Biomolecules

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Biomolecules
The Chemical Building Blocks of Life
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The Chemistry of Carbon

• Organic molecules contain carbon
• Carbons four valence electrons allow it to form
  up to four covalent bonds
• Hydrocarbons consist only of C and H
• Propane CH8
• It can easily bond to itself and form long chains
• Linear - Cyclic - Branched

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Functional Groups

• Chemical properties and reactivity are a result
  of functional groups
• Functional groups maintain chemical properties no
  matter where they occur
• Polar molecules are hydrophilic
• Nonpolar molecules are hydrophobic
• The degree to which organic molecules interact
  with water affects their function
• Hydroxyl group (-OH) is one of the most common
  functional groups, it will make a molecule water
  soluble

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Macromolecules The Sum of the Parts

• Many complex biological activities require large
  macromolecules
• Macromolecules are polymers built by linking
  together small subunits called monomers
• Proteins are polymers of amino acids
• Nucleic acids are polymers of nucleotides
• Starches are polymers of simple sugars

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Condensationaka dehydration synthesis

• Macromolecules are constructed by covalently
  bonding monomers by condensation reactions where
  water is removed from the functional groups of
  the monomers
• Dehydration synthesis (water is removed)
• A hydroxyl (-OH) from one monomer and a hydrogen
  (-H) from another are removed
• Anabolic reaction

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Hydrolysis

• Hydrolysis is the reverse of condensation
• Results in the break down of polymers
• Hydration reactions add water and break bonds
  releasing energy

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Macromolecules

• Perform complex tasks with precision
• Basic structure and function of each family
  similar in all organisms (bacteria humans)

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Families of Biomolecules

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

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Basic Function
Carbos Lipids N. Acids Proteins
Energy Storage Structure Long term storage Insulation Protection Inheritance Blueprint for metabolism Catalysts Hormones Structure
Starch Glycogen Glucose Sucrose Cellulose Lipid Fats Oils Waxes DNA RNA ATP Proteins Enzymes
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CarbohydratesHow Sweet It Is!

• General formula (CH2O)n
• Simple sugars or large molecules made of sugar
  monomers
• Monosaccharides (monomer) are covalently linked
  by condensation reaction to form polysaccharides
  (polymers)

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Sugars

• Monosaccharides
• Five carbon Ribose
• Six carbon glucose and fructose

• Disaccharides
• Sucrose
• Lactose

• Polysaccharides
• Starch
• Cellulose
• Glycogen

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Polysaccharides

• Three Types
• Glycogen animal storage product that
  accumulates in the liver
• - Highly branched
• Glucose?Glycogen?glucose?bloodstream
• Starch plant energy storage
• - Helical
• - Easily digested by animals through hydrolysis

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Cellulose

• Polysaccharide found in plant cell walls
• For humans cellulose is indigestible and forms
  dietary fiber
• Made up entirely of ß glucoses
• Structure is constrained into straight
  microfibrils
• Not an energy source for animals
• Chitin insect exoskeletons

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Lipids

• Long-term energy storage
• Generally insoluble in water
• Structural components of cells (phospholipids)
• Cellular messengers (hormones)

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More FAT

• Triglycerides are composed of three fatty acids
  covalently bonded to one glycerol molecule

• Fatty acids are composed of CH2 units and are
  hydrophobic

• Fatty acids can be saturated (all single bonds)
  or unsaturated (one or more double bonds)

• A fat (mostly saturated) is solid at room temp.
  while an oil (mostly unsaturated) is liquid at
  room temp.

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Phospholipids

• Important structural component of cell memranes
• Phosphate group (head) is polar and water soluble
  (hydrophilic)
• Fatty acid tails are hydrophobic

• This allows the phospholipids to
• form bilayers and membranes

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Other Lipids

• Steroids
• Insoluble in water
• Built around a four ringed skeleton
• Cholesterol
• Component for animal cell membranes
• Formation of myelin sheath covering nerves
• Hormones
• Chemical messengers
• Waxes
• Many fatty acids linked to a long backbone
• Waterproofing in plants, ears, beehives

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Proteins

• 50 dry weight of body
• Mammal cell contains 10,000 proteins
• Control elements (enzymes)
• Organic catalysts
• Mediators of metabolism
• Direct development, maintenance, and growth
• Structural elements (cell membrane, muscles,
  ligaments, hair, fingernails)
• Regulate what goes into/out of cells

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Building Blocks of ProteinsAmino Acids

• Amino acids (monomers) are linked together to
  form proteins (polymers)
• Each unique sequence of amino acids forms a
  different protein
• All living things (even viruses) use the same 20
  amino acids
• 20 different Amino Acids
• Amino end (NH2)
• Carboxyl end (COOH)
• Hydrogen
• R group variable component

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Amino Acids

• Amino Acids are grouped by whether R- group is
  polar or non-polar

• Positively charged side chain

• Negatively charged side chains

• Polar but uncharged side chains

• Hydrophobic side chains

• Special cases

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Protein Assembly

• AAs are linked together by joining the amino end
  of one molecule to the carboxyl end of another

• Peptide bond forms a chain called a polypeptide
• Transcription in nucleus
• DNA code ? mRNA
• Translation on ribosomes
• mRNA ? protein

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Protein Structure

• Primary structure
• Specific linear sequence of AAs in a
  polypeptide
• Determined from code in inherited genetic
  material
• Changes in primary structure can alter proper
  functioning of the protein

• Secondary structure
• the tendency of the polypeptide to coil or
• pleat due to H-bonding between R- groups
• ?-helix, ?-pleated sheet, or random coil

• Tertiary structure
• shape of entire chain folded, twisted, or
• globular
• shape related to function and properties

• Quaternary structure
• more than one polypeptide chain

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Nucleic Acids

• Polymers composed of monomer units known as
  nucleotides
• Information storage
• DNA (deoxyribonucleic acid)
• Protein synthesis
• RNA (ribonucleic acid)
• Energy transfers
• ATP (adenosine tri-phosphate) and NAD
  (nicotinamide adenine dinucleotide)

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Nucleotides

• Nucleotide structure
• Phosphate
• Nitrogenous base
• Purines (double-rings)
• Adenine and Guanine
• Pyrimidines (single-rings)
• Cytosine, Thymine, and Uracil
• Sugar either ribose or deoxyribose
• pentoses in ring form
• Deoxyribose lacks one oxygen

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Functions of Nucleic Acids

• DNA Physical carrier of genetic information
• Restricted to nucleus
• RNA key component of protein synthesis
• Messenger RNA (mRNA) blueprint for construction
  of a protein
• Ribosomal RNA (rRNA) construction site where
  the protein is made
• Transfer RNA (tRNA) truck delivering the proper
  AA to the site of construction

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The End