Chapter 23: Metabolism: Glycolysis, Krebs cycle and Oxidative Phosphorylation

What is glycolysis?

Turning glucose into pyruvate

Where does glycolysis occur?

The cytosol

What does glycolysis require to start?

2 ATP

What is the starting molecule of glycolysis?

Glucose

How many carbon atoms is glucose made out of?

6 carbon

What physical action needs to happen to the glucose molecule in order to develop into pyruvate?

It needs to split in half

What is added to each side of the glucose molecule so it can split in half?

Phosphate (2 total)

What are the 2 split pieces of glucose ( 3 carbon and 1 phosphate molecule) called in glycolysis?

Glyceraldehyde-3-phosphate

What needs to happen for the 3 carbon and 1 phosphate molecule to become pyruvate?

Phosphate needs to be removed

What is pyruvate?

A molecule used to generate energy in aerobic respiration

What kind of respiration does pyruvate generate energy for?

Aerobic

How much net ATP is generated during glycolysis?

2 net ATP

What is another byproduct of glycolysis?

NADH

What has to happen after glycolysis for the Krebs cycle to begin?

Pyruvate oxidation

What is Pyruvate oxidation?

Pyruvate and Coenzyme A attach to form acetyl-CoA

What does Pyruvate attach to in Pyruvate Oxidation?

Coenzyme A

How does pyruvate attach to coenzyme A?

Pyruvate anchors 2 carbons to coenzyme A

What is the product of Pyruvate and Coenzyme A during pyruvate oxidation?

Acetyl-CoA

What is another name for the Krebs cycle? (hint: not citric acid cycle)

Tricarboxylic acid cycle

What is the Krebs cycle?

Turning nutrients into ATP

How many enzymatic reactions take place during the Krebs cycle?

8

Where does the Krebs cycle take place?

The mitochondria

What is the starting molecule of the Krebs cycle?

Acetyl-CoA

What is 2 molecules are combined with to make Citrate (first step of Krebs cycle)?

Acetyl-CoA and Oxaloacetate

Acetyl-CoA and Oxaloacetate combine together to make?

Citrate

What are the products of the citric acid cycle?

CO2, ATP, NADH, FADH2 and H20

How much Co2 does one pyruvate molecule produce during one Krebs cycle?

3 Co2

How much ATP does one pyruvate molecule produce during one Krebs cycle?

1 ATP per cycle

Why does the Krebs cycle not produce 2 ATP even though each of the 2 glucose molecules produces 1 ATP?

The Krebs cycle turns twice per glucose

How much NADH does one pyruvate molecule produce during one Krebs cycle?

4 NADH

How much FADH2 does one pyruvate molecule produce during one Krebs cycle?

1 FADH2

Which products of the Krebs cycle store electrons released during the Krebs cycle?

NADH AND FADH2

Why is Coenzyme A important to the Krebs cycle?

It combines with Pyruvate to make Acetyl-CoA to start the Krebs cycle

When is Coenzyme A released during the Krebs cycle?

After the conversion of succinyl-CoA to succinate

Is Coenzyme A a reusable molecule?

Yes

1 multiple choice option

What is NAD?

Nicotinamide Adenine Dinucleotide

What is NAD oxidized form?

NAD1+

How does NAD1+ turn into NADH?

NAD1+ + H + -2 electrons

How many electrons does NADH store?

2

How many protons does NADH store?

1 (hydrogen)

What is NADH net charge?

0

How many times is NAD1+ converted into NADH during the Krebs cycle?

3 times

Where does NADH carry high energy electrons for ATP production?

Complex I of the electron transport chin

What is FAD?

Flavun Adenosine Dinucleotide

How do you convert FAD to FADH2?

FAD + 2H+ + -2 electrons

How many electrons does FADH2 store?

2

How many protons does FADH2 store?

2 (hydrogen)

When is FAD reduced to FADH2 during the Krebs cycle?

During oxidation of succinate to fumarate

Where does FADH2 carry electrons to when NADH can't carry them? (hint: not the same place)

Complex II of the electron transport chain

Where is the electron transport chain?

Inner mitochondria membrane in Eukaryotes

What is Oxidative Phosphorylation and ATP synthesis?

The generation of more ATP using electrons and protons from the Krebs cycle

Where does Oxidative Phosphorylation and ATP synthesis occur?

The electron transport chain

Which electrons are used from the Krebs cycle during Oxidative Phosphorylation?

Electrons from NADH AND FADH2

Where do high energy NADH electrons go when they are transported down the electron chain during Oxidative Phosphorylation?

Complex I

Where do high energy FADH2 electrons go when they are transported down the electron chain during Oxidative Phosphorylation?

Complex II

What does the energy released after the breaking down of electrons (NADH AND FADH2) cause?

Protons to be released

Where do the protons go after being released during Oxidative Phosphorylation?

Form the cellular matrix to intermebrane space

What is created when the protons move from the cellular matrix to the inter membrane space during Oxidative Phosphorylation?

Electrochemical gradient

What happens when protons flow back down the electrochemical gradient back into the matrix?

Activates ATP synthesis

What happens during ATP synthesis?

ADP -> ATP

What is the final electron receptor during Oxidative Phosphorylation?

Oxygen

What is oxygens role in the last part of Oxidative Phosphorylation?

Oxygen combines electrons and protons to form H2O

Where does oxygen form H2O during Oxidative Phosphorylation?

Complex IV

How much ATP is generated during Oxidative Phosphorylation?

~30+ ATP

How much ATP per glucose is created during Cellular Respiration according to the textbook Martini Fundamentals of A&P?

30-32 ATP per glucose

How much ATP per glucose is created during Cellular Respiration according to the textbook W. H. Flurkey J. Chem. Educ (2010)?

29-32 ATP per glucose

How much ATP per glucose is created during Cellular Respiration according to the textbook and other older bio+biochem books?

36-38 ATP per glucose

Does glycolysis, the Krebs cycle and/or oxidative phosphorylation consume glucose?

Glycolysis

Where is glucose consumed during glycolysis?

The cytosol

Does glycolysis, the Krebs cycle and/or oxidative phosphorylation consume oxygen?

Oxidative Phosphorylation

Where is O2 consumed during Oxidative Phosphorylation?

Inner Mitochondrial Membrane (ETC)

Does glycolysis, the Krebs cycle and/or oxidative phosphorylation produce CO2?

Krebs cycle

Where does the Krebs cycle produce CO2?

Mitochondrail matrix

Does glycolysis, the Krebs cycle and/or oxidative phosphorylation produce H20?

Glycolysis and Oxidative Phosphorylation

Where is H20 produced in glycolysis?

Cytosol

Where is H20 produced in Oxidative Phosphorylation?

Inner Mitochondrial membrane

How much ATP does glycolysis produce?

2 net ATP per glucose

How much ATP does the Krebs cycle produce per cycle?

1

How much ATP does Oxidative Phosphorylation produce?

30+

Where does aerobic respiration take place?

Mitochondria

What takes place during aerobic respiration?

Pyruvate Oxidation, Krebs cycle and Oxidative Phosphorylation

How much ATP is produced during aerobic respiration?

30

When does anaerobic respiration take place?

Before glycolysis

What happens during anaerobic respiration before glycolysis?

Regenerates NAD+ from NADH

What is converted during anaerobic respiration to regenerate NAD+ from NADH?

Conversion of Pyruvate to lactate

How much ATP is created during anaerobic respiration?

2 ATP per glucose