Chapter 16 - Glycogenesis

Front 1

stage 1 - 2nd step

isomeration of glucose 6 phosphate to?
(changing from an aldose to?)

this step is catalyzed by?

Back 1

fructose 6 phosphate

ketose

phosphoglucose isomerase

Front 2

why bother ismerizing g6p to f6p?

Back 2

glucose does not break down into a three carbon as easily as fructose

Front 3

stage 1 - 3rd step

----- of f6p to form ?

catalyzed by?

this is the --- step

Back 3

phosphorylation, f16bp

pfk (phosphofructokinase)

commited

Front 4

PFK is a key ------- ------- enzyme

Back 4

regulatory allosteric

Front 5

Splitting stage

what cleaves f16bp?

what are the two molecules that result?

is this process reversible or irreversible?

Back 5

aldolase

DHAP - dihydroxy acetone

GAP - glyceraldehyde 3 phosphate

reversiblec

Front 6

conversion of DHAP to GAP is -----

achieved through what ensyme?

Back 6

reversible

triose phosphate isomerase

Front 7

Stage 2 - Energy Capture Reaction 1

GAPDH creates ---- and -----

this is ----- and requires ----+

Back 7

NADH, 1,3-BPG

reversibe, NAD+

Front 8

when GAP is turned into 1,3-BPG by GAPDH... there is a ----- intermediate which is more/less stable than the reactants and hence, its formation is spontaneous or nonspontaneous?

the thioester intermediate is less/more stable than the product, which forms ------

there is a coupling of two reaction with GAPDH in which it lowers a large activation barrier (page 258)

Back 8

thioester, more, spontaneously

less, spontaneously

Front 9

Energy Capture 2 - Atp

what converts ADP to ATP using phosphate from ?

this is ---- level phosphorylation

all invest atp is -----

rxn is rev or irrev

1,3-BPG is transformed to 3-phosphoglycerate by ------ ----- to generate -----

Back 9

phosphoglycerate kinase, 1,3-BPG

substrate

recovered

reversible

phosphoglycerate kinase, ATP

Front 10

Preparing for another energy capture

------- ------- rearranges a phosphoryl group from 3-phosphoglyceratte to --------- as a preparatory step

this run is freely rev or irrev?

Back 10

phosphoglycerate mutase

2-phosphoglycerate


freely reversible

Front 11

------ converts 2 phosphoglycerate to ------- via a ---- rxn

the energy of hydrolysis change is ----- kcal/mol for 2-phosphoglycerate
and ---- for PEP

PEP has a high ------ transfer potential

Back 11

ENOLASE, PEP (phosphoenolpyruvate), dehydration

-4.2
-14.8

phosphoryl

Front 12

Second energy capture

--------- converts PEP to -----

this captures -----

this rxn is rev or irrev?

Back 12

pyruvate kinase, pyruvate (TCA)

ATP

irreversible under cell conditions

Front 13

Glycolysis net reaction?

Back 13

glucose + 2 Pi + 2 ADP + 2 NAD+ -->

2 pyruvate +2 ATP + 2 NADH + 2H + 2 H2o

Front 14

Under ----- conditions, ---- is shuttle into the ------

Back 14

aerobic, NADH, mito

Front 15

What three things can pyruvate be turned into?

Back 15

to ACETALDEHYDE which then turns to ETHANOL

LACTATE

ACETYL CoA - this can further undergo oxidation

Front 16

Regeneration of NAD+ is need for glycolysis to proceed

------ reaction produces NADH

under anearobic conditions ---- production is proceeded to produce NAD+

under aerobic conditions the ---- ---- ---- is utilized to make NAD+

Back 16

GAPDH

lactate

electron transport chain

Front 17

Pyruvate destination

1) Ethanol fermentation
done only by ---- and other microorganisms

pyruvate is first turned into ----- by ------.
this enzymes requires vitamin ------

----- is then turned into ----- by ------. this uses NADH and regenerates ----`

Back 17

yeast,

acetaldehyde, pyruvate decarboxylate
thiamin/B1

acetaldehyde, ethanol, alcohol dehydrogenase, NAD+

Front 18

Lactic acid fermentation is the reduction of ----- to ----

this regenerates ------

the enzyme used is ------

Back 18

pyruvate, lactate,


NAD+

lactate dehydrogenase

Front 19

Lactic Acidosis is an emergency state- increase production of --- and decrease use of ----

lactate comes from anaerobic -----

standard blood lactate is approx --- mM
acidosis levels at ---

Back 19

lactate, lactate,

glycolysis

1.2, 5

Front 20

other sugars such as ---- and ---- are metabolized into glycolysis intermediates

most ingested ---- is metabolized by the ----

Back 20

fructose, galactose

fructose, liver

Front 21

Fructose is turned into fructose 1 phosphate by ------

fructose 1 phosphate is then split into ---- and ----

---- can then enter glycolysis

this allows Glyceraldehyde to be phosphorylated by ----- kinase to form ------

Another way: fructose in the ----- tissue can be phosphorylated to -----

fructose in the ---- can be converted to -- and -- as well.

Back 21

fructokinase

glyceraldehyde, DHAP

DHAP

triose, glyceraldehyde 3-phosphate

liver

adipose, fructose 6 phosphate (F6P)

liver,DHAP, GAP

Front 22

Galactose can also be phosphorylated to ----- and then that intermediate can enter glycolysis

Step 1: Galactose is phosphorylate to ------ by ----kinase

Step 2: Together with galactose 1-phosphate, replace glucose on UDP------ to become UDP-galactose which releases a -----

Back 22

G6P


Galactose 1-phosphate, galactokinase

UDP-glucose, glucose 1-phosphate

Front 23

Step 3: UDP ----- is converted to UDP ----


Step 4: convert glucose 1-phosphate to ----------- by what enzyme?

hint: enzyme has the word "mutase"

Back 23

galactose, glucose,


glucose 6-phosphate, phosphoglucomutaste

Front 24

key concept:

enzymes catalyzing ------ reactions in metabolic pathways are points of ----

Back 24

irreversible, reguation

Front 25

What are the regulated enzymes for glycolysis?

Back 25

hexokinase, phosphofructokinase (PK1),Pyruvate kinase

Front 26

Enzymes that are not regulatory often control "----- ----" rxns.

Back 26

near eqilibrium

Front 27

Regulation of glycolysis in the muscle

PFK - irreversible rxn , COMMITED STEP

it is ----- regulated by ATP, ----- binding of ATP incr/decr affinity for F6P

it is ---- regulated by AMP. it competes with ___ for the allosteric binding site

it is ----- regulated by ---pH. need protection from excessive lactic acid fermentation


reaction velocity is high/low with low levels of ATP.

Back 27

negatively, allosteric, decreases


positively, ATP

negatively, low

high

Front 28

Hexokinase is inhibited by?

Back 28

Its own product: glucose 6-phosphate

Front 29

high concentration of glucose 6-phosphate indicate energy charge is ----

hexokinase also becomes inhibited by another regulatory enzyme: ----

Back 29

high

PFK1 (phosphofructokinase)

Front 30

IF PFK1 is inactive then it cannot convert F6P to ?
this leads to high levels of ---- which in turn raises levels of ----.

Rising levels of ---- would thus inhibit hexokinase

Back 30

F 1,6-bisphosphate

F6P, G6P

G6P

Front 31

Regulation of glycolysis in muscle through pyruvate kinase

Pyruvate Kinase is negatively regulated by --- and ---

Positively regulated by ?

Back 31

atp and alanine

fructose 1,6 bisphosphate

Front 32

Regulation of glycolysis in liver

PFK is inhibited by -----

and activated by ----- through increasing PFK's affinity for ---

Back 32

citrate

F-2,6-BP (fructose 2,6 bisphosphate) -->(made from F6P, catalyzed by PFK to make F-1,6-BP)

increas PFK affintiy for F -6P

Front 33

The liver uses an isozyme of hexokinase called ------.
it has a much lower/higher affinity for glucose.

(when glucose is low the liver does/doesn't use it, so it is preserved for the brain and other tissues)

Back 33

glucokinase, lower

doesn't

Front 34

Glucokinase is/isnt inhibited by G6P

Glucokinase generates G6P for ---- and ----- synthesis

Back 34

isnt

glycogen, fatty acid synthesis

Front 35

In the liver, pyruvate kinase is inhibited by -----

Back 35

phosphorylation

Front 36

When blood glucose level is high/low the phosphorylated pyruvate kinase is -------- by -----triggered protein phosphatase. The dephosphorylated pyruvate kinase is now more/less active and able to make ----.

When blood glucose level is low/high, the dephosphorylated pyruvate kinase is phosphorylated by --- and enters a less/more active form.

Back 36

high, dephos, insulin, more, pyruvate

low, ATP, less

Front 37

PFK1 is the first/second commited step in glycolysis

What are the neg and pos allosteric regulators?

Back 37

first

NEGATIVE : low pH (in muscle), ATP, cirate (liver)
POSITIVE : AMP, F 2,6 BP

Front 38

AMP and ATP signal ---- state
pH signals info about the --- environment
citrate signals the availability of --- ----

F 2,6-BP signals the ratio of ----/---- in the blood

Back 38

energy
internal
alternative fuels

insulin/glucose

Front 39

Why is alanine an inhibitor of pyruvate kinase?

Back 39

Alanine is most commonly made by transfer of an amine group to pyruvate. Because transamination reactions are readily reversible, alanine can be easily formed from pyruvate and thus has close links to metabolic pathways such as glycolysis, gluconeogenesis, and the citric acid cycle.

Front 40

Tissue specific regulation - LIVER

The isozyme of hexokinase in liver is glucokinase or hecxokinase IV.

it has a higher/lower km for glucose
G 6-P is also used for ----- synthesis in liver through the ---- ---- pathway

Back 40

higher Km, because lower affinity

glycogen, pentose phosphate

Front 41

continued...

is pfk negative regulation in liver significant?
PFK is ----- by F 2,6BP in liver

Back 41

ATP and low pH regulation not as significant in liver

activated

Front 42

Pyruvate kinase in liver is known as ---- ---- ----.
it is regulated by -------.
Prevents liver from consuming glucose when blood-glucoes levels are low

----induced ---- pathway

Back 42

pyruvate kinase L
phosphorylation

glucagon, cAMP

Front 43

Glycolysis inhibition by -----

----- is a pancreatic hormone and activates ------. this raises/lowers blood glucose levels

Back 43

glucagon
glucagon,gluceogenesis, raises

Front 44

Glucose transporters

Glut1?
Glut3?
Glut4?
Glut2?

Back 44

Red Blood Cell 1

Brain 3

Muscle and Fat Cells 4

Liver and pancreatic beta cells 3

Front 45

Which glucose transporter(s) has a Km of ~1 mM, that is lower than blood glucose levels, AND continually uptake glucose?

Intermediate km?

High km?

which transporters are insulin dependent?

Back 45

Glut 1 and Glut 3 (rbc and brain)


glut 4 (muscle and fat cells)

glut3 (liver and pancreatic beta cells)

glut 4 and glut 3 are insulin dependent

Front 46

insulin stimulates glucose uptake by adipos tissue and muscle by increasing the number of --- --- in the ---- ---.

Back 46

glucose transporters (GLUT4), plasma membrane.

Front 47

There is an overexpression of ---- enyzmes in cancer cells.

Back 47

glycolytic

Front 48

Cancer cells grow more rapidly than the blood vessels to nourish them; thus, as solid tumors grow, they are unable to obtain oxygen efficiently. In other words, they begin to experience -----, a deficiency of oxygen.

Under this condition, glycolysis leading to lactic acid fermentation becomes the primary source of -----.

Glycolysis is made more efficient in hypoxic tumors by the action of a transcription factor, _____-______ _______ tractor.


In the absence of oxygen, ----- increases the expression of most ----- enzymes and the glucose transporters ---- and -----.

Back 48

hypoxia

ATP

hypoxia-inducible transcription factor (HIF-1)

HIF-1, glycolytic, GLUT1, GLUT3

Front 49

Process of glycogen to glucose?

glucose to lactate?

lactate to glucose?

glucose to glycogen?

Back 49

glycogenolysis

glycolysis

gluceoneogenesis

gluconeogenesis

glycogenesis

Front 50

when oxygen is present how much atp per glucose molecule?

when oxygen isnt present?

Back 50

32 ATP

2 ATP

Front 51

Stage 1 - priming of glucose

requires ---- ATP

what is the end result?

Back 51

2

two 3-carbon fragments

Front 52

stage 2 - harvesting ATP

oxidation of what?

and substrate level ----.

Back 52

3 carbon fragment


phosphorylation

Front 53

Stage 1 - 1st step

glucose is converted to --- by ----

this rxn is rev or irrev?

Back 53

G3P - glucose 3 phosphate
hexokinase

irrev

Front 54

Hexokinase phosphorylation of glucose ---- it inside the cell. it is no longer a ---- for the membrane glucose transporters

when glucose binds hexokinase via an ----- fit, it causes a ------ change in hexokinase.

----- then surround the glucose molecule, expelling --- for the environment

--- then binds for ------- group transfer

the removal of water from the active site protects --- from being hydrolyzed by the water

Back 54

traps, ligand

induced, conformational

hydrophobic groups, h2o

atp, phosphoryl

ATP