ATP Why do we use it for Energy? ATP: Adenosine Triphosphate Consists of Adensosine + 3 Phosphates Consists of Adensosine + 3 Phosphates Highly unstable.

ATPATP

Why do we use it for Energy?Why do we use it for Energy?

ATP: Adenosine ATP: Adenosine TriphosphateTriphosphate

Consists of Adensosine + 3 PhosphatesConsists of Adensosine + 3 Phosphates Highly unstable moleculeHighly unstable molecule 3 phosphates each highly negative repel 3 phosphates each highly negative repel

each other (like the wrong end of a each other (like the wrong end of a magnet)magnet)

Hence a phosphate group is removed Hence a phosphate group is removed through hydrolysis energy is released (-7.3 through hydrolysis energy is released (-7.3 kcal/mole) and breaks down into the more kcal/mole) and breaks down into the more stable molecule ADP. stable molecule ADP.

ATP: Pictures

Where does the Negativity come from? Oxygen

Oxygen

I thinkhe’s a bitunstable…don’t you?

How does ATP store energy?How does ATP store energy?

PO–

O–

O

–O PO–

O–

O

–O PO–

O–

O

–OPO–

O–

O

–O PO–

O–

O

–OPO–

O–

O

–O PO–

O–

O

–O PO–

O–

O

–O

Each negative POEach negative PO44 more difficult to add more difficult to add a lot of stored energy in each bonda lot of stored energy in each bond

most energy stored in 3rd Pi = releases energy ∆G = -7.3 kcal/mole

3rd Pi is hardest group to keep bonded to molecule

Bonding of negative PBonding of negative Pi i groups is unstablegroups is unstable spring-loadedspring-loaded PPi i groups “pop” off easily & release energygroups “pop” off easily & release energy

Instability of its P bonds makes ATP an excellent energy donor

AMPAMPADPATP

Can’t store ATP good energy donor,

not good energy storagetoo reactivetransfers Pi too easilyonly short term energy

storage carbohydrates & fats are

long term energy storage

ATP / ADP cycleATP / ADP cycle

A working muscle recycles over 10 million ATPs per second

Whoa!Pass me

the glucose(and O2)!

ATP

ADP Pi+

7.3 kcal/mole

cellularrespiration

Completely off TopicCompletely off Topic

How can you remember what happens in How can you remember what happens in Oxidation or Reduction?Oxidation or Reduction?

OIL RIGOIL RIG

Oxidation is Loss of ElectronsOxidation is Loss of Electrons

Reduction is Gain of ElectronsReduction is Gain of Electrons

PS. Making ATP is phosphorylation not PS. Making ATP is phosphorylation not Oxidation or reduction.Oxidation or reduction.

CELLULAR RESPIRATIONC6H12O6 + O2 → CO2 + H2O + energy

What questions should you be able What questions should you be able to answer at the end of the unit?to answer at the end of the unit?

Why do you breath in oxygen?Why do you breath in oxygen?

What do you breath out and why?What do you breath out and why?

How do mitochondria work?How do mitochondria work?

What is the difference between aerobic What is the difference between aerobic and anaerobic respiration?and anaerobic respiration?

What are the steps of Glycolysis?What are the steps of Glycolysis?

What are the steps of Aerobic and What are the steps of Aerobic and Anaerobic Respiration?Anaerobic Respiration?

CELLULAR RESPIRATIONCELLULAR RESPIRATION

The complex process in which cells make ATP by breaking down organic compounds is known as cellular respiration.

2

36

2 NADH + 2H+

pyruvic acid

ANAEROBIC RESPIRATIONANAEROBIC RESPIRATION

When OWhen O2 2 is absent, is absent,

respiration is respiration is anaerobic and includes anaerobic and includes glycolysis and glycolysis and fermentation. fermentation.

GLYCOLYSIS

Glycolysis is a pathway in which one molecule of glucose is oxidized to produce two molecules of pyruvic acid.

Takes place in the cytosol of the cell.

Glycolysis Glycolysis ContinuedContinued

The endproducts are 2 NADH, and 4 ATP The endproducts are 2 NADH, and 4 ATP

First 3 steps of Glycolysis are First 3 steps of Glycolysis are endothermic, require energy in the form of endothermic, require energy in the form of 2 ATP. Subsequent steps are exothermic.2 ATP. Subsequent steps are exothermic.

What is the Net ATP produced by What is the Net ATP produced by Glycolysis?Glycolysis?

Overview of Glycolysis

-2 ATP

+

4 ATP

2 ATP per molecule of glucose.

What happens if you have too What happens if you have too much ATP?much ATP?

Allosteric InhibitionAllosteric Inhibition

PFK (Phosphofructokinase): Enzyme used PFK (Phosphofructokinase): Enzyme used in step 3 of glycolysis to create the 6 in step 3 of glycolysis to create the 6 carbon sugar that breaks apart into carbon sugar that breaks apart into P-C-C-C C-C-C-PP-C-C-C C-C-C-P

Too much energy? ATP binds to the PFK Too much energy? ATP binds to the PFK halting the steps of gycolysis.halting the steps of gycolysis.

AllostericEnzyme

FERMENTATION When there is no oxygen When there is no oxygen available, the products of available, the products of glycolysis enter glycolysis enter fermentation where fermentation where no no further ATP is yieldedfurther ATP is yielded however NAD is regenerated however NAD is regenerated and is available for and is available for glycolysis again.glycolysis again.

ENERGY YIELD

Who uses Anaerobic Respiration?Who uses Anaerobic Respiration?

You do with Aerobic RespirationYou do with Aerobic RespirationSome bacteria survive on it (Botulinum & Some bacteria survive on it (Botulinum & Tetnus) and can not survive in the Tetnus) and can not survive in the presence of Opresence of O22. They are Obligate . They are Obligate anaerobes.anaerobes. Facultative anaerobes can tolerate Facultative anaerobes can tolerate oxygen: Staph, E.Colioxygen: Staph, E.ColiAnaerobic R. began Millions of years ago Anaerobic R. began Millions of years ago when earths atm. Had no Owhen earths atm. Had no O22..

AEROBIC RESPIRATION

If oxygen is available, pyruvic acid enters the pathways of aerobic respiration: the Krebs cycle and the electron transport chain.

OVERVIEW OF AEROBICRESPIRATION

In the Krebs cycle, the oxidation of glucose that began with glycolysis is completed and NAD is reduced to NADH.

In the electron transport chain, NADH is used to make ATP.

Prokaryotes: Cytosol

Eukaryotes: Mitochondrial Matrix

The Mitochondria

At Work

When pyruvic acid reacts with a molecule called coenzyme A to form acetyl coenzyme A.

MakingVinegar

The Krebs CycleThe Krebs CycleCyclic process that produces Cyclic process that produces the following products: COthe following products: CO22, ,

ATP, NADH + HATP, NADH + H++, and FADH, and FADH22. .

COCO2 2 is released.is released.

NADH + HNADH + H++, and FADH, and FADH2 2 go to the go to the

electron transport chain.electron transport chain. Krebs CycleAt the

Bottom

ELECTRON TRANSPORTCHAIN

In prokaryotes, the electron transport chain lines the cell membrane.ATP is produced by the electron transport chain when NADH and FADH2 release hydrogen atoms, regenerating NAD and FAD.

Electron Transport Chain

E.T.C.revisited

H+

catalytichead

rod

rotor

H+H+

H+

H+ H+

H+H+H+ATP synthaseATP synthase

ATP

But… How is the proton (H+) gradient formed?

ADP P+

Enzyme channel in Enzyme channel in mitochondrial membranemitochondrial membrane permeable to Hpermeable to H++ HH++ flow down flow down

concentration gradientconcentration gradientflow like water over flow like water over water wheelwater wheel

flowing H+ cause flowing H+ cause change in shape of change in shape of ATP synthase enzymeATP synthase enzyme

powers bonding of powers bonding of PPii to ADP: to ADP:

ADP + PADP + Pii ATP ATP

RespirationRespiration

..

Virtual Respiration Lab