Fructose Galactose Pentose Phosphate

Front 1

Name a couple ways fructose metabolism is different from glucose metab? (there are 5 listed)

Back 1

1.Transport of fructose is not insulin dependent
2.Fructose ingestion does not stimulate insulin secretion
3.They are phosphorylated by different kinases
4.Fructose metabolism requires aldolase B
5.Fructose bypasses the critical regulated step

Front 2

Fructose cell entry is dependent on?

Back 2

Fructose concentration...it enters cells via facilitative diffusion using GLUT5

Front 3

Fructokinase is found primarily in what 3 places?

Back 3

liver, intestinal mucosa, and kidney --> so these are main sites of fructose metabolism

Front 4

Essential Fructosuria involves - & will lead to build up of whom?

Back 4

Fructokinase, build up of Fructose

Front 5

Hereditary fructose intolerance involves - and leads to build up of ????

Back 5

Aldolase B, leading to build up of Fructose 1-Phosphate

Front 6

Difference btwn Essential Fructosuria & Hereditary Fructose intolerance?

Back 6

fructokinase or aldolase B,

Front 7

Galactose --> Gal-1-P by whom?

Back 7

Galactokinase

Front 8

Gal-1-P is converted to ? , which is necessary to enter glycolysis

Back 8

Glucose-6-P

Front 9

Nonclassical Galactosemia involves deficiency of ? and buildup of ?

Back 9

galactokinase - galactose

Front 10

Classical galatosemia/ GALT deficiency involves ? and buildup of ?

Back 10

Gal-1-Puridyl transferase, buildup of Galactose-1-P

Front 11

Galactose buildup leads to...

Back 11

Galactitol via aldose reductase -- this accumulation leads to cataracts similar to sorbitol build up

Front 12

Galactose-1-P buildup is involved in which deficiency? and leads to ?

Back 12

Is the Classical galactosemia/GALT, and leads to severe liver damage via an unknown mechanism

Front 13

Some generalities regarding pentose phosphate pway...what is it? why? where? etc

Back 13

It is an alternative metabolic pway for Glucose-6-P
Occurs in cytosol of all cells
Divided into 2 rxns; oxidative/non-oxidative
Makes NADPH
The most common inherited metabolic defect involves this pway

Front 14

What is the dietary source of fructose?

Back 14

fruit, sucrose, HFCS

Front 15

Glucose & Galactose are what?

Back 15

epimers

Front 16

Galactose dietary source?

Back 16

dairy (lactose)

Front 17

Step one of fructose metab, fructose->fructose-1P via ?

Back 17

fructokinase

Front 18

Step 2 fructose-1P-> which two molecules, and whom is responsible for such actions?

Back 18

Fructose-1P is cleaved to DHAP & Glyceraldehyde via Aldolase B

Front 19

DHAP comes from? and can enter...

Back 19

comes from cleavage of frct-1P and can enter glycolysis

Front 20

glyceraldehyde comes from? and can do what?

Back 20

cleavage of frct-1P and can enter glycolysis

Front 21

Explain difference bw Aldolase A & B

Back 21

B is in fructose metabolism, A is from glycolysis. this is important bc in fructose

Front 22

Explain significance in difference bw aldolase A & B?

Back 22

Aldolase B in fructose metab directly produces DHAP, while A in glycolysis is much more regulated via PFK. It has been shown that fructose intake increases lipid levels --> theory is this is caused by lack of regulation in fruct metab (as opposed to gluc reg)

Front 23

lack of what is associated with cataracts ?

Back 23

sorbitol dehydrogenase

Front 24

GLUT # ? is associated with insulin?

Back 24

FOUR aka 4...quad?
2+2 = 4

Front 25

does breast milk contain sucrose?

Back 25

galactose + glucose = lactose

Front 26

GALT = ?

Back 26

gal-1-p-uridyl transferase

Front 27

galactokinase is found?

Back 27

in most tissues! (also converts galactokinase -> galactose 1 P

Front 28

what accumulates in nonclassical galactosemia?

Back 28

galactose ... just galactose

Front 29

what accums in classical galactosemia?

Back 29

aka GALT deficiency, build up of galactose AND galactose-1-P

Front 30

nonclassical galactosemia can lead to conversion of galactose-> ?

Back 30

galactitol = cataracts
-aldose reductase converts