Chemical Basis of Life

1
Chapter 2

• Chemical Basis of Life

2
Matter

• Anything that has mass and takes up space.
• Atoms are the smallest particles of matter.

3
Elements and Atoms

• All matter is composed of elements
• Elements are the basic substances that make up
  matter
• Atoms are the smallest particles of matter
• Living Organisms require about twenty elements
• 95 of human body is made of oxygen, carbon,
  hydrogen, and nitrogen

4
Atomic Structure

• Protons () 1amu
• Neutrons (neutral) 1amu
• Electrons (-) 1/1800 of a proton

5
Drawing Bohr Models of Atoms
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Periodic Table of Elements
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Periodic Table of Elements
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Atom Rules

• of Protons Atomic number
• of Protons of Electrons
• Mass Protons Neutrons

9
Isotopes

• Isotopes have a different number of neutrons but
  the same number of protons
• Radio active isotopes are used to detect problems
  with the thyroid, treat cancer, and detect
  problem with digestion

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Molecules and Compounds

• Molecule when two or more atoms combine
  (usually for nonmetals)
• Compound when two or more atoms of different
  elements combine
• Two types
• Ionic
• Covalent

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Formulas

• Molecular formulas
• Represent the number atoms found in a compound
• Structural formulas
• Atoms of specific elements form a specific of
  bonds
• Shows the structure of the Chemical

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Formulas

• Structural formulas for C4H9N
• Molecular formula is the same, but structural
  formulas can vary

13
Bonding

• Atoms combine with other atoms to either gain
  lose or share electrons
• Electrons are found in shells outside of the
  nucleus
• Valence shell is involved in bonding and is the
  outer most electron shell

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Types of Bonding

• Ionic
• A metal and non metal
• Form ions
• Na
• O2-
• Transfer of electrons
• Ionic compounds
• Ions are important muscle contraction, nerve
  impulse transmission, etc.

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Types of Bonding

• Covalent
• 2 or more non metals
• Sharing of electrons forms a bond.
• Single double or triple
• Molecules formed when two or more atoms combine

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Types of Bonding

• Hydrogen Bond
• Occurs when an atom of hydrogen has a strong
  attraction to two atoms instead of one
• The atoms must be highly electronegative
  (electron loving) like Oxygen, Flourine,
  Nitrogen, Chlorine and Bromine

17
Chemical Reactions

• When two or more substances come together to form
  a new substance
• Types
• Synthesis elements join to form 1 new substance
• Decomposition Substance breaks down into
  components
• Single Replacement 1 element in a compound is
  exchanged for another free element
• Double Replacement 2 elements in two compounds
  are exchanged
• Combustion Oxygen is used to burn a hydrocarbon
  to produce carbon dioxide and water. (respiration)

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Reversible reactions

• Product or products can convert back into the
  reactants
• The direction of reaction depends on several
  factors
• Energy
• Concentration of products
• Catalyst change the rate without being consumed

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Acid Base Chemistry

• Electrolytes substances released into water that
  produces ions and conducts electricity
• Acids substances that release H
• Bases substances that release OH-
• Strong Acid Strong Base ? water and salt
• Example HCl NaOH ? H2O NaCl

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pH Scale

• pH Scale Based on the concentration of H
  (1-14)
• pH of acid lt7
• pH of base gt7
• pH of neutral 7
• If blood pH is either below 6.9 or above 7.8 a
  person cannot survive

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Inorganic Substances

• Water
• Most abundant in living things
• Universal Solvent
• Most reactions occur in water
• Transports wastes, nutrients, etc
• Absorbs heat
• Oxygen
• Cellular respiration to release energy
• Carbon Dioxide
• Waste product of cellular respiration
• Salts
• Major sources on ions used in metabolic processes
• Na, Cl, K, Ca, Mg, P, CO3-2, HCO3-1, SO4-2

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Organic Substances Carbohydrates

• Provides energy for activities
• C, H, O
• Ratio 121 (C6H12O6)
• Monosaccharides simple sugars (glucose)
• (Monomers)
• Disaccharides two simple sugars combined
  together (lactose)
• Polysaccharides complex carbohydrates (glycogen)

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Organic Substances Carbohydrates
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Organic Substances Lipids

• Insoluble in water
• Typically 3 fatty acids and 1 glycerol
  (Triglycerides)
• Store energy and have more energy
• Saturated max amount of Hydrogen
• Unsaturated not the maximum amount of Hydrogen
• Steroids complex rings that includes
  cholesterol
• Phospholipids cell membranes contain phosphate,
  2 fatty acids and a glycerol.

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Organic Molecules Lipids
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Organic Molecules Lipids
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Organic Substances Proteins

• Provide energy, structure, hormones, enzymes,
  receptors, and antibodies.
• Base unit amino acid
• 20 amino acids of which 12 are essential
• C, H, O, N
• Held together by hydrogen bonding so heat, pH
  change, radiation, etc affect the bonding

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Organic Substances Nucleic Acids

• Form genes and take part in protein synthesis
• DNA (Deoxyribonucleic Acid)
• RNA (Ribonucleic Acid)
• Nucleotides Adenine, Guanine, Cytosine,
  Thymine(DNA only), and Uracil (RNA only)