Electron Transport Chain Quiz

The electron transport chain is a process that occurs in the mitochondria, specifically in the inner mitochondrial membrane
The process starts with NADH and FADH2, which are produced in the citric acid cycle and oxidative steps of cellular respiration
NADH drops off its electrons at Complex I, which then passes them to Coenzyme Q
FADH2 drops off its electrons at Complex II, which then passes them to Coenzyme Q

NADH drops off its electrons at Complex I
Electrons are passed from NADH to Complex I, which then passes them to Coenzyme Q
Complex I pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons

FADH2 drops off its electrons at Complex II
Electrons are passed from FADH2 to Complex II, which then passes them to Coenzyme Q
Complex II does not pump protons out of the mitochondrial matrix

Coenzyme Q passes electrons to Complex III
Electrons are passed from Coenzyme Q to Complex III, which then passes them to Cytochrome C
Complex III pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons

Cytochrome C passes electrons to Complex IV
Electrons are passed from Cytochrome C to Complex IV, which then passes them to Oxygen
Complex IV pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons

The proton gradient is the accumulation of protons in the intermembrane space due to the pumping of protons from Complex I, III, and IV
The proton gradient is used to generate ATP through the process of chemiosmosis

ATP synthesis occurs through the process of chemiosmosis
Protons move from high concentration in the intermembrane space to low concentration in the mitochondrial matrix through ATP synthase
The movement of protons drives the rotation of the rotor and rod in ATP synthase
The rotation of the rotor and rod absorbs potential energy, which is used to drive the production of ATP from ADP and inorganic phosphate

ATP synthase is a complex of proteins that spans the mitochondrial membrane
The structure of ATP synthase includes a rotor, rod, catalytic knob, and stat
The catalytic knob is where ADP and inorganic phosphate are bound
The rotation of the rotor and rod drives the production of ATP from ADP and inorganic phosphate### Oxidative Phosphorylation
In oxidative phosphorylation, energy from NADH and FADH2 is used to convert ADP and inorganic phosphate to ATP
This process occurs through a specific type of phosphorylation

One NADH drops off electrons, which pass through complex 1, Q, complex 3, cytochrome C, and complex 4
At complex 1, one proton is pumped out
At complex 3, another proton is pumped out
At complex 4, a third proton is pumped out, resulting in a total of 3 protons
Since 2 electrons are coming from one NADH, this means one NADH gives 3 protons
For every proton moving down its concentration gradient, one ATP is produced, so one NADH gives 3 ATP
One FADH2 drops off electrons, which pass through complex 2, Q, complex 3, cytochrome C, and complex 4
At complex 3, one proton is pumped out
At complex 4, another proton is pumped out, resulting in a total of 2 protons
Since 2 electrons are coming from one FADH2, this means one FADH2 gives 2 protons, or 2 ATP

From the Krebs cycle:
- 6 NADH produced (18 ATP)
- 2 FADH2 produced (4 ATP)
- 2 ATP produced by substrate-level phosphorylation
From the transition step:
- 2 NADH produced (6 ATP)
From glycolysis:
- 2 NADH produced (6 ATP)
- 2 ATP produced by anaerobic mechanisms

The electron transport chain occurs in the mitochondria's inner membrane.
NADH and FADH2, produced in the citric acid cycle and oxidative steps of cellular respiration, start the process.

NADH drops off its electrons at Complex I, which passes them to Coenzyme Q.
FADH2 drops off its electrons at Complex II, which passes them to Coenzyme Q.
Coenzyme Q is a mobile molecule that accepts electrons from Complex I and II and passes them to Complex III.
Cytochrome C is a mobile molecule that accepts electrons from Complex III and passes them to Complex IV.

Complex I pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons.
Complex III pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons.
Complex IV pumps protons out of the mitochondrial matrix into the intermembrane space as it accepts electrons.

The proton gradient is the accumulation of protons in the intermembrane space due to proton pumping.
The proton gradient is used to generate ATP through chemiosmosis.

Protons move from high concentration in the intermembrane space to low concentration in the mitochondrial matrix through ATP synthase.
The movement of protons drives the rotation of the rotor and rod in ATP synthase, producing ATP from ADP and inorganic phosphate.

ATP synthase is a transmembrane protein complex with a rotor, rod, catalytic knob, and stat.
The catalytic knob is where ADP and inorganic phosphate are bound.
The rotation of the rotor and rod drives ATP production from ADP and inorganic phosphate.