Carbohydrates 5 Flashcards
Where does the citric acid cycle occur?
Matrix of the mitochondria
Why is the citric acid cycle very efficient?
Does not need many intermediate compounds
What does the citric acid cycle act as a gateway for?
Any compound that can be converted into acetyl coenzume A or a component of the cycle to enter aerobic respiration
How does the citric acid cycle produce ATP?
Not directly, but through the use of electron carriers that then go to the electron transport chain and produce ATP
What does the citric acid cycle do?
Removes electrons from intermediates and passes them onto NADH and FADH2
Is O2 used in the citric acid cycle?
No
What does the use of O2 allow for glucose?
It to be completely broken down into CO2 and all of its energy to be stored
What substances can be broken down into acetyl coenzyme A and enter the citric acid cycle?
Glucose
Fatty acids
Amino acids
What does the overall metabolism process look like (glycolysis, citric acid cycle and the electron transport chain)?
Why are substances like glucose broken down in lots of little steps and not all at once?
It allows packets of energy to be stored, breaking down the compound at once would release to much enery to be capture so most of it would be lost as heat
What does acetyl coenzyme A allow?
Many intermediates to enter the citric acid cycle
What enzyme coverts pyruvate into acetly coenzyme A?
Pyruvate dehydrogenase complex
How many sub units is pyruvate dehydrogenase complex composed of?
Ten copies of each sub unit (E1 + E2 + E3)
What does each subunit of pyruvate dehdrogenase complex do?
Catalyses a different part of the reaction
What happens to the concentration of the intermediates within the citric acid cycle?
They remain constant as each turn 2 carbons enter (acetyl coenzyme A) and 2 carbons leave (as 2 CO2)
What does the citric acid cycle look like in terms of the amount of carbon each complex has and the use of electron carriers?
What are the intermediates of the citric acid cycle?
What do intermediate products of the citric acid cycle and ATP do to pyruvate dehydrogenase complex?
Regulate it
What substance inhibit pyruvate dehydrogenase complex?
Acetyl coenzyme A
NADH
ATP
What substances activate pyruvate dehydrogenase complex?
Pyruvate
ADP
What does the regulation of pyruvate dehydrogenase complex mean?
Energy is not generated when it is not needed
What are the points of control in the citric acid cycle other than the inhibition of pyruvate dehdrogenase complex?
Regulating the irreversible steps
What enzymes control the irreversible steps of the citric acid cycle that can be regulated?
Isocitrate dehydrogenase and a-ketoglutamate dehydrogenase
What does ATP and NADH do to isocitrate dehyrogenase?
Inhibit it
What does ADP do to isocitrate dehydrogenase?
Activate it
What does ATP, NADH and sucoinyl do to a-ketoglutamate dehydrogenase?
Inhibit it
What does controlling the irreversible steps of the citric acid cycle allow for?
The build up of intermediates (citrate and a-ketoglutamate) which can be used elsewhere
What kind of pathway is the citric acid cycle?
Amphibolic as the intermediates can be used in other anabolic pathways
What does amphilbolic mean?
Serves both catabolic and anabolic processes
What can the citric acid cycle make building blocks for when energy levels are okay?
Nucleotide bases
Heme groups
Proteins
What is a problem with intermediates of the citric acid cycle being used elsewhere?
Can lead to a deficiency of the intermediates, stopping the citric acid cycle and the generation of energy
