MEH Energy Production ( Respiration) Flashcards
(21 cards)
Define cellular respiration
Cellular respiration is the process in which cells break down macromolecules like glucose to produce ATP. An energy currency for the cell.
Name the three stages in cellular respiration
- Glycolysis
- The Krebs cycle (TCA)
- The electron transport chain ( oxidative phosphorylation
Where does glycolysis take place
Cytosol- the soluble portion of a cells cytoplasm
Describe the input and products of Glycolysis
Glucose + 2ATP = 4ATP + 2NADH + 2 Pyruvate
Net ATP production = 2
What is the product of oxidation of Pyruvate
2 x Acetyl CoA and 2 NADH
Where does pyruvate oxidation and the Krebs cycle take place
In the mitochondria
Explain the input and products of the Krebs cycle
Each Acetyyl coA (there are 2 produced) enters the Krebs cycle separately.
Acetyl CoA—> 3NADH + FADH2 + GTP.
So total products 6NADH + 2FADH2 + 2GTP
What are the intermediates that feed into the ETC.
NADH and FADH2
State the approximate yield of ATP from both NADH and FADH2 in the ETC
What is he reason for the difference?
1 NADH= 2.5 ATP
1 FADH2 = 1.5 ATP
NADH carries more energy than FADH2 Therefore NADH is high enough energy to go through the first PTC so goes through 3 PTC’s. FADH2 only has enough energy to go through 2 PTC’s does not go through the first one.
Greater p.m.f ( electrochemical gradient) = more ATP produced.
Explain how the ETC and ATP production are coupled
ATP generation is dependant on the gradient of protons.
No proton gradient = no ATP generated.
Describe the function of uncouplers
Uncouplers increase the permeability of the membrane and so dissipate the proton gradient as protons can re-enter the mitochondria not through the ATPase. P.m.f is reduced.
No drive for ATP synthesis.
Why does energy produced from ox phos need to be stored?
If energy is not stored as ATP- it is lost as heat energy.
Explain how cyanide or carbon monoxide work to inhibit the ETC
These molecules block the flow of electrons.
No electron transport occurs
No oxidative phosphorylation
Explain how diseases can be associated with oxidative phosphorylation
Gene mutations in mitochondria DNA can cause defects in PTC and ATPsynthase.
May not function correctly/be absent.
Decrease in electron transport
Decrease in ATP synthesis.
What is the function of pyruvate dehydrogenase.
It is an enzyme that catalyses the conversion of pyruvate to Acetyl CoA
Explain the role of NAD+ in the production of Acetyl CoA
NAD+ is a co factor to pyruvate dehydrogenase.
That is reduced into NADH as pyruvate is oxidised.
Name one other product that is produced in the creation of Acetyl CoA.
Carbon dioxide
Explain why fatty acids cannot contribute tot he production of glucose.
fatty acids can contribute to production of Acetyl CoA when broken down.
Pyruvate to Acetyl CoA reaction is irreversible.
Therefore the Acetyl CoA produced by fatty acids cannot be converted to pyruvate.
Fatty aids Cannot contribute to gluconeogenesis.
Other than feeding into the citric acid cycle give another function of Acetyl CoA.
Acetyl CoA can be used to produce fatty acids when ATP levels are high.
What is Allosteric regulation
Allo= other
Steric= site
Allosteric regulation involved a molecule that binds on another site ( regulatory site) of an enzyme to activate or inhibit it.
Explain how ATP is an allosteric inhibitor in the regulation of pyruvate dehydrogenase reaction to create Acetyl CoA
If ATP levels are high, the conversion of pyruvate to Acetyl CoA will reduce.
Has Enough Acetyl CoA to be fed into the Krebs cycle and ultimately produce ATP.
