Loading presentation...

Present Remotely

Send the link below via email or IM


Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.


The Importance of Weak and Strong Chemical Bonds

No description

Erika LaTorre

on 28 February 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of The Importance of Weak and Strong Chemical Bonds

The Importance of Weak and Strong Chemical Bonds
Free Energy (G)
-The change in energy during bond breaking and bond forming.

- At equilibrium, there is no further change in the amount of free energy.

- The free energy lost as equilibrium is approached is either transformed into heat or used to increase the amount of entropy.

- The equilibrium constant is exponentially related to free energy.
-The stronger the bond, the greater the change in free energy.
Weak Bonds in Biological Systems
van der Waals
Ionic Bonds
Hydrogen Bond
Characteristics of Chemical Bonds
-What is a Chemical Bond?
-It is an attractive force that holds atoms together.
-Bond Angle
-Freedom of Rotation
Donating Molecules are Unstable
Catalyst and Strong Bonds
-Since covalent bonds have lost energy during formation, they do not have the energy to break apart thus they need help from a catalyst.

-The energy supplied to break the bonds is the activation energy.
-The least amount of energy is needed because a collision of the molecules occurs at the activated state.

-Enzymes catalyze reactions by lowering the activation energies; some reactions will not occur without the help of an enzyme.
Types of Bonds
-van der Waals: attractive force originating when two atoms come close together. All molecules exhibit van der Waals and it is the weakest of the weak bonds; it depends heavily on the distance between the interacting groups.
Chemical Bonds and Energy
-The formation and breakage of bonds converts energy from one form to another.
-The amount of energy that must be added to break a bond is exactly equal to the amount that was released upon formation of the bond
More Weak Bonds
-Organic Molecules that tend to from hydrogen bonds are water soluble.
-Hydrophobic: water fearing
-Hydrophilic: water loving

-Hydrophobic "bonds" stabilize macromolecules.

-Weak bonds attach enzymes to substrates.
-If enzymes were bound to their substrates, or to their products, by more powerful bonds, they would act much more slowly.

-Weak bonds mediate most protein-DNA and protein-protein interactions.
- Equilibrium: number of bond making equals the number of bond breaking.
Polar and Nonpolar
-A combination of separated positive and negative charges is called an electric dipole moment.
- Molecules that have a Dipole moment are Polar molecules.
- Molecules not having a Dipole moment are Nonpolar molecules.
-Main types of Weak Bonds:
-van der Waals, Hydrophobic bonds, Hydrogen bonds, and Ionic bonds.

-They have energies between 1 and 7 kcal/mol.

-They are constantly made and broken at phisiological temperatures.

Hydrogen Bonds
Ionic Bonds
-The electrostatic forces acting between the oppositely charged groups.

-Many organic molecules possess ionic groups that contain one or more units of net positive or negative charge.

-One or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other.

Hydrogen Bonds: are formed between a donor hydrogen atom with some positive charge and a negatively charged acceptor atom.

-Both the donor hydrogen atom and the negative acceptor atoms have a less than a unit of charge.

-The most important hydrogen bonds involve hydrogen atoms covalently bound to oxygen or nitrogen.
-Molecules linked by weak bonds posses a greater amount of free energy than those linked by strong bonds.
-Molecules linked by weak bonds do not require a catalyst to convert into other molecules and are unstable
-They are converted to more stable compounds.
Strong Bonds
-In order for molecules with strong bonds to convert to other molecules they need the help of a catalyst.
-Strong bonded molecules have lost a large amount of free energy in the process of forming.
High Energy Bonds
-Were thought to violate the laws of thermodynamics.

-Upon superficial examination, they were thought to increase free energy upon formation.

-Was found that they do not violate the laws but are based on different reactions than the ones originally thought.

-Precursors are first enzymatically converted to high-energy activated molecules, and in the presence of an enzyme then convert to the desired product.
Biosynthetic Processes
-ATP is the primary energy source of the cell, formed from ADP and inorganic phosphate.

-ATP contains several high-energy bonds.

-Groups linked by high-energy bonds are considered high-energy groups; these high energy groups can be transferred to other molecules by group-transfer reactions.
-Weak and Strong bonds are IMPORTANT
Full transcript