Bio 006 - Cell Respiration

Endothermic

Losing heat.

Exothermic

Gaining heat.

Endergonic

Energy absorbed.

Exergonic

Energy released.

Anabolic

Building bonds.

Catabolic

Breaking bonds.

Reduction

Gaining electrons/hydrogen

Oxidation

Losing electrons/hydrogen

ATP

Adenosine Triphosphate.

• Energy stored in bonds between extra phosphates

Cellular Respiration

• Process which converts ADP back into ATP.

• it’s a Anabolic Reaction

Anabolic Reaction

Adding phosphate = building.

Energy Coupling

• Pairing anabolic and catabolic reactions.

• The process of using energy released from one reaction to drive another reaction.

Stages of Cell Respiration

1. Glycolysis

2. Pyruvate Oxidation

3. Citric Acid Cycle / Krebs Cycle

4. Oxidative Phosphorylation.

Glycolysis

Stage 1 of cell respiration. Only stage which happens outside the mitochondria; occurs in the cytoplasm.

• Input: Glucose, NAD

• Output: Pyruvate, NADH, H2O

• ATP: 2

NAD+

Nicotinamide adenine dinucleotide, reduced to NADH

NADH

Reduced form of NAD+

FAD

Flavin adenine dinucleotide, reduced to FADH2.

FADH2

Reduced form of FAD.

Carbon Dioxide

Produced from the breakdown of glucose.

ATP Production

1 molecule of glucose produces ~ 30 ATP.

Oxidation

NADH → NAD+; FADH2 → FAD.

Catabolic Reaction

Glucose → CO2; energy released.

Energy in Respiration

Energy from catabolism of glucose is used to build intermediate molecules.

Glucose

A simple sugar that is an important energy source in living organisms.

Pyruvate

The output of glycolysis, which is converted into Acetyl-CoA.

Pyruvate Oxidation

Stage 2 of cellular respiration where pyruvate is converted into Acetyl-CoA.

• happens in the matrix

• Input: Pyruvate, NAD, O2

• Output: Acetyl-CoA, CO2, NADH

• ATP: NONE

Acetyl-CoA

A molecule that enters the citric acid cycle after pyruvate oxidation.

CO2

Carbon dioxide, a waste product of cellular respiration.

Citric Acid Cycle

Stage 3 of cellular respiration that takes place in the mitochondrial matrix.

• Input: Acetyl-CoA, NAD, FAD

• Output: CO2 (lots), NADH, FADH2

• ATP: 2

Oxidative Phosphorylation

Stage 4 of cellular respiration where ATP is produced using the electron transport chain.

• Happens across the inner membrane

• Input: NADH, FADH2, O2

• Output: H+, H2O

• ATP: 26 or 28

Enzymes

Proteins that act as catalysts to speed up biochemical reactions.

Dehydrogenase

An enzyme that removes hydrogen atoms from substrates.

• Works with NAD and FAD

Substrate-Level Phosphorylation

A method of generating ATP by directly transferring a phosphate group to ADP.

• an enzyme sticks a phosphate onto ADP, making ATP.

GAPDH

Glyceraldehyde 3-phosphate dehydrogenase, an enzyme that produces ATP and NADH in glycolysis.

Pyruvate Kinase

• The 2nd important enzyme in glycolysis

• An enzyme that converts phosphoenolpyruvate to pyruvate, producing ATP.

Glycolysis

The first stage of cellular respiration that occurs in the cytoplasm and produces pyruvate.

Phosphorylation

The addition of a phosphate group to a molecule, often to ADP to form ATP.

2

The total ATP yield from glycolysis is ___ ATP.

2

The total ATP yield from substrate-level phosphorylation in glycolysis is __ ATP.

Complete Reaction of Cellular Respiration

Glucose is converted to carbon dioxide through a series of reactions.

Anaerobic vs Aerobic

Anaerobic processes occur without oxygen, while aerobic processes require oxygen.

NAD

Nicotinamide adenine dinucleotide, a coenzyme involved in redox reactions.

Pyruvate

The end product of glycolysis, which is converted into Acetyl CoA in the mitochondria.

H2O

Water, produced as a byproduct of oxidative phosphorylation.

ATP

Adenosine triphosphate, the primary energy carrier in cells, with a yield of 2 during glycolysis.

Pyruvate Dehydrogenase

An enzyme that converts pyruvate into Acetyl CoA, producing CO2 and NADH.

Acetyl CoA

The molecule formed from pyruvate that enters the citric acid cycle.

Citric Acid Cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of Acetyl CoA.

FAD

Flavin adenine dinucleotide, a coenzyme involved in redox reactions, similar to NAD.

FADH2

The reduced form of FAD, which also carries electrons to the electron transport chain.

Oxidative Phosphorylation

The process in cellular respiration that produces ATP using energy derived from redox reactions.

ATP Synthase

An enzyme that synthesizes ATP from ADP and inorganic phosphate, powered by H+ ions.

Inner Membrane Space

The space between the inner and outer membranes of the mitochondria where H+ ions accumulate.

Electron Transport Chain

A series of integral proteins in the inner mitochondrial membrane that transfer electrons and pump H+ ions.

Chemiosmosis

The process of H+ ions moving down their concentration gradient through ATP synthase to generate ATP.

Active Transport

The movement of ions or molecules across a membrane against their concentration gradient, requiring energy.

Substrate-Level Phosphorylation

The direct synthesis of ATP from ADP during glycolysis and the citric acid cycle.

Mitochondrial Membranes

The double membrane structure of mitochondria that separates the mitochondrial matrix from the cytoplasm.

Matrix

The innermost compartment of the mitochondria where the citric acid cycle occurs.

CO2

Carbon dioxide, a waste product produced during pyruvate oxidation and the citric acid cycle.

H+

Hydrogen ions that are used to power ATP synthase during oxidative phosphorylation.

O2

Oxygen, the final electron acceptor in the electron transport chain.

Stage 3: Citric Acid Cycle

The stage where Acetyl CoA is oxidized to produce CO2, NADH, and FADH2.

Stage 4: Oxidative Phosphorylation

The final stage of cellular respiration where ATP is produced using the energy from NADH and FADH2.

ATP Yield

The total number of ATP produced during cellular respiration, which can be 26 or 28 during oxidative phosphorylation.

30

1 molecule of Glucose = ____ ATP