II-Biochemistry-Carbohydrate Flashcards
A polymer of 3-10 monosaccharides
Oligosaccharides
The simplest of carbohydrates
Monosaccharides
Long chains of carbohydrates typically undigestable by humans
Polysaccharides
Glucose + Glucose
Mannose
Glucose + Sucrose
Fructose
Lactose is a combination of?
Glucose + Galactose
Failure in metabolizing Galactose leads to the develop of?
Galactosemia and Cataracts
What chemical reaction is Sorbitol produced from?
Reduction of Glucose
This Fructose polymer is use in determining GFR
Inulin
Glucose, Fructose & Galactose are _____ of each other
Isomers
Galactose differs from Glucose at Carbon 4 making it an _____
Epimer
Enantiomerism is defined as
The structural mirror image of each other
Foods with a Glycemic Index <1 are expected to have
Slower glucose absorption rate
Benefits of a low Glycemic Index
Prevents rapid rises in blood glucose and rapid fluctuations in insulin secretion
How does the Glucagon-G-protein receptor binding influence Glycogen Metabolism
Up-regulates Glycogenolysis
How does G-protien Gi affect enzyme contribute to Glycogen metabolism
inhibts Adenylate cyclase-> Up-regulates Glycogenesis, down-regulates Glycogenolysis
G-protein Gs activation acts adenylate cyclase causing?
elevation of the 2nd messenger cAMP
Glucose transporter found on the luminal side the intestines
GLUT 5
Glucose transporter found in the brain, kidney, placenta
GLUT 3
SGLT-2 transporter is found in what organ?
Kidneys
Rate limiting enzymes of Glycolysis.
Hexokinase/Glucokinase, Phoshofructokinase I, Pyruvate Kinase
True or False: Hexokinase and Glucokinase are found in most tissues.
False, althouth Hexokinase can be found in most tissues, Glucokinase is only present in the liver and pancreas
Higher affinity thus lower Km for glucose?
Hexokinase
Glycolytic enzymes that catalyzes substrate level phosphorylation
1,3-Bisphosphoglycerate kinase, Pyruvate Kinase
How many NADH is produced from 6 molecules of Glucose in Glycolysis
12 NADH
1 NADH from Glycolysis via Malate-Asparate Shuttle produces how many ATP?
3 ATP
Arsenic affects these two Glycolytic enzymes.
Glyceraldehyde-3-phosphate Dehydrogenase, Pyruvate Kinase
The most common glycolytic enzyme deficiency causes this
Chronic Hemolytic Anemia (Pyruvate Kinase Deficiency)
Converts pyruvate to oxaloacetate in the mitochondria
Pyruvate carboxylase
Enzymes responsible for the producing ethanol
Pyruvate decarboxylase
Catalyzes the reduction of Pyruvate to regenerate NAD+
Lactate dehydrogenase
Shares thes same cofactors as a-ketogluterate dehydrogenase
Pyruvate dehydrogenase
Co-A requires this B-complex vitamin
Vit. B5 (pantothenic acid)
The four Vitamins need for co-enzymes of Pyruvate Dehydrogenase
Vit. B1 (thiamine), Vit B2 (Riboflavin), Vit. B3 (niacin), & Vit B5 (pantothenic acid)
Substances that up-regulates the activity of Pyruvate Dehydrogenase
NAD+, CoA, Pyruvate
Products of B-oxidation will do what to Pyruvate Dehydrogenase
Down-regulates the activity of Pyruvate Dehydrogenase
Mechanism in Chronic Alcoholism causing aquired Pyruvate Dehydrogenase deficiency
Thiamine deficiency
Common pathway of aerobic Oxidation of ALL nutrients
Kreb’s cycle
Pyruvate Dehydrogenase deficiency disease associated with deprivation of Acetyl-CoA in the brain
Congenital Lactic Acidosis
Rate limiting enzyme of Kreb’s cycle
Isocitrate dehyrdogenase
Enzyme affected by the posion Fluoroacetate
Aconitase
Arsenite inhibits which Kreb Cycle Enzyme
a-Ketoglutarate Dehydrogenase
Products of Kreb’s cycle after 1 molecule of Acetyl-CoA
2 CO2, 1 GTP, 3 NADH, & 1 FADH2
Intermediate of Kreb’s Cycle used Heme Synthesis, Activation of Ketones, & Entry of Proprionyl-CoA
Succinyl-CoA
Intermediate need for Oxaloacetate to exit the Mitochondria
Malate
ONLY enzyme of Kreb’s that catalyzes substrate level phosphorylation
Succinate thiokinase
Principle organ of Gluconeogenesis
Liver
Cycle that converts Lactate from muscles to Glucose
Cori Cycle
Important enzymes of Gluconeogenesis
PEP carboxylase, Pyruvate Carboxylase, Fructose-1,6-Bisphosphatase, Glucose-6-Phosphatase
ALL carboxylase require this vitamin to function properly
Biotin
The rate limting enzyme of Gluconeogenesis
Fructose-1,6-Bisphosphatase
This substrate Inhibitts Fructose-1,6-Bisphosphatase, and Activates Phosphofructokinase 1
Fructose-2,6-Bisphosphate
The enzyme in gluconeogenesis that is absent in Skeletal Muscles
Glucose-6-phosphatase
The loss of this enzyme in the last step of Gluconeogenesis causes this disease
Von Gierk’s
Allosteric binding of AMP will do what to Gluconeogenesis?
Down-regulates/Inhibits Gluconeogenesis
Mechanism behind Alcohol driven Hypoglycemia?
accumulation of cytoplasmic NADH leading to decrease Gluconeogenesis
Enzymes responsible for cytoplasmic NADH elevation in Alcoholics
Alcohol Dehydrogenase, Acetylaldehyde Dehydrogenase
This effect inhibits Acetylaldehyde dehydrogenase leading to an acculumation of Acetylaldehyde
Disulfiram Effect
Energry required to make 1 Glucose molecule in Gluconeogenesis
4 ATP, 2 GTP, 2 NADH = 12 ATP
Responsible for Hyperinsulinemia in Pregnancy
Estrogen
Responsible for Insulin Resistence in Pregnancy
HPL
Major Storage form of Glucose in animals
Glycogen
Which organs do you find glycogen
Liver & Muscles
Reason why Glycogen is ALWAYS destined to be used internally in Muscle cells?
Lacks Glucose-6-Phosphatase
Rate limiting enzyme of Glycogenesis
Glycogen synthase
Activated form of Glucose
UDP-Glucose
Rate limitng enyme of Glycogenolysis
Glycogen Phosphorylase
True or False: Phosphorylation of Glycogen Synthase promotes Glycogenolysis
True, phosphorylation inhibits Glycongen synthase preventing Glycogenesis
True or False: Dephosphorylation of Glycogen Phosphorylase is needed to promote Gluconeogenesis
False, Dephosphorylation inhibits Glycogen phosphorylase preventing production of Glucose-1-phosphate
True or False: Insulin cause phosphorylation of Glycogen Synthase to promote Glycogenesis
Fasle, Insulin dephosphorylates Glycogen synthase to active it
True or False: increasing levels of Glucose-6-Phosphate promotes Glycogenesis
True, allosterically activaes Glycogen Synthase and inhibits Glycogen Phosphorylase
Needed for both muscle contration and mobilization of glygcogen to glucose
Ca 2+
Inability to break a(1->4) bonds in lysosomal degradation of glycogen
Type II Pompe’s diease (acid maltase)
Inability to break a(1->4) bonds in Muscles
Type V McArdle’s disease (muscle glycogen phosphorylase)
Inability to proceed past the last step of Gluconeogenesis
Type I Von Gierke’s disease (glucose-6-phosphatase)
The severe form of Von Gierke’s results from the deficiency of this enzyme
Branching enzyme (Andersen’s disease Type IV)
The same enzyme seen Type V Glycogen Storage Disease, but deficient in the hepatocytes
Type VI Her’s disease (hepatic glycogen phosphorylase)
Inability to break the a(1->6) bonds in glycogen; milder form of Type I
Type III Cori’s disease (Debranching enzyme)
Loss of this enzyme in muscles leads to accumulation of Glucose-6-phosphate promoting Glycogenesis
Type VII Taruis’s disease (Phosphofructokinase I)
Galactosemia manifesting as early childhood cataracts
Galactokinase Deficiency
Galactosemia, cataracts within a few days of birth, hypoglycemia, lethargy and mental retardation
Gal-1-P Uridyltransferase Deficiency
Fastest metabolism all monosaccharides and yeilds the greastest ATP production
Fructose
Enzyme that allows Fructose-6-P to bypass conversion by Phosphofructokinase
Aldolase B
Enzyme deficient in Essential Fructosuria
Fructokinase
Deficiency in Aldolase B
Fructose Intolerance
ONLY symptom seen in Essential Fructosuria
Fructose in blood and urine
Proximal RenalTubular Disorder resembling Fanconi Syndrome
Aldolase B Deficiency
Enzyme absent in lens leading to Sorbitol accumlation causing cataracts in DM patients
Fructose dehydrogenase
Pathway important in generating NADPH for the other metabolic cycles to function.
Pentose Phosphate Pathway (Hexose Monophosphate Shunt)
Rate Limiting Enzyme in PPP
Glucose-6-Phosphate Dehydrogenase
Important Vitamin needed for the PPP
Vitamin B1 (Thiamine)
True or False: The Oxidative phase of PPP is irreversible
TRUE
2 important products produced by the PPP
NADPH & ribose-5-phosphate
NADPH’s role in the removal of peroxide by glutathione
Need in by Glutathione Reductase to reduced of oxidized glutathione
Deficiency making RBC more susceptible to oxidative stress
G-6-PD Deficiency
percipitates of Hemoglobin seen in RBCs of G6PD deficient patients
Heinz bodies
Immune disease associated with NADPH oxidase deficiency responsible for respiratory burst in WBC
Chronic Granulomatous Disease
Test used to determine Thiamine deficiency
RBC transketolase activity
Metabolic Pathway dependent on NADPH
Fatty acid synthesis
Co-factor important for Glutathione Peroxidase
Selenium