Chapter 9 pt: 4,5 Flashcards
What is the Electron transport chain?
- A network of proteins in the inner mitochondrial membrane.
- These proteins complex with molecules that are electronegative, meaning they readily accept electrons
- These proteins are arranged so that each step in the chain is slightly more electronegative than the previous one.
Where are electrons passed from prior to entering the chain?
- NADH or FADH2
What happens to potential energy and the energy state as you move further down the electron transport chain?
Decreases
What are the functional groups of the electrons transport chain that receive electrons?
- FMN: flavin-containing prosthetic group in flavor protein.
- Fe-S: protein with an iron-sulfur cofactor
- Cyt: protein with a heme prosthetic group
- Q: ubiquinone, a nonprotein coenzyme
At the end of complex one where do the electrons get picked up?
- inner membrane space by ubiquinone.
Where does the electron transport chain take place in?
Inner membrane of the mitochondria.
Where are the protons that are produced using the energy from the electrons donated by NADH found?
- the complex’s proton pump moves them from the mitochondrial matrix to the intermembrane space.
where does ubiquinone move the electrons from complex one?
Complex three.
What picks up the electrons in the inner membrane space following complex three?
Cyt-c swoops
Where does Cyt-c take the electrons?
Complex four
What happens to the electrons after complex four uses their energy to make protons?
- O2 outside the complex nabs the electrons and uses them to reduce it’s to water.
What was the point of the electrons in step four of the electron transport chain?
Create a proton gradient.
How do the journey of the electrons from FADH differ from those in NADH?
- they begin at complex 2, following complex two they are picked up by ubiquinone and then taken to three… (same path from this point on)
- Purpose is also the same.
Where are the differences in charges as a result of the proton concentration gradient?
+: intermembrane space
- : mitochondrial matrix
- Creating a large gradient across the inner mitochondrial membrane
What is the Proton-Motive force?
It is the large proton gradient in the inner mitochondrial membrane that represents a large amount of potential energy.
What is Chemiosmosis?
- It is the potential energy that is from the proton motive force, and it is used for the creation of ATP.
How is the Chemiosmosis mediated?
- ATP synthesis.
What is happening during chemiosmosis coupling?
- Same thing as chemiosmosis?
- protons enter the channel, which releases energy as they move down the gradient.
- that energy is used to turn the F1 unit
- The F1 unit moves ADP and Pi closer together to form an ATP molecule.
What is oxidative phosphorylation?
- It is ATP that is produced from the energy of the proton motive force that was generate via the ETC.
The efficiency of cellular respiration is dependent upon what?
- wide variety of factors, most of which pertain to its cell type.
What is the avg yield for ATP from one glucose molecule in the cellular respiration process?
29
what percent efficiency is cellular respiration in terms of efficiency?
31
What is a catabolic pathway?
- A pathway that breaks down macromolecules
What does an anabolic pathway do?
- Creates macromolecules, or makes larger things
What can cells pull from the citric acid cycle in order to make amino acids
- substrates for amino acids.
What happens if oxygen isn’t present to serve as the final accepter in the electron transport chain?
- if there is no oxygen available than the electrons in complex four have no where to go.
- starting a traffic jam, nothing in or out of complex four.
- Then this causes serious back up through out all complexes, as NADH and FADH2 can no longer give off or accept electrons.
- Therefore, the cell can no longer give off NAD+.
In eukaryotes what is always the final electron acceptor?
Oxygen, reduces to make water.
In prokaryotes what is/can be the final electron acceptor?
- Typically some other electronegative molecule (sulfur containing)
- Oxygen
If the cell can no longer reduce NADH to NAD + because a lack of oxygen as the final accepter in the ETC what is the cause?
- you lose an important substrate that is vital for the process of making ATP.
Without oxygen as the final accepter in the ETC, how does the cell reduce NADH to NAD +?
Fermentation: process that is a branch from cellular respiration, this follows glycolysis. This provides an alternate way for a NADH back to NAD +.
In humans were do we carry hour fermentation?
Latic acid pathway: pyruvate accepts electrons from NADH
What is proton leak?
It is a leak in the Mitochondrial membrane that allows protons to move down the electrochemical gradient, but none of this energy is being captured.
- Wasteful
- this wasted energy is turned to heat.
Why is the wasted energy that is converted to heat sometimes beneficial?
Brown fat: type of tissue that is specialized for heat production.
- Concentration decreases as you age.
