Cellular Respiration and Fermentation

Cellular Respiration

The process of converting glucose and oxygen into water and carbon dioxide and producing energy for the cell to use through the synthesis of ATP

Mitochondria

Where cellular respiration occurs

Redox reaction

The kind of reaction cellular respiration is

Glycolysis, Aerobic Respiration

Forms of cellular respiration (2)

Breakdown of pyruvate, Citric acid cycle, Oxidative phosphorylation

Stages of aerobic respiration (3)

Anaerobic Respiration (Fermentation)

Occurs without oxygen, produces less ATP

Glycolysis

A form of substrate level phosphorylation, Produces 2 pyruvate, 2ATP, and 2NADH

Substrate Level Phosphorylation

The direct transfer, via an enzyme, of a phosphate from an organic molecule to ADP to ATP, Glycolysis is an example of this

Cytosol

Where glycolysis occurs (since it doesn’t require oxygen)

Energy investment phase, Cleavage phase, Energy liberation phase

Three phases of glycolysis

Energy Investment Phase

Phase of glycolysis that uses ATP to add a phosphate to glucose, producing fructose-1-6-biphosphate

Cleavage Phase

Phase of glycolysis that splits fructose-1-6-biphosphate into 2 molecules of glyceraldehyde-3-phosphate

Energy Liberation Phase

Phase of glycolysis that converts glyceraldehyde-3-phosphate into pyruvate and produces ATP

2

The net production of ATP from glycolysis

Hexokinase

Enzyme utilized in the energy investment phase of glycolysis that phosphorylates glucose into glucose-6-phosphate by using a phosphate from ATP, changing it back into ADP

Glucose-6-phosphate

Phosphorylated glucose that is more easily trapped in the cell than glucose

Fructose-6-phosphate

Isomer of glucose-6-phosphate that will eventually become phosphorylated

Phosphofructokinase

Enzyme utilized during the energy investment phase of glycolysis that phosphorylates fructose-6-phosphate into fructose-1-6-biphosphate, ATP can bind to the allosteric site of this enzyme for feedback inhibition (speed it up or slow it down)

Fructose-1-6-biphosphate

Phosphorylated fructose-6-phosphate that will eventually split during the cleavage phase

Glyceraldehyde-3-phosphate

Two of this molecule forms when fructose-1-6-biphosphate is split during the cleavage phase

1,3-biphosphate

Two of this molecule form when glyceraldehyde-3-phosphate is oxidized during the energy liberation phase, 2 NADH is formed

Phosphoenolpyruvate

Two of these molecules are used to form 2 pyruvate, The phosphate group in the molecule is destabilized, so the bond will break in a highly exergonic reaction

Pyruvate Kinase

Enzyme utilized in the energy liberation phase of glycolysis that catalyzes the transfer of the phosphate group from phosphoenolpyruvate to ADP, creating ATP and pyruvate (2x)

Energy Investment and Cleavage Phase

Which phase(s) of glycolysis is this?

Energy Liberation Phase

Which phase(s) of glycolysis is this?

Pyruvate

Two of these molecules are formed when a phosphate is removed from phosphoenolpyruvate, which is then transferred to ADP to form ATP

2 pyruvate

2 NADH

2 ATP

2 H₂O

2 H⁺

The net production of molecules after glycolysis

Breakdown of Pyruvate

Stage of aerobic respiration where the 2 pyruvate that form during glycolysis travels to the mitochondrial matrix to be broken down

2 pyruvate + 2 CoA + 2NAD+ —> 2 Acetyl CoA + 2CO₂ + 2NADH

“Chemical reaction” of pyruvate breakdown

Pyruvate Dehydrogenase

Enzyme utilized during breakdown of pyruvate that oxidizes pyruvate into Acetyl CoA and CO₂ (2x)

2 Acetyl CoA

2 NADH

2 CO₂

Net production of molecules following breakdown of pyruvate

2 Acetyl

4 NADH

2 ATP

2 CO₂

2 H₂O

2 H⁺

Net production of molecules following glycolysis AND oxidation of pyruvate

Citric Acid Cycle/Krebs Cycle

A metabolic cycle that recycles different components that help continue the cyclic reaction

Mitochondrial Matrix

Where the Krebs Cycle occurs

Citrate

Forms during the first step of the Krebs Cycle when Acetyl CoA attaches to oxaloacetate

Isocitrate Dehydrogenase

Enzyme utilized during the Krebs Cycle that regulates the speed of the cycle, Catalyzes the oxidation of isocitrate into alpha-ketoglutarate, NAD+ is reduced to NADH

Alpha-Ketoglutarate Dehydrogenase

Enzyme utilized during the Krebs Cycle that helps regulate the cycle, Catalyzes the oxidation of alpha-ketoglutarate as it combines with CoA to form succinyl CoA, CO₂ and NADH are also formed, More CO₂ is released soon after this stage

Oxaloacetate

A set of reactions during the Krebs Cycle, such as the phosphorylation of GDP and ADP into ATP and GTP, FAD becoming FADH₂, and NAD+ becoming NADH, regenerates this starting molecule (that binds to Acetyl CoA) to restart the cycle

Citrate Synthetase

Enzyme utilized during the Krebs Cycle that catalyzes oxaloacetate and Acetyl CoA to form citrate

Inhibitors, Activators

ATP and NADH act as ______ of isocitrate dehydrogenase, while ADP and NAD+ act as ______

2 CoA

4 CO₂

6 NADH

2 FADH₂

2 GTP

2 ATP

6 H⁺

Net production of molecules after the Krebs Cycle

10 NADH

4 ATP

6 CO₂

8 H⁺

2 FADH₂

Net production of molecules after glycolysis, pyruvate oxidation, AND the Krebs Cycle

Oxidative Phosphorylation

Involves the oxidation of NADH and FADH₂ and ADP becomes phosphorylated via the electron transport chain and the chemiosmosis of H⁺ through the ATP synthase

Oxygen

The final electron acceptor following oxidative phosphorylation

Electron Transport Chain

A group of protein complexes and small organic molecules within the inner membranes of mitochondria and chloroplasts and the plasma membrane of prokaryotes, The components accept and donate electrons to each other in a linear manner and produce a H⁺ electrochemical gradient

Chemiosmosis

A process for making ATP in which energy stored in an ion electrochemical gradient is used to make ATP from ADP and P, Transpots H⁺ ions through the ATP synthase

ATP Synthase

An enzyme that utilizes the energy stored in a H⁺ electrochemical gradient for the synthesis of ATP via chemiosmosis

NADH Dehydrogenase

Enzyme utilized during oxidative phosphorylation that transfers high-energy electrons directly to the respiratory chain, NADH becomes NAD+ here

Cytochrome Oxidase

Enzyme utilized during oxidative phosphorylation that receives some electrons from cytochrome c, Some energy is harness to pump H⁺ into the intermembrane space, Electrons are transferred to oxygen, Water is produced, ATP binds to the allosteric site of the enzyme to inhibit the electron transport chain

10 NAD+

2 FAD
10 H₂O

30-34 ATP

Net production of molecules following oxidative phosphorylation

34-38 ATP

6 CO₂

10 H₂O (not through dehydration)

Net production of molecules after cellular respiration

Bacteriohodopsin

A light-driven H⁺ pump

Glucose

What carbs are broken down/rearranged into to enter glycolysis

Amino acids, Pyruvate, Acetyl CoA

Proteins are broken down into _____ _____ first, then they are processed differently at different points as _____, _______, or by entering the Krebs Cycle

Fatty acids, Glycerol

What fats are broken down into (2)

Glyceraldehyde-3-phosphate, Acetyl CoA

Glycerol can become ______ and enter glycolysis, while fatty acids can become ______ and get broken down by the Krebs Cycle

NADH, NAD+

During anaerobic respiration, glycolysis produces ______ and depletes ______.

It reacts with cellular components and generates damaging free radicals

It’s necessary for glycolysis to continue in order to produce ATP

Why NAD+ is important during cellular respiration (2)

Nitrate (NO₃^-)

The final electron acceptor following anaerobic respiration

Muscle Fermentation, Yeast Fermentation

Two kinds of fermentation

Muscle Fermentation

Type of fermentation where pyruvate and NADH become lactic acid and NAD+

Yeast Fermentation

Type of fermentation where either pyruvate becomes CO₂ and acetaldyhyde, or acetaldehyde and NADH become ethanol and NAD+