Chapter 16 - Glucose

may be missing stuff because the review note slide numbers are wrong

glycolysis

the sequence of reactions that metabolizes one molecule of glucose to two molecules of pyruvate with the net production of two molecules of ATP

anaerobic

glycolysis is this, not requiring any O2

gluconeogenesis

the process by which metabolic products are salvaged to synthesize glucose

pyruvate

the end product of glycolysis

alpha-amylase

a pancreatic enzyme that digests starch and glycogen

alpha-1,4

which bonds does alpha-amylase cleave?

maltose

what does alpha-amylase produce?

alpha-glucosidase

intestinal surface enzyme breaks maltose, maltotriose, and other α-1,4-linked oligosaccharides into glucose molecules

sucrase

intestinal surface enzyme that degrades ingested sucrose to fructose and glucose

glucose transporters

mediate the thermodynamically downhill movement of glucose across animal plasma membranes

stage 1

this part of glycolysis does not form any ATP and traps/modifies glucose

stage 2

this part of glycolysis oxidizes the 3-carbon structures and makes 4 ATP (2 net)

2

how many molecules of ATP does the first stage require?

hexokinase

this enzyme uses 1 ATP to phosphorylate glucose to G-6P

Mg, Mn

hexokinase requires this as a cofactor?

phosphoglucose isomerase

this catalyzes the isomerization of G-6P to F-6P

PFK

this enzyme uses ATP to phosphorylate F-6P to F-1,6-BP

PFK

this enzyme is the rate-determining step, and commits the molecule to undergoing glycolysis

aldose

this cleaves F-1,6-BP into GAP and DHAP, reversible step

GAP

only product from the end of stage 1 of glycolysis can turn into pyruvate

DHAP

these are the first 3-carbon structures to appear in glycolysis

TPI

this catalyzes the isomerization of DHAP to GAP

GAPDH

this catalyzes the conversion of GAP into 1,3-BPG

NAD+

this oxidizes the aldehyde to a COOH and a Pi is added (coupled step)

phosphoglycerate kinase

this catalyzes the transfer of a Pi group onto ADP from 1,3-BPG

phosphoglycerate mutase

this step catalyzes the conversion of 3- phosphoglycerate to 2-phosphoglycerate

2,3-BPG

phosphoglycerate mutase requires a small amount of what to maintain an  active-site His residue in a phosphorylated form?

enolase

this catalyzes the dehydration of 2- phosphoglycerate to PEP

traps the molecule in its unstable enol form

why does PEP have a high phosphoryl transfer rate?

pyruvate kinase

this catalyzes the transfer of a phosphoryl from PEP to ADP, forming pyruvate and ATP

1 Glucose + 2Pi + 2ADP + 2NAD+ =

2 pyruvate + 2ATP + 2NADH + 2H + 2H2O

glycolysis net reaction

pyruvate

NAD+ can be regenerated through oxidation or fermentation of this?

oxidation

in aerobic conditions pyruvate will undergo this to form NAD+

fermentation

in anaerobic conditions pyruvate will undergo this to form NAD+

pyruvate decarboxylas

in step 1 of ethanol fermentation, this catalyzes the decarboxylation of pyruvate

thiamine pyrophosphate

step 1 of ethanol fermentation requires this coenzyme

alcohol dehydrogenase

step 2 of ethanol fermentation, this catalyzes the reduction of acetaldehyde to ethanol by NADH, reforming NAD+

Glucose + 2Pi + 2ADP + 2 H =

2 ethanol + 2CO2 + 2ATP + 2H2O

ethanol fermentation net reaction

lactic acid fermentation

the conversion of glucose into lactate in anerobic conditions

skeletal MT

where in the human body does lactic acid fermentation occur?

lactase dehydrogenase

in lactic acid fermentation, this catalyzes the reduction of pyruvate by NADH to lactate

Glucose + 2Pi + 2ADP =

2 lactate + 2ATP + 2H2O

lactic acid fermentation net reaction

CAC, electron transport chain

how pyruvate is metabolized under aerobic conditions

fructokinase

this enzyme converts fructose into glycolytic intermediates

G-6P

galactose can be directly converted into what?

F-6P

fructose from fat can be directly converted into what?

DHAP, GAP

fructose from the liver can be directly converted into what two things?

galactokinase

this converts galactose into 6-GP

UDP-glucose

this is an activated intermediate in the synthesis of carbohydrates

phosphoglucomutase

this isomerizes glucose 1-phosphate to glucose 6-phosphate

hexokinase, phosphofructokinase, pyruvate kinase

the three enzymes that catalyze irreversible reactions in glycolysis

contraction

glycolysis in skeletal muscle provides ATP primarily to power what?

phosphofructokinase

high levels of ATP allosterically inhibits what? (inhibits the enzymes binding affinity for F-6P)

pH

a low what in muscle tissue inhibits PFK activity, increasing the inhibitory effect of ATP to reduce muscle damage

product

hexokinase is inhibited by G-6P, which is its what?

ATP

pyruvate kinase is allosterically inhibited by what?

feedforward stimulation

occurs when products of a preceding irreversible step activate the enzyme

ATP, pH

liver phosphofructokinase can be inhibited by what?

citrate

phosphofructokinase is inhibited by what?

F-2,6-BP

phosphofructokinase is activated by what?

glucokinase

a specialized isozyme of hexokinase that provides G-6P for glycogen synthesis and fatty acid formation

starvation, fasting

in what conditions would gluconeogensis be used?

pyruvate carboxylase

this catalyzes the carboxylation of pyruvate to oxaloacetate using a molecule of ATP

the mitochondria

where does oxaloacetate form?

NAD+-linked malate dehydrogenase

this brings malate into the cytoplasm

inverse

glycolysis and gluconeogenesis have what kind of relationship?

cori cycle

a series of reactions carried out by cooperation between the liver and muscle

glucose

lactate from contracting muscles is converted into what by your liver?

pyruvate

the nitrogenous byproducts of muscle contraction are used in formation of what?