The Big Four Biological Macromolecules

Biology Ch. 2 Vocab

Macromolecule

• very large organic molecules built from multiple, smaller subunits

• 4 groups/ families

  • 3 shared features:

    • monomers share common chem composition

      • all = CHO, some = PNS

    • monomers built w/ constant C-backbone w/ variable function groups

    • build/ break reactions:

      • dehydration synthesis

      • hydrolysis

Monomer

• small, repeating subunits that form polymers (+ macromolecules)

  • individual small molecules that bond together like beads on string (polymerization)

• share common chemical composition across B4

  • all contain: CHO

  • some contain: PNS

• built w/ constant C-backbone w/ variable function groups

Polymer

• anything built of monomer chains

  • not all polymers = macromolecules; not quite large enough

Hydrolysis

• reaction that BREAKS DOWN all B4 polymers

• energy in, water out

  • use water to pull big molecule apart into 2 smaller molecules

• reuses building blocks from producers + consumers we eat

Dehydration Synthesis

• reaction that BUILDS all B4 polymers

• water in, energy out

  • water molecule squeezed out of 2 small molecules → 1 big molecule

Nucleotide

• monomer that forms nucleic acid

• 3 components:

  • 5-C sugar

    • ex: ribose, deoxyribose

  • phosphate group

  • nitrogenous base

Nucleic Acid

• Structure:

  • polymer made of nucleotides

  • long thin macromolecule

• Roles:

  • store info to make proteins

  • heritable from parents → offspring

    • carry hereditary info from parents to offspring

• Ex:

  • RNA

    • ribonucleic acid

    • sugar = ribose

    • role: construction of proteins

  • DNA

    • deoxyribonucleic acid

    • sugar = deoxyribose

    • role: carries genetic material from parent → offspring

Amino Acid

• monomer that forms proteins

• 4 components:

  • carboxyl group (O + H) + amino group (N) attached to central C

  • ALONG w/: one of 20 diff. side chains → give aa its identity

• linked by peptide bonds (covalent bonds)

Protein

• AKA: peptides

• Structure:

  • polymers made of amino acids

  • structural + chemical versatility → many roles

• Roles: molecular machines that do ALL MAJOR CELLULAR WORK…

  • control + regulate chemical reactions + activity of cells

  • = components of cell membranes/ other structures

  • transport materials across cell membranes

  • fight disease (immune system antibodies)

  • control muscles

Monosaccharide

• monomer that forms carbohydrates

• = simple sugars

• Ex:

  • fructose

  • glucose

    • main fuel for cells

Carbohydrate

• Structure:

  • polymer of monosaccharides

  • combines C+H+O

  • linked strands → sheets→ layers → create touch structural material cellulose

• Roles:

  • stores energy for cell (main fuel source)

  • supports cell structure (plant cells)

    • cellulose + chitin

• Ex:

  • Starch

    • made of glucose monomers

    • stored in plant roots as energy

      • built up + broken down as energy is required or stored for later

  • Glycogen

    • bodies convert unused glucose → starch-like polysaccharide

    • stored in liver + muscle tissue until glucose needed

Fatty Acid

• monomer that forms lipids

• components:

  • hydrocarbon chains 4-28 C atoms long

    • HC’s in lipids = loaded w/ energy (2x carbs)

• can be saturated…

Lipid

• Structure:

  • polymer made of fatty acids

  • include fats, oils, cholesterols

  • insoluble in water

  • rich sources of energy

    • building blocks of biological membranes

• Roles:

  • stores energy for cell

  • creates cell structure (cell membranes!)

    • phospholipid bilayer…

• Ex:

  • Triglyceride

    • typical lipid

    • glycerol head attached to 3 long fatty acid mol’s

  • Saturated Fat

    • lipid/ fat w/ 3 saturated fatty acid chains