DH: number of subunits and enzymes; cofactors and regulation |
2 subunits, 3 enzymes, 5 cofactors (NAD, FAD, CoA, lipoic acid, TPP), -acetyl CoA, -NADH |
| Congenital lactic acidosis |
pyruvate DH not working; bypass with ketogenic diet |
| TCA cycle (enzymes included) |
acetyl CoA with Oxaloacetate (citrate synthase) citrate (aconitase) isocitrate (isocitrate DH) alpha ketoglutarate (alpha ketoglutarate DH) succinyl CoA (succinate thiokinase) succinate (succinate DH) fumarate (fumurase) malate (malate DH) oxaloacetate |
| NADH in TCA comes from what rxns |
isocitrate DH, alpha ketoglutarate DH, malate DH |
| FADH in TCA comes from what rxn |
succinate DH |
| GTP in TCA comes from what rxn |
succinate thiokinase |
| CO2 in TCA leaves from what rxn |
isocitrate DH, alpha ketoglutarate DH |
| Alpha ketoglutarate cofactors |
FAD, NAD, TPP, lipoic acid, CoA |
| Regulated TCA steps |
citrate synthase, isocitrate DH, alpha ketoglutarate DH |
| TCA regulators |
-ATP, -NADH, -Succinyl CoA, +ADP |
| Anapleurotic rxns |
(fill up) replenish depleted cycle intermediates |
| Amphibolic cycle |
eg TCA cycle; both degredation and biosynthesis processes occur |
| Other citrate uses |
make fatty acids and cholesterol |
| Other alpha ketoglutarate uses |
glutamate and glutamine |
| Other succinyl CoA uses |
needs odd chain fatty acids, isoleucine, methionine, valine; used to make porphyrins |
| Other fumarate uses |
needs aspartate, phenylalanine, tyrosine |
| Other malate uses |
glucose formation |
| Other oxaloacetate uses |
needs/makes amino acids; made from pyruvate and CO2 |
| Glycerol-phosphate shuttle |
dihydroxyacetone phosphate oxidizes NADH (cytoplasmic glycerol3PDH) glycerol3P reduces FAD (mitochondrial Glycerol3PDH) only 2 ATP’s |
| Malate-aspartate shuttle |
3ATP’s |
| Superoxide dismutase |
conversts superoxide to hydrogen peroxide |
| Mutations in superoxide dismuatese leads to |
LAS (lu Gherig’s disease) |
| Glutathione |
used in turning hydrogen peroxide into water |
| Enzymes in converting hydrogen peroxide into water |
glutathione peroxidase and glutathione reductase |
| NADPH |
used to reduce glutathione |
| Goals of PPP |
NADPH and nucleotide biosynthesis |
| Pathways that require NADPH |
reduce glutathione, FA synthesis, FA chain elongation, cholesterol synthesis, neurotransmitter synthesis, nucleotide synthesis |
| PPP oxidative steps |
glucose6P to ribulose5P givine off 2 NADPH and CO2 |
| PPP first step enzyme |
glucose 6PDH |
| Transketolase |
rxns 5 and 7 in PPP; requires TPP; transfers 2 Carbons |
| Transaldolase |
rxn 6 in PPP; transfers 3 carbons |
| Glucose6PDH deficiency |
acute hemolytic anemia |
| Tissue dependent on glucose |
Brain, RBC, kidney medulla, cornea of eye |
| % of guconeogenesis in liver and kidney |
90% liver 10% kidney |
| 3 purposes of gluconeogenesis |
1)production of blood sugar 2)maintain levels of TCA cycle intermediates 3) clears lactate |
| gluconeogenesis cycle |
lactate (lactate DH) or alanine (transamination) to pyruvate (pyruvate carboxylase) oxaloacetate (PEP carboxykinase)… glyceraldehyde3P… (fructose 16Bisphosphotase)… (glucose6phosphotase) |
| formation of dihydroxyacetoneP in gluconeogenesis |
glycerol (kinase) glycerol3P (glycerol 3PDH) dihydroxyacetoneP |
| is Acetyl CoA a precursor for gluconeogenesis |
NO NO NO NO NO |
| required for pyruvate carboxylase |
biotin, CO2, ATP |
| where is glucose6Pase found |
liver and kidney |
| how many ATP equivalents are needed to make one glucose molecule through gluconeogensis |
6 |
| regulation of pyruvate carboxylase |
+acetyl CoA |
| regulation of PEP carboxykinase |
+glucagon, +epinephrine, +glucocorticoids, -insulin |
| regulation of fructose1,6BPase |
-F26BP, +ATP, +citrate, +glucagon |
| regulation of glucose6Pase |
+glucagon |
| cori cycle |
reconversion of lactate to glucose in liver |
| problem with too much ethanol on an empty stomach |
makes lots of NADH which then moves NADH rxns towards lactate, glycerolBP, and malate. Also, lactate, alanine, and glycerol are not used for gluconeogenesis |
| effect of insulin in liver |
-cAMP, -PKA, noP on PFK2/F26BPase, +PFK2/-F26BPase, +glycolysis |
| effect of glucagon/epinephrin in liver |
+cAMP, +PKA, P on PFK2/F26BPase, -PFK2/+F26BPase, +gluconeogenesis |
| effect of epinephrine in muscle |
+PKA, P on PFK2/F26BPase, +PFK2/-F26BPase, +glycolysis |
| effect of insulin in muscle |
-PKA, no P on PFK2/F26BPase, -PFK2/+F26BPase, -glycolysis, glucose goes to glycogen |
| where in the cell is glycogen stored |
cytoplasmic granules |
| 3 reasons for glycogen |
1)rapid mobilization 2)source of ATP even in absence of O2 3)maintain blood glucose levels |
| glycogenen |
protein that starts it all off; adds up to 8 glucose molecules onto itself after which glycogen synthase takes over |
| glycogen degredation |
glycogen phosphorylase uses an inorganic phosphate (not ATP) to make Glucose1P; debranching enzyme moves last 3 of 4 |
| phosphoglucomutase |
glucose1P to glucose6P |
| glycogen synthesis |
glucose1P with UTP (UDP glucose pyrophosphorylase) UDP glucose with 2Pi; UDP glu can’t add until there are 8 glu molecules; UDP glucose (glycogen synthase) branching enzyme (must be 4 glc between each branch) |
| regulation of glycogen synthase |
+G6P, -cAMP dep P |
| regulation of glycogen phosphorylase |
-G6P, -ATP, +P of phosphorylase kinase, (-glucose (liver), + AMP (muscle)) |
| regulation of phosphorylase kinase |
+Ca2+, +cAMP dep P |
| glycogen regulation by epinephrine in liver or muscle |
+cAMP, +PKA, P of phosphorylase kinase (active), P of phosphorylase (active), degredation of glycogen |
| glycogen storage diseases |
most are recessive |
| glucose 6 phosphatase defficiency |
increased amount of glycogen with normal structure; liver enlarged, failure to thrive, severe hypoglycemia, ketosis, hyperuricemia, hyperlipemia (give frequent high carb feedings) |