Interfacing Chemistry and Biology Since 2005

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IImportant mportant TThermodynamichermodynamic

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Outline of teachable unit:

Day 1: Provide an environment that reduces the fear of chemistry in students.

Day 2: Chemical equilibrium, steady state, as well as how and why cells/life are not at equilibrium

Day 3: Chemical potential, entropy, and diffusion

Day 4: Enzyme kinetics, catalysis, transition states, binding of substrate, and activation energy

With which of the following are you least comfortable?

a. Physiologyb. Molecular Biologyc. Geneticsd. Thermodynamicse. Ecology

When you see the graph above, how do you feel about interpreting it?a- confidentb- if I have toc- neutrald- warye- scared out of my mind…I am dropping biology immediately!

___________________________________________________________________Ratio of the Concentration of Products:Reactants

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Based on these data which reaction would have the highest ratio of the concentration of products:reactants at equilibrium?

A – green (bottom)B – blue (middle)C – red (top)

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Ratio of the Concentration of Products:Reactants

Some basic biology:

1. Why do we eat?

Some basic biology:

1. Why do we eat?2. Where is this energy used

in our body?

Some basic biology:

1. Why do we eat?2. Where is this energy used

in our body?3. Why do cells need energy?

From where might the energy come that is required for these cellular processes we just discussed?

a. The oxygen we breatheb. The water we ingestc. The caffeine we drinkd. The vitamin pills we takee. The sugar we break down

Can energy be created?

Can energy be destroyed?

Energy Releasing Reactions

Energy Requiring Reactions

Energy Releasing Reactions

Energy Requiring Reactions

Biological processes can COUPLE these reactions

Ratio of the Concentration of Products:Reactants

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Ratio of the Concentration of Products:Reactants

Figure 5.16 Making a polypeptide chain

Figure 5.16 Making a polypeptide chain

The ∆G forthis reactionis 6 kcal/mole

In the cells of your body, glucose and oxygen are converted to carbon dioxide and water.

This process is called cellular respiration.

Consider the synthesis in a cell of a protein having 101 amino acid subunits. This requires the formation of 100 peptide bonds. The G for peptide bond formation is 6 kcal/mol. The complete breakdown of glucose in cellular respiration releases 600 kcal/mole.

How many moles of glucose molecules does it take to make a mole of this protein?

a. < 1

a. 1

b. > 1

∆Go’

∆Go’

Standard State

∆Go’

Equilibrium Point

Standard State

Based on the lesson just presented, when you see the graph above, how do you feel about interpreting it?

a- confidentb- if I have toc- neutrald- warye- STILL scared out of my mind…I am dropping biology immediately!

Based on these data which reaction(s) would have the lowest ratio of the concentration of products:reactants at equilibrium?

A – green (bottom)B – blue (middle)C – red (top)

Congratulations!

You just did thermodynamics!!!

A <---> B

B <---> C

A <---> C

Sum of abovereactions:

Homework 1: The reactions A <---> B and B <---> C occur sequentially and can be summed to yield the reaction A <---> C. What is the G of this reaction when the reaction occurs under standard state conditions? Homework 2: Concept map. See course web site for instructions.

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“Much to learn, you still have.”

Cornell University Rutgers, the State University of NJ Kuei-Chiu Chen Diana Martin Tom Owens Gregg Transue

Dartmouth College University of Alabama Jon Kull Kim Caldwell Roger Sloboda

And driven mercilessly by:

Ishrat Khan (Clark Atlanta) and Lillian Tong (University of Wisconsin-Madison)