I' Atoms and Molecules'

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I. Atoms and Molecules.

• A. Biological function starts at chemical level
• To understand chemical structure and function in
  life, we must start small and see how the
  structures at each level are combined into each
  higher level.
• The matter in all living things is made of
  separate chemicals. In muscle, actin is just one
  of these chemicals.
• At every level, structure and function are
  strongly interrelated. Actin is a complex
  chemical (molecule) composed of smaller parts
  (atoms), bonded together in a way that allows the
  molecule to participate in muscle contraction.

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• B. Life requires about 25 chemical elements
• Chemical elements are the basic chemical units
  that cannot be broken apart by chemical
  processes.
• There are 92 naturally occurring elements
  Oxygen, carbon, nitrogen, calcium, sodium, etc.
• Chemical Symbols
• Abbreviations for the name of each element.
• Usually one or two letters of the English or
  Latin name of the element
• First letter upper case, second letter lower
  case. Example Helium (He), sodium (Na),
  potassium (K), oxygen (O).
• The symbol for gold, (Au), is from the Latin word
  aurum.

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• Main Elements About 96 of the human body is
  made up of four elements.
• Oxygen (O) 65 body mass
• Cellular respiration, component of water, and
  most organic compounds.
• Carbon (C) 18.5 of body mass.
• Backbone of all organic compounds.
• Hydrogen (H) 9.5 of body mass.
• Component of water and most organic compounds.
• Nitrogen (N) 3.3 of body mass.
• Component of proteins and nucleic acids (DNA)

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• Minor Elements Found in low amounts. Remaining
  4 .
• Calcium (Ca) 1.5 of body mass.
• Bones, teeth, clotting, muscle and nerve
  function.
• Phosphorus (P) 1 of body mass
• Bones, nucleic acids, energy transfer (ATP).
• Potassium (K) 0.4 of body mass
• Main positive ion inside cells.
• Nerve and muscle function.
• Sulfur (S) 0.3 of body mass
• Component of most proteins.

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• Minor Elements Found in low amounts cont.
• Sodium (Na) 0.2 of body mass
• Main positive ion outside cells.
• Fluid balance, nerve function.
• Chlorine (Cl) 0.2 of body mass
• Main negative ion outside cells.
• Fluid balance.
• Magnesium (Mg) 0.1 of body mass
• Component of many enzymes and chlorophyll.

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• Trace elements Less than 0.01 of mass
• Boron (B)
• Chromium (Cr)
• Cobalt (Co)
• Copper (Cu)
• Iron (Fe)
• Fluorine (F)
• Iodine (I)
• Manganese (Mn)
• Molybdenum (Mo)
• Selenium (Se)

• Silicon (Si)
• Tin (Sn)
• Vanadium (V)
• Zinc (Zn)

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• Carbon, hydrogen, oxygen, and nitrogen make up
  the bulk of living matter, but there are other
  elements necessary for life

Table 2.2
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Elements can combine to form compounds

• Chemical elements combine in fixed ratios to form
  compounds or Molecules.
• Example sodium chlorine ? sodium chloride
• Na Cl- ? NaCl

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Atoms consist of protons, neutrons, and electrons

• The smallest particle of an element is an atom
• Different elements have different types of atoms

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• D. Atoms consist of proton, neutron, and
  electrons.
• Atoms Smallest particle of an element that
  retains its chemical properties. Made up of
  three main subatomic particles. It would take
  about a million atoms to stretch across the
  period printed at the end of this sentence.
• Particle Location Mass Charge
• Proton (p) In nucleus 1
  1
• Neutron (no) In nucleus 1 0
• Electron (e-) Outside nucleus 0
  -1
• Mass is negligible for our purposes.
• Opposite charges ( and - ) attract each other,
  neutron is neutral (has no electrical charge).

Electrical
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Helium atom
Carbon atom
2 neutrons and 2 protons are tightly packed in
the atoms central core, or nucleus. Two electrons
orbit the nucleus at nearly the speed of light.
The negatively charged electrons and positively
charged protons are attracted to each other.
Elements differ in the number of subatomic
particles in their atoms.
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• Atomic number protons
• The number of protons is unique for each element
• Each element has a fixed number of protons in its
  nucleus. This number will never change for a
  given element.
• Written as a subscript to left of element symbol.
• Examples 2He, 6C, 8O, 16S, 20Ca
• Because atoms are electrically neutral (no
  charge), the number of electrons and protons are
  always the same.
• In the periodic table elements are organized by
  increasing atomic number.

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3. Nucleic Acids

• a. Contain C,H,O,N,P
• b. precursor nucleotide
• c. There are three types

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• 1) DNA deoxyribonucleic acid
• a) located inside the nucleus
• b) encodes (contains) hereditary
  information
• 2) RNA ribonucleic acid
• a) three different types
• b) used in producing proteins
• 3) ATP adenosine triphosphate body uses
  this
• chemical for short term storage of
  energy

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ATP
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DNA
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RNA
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4. Lipids

• Contains only C, H O
• b. Three types
• 1) Fats
• Long term energy storage
• b) Insulation
• Cushion
• 2) Phospholipids
• 3) Steroids

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Lipids

• c. Precursors
• 1) glycerol
• 2) 1 3 fatty acids

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Fats
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Phospholipids
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Steroids
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Steroids