Gycolysis and Anaerobic Respiration

what is cellular respiration

series of chemical reactions, some of which require *oxygen* and some of which do not, that produce the bulk of cellular energy

what is the quantity like in cellular respiraton and what does it produce?

synthesized in large quantities and produces ATP

who does cell respiration?

all cells, all living things to produce the necessary energy to promote normal cellular processes

what is the net reaction of cellular respiration

C6H12O6 + __6__O2 → __6__CO2 + __6__H2O + (**ATP x 36**)

where does glycolysis occur

in the cytosol

who can perform glycolysis

it is produced in every cell since it doesn’t require oxygen

what do electron carriers do

they carry electrons H+ to the electron transport change to promote oxidative phosphorylation

what are the four main stages of cell respiration

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gycolysis → pyruvate oxidation → kreb cycle → oxidative phosphorylation

what are the two electron carriers in cell respiration

NADH: synthesized from B3 and releases e- to ETC to become NAD+

FADH2: synthesized from B2 and releases 2 e-

are the electron carriers being reduced or oxidized?

oxydized because they are losing an electron

what oxidation process occurs in glycolysis

with the sugar to pyruvate, it goes from a 6 chain carbon to 1 carbon

what is the overview of glycolysis

anaerobic respiration that place in all cells and converts one molecule of glucose into two pyruvates a three carbon sugar

what is produced at the end of glycolysis

2NADH molecules that will be used in oxidative phosphorylation

4 ATP molecules but 2 get used up in first phase of glycolysis

2 waters

2H+

what is the net reaction of glycolysis

C6H12O6 (Glucose) + __2__NAD+ + __2__ADP + __2__Pi (Inorganic Phosphate) → __2__C3H4O3 (Pyruvate/ Pyruvic Acid) + __2__NADH + __2__H+ + __2__ATP + __2__H2O

what are the irreversible reactions of glycolysis and why are they irreversible

reaction 1, 3, 10

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they involve high energy phosphate group to form sugar and creates unfavorable reactions (entropy)

what happens during reaction 1

glucose binds with ATP to attach a phosphate onto the glucose

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creates glucose - 6 - phosphate and ADP

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ATP is hydrolisized and becomes ADP + P1 which is attached to glucose

what enzyme catalyzes reaction 1?

hexokinase which has quarternary structure with 6 tertiary subunits and it finds to glucose to catalyze it in order to attach the phosphate onto it

where does the phosphate bind in reaction one

on the 6th carbon of the sugar molecule

why is reaction one irreverseible

to synthesize ATP you would need water and go through condensation

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adding phosphate onto something, it’s not going to want to come off if it is not ATP

what happens during reaction 3

intermiediate from reaction 2 frutose-6-phosphate takes a phosphate from ATP to make a molecule that now has two phosphates onto it

what enzyme is used in reaction 3

phosphofrutosekinase - 1 which adds phosphate so now there is a phosphate on carbon 1 and 5

why is reaction 3 irreversible

same reasons as reaction 1

what is the reactant of reaction 10 and what is the enzyme used

phosphenolpyruvate pyruvate kinase

what is the enzyme used in reaction 10

pyruvate kinase

what are the different phases of glycolysis and what reactions do they include

investment phase: 1 - 5

* two ATP used to break glucose down

Payoff: 6-10

* 2 ATP created

what is the investment phase

phase where 2 ATP molecules are used and no molecules are produced

what is produced at the end of the investment phase

2 glyceraldehyde-3-phosphate (g3p) which are 3-carbon carbohydrate intermediates

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started with 6 carbons, so you have 2 3-carbons

what is the payoff phase

4 ATP produced which leads to net gain of 2 ATP over the entire system

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(2 ATP produced for each G3P)

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2 pyruvates are produced

what determines if pyruvates form or not

the presence of oxygen

what does the presence of oxygen do?

if oxygen:

pyruvate be shuttled into the mitochondria and converted to Acetyl-CoA for aerobic respiration

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if NO oxygen:

pyruvate is used as substrate to produce lactate or ethanol depending on the enzymes present FERMENTATION will occur in the cytosol

why is glyocolysis more flexible

cells are capable of skipping reactions they just need to get through the irreversible reactions

* they can hit pause, stop, or go backwards on reversible reactions if needed to

why can the cell skip reactions

depends on the carbohydrates that you consume and also if the body feels that the products of some glycolysis reactions can be used elsewhere to make other things

why is skipping reactions considered favorable

you’re not using ATP as much in the investment phase and you can potentially make more ATP

how does glucose-6-phosphate shunt or interrupt glycolysis

it can be used as a substrate to synthesize glycogen for the body

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gluconeogenesis: goes back one step and resynthesize glucose

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pentose phosphate pathway: uses glucose-6-phosphate to create pentose or 5-carbon sugars

how can reaction 5 shunt or interrupt the cycle

glyceraldehyde-3-phosphate can be used to synthesize glycolipids: triglycerides

how does pyruvate interrupt the cycle

can be used to synthesize fatty acids but also some amino acids

how do some amino acids that are not consumed made in the body

use carbohydrates and convert into ketones and then those ketones are used to synthesize the remaining amino acids that we need

where does the pyruvate get transported to participate in cell respiration

the matrix

what is the pyruvate necessary for

the kreb cycle once it is converted into Acetyl-CoA

how is Acetyl-CoA created

two-carbon molecule with a large coenzyme A attached to it

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there is a removal of carbon

what happens to the third carbon in the pyruvate when it gets converted into Acetyl CoA

CO2 is produced and leaves the cell

what is being oxidized in pyruvate oxidation and what is being reduced

pyruvate: oxidizes and loses a carbon

NAD+: reduces to NADH and the additional will be used in oxidative phosphorylation

how are pyruvates and electron carriers able to move into the matrix

through transport membrane proteins

what is lactic acid fermentation

pyruvate is converted to lactate when there isn’t any oxygen or in prokaryotes where they can’t do aerobic respiration since they don’t have a mitochondria

where does lactic acid fermentation occur

in highly active muscle tiessue that cannot obtain enough oxygen at a fast enough rate to allow for aerobic respiration

what happens in lactic acid fermentation

NADH recycled/oxidixed to NAD+ and will go back to reaction 6 for it to be reduced back to NADH

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the pyruvate is going to be converted back to glucose until there is oxygen present for it to continue with cell respiration

what is an example of lactic acid fermentation being used in the body

converts from lactate back to pyruvate back to glucose through gluconeogenesis in the liver

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if muscle tissues make a high quantity of lactate, it will be transported to the liver through the blood stream so that it can be used to resynthesize glucose

what is alcohol fermentation

pyruvate is converted to an intermediate acetaldehyde and then to alcohol

what is also produced during alcohol fermentation

CO2 and NADH is recycled to NAD+ back into reaction 6

how is CO2 produced in alcohol fermentation

when converted into actealdehyde it loses a carbon

what is the intermediate in alcohol fermentation

acetaldehyde

what is the product of reaction one

glucose-6-phosphate

what is the reactant and product of reaction 3

frutose-6-phosphate, frutose-1,6,-biphosphate

what is the reactant of reaction 10

phosphenolpyruvate

what is produced in reaction 5

glyceraldehyde-3-phosphate

at what reaction are the NADH produced

reaction 6

at what reaction is water produced

reaction 9