Bioenergetics I

Professor Michael Chorney

Susquehanna MAGNET

January 27, 2014

LO’s

• Discuss the first two laws of

thermodynamics

• Describe entropy and Gibbs free energy

• Explain why ATP is so important to life

• Discuss the activated carriers critical for

electron and atom transfer

Laws 1 and 2 of

Thermodynamics

• 1. energy constant but can exchange

• 2. reactions occur that favor probability,

entropy increases

Figure 2-37 Molecular Biology of the Cell (© Garland Science 2008)

e.g.

Figure 2-36 Molecular Biology of the Cell (© Garland Science 2008)

Breakdown Synthesis

Nucleoside

triphosphate

especially ATP

Figure 2-38 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-30 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-17 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-40 Molecular Biology of the Cell (© Garland Science 2008)

The Sun’s energy drives everything.

Figure 2-41 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-42 Molecular Biology of the Cell (© Garland Science 2008)

Gibb’s Free Energy of a Reaction

<1 exergonic, spontaneous, energy released

0

>1 endergonic, unfavorable, energy required

Figure 2-50 Molecular Biology of the Cell (© Garland Science 2008)

The cell creates order through a myriad of

unfavorable reactions coupled to favorable

reactions through the exploitation of activated

carriers like ATP and others

Figure 2-27 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-55 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-26 Molecular Biology of the Cell (© Garland Science 2008)

1

2

3

ΔGo = -1.42logK where K is [products]/[reactants]*

For ATP ADP + Pi

ΔGo = -11 to -13 kcal/mole, K is 11, or the products are

100,000 greater concentration than the starting ATP

At equilibrium, the rate of ATP breakdown equals the

rate of ADP + Pi giving rise to ATP, very low

* ΔG = ΔGo + RTlogK

Table 2-4 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-51 Molecular Biology of the Cell (© Garland Science 2008)

A coupled reax where

final ΔGo is based on

additive ΔGs, thus

The reaction produces

products D and Y

at the expense of

C’s and X’s conversion

X to Y most favored

Figure 2-54 Molecular Biology of the Cell (© Garland Science 2008)

Note the change in

Equilibria denoted by the

arrows

If X to Y is slow, but Y to Z fast, the sequential reax’s deplete X, Y

Figure 2-44 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-45 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-47 Molecular Biology of the Cell (© Garland Science 2008)

Enzymes can lower activation energy by

Bringing reactants together

By coupling reactions in order to create

unstable, high energy intermediates that drive

the equilibrium toward products

Figure 2-59a Molecular Biology of the Cell (© Garland Science 2008)

In a general sense,

Consider the following

Figure 2-59b Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-58 Molecular Biology of the Cell (© Garland Science 2008)

ATP provides

energy and

the phosphate

group

The nucleotide-like molecules NADH

and NADPH are activated carriers

of

Protons (H+) and electrons (e-)

Figure 2-60b Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-60a Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-61 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-62 Molecular Biology of the Cell (© Garland Science 2008)

Table 2-5 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-63 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-64 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-65 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-66 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-67 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-18 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-19 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-20 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-34 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-69 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-70 Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-71a Molecular Biology of the Cell (© Garland Science 2008)

Figure 2-71b Molecular Biology of the Cell (© Garland Science 2008)

Case study

A young boy is diagnosed with von Gierke’s disease.

What is this, what is the clinical picture? What is the defect?

What product builds up?

What pathway(s) can the latter product filter into?

What is glycogen and glycogenolysis?