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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The Molecular Logic of Life

• Small molecules, common to all organisms, are
  arranged into unique macromolecules (Campbell p.
  62)

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Macromolecules The Sum of the Parts

• Many complex biological activities require large
  macromolecules
• Macromolecules are polymers
• poly many
• mer units
• ex proteins, nucleic acids, starches

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Polymers are built by covalently linking together
small similar (or in some cases, identical)
subunits/building blocks called monomers mono
one mer unit ex amino acids,
nucleotides, monosaccharides
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4 Classes of Organic Compounds, or
Biomolecules- necessary for an organism to
surviveProteins are polymers of amino
acidsNucleic acids are polymers of
nucleotidesStarches are polymers of simple
sugars called monosaccharidesLipids arent
REALLY polymers, since they dont have repeating
chains. BUT they are important biomolecules.
The building blocks (monomers) of some types of
lipids are glycerol and fatty acids
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CondensationIts not just for the water cycle
anymore!This is how we link monomers together to
create polymers

• 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- requires energy

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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-- catabolic

animation
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Macromolecules- why are they so important?

• Each macromolecule performs complex tasks with
  precision
• The basic structure and function of each class of
  macromolecules is similar in all organisms (from
  the simplest bacteria to complex humans)
  indicates an evolutionary link.

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Classes of Biomolecules

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

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Basic Function
Carbos Lipids N. Acids Proteins
Energy Storage Structure Strength Long term storage Insulation Protection Hormones Inheritance Blueprint for metabolism Catalysts Hormones Structure Defense
Sugars (glucose) Starch/ Glycogen Cellulose/ Chitin Fats Oils/Waxes Phospholipids Steroid hormones 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
• Glycogen
• Chitin
• Cellulose

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Polysaccharides

• Two Types for Storage
• 1. Glycogen animal energy storage product that
  accumulates in the liver/muscles
• - Highly branched
• Glucose?Glycogen?glucose?bloodstream
• 2. Starch plant energy storage
• - Helical
• - Easily digested by animals through hydrolysis

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Two Types for Structure

• 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
• 2. Chitin insect exoskeletons

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So whats the difference between condensation and
hydration reactions?

• animation

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Lipids

• Functions
• Long-term energy storage/insulation (fats)
• 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- contain tons of energy in their
  hydrocarbons!

• 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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video

• Glycerol is a molecule with three carbons in a
  row, each with a hydroxide group
• Fatty acid chains are hydrocarbons
• that is, they are composed of mostly carbons and
  hydrogens.
• This is a molecule that is VERY hydrophobic.
• When glycerol combines with the fatty acid chains
  it forms a carboxyl group between them
• They link by the loss of a water molecule.

Carbon can bond to four different substances, but
sometimes it will share more than one pair of
electrons.
animation
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Phospholipids

• Important structural component of cell membranes
• Phosphate group (head) is polar and water soluble
  (hydrophilic)
• Two 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

overview
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Proteins

• 50 dry weight of body
• Mammal cell contains 10,000 proteins
• Enzymes (regulate chemical reactions)
• Structural elements (cell membrane, muscles,
  ligaments, hair, fingernails)
• Carriers (regulate what goes into/out of cells)
• Send and receive messages (hormones)
• Movement

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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

http//www.biotopics.co.uk/as/aminocon.html
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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

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Hormone Insulin

• Frederick Sanger (1940s, 50s), discovered the
  amino acid sequence of Insulin
• Causes cells to take up more glucose, and liver
  and muscle cells to create glycogen
• Diabetes is a deficiency of insulin

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Carrier Hemoglobin
-Protein that carries oxygen to your cells -Iron
an important co-factor, iron deficiency anemia
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Sickle Cell Disease
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Spider silk a structural protein

• Spider Silk Video

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Enzyme Salivary Amylase

• Hydrolyzes starch while chewing

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Enzyme Rubisco
Catalyzes first step of carbon fixation in
photosynthesis
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Movement Actin and Myosin
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• Secondary structure
• the tendency of the polypeptide to coil or pleat
  due to H-bonding between R- groups
• ?-helix, ?-pleated sheet, or random coil

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

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• 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

• 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