Phase 1 of Glycolysis

what is the goal of glycolysis

use 6 carbon compounds to produce 3 carbon intermediates for production of energy in form of ATP

1st law of thermodynamics

matter can be neither created nor destroyed

where is the energy in the carbon-carbon bonds of glucose transferred

to ADP to form ATP

what is glucose broken down into in glycolysis

pyruvate

how many carbons are in pyruvate

3

how many reactions occur to produce pyruvate from glucose

10

how many ATP are used in glycolysis

2

how many ATP are gained in glycolysis

4

what is the net gain of ATP in glycolysis

2 ATP

what is the fate of pyruvate under aerobic conditions

citric acid cycle breaks down pyruvate into CO3 and H2O, reduces NAD+ and FAD to NADH and FADH2

what is the fate of pyruvate under anaerobic conditions

fermentation and anaerobic glycolysis

fermentation of pyruvate

loss of CO2 and reduction to ethanol

anaerobic glycolysis of pyruvate

reduction of pyruvate to lactate

where does fermentation and anaerobic glycolysis occur in the body

muscle cells

who was the inventor of pasteurization and determined that glucose supplied more energy in presence of O2

Louis Pasteur (1822-1895)

who was the german biochemist that determined the intermediates of glycolysis

meyerhof (1884-1951)

who was the german biochemist that worked out precise steps involved in the breakdown of glucose

embden (1874-1933)

phase 1 of glycolysis

Energy is used to make adjustments so that the six-carbon sugar molecule can be split evenly into two three-carbon pyruvate molecules

what is formed following the first "priming reaction" of phosphorylating glucose

fructose 1,6-bisphosphate

what happens to the fructose 1,6-bisphosphate following the second priming reaction

splits into 2 molecules of glyceraldehyde-3-phosphate

phase 2 of glycolysis

conversion of glyceraldehyde-3-phosphate to pyruvate and coupled formation of 4 ATP

sugars/carbohydrates/saccharides

simple organic compounds that are aldehydes or ketones with many hydroxyl groups added

what range of carbons exist in sugars

3-7

sugars contain different configural substituents which are referred to as what?

optical isomers or stereoisomers

which stereoisomer is used in glycolysis

D-carbohydrates

how to determine D and L isomers for sugars with more than 3 carbons

the position of the OH on the highest carbon number chiral carbon defines D or L

what is numbering of carbons based on

aldehyde sugars

which carbon is carbon #1 in aldehyde sugars

the most oxidized carbon

which carbon is oxidized in ketone sugars

carbon #2

which sugars normally exist as cyclic structures

5 or 6 carbon sugars

what do the free electrons on OH of carbon 5 bond with

carbon 1, which forms a cyclic structure

pyran

six membered ring with 5 carbosn and 1 oxygen

fischer projection

2D representation of the stereochemisty of 3D molecule

haworth projection

a perspective representation of the cyclic forms of sugars

what does step 1 of phase 1 of glycolysis produce

glucose-6-phosphate

which enzyme carries out the phosphorylation of glucose to G6P (step 1, phase 1)

hexokinase

Besides hexokinase, what 2 things are required for the phosphorylation of glucose to G6P to occur

ATP and Mg2+

why is ATP required for the first step of phase 1 of glycolysis

phosphorylation of glucose without ATP is thermodynamically unfavorable (deltaG= 3.3 kcal/mole)

what is the free energy of phosphorylation of glucose without ATP

3.3 kcal/mole

what is the free energy of phosphorylation of glucose when couped with ATP

-4.0 kcal/mole

kinase

enzyme that transfers a phosphate from ATP to substrate

what happens to hexokinase when glucose binds

conformational change

what happens to glucose when it binds to hexokinase

becomes completely surrounded by enzyme and inaccessible to solute

what kind of enzyme-substrate interaction is hexokinase binding to glucose

induced-fit

what happens in step 2 of phase 1 of glycolysis

G6P is isomerized to fructose-6-phosphate (F6P)

what happens to the structure following the isomerization of G6P to F6P

change from 6 membered ring to 5 membered ring

which enzyme carries out the isomerization of G6P to F6P (step 2, phase 1)

glucosephosphate isomerase

t/f: there is no net oxidation or reduction in the second step of phase 1 of glycolysis

true

1 multiple choice option

what happens in step 3 of phase 1 of glycolysis

F6P is phosphorylated to give fructose-1,6-biphosphate

which enzyme carries out the phosphorylation of F6P to fructose-1,6-biphosphate (step 3, phase 1)

phosphofructokinase (PFK)

besides PFK, what else is required in step 3 of phase 1 of glycolysis (phosphorylation of F6P to fructose-1,6-biphosphate)

ATP and Mg2+

what is the free energy of phosphorylation of F6P without ATP

deltaG > 0 (thermodynamically unfavorable)

what is the free energy of phosphorylation of F6P when coupled with ATP

detaG = -3.4 kcal/mole

what happens to G6P and F6P following step 3

can be utilized by other pathways or react with phosphofructokinase (PFK)

3 multiple choice options

t/f: G6P and F6P do not have to proceed through glycolysis

true

1 multiple choice option

what happens once PFK produces fructose-1,6-bisphosphate

it is committed to glycolysis

t/f: production of fructose-1,6-bisphosphate from G6P and F6P is reversible

false

1 multiple choice option

what kind of enzyme is PFK

regulatory

what serves as an allosteric regulator of PFK

ATP

3 multiple choice options

what induces PFK enzyme activity

low [ATP]

what happens to PFK activity at high [ATP]

activity is suppressed

why is PFK activity suppressed in the presence of high cellular [ATP]

no need for ATP production since it is present in high levels

what happens at high cellular [ATP]

PFK inactivation, glycolysis shuts down

why is PFK enzyme activity induced at low cellular [ATP]

requirement for ATP

what happens at low cellular [ATP]

PFK activated, glycolysis starts up

what happens in step 4 of phase 1 of glycolysis

fructose-1,6-bisphosphate is split into two 3-carbon molecules

what 2 molecules is fructose-1,6-bisphosphate split into during step 4 of phase 1 of glycolysis

dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GA3P)

which enzyme carries out the reaction that splits fructose-1,6-bisphosphate into DHAP and GA3P

aldolase

what happens to the intermmediates once they are split into the two 3-carbon molecules (DHAP and GA3P)

they are no longer cyclic

what form are DHAP and GA3P

linear

1 multiple choice option

what happens in step 5 of phase 1 of glycolysis

DHAP is converted to glyceraldehyde-3-phosphate (GA3P)

which enzyme carries out the conversion of DHAP to GA3P

triosephosphate isomerase

what is the end result of phase 1 of glycolysis

6 carbon glucose converted to two 3-carbon GA3P (glyceraldehyde-3-phosphate)