6.12- Review: Each molecule of glucose yields many molecules of ATP, 6.7- Glycolysis harvests chemical energy by oxidizing glucose to pyruvate, Ap bio quiz chapter 8 section 4&5 krebs cycle, 6.7- Glycolysis harvests chemical energy by oxidizing gluco...

Essentially, what happens in oxidative phosphorylation?

1. Electron carriers in membrane create H+ concentration gradient across membrane 2. Use energy of gradient to drive ATP synthesis by using ATP synthase.

What is the structure of ATP synthase? How does it work?

1. Hydrogen ions move one by one into binding sites within ATP synthase (the rotor), causing it to spin. 2. After once around, they are spit out into matrix. 3. Spinning rotor turns internal rod, which activates sites in catalytic knob that phosphorylate ADP to ATP.

Oxidative phosphorylation

1. NADH and FADH2 deliver electrons to electron transport chain, where they are finally passed to O2, forming H2O. 2. Electron transport chain pumps H+ into the intermembrane space. 3. Resulting H+ gradient is tapped by ATP synthase to produce about 28 molecules of ATP by oxidative phosphorylation.

What is the overall yield of energy-rich molecules per molecule of glucose in the citric acid cycle?

2 ATP 6 NADH 2 FADH2 (cycle runs twice per glucose molecule coz glycolysis produces 2 molecules of acetyl CoA).

How much energy that a cell can harvest from a glucose molecule does glycolysis produce?

2 ATP: 6% 2 NADH: 16% (unavailable without oxygen)

inputs of the Krebs cycle(citric acid cycle)

2 Acetyl groups, 6 NAD+, 2 FAD, 2 ADP, +2P

For each glucose molecule processed, what are the net molecular products of glycolysis?

2 NADH 2 Pyruvate 2 ATP 2 H2O

Essentially, what happens in the energy payoff phase?

2 NADH molecules r produced for each initial glucose molecule, and 4 ATP molecules r generated.

Citric acid cycle

2 acetyl CoA feed into citric acid cycle Yields 6 NADH Yields 2 FADH2 Yields 2 ATP by substrate-level phosphorylation

Essentially, what happens in the energy investment phase?

2 molecules of ATP are used to energize a glucose molecule, which is then split into 2 small sugars.

Overview of the citric acid cycle

2-carbon acetyl group= joined to 4-carbon molecule. Result= 6-carbon molecule (citrate) 2 carbon atoms r removed as CO2, and the 4-carbon molecule is regenerated.

How many energy-rich molecules have been produced by processing 1 molecule of glucose through glycolysis and the citric acid cycle?

4 ATP (all from substrate-level phosphorylation) 10 NADH 2 FADH2 6 Co2

outputs of the Krebs cycle (citric acid cycle)

4 Carbon Dioxide, 6 NADH, 2 FADH, 2 ATP

How many chemical reactions are involved to change glucose to pyruvate?

9, each catalyzed by its own enzyme.

As the reactions occur, what is reduced to what? There is a net gain of how many ATP molecules?

As the reactions occur: 2 molecules of NAD+ r reduced to 2 molecules of NADH Net gain of 2 molecules of ATP

How much energy does the citric acid cycle generate for the cell?

Each turn of cycle: Makes 1 ATP molecule by substrate-level phosphorylation 3 NADH molecules 1 FADH2 molecule (another electron carrier)

Electron transport chain: active transport of H+ across membrane.

Electron carriers bind + release electrons (redox reactions), passing electrons down "energy hill." 3 protein complexes use energy released from electron transfers to actively transport H+ across membrane H+ is less concentrated to where H+ is more concentrated. H+= transported from matrix into intermembrane space.

What are the 2 main processes that oxidative phosphorylation uses?

Electron transport chain Chemiosmosis

Electron transport chain: why is oxygen so important?

Electrons transported from NADH and FADH2 through electron transport chain to oxygen. Oxygen= final electron acceptor. Each oxygen atom (½ O2)= accepts 2 electrons from chain and picks up 2 H+ from surrounding solution. Forms H2O.

In brief terms, where is ATP synthase found, and what does it do?

Embedded in membrane Enzyme complex, which synthesizes ATP.

What are the 2 main phases in which the steps of glycolysis can be grouped into?

Energy investment phase Steps 1-4 Consume energy Energy payoff phase Steps 5-9 Yield energy

Why are the folds (cristae) of the membrane so important?

Enlarge surface area Space for thousands of copies of electron transport chain.

What is the role of ATP synthase in chemiosmosis?

H+ concentration gradient across membrane stores potential energy. ATP synthases in inner membrane= mini turbines. Rush of H+ ions down concentration gradient turn the wheels (rotary motor).

What are intermediates?

Intermediates= Compounds that form between the initial reactant, glucose, and the final product, pyruvate. Intermediates r products of a previous step, and serve as reactants of the next step Eg: glucose-6-phosphate= product of step 1, reactant for step 2.

where is the Krebs cycle located?

Matrix of the mitochondria

Electron transport chain: where are the electron carriers found?

Most reside in 4 main protein complexes. 2 mobile carriers transport electrons between protein complexes.

Why can't the number of ATP molecules be stated exactly?

NADH produced in glycolysis= Passes its electrons across membrane to either NAD+ or FAD. FADH2 adds its electrons farther along electron transport chain= contributes less to H+ gradient; thus generates less ATP. Some energy of H+ gradient= may be used for work other than ATP production (such as active transport of pyruvate into mitochondrion). Most ATP made by cellular respiration results from oxidative phosphorylation= ATP yield depends enough supply of oxygen to cell. Without oxygen to function as final electron acceptor, electron transport and ATP production stop.

Glycolysis

Occurs in cytosol Oxidizes glucose to 2 molecules of pyruvate Produces 2 NADH Produces net of 2 ATP by substrate-level phosphorylation

Pyruvate oxidation/intermediate step

Occurs within the mitochondrion Oxidation of pyruvate yields 2 NADH and 2 acetyl CoA.

Essentially, what does the citric acid cycle do?

Oxidizes the acetyl CoA derived from pyruvate.

How does the cell harvest the energy banked in NADH and FADH2?

Shuttle high-energy electrons to electron transport chain. Energy from oxidation of organic molecules= used to phosphorylate ADP to ATP (oxidative phosphorylation).

A quick overview of glycolysis. What does it start with? What does end with?

Starts with: 1 molecule of glucose. Ends with: 2 molecules of pyruvate. Glucose= 6 carbons Same 6 carbons end up in 2 molecules of pyruvate (3 in each).

How is ATP formed in glycolysis?

Substrate-level phosphorylation. Enzyme transfers phosphate group from substrate to ADP, forming ATP. Oxidation of glucose to pyruvate= Releases energy Stored in ATP and NADH Cell can use energy in ATP immediately Energy in NADH= electrons from NADH pass down electron transport chain located in inner mitochondrial membrane. Most energy stored in pyruvate molecules

What part of the acetyl CoA enters the cycle?

The 2 carbons (CoA splits off and is recycled).

Essentially, what is chemiosmosis?

Uses energy stored in hydrogen ion gradient across membrane to drive ATP synthesis.