Chapter 15 The Electron Transport Complex, Oxidative Phosphorylation, and Chemiosmosis Flashcards
Why is oxygen needed to generate energy?
In glycolysis the NADH and pyruvate were considered waste products, both carry energy but in the absence of oxygen we cannot utilize the energy.
What are the two ways ATP is synthesized in our body? Which way is the one where the majority of the ATP is synthesized?
substrate level phosphorylation
Electron Transport Complex, Oxidative Phosphorylation, and Chemiosomosis
Electron Transport Complex, Oxidative Phosphorylation, and Chemiosmosis is how majority of our ATP get synthesized.
Uniport
single molecule moves across membrane
Symport
the movement of one molecule drives the movement of another molecule in the same direction.
Antiport
the movement of one molecule drives the movement of another molecule in the opposite direction
Cotransport
symport and antiport
Active Transport
moving ions or molecules against a concentration gradient which requires an input of energy
Primary Active Transport
energy is used to drive a conformational change.
Secondary Active Transport
energy is used to establish an electrochemical gradient of one molecule.
What is the major difference between the inner and outer mitochondrial membrane?
outer membrane facing the cytoplasm has many transmembrane porin proteins and is highly permeable to many small molecules and ions.
inner membrane is almost completely impermeable to most molecules and ions. Highly selective transporters are needed to cross.
Explain the terms matrix side and cytoplasmic side as they refer to the inner membrane.
Inner membrane is divided into two distinct sides, the side facing the matrix is called the matrix side and the side facing the cytoplasm is called the cytoplasmic side.
Which sides of the inner membrane have a positive vs. negative charge?
The cytoplasmic side has a net positive charge.
The matrix side has a net negative charge.
Mitofusion
fusion of mitochondria
Mitofission
pinch mitochondria into two pieces.
Mitophagy
selective breakdown of mitochondria into its constituent parts
Why are the electrons not directly transferred to oxygen in the electron transport complex?
if the electrons were transferred directly to oxygen, we would be releasing a large amount of energy in one step which would be difficult to capture in one step.
Instead the electron is transferred in multiple steps.
What are the electron carriers used in the ETC?
- NAD+ from dehydrogenases
- FAD/FMN proteins
- The ubiquinones (coenzyme Q)
- Cytochromes
- Iron-sulfur clusters
Which electron carrier of the electron transport complex can move between certain complexes?
cytochrome protein
How can we determine the sequence of the electron pathway in the ETC?
- measure the reduction potentials of each of the components, electrons will go from positive to negative
- Initiate ETC in the absence of oxygen: backlog of ETC, once oxygen is introduced the components closest to oxygen will be oxidized first.
- use of electron transport inhibitors: inhibitor blocks movement of electrons, carriers before block will be reduced, while those after block will be oxidized.
Where is the electron transport chain located?
inner mitochondrial membrane
What are respirasomes?
tightly assembled electron transport complexes.
What lipid is required for a functional ETC?
cardiolipin
What is the function of complex I?
transfer electrons from NADH to the Q pool
pump protons out of the mitochondrial matrix
What is the Q pool?
preexisting pool of fully reduced (QH2) and fully oxidized quinones (Q).
What is the proton count at the end of complex I?
4 protons are carried across the membrane from pump, 2 protons went to Q pool, 1 proton gained from NAD+.
What is the adaptor role of FMN in complex I?
Iron sulfur cluster can accept one electron at a time
NADH must drop 2 electrons at a time
FMN can transfer either one or two electrons serving as an adaptor between Fe-S clusters and NADH.
What is the electron donor and the electron acceptor in complex I?
Electron donor: NADH
Electron acceptor: FMN accepts electrons and passes it along a series of Fe-S clusters until finally the electrons are passed onto Q to make QH2 and rejoins the Q-pool
Which complex is shared with the citric acid cycle?
Complex II, it is the succinate dehydrogenase from the citric acid cycle.
What is the electron donor of complex II?
FADH2
What is the electron acceptor of complex II?
oxidized quinone from Q pool
How many protons are pumped from complex II?
no protons are pumped from complex II