Term
| Dangers of Sugar Consumption |
|
Definition
-above 25%=decrease in Calcium, magnesium, zinc and iron
-added fructose increases BP and insulin resistance |
|
|
Term
|
Definition
-3-9 carbon atoms
-hydroxyl groups (bind other groups)
-carbonyl group (aldehyde or ketone); carbonyl carbon most active
-contain chiral centers |
|
|
Term
|
Definition
-farther from carbonyl/anomeric carbon
-four different atoms attached
-determines L (opposite) vs. D (same) |
|
|
Term
|
Definition
alpha: OH below plane of ring
beta: OH above plane of ring |
|
|
Term
|
Definition
-found naturally in few foods
-product of starch digestion (starch->amylopectin->glucose) |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| not found in foods, by product of digestion |
|
|
Term
|
Definition
-2-10 monosaccharides
-disaccharide most abundant
-contain glycosidic bonds (alpha=digestible, beta=non-digestible) |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
-beta 1,2 linkage; non-digestible
-lowers pH in gut by production of SCFA; kills pathogenic bacteria
-low pH keeps ammonia in gut instead of blood stream; important in advanced liver disease
-bulks stool |
|
|
Term
|
Definition
| butyrate, acetate and proprionate |
|
|
Term
|
Definition
-Olestra
-sucrose with 6-8 SCFA
-not recognized by lipase or amylase
-can cause anal leakage |
|
|
Term
|
Definition
-Splenda
-3 OH replaced with Cl
-becomes 600x sweeter |
|
|
Term
|
Definition
-55-65% fructose to glucose
-metabolized in liver and enters below first key step in glycolysis (glucose->glucose-6-fructose)
-causes build up of glyceraldehyde-3-P which contributes to TG and FA
-lowers HDL and disrupts uric acid synthesis which increases BP |
|
|
Term
|
Definition
-glucose hydrolyzed from corn starch
-used in IV |
|
|
Term
|
Definition
-over 10 mono
-can be digestible or not
-has reducing (can donate e-) or non-reducing ends (can't donate e-) |
|
|
Term
|
Definition
-70% amylopectin (branched) and 30% amalose
-used to thicken liquids |
|
|
Term
|
Definition
-alpha 1,4 and 1,6 linkages
-digestible |
|
|
Term
|
Definition
-non-digestible
-beta 1,4
-bulks up stool and exercises colonic muscles |
|
|
Term
|
Definition
|
|
Term
|
Definition
-alpha 1,2 and 1,4; somewhat fermentable
-releases SCFA which decreases pH; energy source for colonisides and maintain healthy colon wall
-SCFA also shut down enzymes in cholesterol synthesis |
|
|
Term
|
Definition
-salivary amylase: alpha 1,4, operates in pH=7
-inactivated in stomach (too acidic)
-continues in neonates b/c pancreatic amylase doesn't develop until 6 mths. |
|
|
Term
|
Definition
-chyme enters deodenum->secretin and CCK release
-Secretin causes pancreas to release bi-carbonate and CCK, amylase |
|
|
Term
|
Definition
-digests 90% oligo into dextrins, maltriose and maltose
-binds to 5 glucose molecules and breaks between 2nd and 3rd molecule
-alpha 1,4 specific
-cannot digest alpha 1,6 |
|
|
Term
|
Definition
Principle Substrate: sucrose, malto-oligo (alpha 1,4 only)
Km=18 (S) and 3 (M) |
|
|
Term
|
Definition
Principle Substrate: alpha dextrins (alpha 1,4 and 1,6)
Km=2-4 |
|
|
Term
|
Definition
Principe Substrates: malto-oligosaccharides, alpha dextrins (alpha 1,4 only)
Km=1-4(M) and 1 (D) |
|
|
Term
|
Definition
Principle Substrate: Trehalose
Km=3 |
|
|
Term
| Beta-Galactosidase Lactase |
|
Definition
Principle Substrate: Lactose
Km=2 |
|
|
Term
|
Definition
-transfers glucose (or galactose) and Na (cotransport)
-on apical membrane
-Na is removed from enterocyte via Na/K Pump (2 come out, 3 K come in)
-against concentration gradient |
|
|
Term
|
Definition
-found in liver, pancreatic beta cells, basal lateral surface of SI, kidney
-promotes absorption from enterocyte into portal circulation
-low affinity for mono, so need very high concentration for activation
-when levels are low, liver doesn't need, so goes to brain and RBC instead
-uses facilitated diffusion and doesn't discriminate between mono |
|
|
Term
|
Definition
-found in SI, testes and kidney
-transports fructose from lumen into enterocyte
-uses passive diffusion (no energy use); moves downstream |
|
|
Term
|
Definition
| -found on RBC, brain and low levels on all cells |
|
|
Term
|
Definition
| -found on brain and low levels on all cells |
|
|
Term
|
Definition
-found on heart, muscle, adipose tissue and brain
-dependent on insulin
-transported via vesicles stimulated by insulin
-translocation of genes into vesicles which are released in the presence of insulin |
|
|
Term
|
Definition
-taken in via GLUT4 which is activated by insulin
-hexokinase catalyzes transformation from glucose to glucose-6-phosphate
-glucose trapped in muscle because glucose-6-phosphate can't be dephos |
|
|
Term
|
Definition
-enters via GLUT2 which requires very high concentrations to be active
-Glucokinase catalyzes transformation of glucose to glucose-6-phosphate; positively effected by insulin
-glucose can move back out via glucose-6-phosphotase |
|
|
Term
|
Definition
1. Availability of substrate
2. Activity of key enzymes |
|
|
Term
| Mechanisms of Enzyme Control |
|
Definition
1. Allosteric Modification
2. Covalent Modification
3. Gene Expression |
|
|
Term
|
Definition
-pathway intermediates that either aid or inhibit enzyme activity
-positive (T->R) or negative (R->T) effectors
-catalyze non-reversible rxns
-moderated by ATP and NAD) |
|
|
Term
|
Definition
-reversible phosphorylation
-phosphate binding increases or decreases activity
-occurs b/c of hormonal changes
-mediated by kinase and phosphatases
-reversible |
|
|
Term
|
Definition
-slow acting through transcription or translation
-induction: increase mRNA transcription or translation at ribosome |
|
|
Term
| Key Control Point for Blood Sugar |
|
Definition
|
|
Term
|
Definition
-High insulin
-Low glucagon
-Liver: decreases glycogenolysis
decreases gluconeogenesis
decreases glycogen synthesis
-decreases glucose output by liver and decreases plasma glucose |
|
|
Term
|
Definition
| conversion of glycogen polymers to glucose monomers |
|
|
Term
|
Definition
| produces glucose from non carbohydrate sources such as lactate and AA |
|
|
Term
|
Definition
| storage form of glucose in liver and muscles |
|
|
Term
|
Definition
-low insulin levels
-high glucagon levels
-Liver: increase glycogenolysis, gluconeogenesis; decreases glycogen synthesis
-Leads to increase in hepatic glucose output and increased plasma glucose |
|
|
Term
|
Definition
| hormone secreted from pancreas that raises blood glucose levels; opposite function of insulin |
|
|
Term
| Glucose Metabolism in Liver |
|
Definition
-stores excess glucose as glycogen
-converts glucose to pyruvate
-releases glucose to other tissues via gluconeogenesis and glycogenolysis |
|
|
Term
| RBC and Glucose Metabolism |
|
Definition
-no mitochondria
-rely on glycolytic pathway for energy
-requires oxygen |
|
|
Term
| Brain and Glucose Metabolism |
|
Definition
| -can completely oxidize glucose under aerobic conditions |
|
|
Term
| Muscle and Glucose Metabolism |
|
Definition
| -oxidize glucose and store for its own use |
|
|
Term
| Adipose and Glucose Metabolism |
|
Definition
| can completely oxidize glucose at low levels; uses glucose |
|
|
Term
|
Definition
-10 sequential steps that yields 38 possible ATP
-Pyruvate: 24 ATP
-2 ATP
-NADH: 6 ATP
-Glucose (if oxidized): 6 ATP
-generates glucose-6-phosphate for glycolysis, glycogen synthesis and pentose phosphate pathway |
|
|
Term
|
Definition
| Glucose->glucose-6-phosphate->fructose-6-phosphate->fructose-1-6-phosphate->glyceraldehyde-3-phosphate->1,3-bisphosphoglycerate->3-phosphoglycerate->2-phosphoglycerate->phosphoenolpyruvate->pyruvate->lactate and ATP |
|
|
Term
|
Definition
-catalyzes transformation of glucose to glucose-6-phosphate
-high Km for glucose (needs lots of substrate)
-inactive when bound to regulatory protein (GKRP)
-high fructose-1-phosphate and low fructose-6-phosphate causes GKRP to dissociate and GK to become active
-fructose-1-phosphate only exists when fructose is high
-induced by insulin |
|
|
Term
|
Definition
-high Km for glucose-6-phosphate (need lots of substrate)
-clips phosphate so glucogen can be used as glucose
-repressed by insulin and induced by cortisol (genetic) |
|
|
Term
|
Definition
-requires ATP and magnesium
-catalyzes transformation of fructose-6-phosphate to fructose-1-6-diphosphate (F16P2)
-first committed step of glycolysis
-induced by insulin and repressed by glucagon
-Positive Effectors: AMP/ADP, Fructose 2,6 diphosphate
-Negative Effectors: ATP, citrate |
|
|
Term
| Fructose 1,6 Diphosphatase |
|
Definition
-catalyzes conversion of fructose-1-6-diphosphate to fructose-6-phosphate
-induced by glucagon and repressed by insulin
-Negative Effector: AMP/ADP, fructose 2,6 diphosphate |
|
|
Term
|
Definition
-synthesis and degredation determined by 6PF-2K or F2,6Pase respectfully
-modified covalently |
|
|
Term
|
Definition
-occurs during fasting
-glucagon binds to receptor and causes dissociation of G alpha complex from G protein via GDP->GTP
-G alpha complex binds to adenylate cyclase which increases cAMP
-cAMP activates protein kinase A by binding to regulatory units
-Protein Kinase A phosphorylates bifunctional enzyme which inhibits 6PF-2K and activates F2,6Pase
-favors gluconeogenesis over glycolysis |
|
|
Term
|
Definition
-occurs during fed state
-Insulin binds to receptors and activates secondary messengers that phosphorylate many proteins including phosphodiesterase (decreases cAMP) and protein phosphatase
-binding of insulin causes change in beta transmembrane protein
-activates tyrosine residues which autophosphorylate and serve as docking points for relay proteins that phosphorylate phosphodiesterase and protein phosphatase
-protein phosphatase dephosphorylates bifunctional enzyme and activates 6PF-2K and inhibits F2-6Pase
-favors glycolysis over gluconeogenesis |
|
|
Term
|
Definition
-need ADP
-catalyzes transformation of phosphoenolpyruvate to pyruvate
-only found in mitochondria
-Positive effectors: F-1-6P2
-Negative effectors: ATP, acetyl coA, alanine
-Induced by insulin |
|
|
Term
| Pyruvate Carboxylase and Phosphoenolpyruvate carboxykinase |
|
Definition
-catalyze rxn of pyruvate to phosphoenolpyruvate and OAA
-needs ATP, CO2, biotin and GTP
-products are needed in more than one pathway
-Positive Effector: Acetyl CoA (PC)
-PEPCK induced by glucagon and repressed by insulin (use similar mechanism as 6FP-2K/F2-6Pase (PEPCK uses G protein and PK uses second messenger) |
|
|
Term
|
Definition
-changed to OAA in mitochondria using PC
-OAA converted to aspartate, malate and PEP
-crosses into cytosol through the use of ADH, MDH and PEPCK
-ADH and MDH release NADH to keep gluconeogenesis going |
|
|
Term
| Structural and Metabolic Differences between HFCS and sucrose |
|
Definition
-HFCS contains glucose and fructose monomers vs. sucrose is a dissacharide
-HFCS monomers don't need to be broken down vs. sucrose that must be cleaved |
|
|
Term
| Metabolic Effects Associated with High HFCS Intake |
|
Definition
1. Dyslipidemia
2. Hyperuricemia
3. Insulin Resistance
4. Appetite changes associated with weight gain |
|
|
Term
| Uric Acid Formation from Fructose |
|
Definition
| -when fructose is changed to F-1-P it releases ADP, AMP and uric acid |
|
|
Term
|
Definition
| AMP->IMP->Inosine->hypoxanthine->xanthine->urate |
|
|
Term
|
Definition
-acts as primer for growing chain on glycogen
-has glucosyl transferase: catalyzes bond between glucose and glycogen
-glucose linked via alpha 1,4 and 1,6 bonds at branched points |
|
|
Term
| Glycogen Synthesis in Liver |
|
Definition
| Glucose->G-6-P->G-1-P->glycogen primer->elongation using 2 UDP=glycogen |
|
|
Term
|
Definition
-UDP-glucose gives up glucose to non-reducing end
-forms alpha 1,4 glycosidic bond
-branching enzyme takes over and cleaves a bond 4-6 units from branch point
-forms alpha 1,6 bond which provides new site for elongation |
|
|
Term
|
Definition
Milk: 12
Bread/Cereal: 15
Vegetables: 5
Fruit: 15
Deserts: 15 |
|
|
Term
| Guidelines for Sugar Consumption |
|
Definition
Dietary Guidelines for Americans: 6%
Institute of Medicine: no more than 25%
World Health Organization: no more than 10%
Average teen: 16% |
|
|
Term
|
Definition
| Formed by rxn of hydroxyl group of C-5 with anomeric carbon on C-1 |
|
|
Term
|
Definition
| specific for alpha 1,4 bonds |
|
|
Term
| Amylase Digestion Products |
|
Definition
| dextrins, maltriose and maltose |
|
|
Term
|
Definition
| as we get older we consume less lactose and lactase decreases as a result |
|
|
Term
| Range of Normal Blood Sugar |
|
Definition
|
|
Term
|
Definition
| Eventually turns into triglyceride backbone via glycerol-3-phosphatase |
|
|
Term
| Uses of Glucose-6-Phosphate |
|
Definition
-glycolysis
-glycogen synthesis
-pentose phosphate pathway (ribose 5 phosphate synthesis) |
|
|
