Biochemistry

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Biochemistry
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Particles of Matter

• An element is a substance made of only one type
  of atom
• A compound is made of more than one type of atom
• (ex. CO2, H2O)
• An atom is the smallest part of an element that
  has the same properties as the element
• A molecule is the smallest
• part of a compound that has
• the same properties as the compound

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Structure of an Atom
- charge
Nucleus
Protons And Neutrons

charge
electrons
0 charge
_
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Sub-Atomic Particles

• Protons and neutrons make up the mass of the atom
  (atomic mass)
• The arrangement of electrons determines the
  chemical properties of the atom (how it behaves
  in a chemical reaction)

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Isotopes

• Atoms of the same element that differ in their
  number of neutrons
• Some isotopes are unstable and give off radiation
  (radioisotopes)

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Radioisotopes

• Uses of radioisotopes
• Used to treat cancer (radiation kills cancer
  cells)
• Used to date fossils
• Used in medical imaging (radioactive tracers)

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What is an ION?

• An atom or group of atoms with a charge (either
  or -)
• Ions are involved in thousands of chemical
  processes in the body

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Acids, Bases, and Buffers
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What is an acid?

• any substance that forms
• hydrogen ions (H) in a solution

Examples of acids HCl H2SO4 HNO3
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What is a base?

• any substance that forms hydroxide ions (OH-) in
  a
• solution

Examples of bases NaOH KOH Ca(OH)2
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pH Scale

• measures the concentration of H ions in a
  solution

Pure H2O
BASIC
ACIDIC
7
0
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A change is one on the pH scale represents a 10
fold increase in H ions Ex. pH of 3 is 10 times
more acidic than pH 4 pH of 3 is 100 times
more acidic than pH 5
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What is a Buffer?

• A buffer is a substance that neutralizes excess
  acids or bases to keep the pH of a solution
  constant
• Buffers are present in all of the cells and
  fluids in your body