SBI4U: Thermodynamics and Metabolism



SBI4U: Thermodynamics and Metabolism

Important Terms:

Metabolism: all chemical reactions occurring __________________________

Anabolism: chemical reactions that ________________ energy to make new chemical bonds

Ex. _________________________ is an anabolic reaction

Catabolism: chemical reactions that harvest energy when bonds are broken

Ex. ___________________________ is a catabolic reaction

Flow of Energy

Potential energy stored in chemical bonds can be _______________________ from one molecule to another through ______________________.

oxidation: ________________ of electrons (LEO)

reduction: ________________ of electrons (GER)

redox reactions are _________________ to each other.

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Laws of Thermodynamics

First Law of Thermodynamics: Energy cannot be _____________________ or _______________

-energy can only be ________________________ from one form to another

How does photosynthesis demonstrate the first law of thermodynamics?

_______________________________________________________________

Second Law of Thermodynamics: __________________ is more likely than __________________

-entropy: ______________ in the universe

*The 2nd Law of Thermodynamics states that entropy is always ___________________

“The messy bedroom law…”

Gibb’s Free Energy

Free energy: the energy available to do ___________________

-free energy symbol: G (__________________ free energy)

-Enthalpy: energy contained in a molecule’s __________________________

Changes in Free Energy

• Chemical reactions can create ____________________ in free energy.

• When products contain more free energy than reactants ΔG is ______________

• When reactants contain more free energy than products ΔG is ______________

Chemical reactions can be described by the transfer of energy that occurs:

endergonic reaction: a reaction requiring an _________________ of energy

- ΔG is __________________

exergonic reaction: a reaction that __________________ free energy

- ΔG is ____________________

Most reactions require some energy to get started.

activation energy: ____________ needed to get a reaction started

-___________________ existing chemical bonds

-required even for _________________ reactions

catalysts: substances that ________ the activation energy of a reaction

*What do we call a catalyst that speeds up biological reactions?

__________________________

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Energy Currency of Cells

ATP = ____________________________

-the energy “_____________________” of cells

ATP structure:

-ribose, a 5-carbon sugar

-adenine

-three _______________________

How do we use ATP?

ATP stores energy in the _____________________ between phosphates.

Phosphates are highly negative, therefore:

-the phosphates ____________________ each other

-Lots of energy is required to keep the phosphates __________________ to each other

-Lots of energy is ____________________ when the bond between two phosphates is broken

When the bond between phosphates is broken:

ATP ADP + Pi

energy is released

Is this reaction exergonic or endergonic? ____________________

Is this reaction anabolic or catabolic? _____________________

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Redox Reactions

ATP Structure

ADP = adenosine diphosphate

Pi = inorganic ____________________________

This reaction is ________________________!

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