Kaplan Biochemistry: Chapter 9 Carbohydrate Metabolism I Flashcards
what type of cells would you find a GLUT 2 transporter
hepatocytes and pancreatic cells.
Km for GLUT 2 is ___
high.
blood travelining through the hepatic portal vein from the intestine is rich in glucose after a meal. Glut 2 captures excess glucose primarily for STORAGE. with a high Km, GLUT 2 only captures EXCESS glucose.
what type of glucose transporter is housed by adipose tissues and muscles
GLUT4.
effects of insulin on GLUT4
when insulin binds upon a large meal, GLUT 4 transporters are brought to the surface and begin to pump glucose into the cell.
where does glycolysis occur
in the cytoplasm of cells.
yield of glycolysis of ONE glucose
2 pyruvates, 2 NADH, and net 2 ATP.
name the intermediates of glycolysis
- glucose + ATP
- glucose 6 phosphate
- fructose 6 phosphate + ATP
- fructose 1,6 biphosphate
- dihydroxyacetone phosphate, glyceraldehyde 3 phosphate
- 1,3 diphosphoglycerate + NADH
- 3 phosphoglycerate + ATP
- 2 phosphoglycerate
- phosphoenolpyruvate
- pyruvate + ATP
in fermentation, pyruvate is oxidized to ___, creating ___
oxidized to lactate, creating NAD+
outline GALACTOSE metabolism.
mainsource of galactose is lactose, which is glucose-galactose.
- galactose gets converted to galatose 1 Phosphate via galactokinase
- gal-1-P gets converted to glucose-1-P via uridyltransferase.
- glu-1-P can undergo glycolysis by getting converted to glucose - 6 PHOSPHATE (via phosphoglucomutase), or be converted to glucose and then glycogen for storage.
sucrose is broken down into
glucose and fructose.
sucrose is hydrolyzed by disaccharidases at the brush boarder, and the resulting monosaccharides are absorbed into the hepatic portal vein.
outline FRUCTOSE metabolism
liver phosphorylates fructose into fructose 1-P via fructokinase
fructose 1 P gets cleaved into dihydroxyacetone phosphate and glyceraldehyde via aldolase. these products can undergo glycolysis, glycogenolysis and gluconeogenesis.
enzyme responsible for converting pyruvate to acetyl coA
pyruvate dehydrogenase. desults in acetyl coA and NADH.
what type of anomer is found in glycogen
alpha glucoses with 1-4 linkages and 1-6 linkages.
outline glycogenesis
1) glucose is converted to gluocse 6 p
2) glucose 6 P is converted to glucose 1 P
3) glucose 1 P is activate via UTP coupling, which forms UDP-glucose.
4) Glycogen synthase adds the UDP glucose to the anomeric carbon of a preexisting glycogen chain.
____ ___ makes ____ glycosidic bonds between glucose 1 phosphate and the preexisting glycogen chain, and ____ enzymes makes the ____ linkages
GLYCOGEN SYNTHASE makes 1-4 ALPHA glycosidic bonds between glucose 1 phosphate and the preexisting glycogen chain, and BRANCHING enzymes makes the 1-6 ALPHA linkages
ROLE OF phosphosphatase
removes a phosphate from a molecule
___ __ BREAKS alpha 1-4- glycosidic bonds of glycgen during glycogenolysis
glycogen phosphorylase. it then releases a glucose-1-phosphate
T/F: glycogen phosphorylase can break the 1-6 linkages of glycogen
false. you need a debranching enzyme. removes the branch and reattaches to the end of the 1-4-chain, where glycogen phosphorylase can break the branch.
outline the parts of gluconeogenesis that occur in the mitochondria, and the parts that take place in the cytoplasm
mito: pyruvate is converted to oxaloacetate
cytoplasm: OAA SHUTTLES to the cytoplasm via MALATE ASPARATE SHUTTLE and gets converted to PEP via PEPcarboxykinase using GTP
- PEP turns into glyceraldehyde -3-P using the reverse steps of glycolyss
PFK-1 catalyzes fructose 1 P into fructose 1-6biP. What catalyzes the reverse reaction
fructose-1-6 biphosphatase
hexokinase catalyzes glucose into glucose-6-P. what catalyzes the reverse reaction
glucose-6-phosphatase.
what does pyruvate carbolxylase do
creates oxaloacetate from pyruvate and CO2.
2 main products of pentose phosphate pathway and its purpose
1) NADH
2) ribose 5 phosphate
for nucleotide synthesis.
T/F the pentose phosphate pathway is reversible
false
what induces the PP pathway? What inhibits it?
induces: insulin
inhibition: NADPH or ribose 5 phosphate.
_____ is a biological reducing agent that can reverse radical formation before damage is done to the cell
Glutathione. its purpose is to nutralize H2O2 that is produced during aerobic metabolism.
