AP Biology 04/20/23

The Point is to Make ATP!

ATP

Making energy!

AP Biology 04/20/23

Energy needs of life Organisms are endergonic systems

What do we need energy for?

synthesis (biomolecules) reproduction active transport movement temperature regulation

AP Biology

Transformations between kinetic and potential energyMore potential energy.

Potential energy converted to kinetic energy.

Kinetic Energy Converted toPotential Energy

Less potential energy

AP Biology 04/20/23

energy

Where do we get the energy from? Work of life is done by energy coupling

use exergonic (catabolic) reactions to fuel endergonic (anabolic) reactions

+ + energy

+ energy+

AP Biology

The two laws of thermodynamics

(a) First law of thermodynamics: Energy

can be transferred or transformed but

neither created nor destroyed.

Second law of thermodynamics: Every energy transfer or transformation increases the disorder (entropy) of the universe.

(b)

Chemicalenergy

Heatco2

H2O+

AP Biology

H2 + 1/2 O2 2 H 1/2 O2

(from food via NADH)

2 H+ + 2 e–

2 H+

2 e–

H2O

1/2 O2

Controlled release of energy for synthesis of

ATPATP

ATP

ATP

Electro

n tran

spo

rt chain

F

ree

ener

gy, G

(b) Cellular respiration(a) Uncontrolled reaction

Fre

e en

ergy

, G

H2O

Explosiverelease of

heat and lightenergy

+

How Food Becomes Energy

AP Biology

Where do we get the energy from? Work of life is done by energy coupling use exergonic (catabolic) reactions to

fuel endergonic (anabolic) reactions

+ + energy

+ energy+

digestion

synthesis

AP Biology 04/20/23

Living economy Fueling the economy

eat high energy organic molecules (food) break them down = catabolism (digest) capture energy in form cell can use

Need an energy currency a way to pass energy around

ATPWhoa!

Hot stuff!

AP Biology 04/20/23

ATP Adenosine Triphosphate

modified nucleotide adenine + ribose + Pi AMP

AMP + Pi ADP

ADP + Pi ATP

an RNA nucleotide

How efficient!Build once,

use many ways

AP Biology 04/20/23

Why 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 Pi group more difficult to add a lot of stored energy in each bond

most stored in 3rd Pi

∆G = -7.3 kcal/mole

Close packing of negative Pi groups

I think he’s a bit unstable… don’t you?

spring-loaded

instability of its P bonds makes ATP an excellent energy donor

AP Biology 04/20/23

How does ATP transfer energy?

PO–

O–

O

–O PO–

O–

O

–O PO–

O–

O

–O energyPO–

O–

O

–O +

Phosphorylation when ATP does work, it transfers

its 3rd Pi to other molecules ATP ADP releases energy

∆G = -7.3 kcal/mole it destabilizes the other molecule

Why is 3rd phosphate

like a baaad

boyfriend?

AP Biology 04/20/23

it’s never that simple!

An example of Phosphorylation… Building polymers from monomers

need ATP for energy & to take the water out

C

H

OH

H

OHC C

H

O

H

C+ H2O++4.2 kcal/mol

C

H

OH+ C

H

P+ATP ADP

-7.3 kcal/mol

H

OHC C

H

O

H

C+ +C

H

PPi

-3.1 kcal/mol

“kinase” enzyme

AP Biology 04/20/23

glucoseC-C-C-C-C-C

fructose-6PP-C-C-C-C-C-C-P

DHAPP-C-C-C

PGALC-C-C-P

2 ATP2 ADP

Another example of Phosphorylation… The first steps of cellular respiration

beginning the breakdown of glucose ATP

those phosphates sure make it uncomfortab

le around here

enzyme 1

enzyme 3 enzyme 4enzyme 5

enzyme 6

enzyme 2

AP Biology 04/20/23

ATP / ADP cycle

A working muscle recycles over 10 million ATPs per secondWhoa!

Pass me the glucose & oxygen!

Can’t store ATP too reactive transfers Pi too

easily only short term

energy storage carbs & fats are

long term energy storage

AP Biology 04/20/23

What’s the point? Cells spend a lot of time making ATP!

“The point is to make ATP!”

I didn’t HEAR you!

Make ATP! That’s all I do all day. And no one

even notices!

AP Biology 04/20/23

Any Questions??