intermediary metabolism 3- bioenergetics Flashcards
what is the product of anaerobic metabolism vs. aerobic metabolism?
anaerobic = glucose - pyruvate product
aerobic= glucose - CO2 and H2O product
Describe the two ways ATP is produced
a) directly - substrate level phosphorylation
b) indirectly - oxidative phosphorylation - NADH and FADH2- act as carriers of energy in the form of ‘reducing power’ electrons
how many ATP does one NADH or one FADH2 produce?
NADH = 3 ATP
FADH2= 2 ATP
what is the end product of glycolysis?
pyruvate
Pyruvate is converted to what molecule that enters the TCA cycle?
converted to acetyl CoA - which enters the TCA cycle
1 glucose produces how much ATP max under aerobic metabolism?
38 ATP
what cycle is responsible for the bulk of ATP production in oxidative metabolism?
the TCA cycle
where does glycolysis occur?
the TCA cycle?
glycolysis= in the cytoplasm
TCA= mitochondrion
where does the pyruvate transporter exist?
in the inner mitochondrial membrane
where is pyruvate converted into acetyl - coA?
in the matrix
What enzyme converts pyruvate into acetyl-CoA?
pyruvate dehydrogenase ocmplex (which contains 3 distinct enzymes)
what regulates the activity of pyruvate dehydrogenase?
it is allosterically inhibited by Acetyl-CoA and NADH
what is the advantage of the pyruvate dehyrogenase complex?
the complex (consisting of 3 distrinct enzymes) allows pyruvate to be converted to Acetyl CoA without releasing any of the intermediate molecules
What occurs in pyruvate dehydrogenase deficiency?
pyruvate cannot be converted to Acetyl Co A - and it is insted converted to lactic -acid - even in the presecne of oxygen.
Symptoms of this include developmental defects, muscular spacticity, and early death
What does arsenic poisoning effect?
arsenic poisoning -
arsenic is an inhibitor of enzymes that use lipoic-acid as a cofactor- therefore, it will inhibit pyruvate dehydrogenase - symptoms include neurological disturbances and death
what four vitamins are essential for pyruvate dehydrogenase function?
- panthotenic acid
- niacin
- riboflavin
- thiamine
b/c these vitamins are required to synthesize CoA, NAD, FAD, and TPP
what is the importance of the TCA cycle?
generation of NADH from NAD +
now the NADH is ‘loaded’ with electrons that it can use to make ATP
Describe the reaction of alpha-ketoglutarate dehydrogenase
this is a complex that reduces NAD+ to NADH
by transforming alphaketoglutarate into succinyl coA
Describe the reaction of succinate thiokinase
succinate thiokinase involves substrate level phosphorylation producing GTP
from the reaction converting succinyl CoA to succinate
what enzyme generates FADH2?
Succinate Dehydrogenase
What is the role of Fumarase?
it hydrates fumarate converting it to malate
for each turn of the TCA cycle, how many NADH, FADH2, and GTP are produced?
3 NADH
1FADH2
1 GTP
what is the rate limiting step of the TCA cycle?
isocitrate dehydrogenase
What are the three key points of regulation in the TCA cycle?
- citrate synthase
- isocitrate dehydrogenase
- alphaketoglutarate dehydrogenase
the TCA cycle is amphibolic… what does that mean?
it is involved in both anabolic and catabolic pathways
