Chapter 9.2.2 (Exam 2) The Citric Acid Cycle Flashcards
In the Presence of Oxygen, Glucose Is Fully Oxidized
What is the starting point of the citric acid cycle/Krebs cycle?
Acetyl CoA
How many reactions are in the citric acid cycle?
8 reactions
How many CO2 molecules are produced by the citric acid cycle?
2 CO2 molecules
Which molecules capture the energy released by the citric acid cycle?
GDP → GTP
FAD+ → FADH2
NAD+ → NADH
Is oxaloacetate a reactant or a product of the citric acid cycle?
It is both, it is used in the first step to form citrate, and then regenerated so that the cycle can restart
How many citric acid cycles are needed to break down one molecule of glucose?
2 cycles; One glucose forms two pyruvate, one pyruvate forms one Acetyl CoA which starts the citric acid cycle
What are the inputs of the citric acid cycle?
Acetyl CoA
NAD+
FAD+
H2O
What are the outputs of the citric acid cycle?
CoA
CO2
NADH
FADH2
GTP
If the citric acid cycle outputs GTP instead of ATP, how does it produce energy efficiently?
Energy in the bonds of GTP immediately gets transferred into energy in the bonds of ATP
GTP + ADP → ATP + GDP
How many CO2 molecules and reduced electron carriers does the citric acid cycle output?
Produces 2 CO2 molecules and 4 reduced electron carriers
What is the overall yield of the breakdown of one glucose molecule after glycolysis, pyruvate oxidation, and the citric acid cycle, NOT including the electron transport chain and oxidative phosphorylation?
6 CO₂
10 NADH
2 FADH₂
4 ATP
What needs to happen for the citric acid cycle and pyruvate oxidation to continue?
Replenishing acetyl CoA
Replenishing oxidized electron carriers
(The electron carriers are reduced and they must be oxidized)
How can the electron carriers be oxidized so that the citric acid cycle can carry on if oxygen is present?
If O₂ is present, it accepts the electrons and H₂O is formed, but the electrons are not passed directly to O₂
