Cellular Respiration

Cellular Respiration

KEY WORDS:OxidationReductionNAD/ NADHFAD/ FADH2

Cellular respirationGlycolysisKreb’s cycleElectron transport chainATP synthase

Food is used to energize ATP

Electrons transfer energy toEnergize ATP

REDOX REACTIONS

Oxidation = Losing electrons

Reduction = Gaining electrons

TIP: OIL RIG

Gradual transfer of electrons provides most energy (ATP) from food

Main Players: Making ATPFood used to make ATP and NADH & FADH2

Electrons provide energy to pump H+ across inner mitochondrial membrane

NAD+/H carry electrons FAD/H2 carry electrons

H+ provide energy for synthesis of ATP

O2 final electron acceptor in ETC

Cytosol location of glycolysis Mitochondria location of Kreb’s cycle & ETC

ATP Synthase brings together ADP and P to make ATP

Obtaining Energy from Food

C6H12O6 + 6O2 6CO2 + 6H2O + Energy

• Organisms extract energy from food over several steps in small “bite sized” pieces

C6H12O6+ 6O2

Energy Energy Energy

6CO2+6H2O

ATP

CellularRespiration

Occurs in 3 stages:

1.Glycolysis2.Kreb’s cycle3.ETC

1. Glycolysis•Takes place in the cytoplasm

NAD+

A closer look at glycolysis: energy investment phase (Layer 1)

Good News! You don’t need to know the steps of glycolysis!

You need to know what goes in and what comes out

But here are the steps, FYI…

A closer look at glycolysis: energy investment phase (Layer 2)

A closer look at glycolysis: energy payoff phase (Layer 3)

A closer look at glycolysis: energy payoff phase (Layer 4)

What’s Happened so far?Glycolysis

O2

Used?

Glucose C now Product:

ATP

#

NADH

#

Glycolysis

glucose

What’s Happened so far?Glycolysis

O2

Used?

Glucose C now Product:

ATP

#

NADH

#

Glycolysis No Pyruvate 2 2

pyruvate

pyruvate

glucose

Electron carriers

Some energy captured as electrons

•Energy in food in form of high energy electrons•Electrons captured when food is broken down

•Held by electron carriers•NADH, FADH

NAD+ as an electron shuttle

Pyruvate as a key juncture in catabolism

After Glycolysis•Pyruvic Acid shipped into mitochondria•One carbon is removed as CO2

•Attach Coenzyme-A Acetyl-Co-A

•Make one NADH for each pyruvic acid

2. Krebs Cycle

•Remaining two carbons removed as CO2

•For each Acetyl-Co-A:

Make •1 ATP•3 NADH•1 FADH2

A closer look at the Krebs cycle (Layer 1)




This is what you need to know

What’s Happened so far?Krebs Cycle

Original C of glucose are

now

ATP NADH FADH2

Glycolysis 2 pyruvate 2 2

Acetyl CoA formation

2 CO2

& 2 acetyl CoA

2

Krebs Cycle

Total

glucose

What’s Happened so far?Krebs Cycle

Original C of glucose are

now

ATP NADH FADH2

Glycolysis 2 pyruvate 2 2

Acetyl CoA formation

2 CO2

& 2 acetyl CoA

2

Krebs Cycle 4 more CO2 2 6 2

Total 6 CO2 4 10 2

glucose

3. Electron Transport Chain (ETC)

•Electrons give up energy as passed along

•Electrons are passed between several molecules

What is oxygen for?

Receives electrons at the end of the ETC

With H+, forms water

ATP synthase

•Works like hydro-electric dam

•Large concentration gradient of H+ builds up across the mitochondrial membrane

*H+ is pumped against its gradient into the mitochondrial matrix.*Energy for active transport comes from electrons

Harnessing energy in small steps allows the cell to get more energy that can be used to do work

Free energy of electrons decreases as they are

passed through the ETC

Chemiosmosis couples the electron transport chain to ATP synthesis

ATP synthase, a molecular mill

1. Enzymes2. ATP3. NAD+

4. vitamins5. proteins

You need energy to think, to keep your heart beating, to play a sport, and to study this book. This energy is directly supplied by _____, which is (are) produced in the process of cellular respiration.

1. transported ... becoming more energetic2. digested ... becoming more energetic3. reduced ... losing electrons to it4. oxidized ... losing electrons to it5. oxidized ... gaining electrons from it

Energy transfer in living things works through redox reactions, in which one substance is _____ by another substance, thereby _____.

1. glycolysis ... the Krebs cycle ... yield of electrons transported to the ETC

2. glycolysis ... the ETC ... yield of electrons transported to the cytosol

3. Redox reactions ... fatty acid breakdown ... yield of calories

4. The Krebs cycle ... the ETC ... numerous redox reactions

5. The Krebs cycle ... the ETC ... fatty-acid breakdown

_____ and _____ are important not so much for the ATP produced in them, but for their _____.

1. 22. 83. 244. 365. 75

At most, how many molecules of ATP can be produced per glucose molecule in cellular respiration?

1. both atmospheric nitrogen and the oxygen for energy transformation

2. oxygen to donate electrons to3. nitrogen to donate phosphate groups to oxygen4. oxygen to act as the final acceptor of electrons in the

ETC5. oxygen to donate phosphate groups to ADP, making it

ATP

We need to breathe because we need

Anaerobic Respiration

Fermentation•live off glycolysis alone

Alcoholic Fermentation

Pyruvate + NADH

Ethanol + CO2 + NAD+

Vinegar

Lactic Acid Fermentation

Pyruvate + NADH

Lactic Acid + NAD+

Fermentation allows the cycle of glycolysis to continue by regenerating NAD+

Fermentation

An overview of cellular respiration (Layer 1)


Substrate-level phosphorylation


Max of 36 ATP per Glucose

What is all of the ATP used for?

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Cellular Respiration