Chapter 10 (Cell bio)

1. Glycolysis

2. Pyruvate Oxidation and TCA or Krebs Cycle

3. Electron Transport Chain

4. ATP Synthesis by Chemiosmosis

What are the steps of Aerobic Respiration ?

Outer membrane

Inner membrane with cristae

Inter-membrane space

Matrix

What are the four main structural components of a mitochondrion ?

Outer membrane

the outer boundary of the mitochondrion

Inner membrane

the membrane containing the electron transport chain and ATP synthase

Cristae

folds of the inner membrane that increase its surface area

Intermembrane space

the space between the outer and inner membranes

Matrix

the innermost compartment containing enzymes for pyruvate oxidation, fatty acid oxidation, and the Krebs cycle

Forms the outer boundary and contains porins that allow certain solutes to pass.

What is the major role of the outer membrane of the mitochondria ?

Contains the electron transport chain and ATP synthase, which help produce ATP.

What is the major role of the inner membrane of the mitochondria ?

Increase the inner membrane’s surface area for energy-producing reactions.

What is the major role of the cristae of the mitochondria ?

Accumulates H⁺ ions to establish the proton gradient used for ATP synthesis.

What is the major role of the intermembrane space of the mitochondria ?

Contains enzymes for pyruvate oxidation, fatty acid oxidation, and the Krebs cycle.

What is the major role of the Matrix of the mitochondria ?

Mitochondria

cells “energy powerhouse”

• energy metabolism

• fatty acid oxidation

energy metabolism

fatty acid oxidation

Beyond being called the cell's "energy powerhouse," what two specific metabolic processes take place in the mitochondria ?

Mitochondria are found in the highest amounts where energy is needed most by the cell or tissue

Where is the distribution of mitochondria the greatest ?

Outer membrane and Inner membrane

What structural features are found in the outer and inner membranes surrounding the inter-membrane space ?

outer membrane

The _____ has porins for solute movement.

inner membrane

The _____ contains the ETC components and F₀F₁ complexes.

1. Pyruvate oxidation

2. Fatty acid oxidation

3. Krebs (TCA) cycle

Which three major metabolic pathways have their enzymes located specifically within the interior matrix ?

In the matrix of mitochondria

Where does the Krebs cycle occur ?

1. Transfer of pyruvate into matrix

2. Oxidation and decarboxylation of pyruvate by (pyruvate dehydrogenase (PDH)

3. Formation of Acetyl CoA

4. Fed into TCA

What are the steps of the Kreb cycle and how is the pyruvate prepared for it ?

1. Reaction of Acetyl CoA with OAA

2. Reorganization of Citrate

3. Oxidation/decarboxylation of isocitrate

4. Oxidation/decarboxylation of ketogluterate

5. Hydroxylation of Succinyl CoA

What are the five major reactions of the Kreb Cycle ?

Reaction of Acetyl CoA with OAA

generates citrate

Reorganization of Citrate

generates isocitrate

Oxidation/decarboxylation of isocitrate

Generates NADH, CO₂ and α-ketogluterate

Oxidation/decarboxylation of ketogluterate

Yields NADH, CO₂ and Succinyl CoA

Hydroxylation of Succinyl CoA

Yields Succinate, and one molecule of ATP

1. Acetyl CoA reacts with OAA to generate citrate.

2. Citrate reorganizes into isocitrate.

3. Isocitrate undergoes oxidation/decarboxylation to generate NADH, CO₂ , and α-ketoglutarate.

What are the first three reactions of the Krebs cycle and their key generated products ?

Oxidation of α-ketoglutarate yields NADH, CO₂

Succinyl CoA. Hydroxylation of Succinyl CoA yields Succinate and 1 ATP

What is yielded from the oxidation of α-ketoglutarate and the subsequent hydroxylation of Succinyl CoA ?

1. Oxidation of Succinate yields FADH₂ and fumarate.

2. Hydroxylation of Fumarate yields malate.

3. Oxidation of Malate yields NADH and OAA.

What three steps complete the Krebs cycle by regenerating OAA from succinate ?

FADH₂. and fumerate

Oxidation of Succinate yields ?

malate

Hydroxylation of Fumerate yields ?

NADH and oxalo acetic acid (OAA)

Oxidation of Malate yields ?

1. Pyruvate dehydrogenase

2. Isocitrate dehydrogenase

3. Α-ketogluterate dehydrogenase

4. Malate dehydrogenase

Which four key enzymes regulate the TCA cycle ?

They are primarily regulated via allosteric or feedback regulation

What mechanism do most of four key enzymes regulate the TCA cycle use ?

Triglycerides are oxidized to fatty acids, then to Acetyl CoA.

How do triglycerides enter the Krebs cycle ?

Proteins are broken down to peptides, and those peptides are then broken down to amino acids. These amino acids undergo oxidative deamination and transamination, which ultimately results in the formation of acetyl CoA.

How do proteins enter the Krebs cycle ?

Acetyl CoA

1 ADP

3 NAD

FAD

What are the exact inputs of the Krebs cycle ledger per cycle ?

CO2

1 ATP

3 NADH

1 FADH2

What are the exact outputs of the Krebs cycle ledger per cycle ?

Inner mitochondrial membrane

Where is the ETC located ?

1. To transfer of electrons from NADH and FADH to oxygen.

2. Creation of H+ gradient that is then used for ATP synthesis.

What are its two core biological functions of the ETC ?

1) Flavoproteins

2) Iron-sulfur proteins

3) Cytochromes

4) Copper-containing cytochromes

5) Coenzyme Q (quinones)

What are the five major electron carriers ?

Complexes I, II, III and IV

What are the functional organization units of the ETC ?

Chemiosmosis

is the process in which H⁺ ions flow down their electrochemical gradient through ATP synthase, providing the energy needed to produce ATP from ADP and phosphate.

1. The need for closed vesicles

2. Effect of uncouplers

3. Direct evidence by experiments of Jagendorf

4. Evidence from Raker and Stokneous; (Bacteriorhodopsin)

What four lines of experimental evidence support Mitchell's chemiosmotic hypothesis ?

1. Glycolysis:

• 2 per glucose molecule

2. Pyruvate Oxidation:

• 2 per glucose molecule

3. Krebs Cycle:

• 2 per glucose molecule.

4. ETC:

• 30 or 32

5. Total ATPs Produced:

• 36 or 38

Most ATP is produced by chemiosmosis following the ETC.

What is the step-by-step breakdown of ATP production per glucose, and where is most of it made ?