the biomolecules
TRANSCRIPT
THE BIOMOLECULES Life’s Construc/on Materials
Carbohydrates Lipids (Fats) Proteins Nucleic Acids (DNA, RNA)
Organic Compounds (biomolecules))
• Compounds that contain carbon
• Hydrogen, oxygen, nitrogen, phosphorus and sulfur can also be found in organic compounds
A lipid (a.k.a. fat)
Why Carbon?
• Carbon can form more bonds than any other element (4)
• This property allows carbon based molecules to be quite large and diverse
C C Single Bond (one pair of e- shared)
C C Double Bond (2 pairs of e- shared)
C C Triple Bond (3 pairs of e- shared)
Monomers and Polymers
Organic compounds are made of monomers - individual subunits
Many monomers form polymers - larger molecules
Condensa/on and Hydrolysis Reac/ons
• Hydrolysis reac/ons break large molecules (polymers) into smaller ones by adding water
• CondensaEon, or dehydraEon synthesis builds large molecules from smaller ones by removing water
Two amino acids are shown at the top. In condensa/on, the amino acids are combined into a dipep/de. In hydrolysis, the dipep/de is split into two amino acids again.
Monosaccharides (glucose, fructose, galactose)
Condensa/on Reac/on (forming maltose – a disaccharide)
Polysaccharides (starch vs. cellulose)
Glycerol (monomer)
3 Fatty acids (monomers) Lipid (polymer)
Saturated and Unsaturated FaNy Acids
DNA (Nucleic Acid polymer)
Nucleotides (monomers)
Nucleo/de
Five carbon sugar
Nitrogen base Phosphate group
Two amino acids bonded together (dipeptide)
Amino acid (monomer) Amino acid (monomer)
Protein Structure
• Proteins are polymers made of amino acid monomers
• The shape of a protein determines its func/on
• The shape is determined by the order of amino acids in the protein
p53 tumor suppressor protein
Structure of an Amino Acid
hNp://cornellbiochem.wikispaces.com/23.2
Alpha carbon
Four Levels of Protein Structure
• Primary‐ arrangement of amino acids in a polypep/de chain
• Secondary – forma/on of por/ons of the amino acid chain into alpha helices or beta‐pleated sheets
• TerEary – folding of whole polypep/de chain into a 3‐D structure (due to interac/ons of R‐groups of amino acids in the chain)
• Quaternary – aNrac/ons between more than one polypep/de chain (results in a larger func/onal protein)
Enzymes • Proteins that regulate chemical reac/ons in an organism
• Enzymes speed up the rate of chemical reac/ons
Chemical Reac/ons
reactants products
C6H12O6 + 6 O2 6 CO2 + 6 H2O (cellular respiration)
The atoms of the reactants are rearranged to form products.
Enzymes act as Catalysts
Catalysts speed up chemical reactions without being used up or changed during
the reaction
How do Enzymes Speed up Chemical ReacEons?
• The energy required to get a chemical reac/on started is the ac#va#on energy
• Enzymes work by lowering the ac.va.on energy of a given reac/on to speed up the reac/on
Specificity
• Every enzyme acts on a substrate
• The acEve site is the area where the enzyme modifies the substrate
• Induced fit – substrate binds to enzyme cause enzyme to “mold” around the substrate (conforma/onal change)
hNp://www.websters‐online‐dic/onary.org/defini/ons/Enzyme?cx=partner‐pub‐0939450753529744%3Av0qd01‐tdlq&cof=FORID%3A9&ie=UTF‐8&q=Enzyme&sa=Search#922
Factors affec/ng the rate of an enzyme catalyzed reac/on
• Amount of enzyme present
• Amount of substrate present
• Temperature and pH
• Inhibitors
Inhibitors (compe//ve vs. noncompe//ve)
• Compe//ve inhibitors bind at the ac/ve site of the enzyme
• Noncompe//ve inhibitors don’t bind at the ac/ve site, but cause a conforma/onal change in the ac/ve site
• Both slow down reac/on rate of the enzyme Compe//ve vs. noncompe//ve
inhibi/on
Enzyme Denatura/on Enzyme is shown in yellow Blue molecules are the substrate
Heat or pH change
Reac/on takes place normally
No reac/on occurs (ac/ve site is damaged and substrate no longer fits)