quiz 2.3 glycogen Flashcards by Zeth Renae Raquedan

weight contribution of glycogen in the liver and skeletal muscle

20% in liver

1-2% in skel muscle

How well did you know this?

Not at all

Perfectly

muscle glycogen quickly provides energy during when

strenuous exercise like studying, practicals, thesis-ing

How well did you know this?

Not at all

Perfectly

explain itsura ng glycogen

sorage form of glucose, highly branched polysacch of glucose linked via alpha 1-4 bonds with alpha 1-6 branches every 8-10

How well did you know this?

Not at all

Perfectly

the only anomeric carbon that is not linked to another glucose residue that is located at the beginning

glycogenin

How well did you know this?

Not at all

Perfectly

features of glycogenin

only anomeric carbon

@ the beginning of the polysacch chain

How well did you know this?

Not at all

Perfectly

starting point of glycogen synthesis

formation of gluc-6-PO4

How well did you know this?

Not at all

Perfectly

2nd step in glycogen synth

glucose-6-PO4 is converted to gluc-1-PO4 by phosphoglucomutase

How well did you know this?

Not at all

Perfectly

in the 2nd step, gluc-4-PO4 is converted to ______ by _______

gluc-1-PO4

phosphoglucomutase

How well did you know this?

Not at all

Perfectly

in the 3rd step, gluc-1-PO4 is converted to ___ by ____

UDP-glucose

UDP-glucose pyrophosphates

How well did you know this?

Not at all

Perfectly

the 3rd step is highly exergonic so it ensures that the UDP-glucose pyrophosphate proceeds in the direction of formation of

UDP-glucose

How well did you know this?

Not at all

Perfectly

immediate donor of glucose residues in the reaction catalyzed by glycogen synthesis

UDP-glucose

How well did you know this?

Not at all

Perfectly

this enzyme promotes the transfer of the glucose residue from UDP-glucose to the nonreducing end of a branched glycogen molecule

glycogen synthase

How well did you know this?

Not at all

Perfectly

a primer in glycogenesis acts as what or how

acceptor of glucose residue from UDP-glucose

How well did you know this?

Not at all

Perfectly

possible primers in glycogen synthesis

pre-formed alpha 1-4 polyglucose or branch having at least 8 gluc residues (glycogen fragment)

How well did you know this?

Not at all

Perfectly

in the absence of a glycogen fragment, _ can act as glucose residue acceptor

glycogenin

How well did you know this?

Not at all

Perfectly

serves as the site where the initial glucosyl unit is attached

side chain -OH os a spefici tyrosine in glycogenin

How well did you know this?

Not at all

Perfectly

whta catalyzes the attachment of the glucosyl unit in the side chain OH of specific tyrosine in the glycogenin

glycogenin thru autoglucosylation

How well did you know this?

Not at all

Perfectly

the rxn of the sequential addition of seven more glucose residues derived from UDP-glucose is catalyzed by the __________ activity of glycogenin

chain-extending

How well did you know this?

Not at all

Perfectly

the elongation of glycogen involves the transfer of glucose from DUG-glucose ti the _______ of the growing chain

nonreducing end

How well did you know this?

Not at all

Perfectly

the enzyme responsible for making the linear linkages in glycogen

glycogen synthase

How well did you know this?

Not at all

Perfectly

what forms the branch points of glycogen

amylo(1-4) to (1-6) transglycosylase/ glycogen 4-6 transferase

How well did you know this?

Not at all

Perfectly

catalyzes the transfer of 6 or 7 glucose residues from the nonreducing end of a glycogen branch having at least 11 residues to the C-6 OH group of a glucose reside at a more interior portion of the same or another glycogen chsin

amylo(1-4) to (1-6) transglycosylase/ glycogen 4-6 transferase

How well did you know this?

Not at all

Perfectly

biological effect of branching is to make the glycogen ___

more soluble and to increase number of nonreducing ends

How well did you know this?

Not at all

Perfectly

3 enzymes involved in glycogenolysis

glycogen phosphorylase
glycogen debranching enzyme
phosphoglucomutase

How well did you know this?

Not at all

Perfectly

catalyzes the rxn in which the alpha 1-4 glycosidic linkage between two glucose residues at a nonreducing end of glycogen undergoes attack by inorganic phosphate

glycogen phosphorylase

essential cofactor for the glycogen phosphorylase rxn

pyridoxal phosphate

glycogen phosphatase removes what

terminal glucose residue as alpha-D-glucose-PO4

where does the action of glycogen phosphorylase stop

4 glucose away from a branch point

after the Ction of glycogen phosphorylase, what enzyme removes the glucose residues near a branch pointw

debranching enzyme aka oligo(a1-6) to (a1-4) glucan-transferase

first step in debranching enzyme

transfer a 3-block glucose to a nonreducing end

two activities of the debranching enzyme

transferase | (a1-6) glucosidase

2nd step in debranching enzyme

release the single glucose residue at the branhpoint

after the action of debranching enzyme, ano sunod

glycogen phosphorylase again

the gluc1PO4 by glycogen phosphorylase is converted in the ___ to ____ by _____

cytosok gluc6PO4 phosphoglucomutase

in the liver, the gluc6PO4 is transported to the ____ by _____

ER | gluc6PO4 translocase

in the ER of hepatocytes, the gluc6PO4 is converted to ___ by ____

glucose | gluc6PO4ase

in the muscles during need for energy, ano fate ng gluc6PO4

enters glucolysis | not released to blood coz no gluc6PO4ase

binding of what hormones signal the need for glycogen degradation

glucagon | epineph

ano signal transduction shit ng hormone regulation ng glycogenesis and lysis

PKA adenylyl cyclase cAMP

the active state of the phosphorylase kinase and phosphorylase maintained bcoz ____ is inhibited by the proteins also phosphorylates by cAMP w

protein phosphatase-1

how does insulin oppose the effects of glucagon and epinephrine

actiavtes phosphodiesterase that degrades cAMP and activates PP1

in liver, free glucose is also an allosteric inhibitor of ______ making it a better substrate for PP1

glycogen phsphorylase

glycogen storage dse: no glycogen synthase

type 0

glycogen storage dse: low gluc6PO4

type 1a (von Gierke's)

glycogen storage dse: loe lysosomal glucosidase

type II (Pompe's)

glycogen storage dse: glycogen storage dse: low debranching enzyme

type III (Cori's or Forbe's)

glycogen storage dse: low branching

type IV (Andersen's)

glycogen storage dse: low muscle phosphorylase

type V McArdle's

glycogen storage dse: low liver phosphorylase

type VI Hers'

alternate pathway for metab pf glucose

pentose phosphate pathway/HMP

two major function of HMP/PPP

formation of NADPH for synthesis of fatty acids and steroids | synthesis of ribose for nucleotide and nucleic acid formation

which phase of HMP/PP is reversible

nonoxidative phase

what are formed in the oxidative phase of PP/HMP

ribulose-5-PO4 CO2 2 mol. of NAPDH

1st step in PPP/HMP

gluc6PO4 is converted to 6-phosphogluconalactone by G6PD

in the 1st step of the PP/HMP, gluc6PO4 is ultimately converted to ___

6-phosphogluconate

potent competitive inhibitor of G6PD

NADPH

when there is an increased demand for NADPH, the NADPH/NADP ratio decreases and the flux of the forward rxn increases in response to _______

enhacned activity of G6PD

6-phosphogluconolactone is hydrolyzed to the _____ by a specific ____

free acid 6-phosphogluconate

in the 1st step, gluc6PO4 is initially converted to _____ by _____

6-phosphogluconolactone | G6PD

2ns step in PPP/HMP

oxidative decarboxylation of 6-phosphogluconate to ribulose-5-PO4 by 6-phosphogluconate dehydrogenase

the irreversible rxn of the oxidative decarboxylation og 6-phosphogluconate forms what

ribulose-5-PO4 CO2 2nd NADPH

the reversible nonoxid rxns of the PP/HMP allows the formation of

ribose-5-PO4 fructose-6-PO4 glyceraldehyde-3-PO4

first step in the non-oxid rxns of PPP/HMP

ribulose-5-PO4 is converted to xylulose-5-PO4 by ribulose-5-PO4 3-epimerase

in one rxn in the 1st nonoxid phase of PPP/HMP, ribulose-5-PO4 is converted to ____ by ____

xylulose-5-PO4 | ribulose-5-PO4 3-epimerase

in the another nonoxid rxn of the HMP/PPP for nucleotide and nucleic acid synthesis, ribulose-5-PO4 is converted to _____ by _____

ribose-5-PO4 | ribose-5-PO4 ketoisomerase

two enzymes unique to the PPP that act in the interconversion of sugars

transketolase | transaldolase

the enzyme transketolase requires which coenzyme

TPP

in the PP, what transfers the C1 and C2 of xylulose-5-PO4 to ribose-5-PO4

transketolase

in the 1st transketolase rxn of PPP/HMP, the xylulose-5-PO4 and ribose-5-PO4 are converted to

glyceraldehyde-3-PO4 | sedoheptulose-7-PO4

in the transaldolase rxn, 3-carbon fragment from sedoheptulose-7-PO4 is condensed with glyceraldehyde-3-PO4 and then turned to

fructose-6-PO4 | erythrose-4-PO4

in the 2nd transketolase rxn of PPP, _________ is converted to _______

xylulose-5-PO4 and erythrose-4-PO4 | glyceraldehyde-3-PO4 and fructose-6-PO4

in summary, the non-oxid rxns of PPP uses ________ to form _______

6 pentoses | 5 hexoses

in which pathway does glucose become glucoronic acid, ascorbic acid, and pentoses

uronic acid athway

does the PPP/HMP lead to ATP formation

does the uronic acid pathway lead to ATP production

1st step in uronic acid path

gluc6PO4 is isomerized to gluc1PO4 > reacts with UTP to form UDPGluc by UDPGluc phosphorylase

what enzyme is used in the formation of UDPGluc from UTP and gluc1PO4

UDPGluc phosphorylase

when forming the UDP-glucoronate, what happens to UDPGlc

oxidized @ C6 by UDPGlc dehydrogenase

2nd step of uronic acid path

UDPGlc oxidized to UDP-glucoronate

what oxidized the C6 at UDPGlc in the 2nd step of uronic acid pathway

NAD-dependent UDPGlc dehydrogenase

direct precursor of ascorbic acid

L-gulonate

3rd step in the uronic acid path

glucoronate is reduced to L-gulonate

in the 3rd of the uronic acid path, glucoronate is reduced to

L-gulonate

why can't ascorbic acid be synthesized in humans

absence of L-gulonolactone oxidase

enzyme used to synthesize ascorbic acid from L-gulonate

L-gulonolactone oxidase

in the last series of steps of the uronic acid pathway, l-gulonate is oxidized to

3-keto-L-gulonate

in the last series of steps of the uronic acid pathway, 3-keto-L-gulonate is decarboxylated to L-xylulose

L-xylulose

L-xylulose is converted to the D isomer by an NADPH-dependent reduction to _

xylitol

component of the uro nic acid pathway that is metabolized further in the PPP/HMP

D-xylulose-5-PO4

this is the 'busog ka na' hormone

leptin

first step in fructose metab

phosphorylation of fructose

what catalyzes the phoshporylation of fructose

fructokinase/hexokinase

hexokinase has a ____ affinity for fructose

low

action of fructokinase

fructose to fruc-1-PO4

2ns step in fructose metab

cleavage of furctose-1-PO4 to DHAP and glyceraldehyde

what catalyzes the 2nd step of the fructose metab

aldolase B aka fructose-1-PO4 aldolase

why is fructose metab faster than glucose metab

fructose metab bypass PFK-1 rxn

which component of the fructose metab can more readily enter the glycolysis pathway

DHAP

what converts glyceraldehyde to glyceraldehyde-3-PO4

triose kinase

insulin-independent organs

BRICK-L ``` brain RBCs intestine cornea kidney liver ```

insulin-dep organs

adipose | muscles

major carb source of sperm cells

fructose

how to make fructose from glucose

via sorbitol glucose > aldose reductase > sorbitol > sorbitol dehydrogenase

saan organs pwede pa maging fructose ung sorbitol

seminal vesicles liver ovaries

sobitol aka

polyol

explain cataracts, peripheral neuropathy, microvascular problems leading to nephropathy and retinopathy in diabetes

accumulation of sorbitol > water retention > swelling

autosomal defiency of fructokinase

essential fructosuria

aldoalse B deficiency

hereditary fructose intolerance

symptoms/complciations of HFI

severe hypoglycemia hepatomegaly due to accumulation renal dysfunction

ang essential fructosuria malignant or benign condition

benign whut

galactose metabolism explain mo na bes para sa ikauunlad ng bansa

galactose > (galactokinase) > glactose-1-PO4 > (glactose-1-PO4 uridylyltransferase/GALT/GAL1PUT) > UDP-galactose > (UDP-hexose 4 epimerase) > UDP-glucose

GALT deficiency

classic galactosemia

a metab due to accumulation of galactose,causing cataracts and etc

galactitol

dse where there is accumulation of galactitol

galactokinase deficiency

one of the most blabla na caused b y accumulation of galactitol

cataract

how is mannose converted to fructose6PO4

mannose > mannose6PO4 > (phosphomannose isomerase) > fructose6PO4

where synthesis ng lactose

golgi apparatus by lactose synthase

lactose synthase aka

UDP-galactose:glucose galactosyltransferase

which of protein of lactose synthase involved sa formation of N-acetyllactosamine

protein A

which protein of lactose sythase involved sa formation ng prolactin

protein B