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Biochemistry

Intro to Biochemistry

  • 118 Known elements 

  • Most common in living things are Carbon, Nitrogen, Oxygen, and Hydrogen  

  • Elements are made of atoms; atoms are made of particles: protons (+) neutrons and electrons (-)

  • Protons and Neutrons are located in the center and electrons are found in the out shell 

  • When atom has an equal # of protons and electrons the charges balance and the atom is electrically neutral over all

Ion

  • When the protons and electrons aren’t balanced the molecule is ion 


Covalent Bonds:

  • A molecule is a structure made up of 2 or more atoms 

  • Chemical bond that connects a pair of atoms

  • Covalent bonds are the most common bond in living things

  • They are formed by electrons 

  • The # of bonds an atoms can for = to the # of unpaired electrons in the outer shell

  • When 2 atoms share electrons a covalent bond is made atoms are most stable when outer shell is full  


Electronegitivity : tendency of an atom to attract electrons 

  • O>N>C=H

  • Increases on the periodic table as you go up and right 

  • Electro(electrons) negativity (-) creates polarity

  • Attracts the negative charge of electrons 

  • Atoms have different electronegativities 

  • Nonpolar: equal sharing 

  • Polar: unequal sharing, results in partial negative and positive charges on the atoms 


Covalent bonds can be: 

Non-polar

  • Sharing of electrons 

  • No partial charge on either atom

Polar 

  • Unequal sharing of electron pair 

  • Results in a partial charge on the atom (greek letter)

  • To determine if the bond is polar or non polar subtract the values and if the value is greater the .4 it results in a polar bond 


Water

  • Polar 

  • Made up of 1 Oxygen atom and 2 Hydrogen atom (Oxygen is more electronegative of the atoms)

  • Partial polar charges 

  • Some molecules can form H-bonds (hydrophilic) has partial charges (polar)

  • Some molecules can’t form H-bonds ( hydrophobic) lacks partial charges (non-polar)

  • Exception to the rule is carbon dioxide its non-polar and hydrophobic 


Hydrogen bond 

  • Weak attraction compared to covalent bonds

  • H bonds are the dotted line formed from attraction between electrical charges  

  • H bonds are easy to break 

  • Hydrogen partial positive charge and negative partial charge 


Macromolecules 

Carbohydrates : monosaccharides 

Protein: amino acids 

Nucleic acids: nucleotides 


Acids

  • release H+ protons 

  • Lowers the pH

Bases

  • accepts H+ protons 

  • Increases the pH