Fate of Pyruvate Flashcards
what are the 3 fates of pyruvate?
citric acid cycle , homolactic fermintation, alcohol fermination
During aerobic conditions what happens to pyruvate?
citric acid cycle
What happens to pyruvate in anaerobic conditions in muscle
homolactic fermintation
anaerobic conditions in yeast
alcohol fermintation
what 2 products are produced during alcohol fermintation?
co2 and ethanol
what product is produced during homolactic fermintation?
lactate
what is the name of the enzyme used in homolactic fermintation?
lactate dehydrogenase
do we see oxidative phosphorylation or anarobic phosphorylation during intense exercise?
in the muscle when demand for ATP is high and o2 is low, ATP is synthesized via anarobic glycolysis which rapidly generates ATP.
What is often refferred to as Reaction 11 of glycolysis?
Homolactic Fermintation
is pyruvate to lactate reversible or irreversible?
LDH reaction is freely reversible
where does homolactic fermintation occur?
Overall process of anaerobic glycolysis in muscle
Write out the reaction for homolactic fermentation
Glucose + 2 ADP + 2 Pi ➔ 2 lactate + 2 ATP + 2 H20 + 2 H+
once lactate has been created what will happen to the lactate?
Lactate can either be exported from the cell or converted back to pyruvate
What happens to Lactate produced in skeletal muscle cells ?
Lactate produced in skeletal muscle cells is carried by the blood to the liver, where it is used to synthesize glucose
why do we have the 3 phates of pyruvate?
WE NEED TO GATHER MORE NAD+ which is why we use one of these 3 fates.
What is the overall goal of homolactic fermintation?
The overall goal is to get more NAD+
since the NADH is losing hydrogens , it is getting oxidized. this means that we are reducing the pyruvate.
Where do we see alcohol fermintation
Under anaerobic conditions in yeast
what are the products generated in alcohol fermintation?
Conversion of pyruvate to ethanol and CO2
Yeast produces ethanol and CO2 via two consecutive reactions: Describe them!
- The decarboxylation of pyruvate to form acetaldehyde and CO2 as catalyzed by pyruvate decarboxylase
Enzyme not present in animals
2.The reduction of acetaldehyde to ethanol by NADH as catalyzed by alcohol dehydrogenase
Regenerates NAD+ for use in the GAPDH reaction of glycolysis.
what are the 2 enzymes in alcohol fermintation
pyruvate decarboxylase
alcohol dehydrogenase
True/ False pyruvate decarboxylase is not found in animals
True, pyruvate decarboxylase
enzyme is not present in animals
Alcohol dehydrogenase is a reversible process, yet we only see an arrow going in one direction . Why is this?
Even though that step is reversible we only see an brown going in one direction . this is because that first step ( pyruvate decarboxylase) is a very negative process. due to the idea of coupling it powers the next reaction and therefore prevents it from being reversible.
What is the name of the coenzyme that pyruvate decarboxylase has?
Pyruvate decarboxylase contains the coenzyme thiamine pyrophosphate (TPP; also called thiamine diphosphate; ThDP)
what is TPp Synthesized from?
Synthesized from thiamine (vitamin B1)
T/F Tpp binds covalently to pyruvate decarboxylase
False .Binds tightly but noncovalently to pyruvate decarboxylase
is TPp a prostetic group?
Yes. TPP is an example of a prosthetic group, permanent it stays with the enzyme
Does Tpp act as an electron sink
yes
what vitamin is thiamine
Thiamine (vitamin B1)
thiamine is necessary for synthesis of ____
thiamine is necessary for synthesis of TPP
what is the name of the Enzyme that converts acetaldehyde to ethanol
Yeast alcohol dehydrogenase (YADH)
what is the function of the Zn charge in yeast alcohol dehydrogenase
Zn2+ polarizes the carbonyl group of acetaldehyde to stabilize the developing negative charge in the transition state of the reaction
