Cellular Respiration

Glycolysis

Breakdown of sugar (glucose is a 6 carbon sugar)
Produces 2 pyruvates (3 carbon sugars)
Takes place in cytoplasm
2 ATP lost but 4 produced (net of 2 ATP)
2 NADH produced

aerobic respiration

cellular respiration that uses oxygen

anaerobic respiration

Process in which prokaryotes use substances other than oxygen as reactants in the process that harvest chemical energy without oxygen

NADH

Formed by dehydrogenase
Electron Carrier
Used in the electron transport chain to produce more ATP

Link reaction

2 pyruvate in and out is 2 CO2 and 2 Acetyl attached to coenzyme A (coA)

Citric Acid Cycle (Krebs Cycle)

Takes place in the matrix of mitochondria
2 carbon molecule (Acetyl CoA) and 4 carbon molecule (oxaloacetate) combine to produce 6 carbon molecule (Citrate)
6 carbon molecule goes through changes and produced the original 4 carbon molecule at the end
Prod

FADH2

electron carrier produced during the Krebs cycle
Used in the electron transport chain to produce more ATP

Acetyl CoA

Made from pyruvate that is oxidized (a two carbon fragment of pyruvate attached to a coenzyme)

Electron Transport Chain

A series of protein complexes embedded in the mitochondrial membrane where the electrons and protons released by oxidized NADH and FADH2 (go back to NAD+ and FAD) are transferred through, moving down in energy levels, energy is released allowing hydrogen

oxidative phosphorylation

Hydrogen ions (protons) move down their concentration gradients and enter the ATP synthase resulting in the rotation of the ATP synthase (due to proton motive force) which synthesizes ATP from ADP and Pi
Outputs are CO2 and H2O as well as 34 ATP

ATP synthase

The enzyme that make ATP from ADP and inorganic phosphate as protons move through it

Oxidation Reduction Reaction (redox reaction)

Reactions involving electron transfers

Oxidized

Loses electrons

Reduced

Gains electrons

Reducing agent

The electron donor in a redox reaction

Oxidizing agent

The electron acceptor in a redox reaction

Four substages of cellular respiration

Glycolysis
Prep Cycle and Citric Acid Cycle
Electron Transport Chain
Oxidative phosphorylation

Fermentation

A partial degradation of sugars or other organic fuel that occurs without the use of oxygen
Makes it possible for ATP to be continually produced in the absence of oxygen
Involves glycolysis followed by the reduction of pyruvate by NADH
Produces a yield of

How much ATP is produced from one glucose molecule? (How much is invested? How much is made? What is the total yield?) during which stages?

38
2 are invested in glycolysis with 4 produced (net of 2)
2 are produced in the Citric Acid Cycle
34 are produced through oxidative phosphorylation

NAD+

A coenzyme that cycles easily between oxidized and reduced state, thus acting as an electron carrier
Reusable

FAD

an electron carrier that is changed to FADH2, similar to NAD+
Reusable

Why does the oxidation of FADH2 yield less ATP than NADH

because it enters the electron transport chain at a later stage

Glycolysis occurs in the ______ and starts with ______ and produces ______ and ______

cytoplasm
Glucose
2 pyruvate
2 net ATP (4 but needed 2 to start)

Link reaction occurs in the ______ and starts with ______ and produces ______ and ______

Matrix of the mitochondria
2 pyruvate
2 CO2
Acetyl-CoA (Acetyl linked to coenzyme A)

The citric acid cycle occurs in the ______ and starts with ______ and ______ and produces ______ with outputs including ______ and ______

Matrix of the mitochondria
Acetyl
Oxaloacetate
Oxaloacetate
2 ATP
2CO2

The Electron Transport Chain occurs in the ______ and starts with ______ and ______ and produces ______ where the ______ are moved through and release ______allowing ______ to be moved through the protein channels against their concentration gradient. At

Cristae of the mitochondria
NADH
FADH2
Lots of H+
Electrons
Energy
Protons

oxidative phosphorylation # of ATP

34

substrate level phosphorylation vs oxidative phosphorylation

Substrate-level phosphorylation is directly phosphorylating ADP with a phosphate and energy provided from a coupled reaction while Oxidative phosphorylation is when ATP is generated from the oxidation of NADH and FADH2 and the subsequent transfer of elect

oxidative phosphorylation is used in

ATP Synthesis

substrate level phosphorylation is used in

Glycolysis and the Citric Acid Cycle

How is oxaloacetate important in this cycle?

oxaloacetate is joined with acetyl-CoA to form citric acid and is formed at the end of the cycle (which is what makes it a cycle)

What happens when electrons are moved close to an electronegative atom? How is this useful in Cellular Respiration? Why is oxygen of particular interest in this process?

When electrons are moved close to an electronegative atom energy is released, this is useful in cellular respiration because the energy released is used to push H+ against their concentration gradient. The electrons after going through the electron transp

catabolic pathways

Metabolic pathways that release stored energy by breaking down complex molecules into simpler compounds

cellular respiration

The catabolic pathways of aerobic and anaerobic respiration which break down organic molecules and use an electron transport chain for the production of ATP

Chemiosmosis

When H + flows down gradient through the ATP synthase complex, energy is released and used to form ATP

Why is NAD+ called a coenzyme of oxidation-reduction

It becomes a reduced when it accepts electrons from a substrate and becomes oxidized when it passes electrons on to another carrier

The molecule glucose is ______ while oxygen is ______. Cellular respiration is an ______ reaction

Oxidized
Reduced
Exergonic

Why is NAD+ called a coenzyme of oxidation-reduction

It becomes reduced when it accepts electrons from a substrate and becomes oxidized when it passes electrons on to another carrier

What type of phosphorylation occurs during glycolysis

Substrate-level phosphorylation

What coenzyme carries out oxidation of substrates during glycolysis

NAD+

What is the output of glycolysis per glucose molecule

2NADH, 2 pyruvate, and 2 net ATP

A two-carbon molecule acetyl group enters the citric acid cycle. What carbon molecules derived from the acetyl group leave the citric acid cycle?

CO2

What coenzymes carry out oxidation of substrates in the citric acid cycle?

NAD+

What are the outputs of the citric acid cycle

6 NADH, 2 ATP, 2 FADH & 4 CO2

What coenzymes bring hydrogen atoms to the electron transport chain

NADH and FADH2

In the electron transport chain the electrons are ______ and the hydrogen ions are ______

Moved down the electron transport chain
Pumped out into the intermembrane space

Each pair of electrons carried by NADH from the citric acid cycle that passes down the electron transport chain accounts for the build up of how many ATPs?

3

During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is where?

Retained in the two pyruvates

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could

Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis

In the citric acid cycle, pyruvate is oxidized to ______

CO2

In the citric acid cycle...

The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle

The chemiosmotic synthesis of ATP requires what

That the electron transport in the inner mitochondrial membrane be coupled to proton transport across the membrane

The redox reactions of the electron transport chain

Are directly coupled to the movement of protons across a membrane

How do cellular respiration and breathing differ

Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level