Macromolecules - DNA, protein, lipid, and carbohydrates
Structures - vesicles and organelles
Carbon: 1s2 2s2 2p2
Bond formation is all about stabilizing the atom’s electron clouds.
Methane and air → Carbon dioxide and water
Energy (as heat) is released when CO2 and H2O form, not when CH4 and O2 break.
Bond formation follows a downhill flow of energy.
Energy: ability to cause matter to move and its resulting motion.
Atomic bonds bring electrons into lower energy states (less motion in orbits)
As more stable bonds are made, lost energy of motion is released.
It takes energy to break bonds.
Combustion of acetylene yields more lower-energy bonds.
More energy is released to move other molecules (heat)
Water:
● 71% of Earth’s surface
● 75% - 85% of a living cell
● 60% of entire body
● Polar and cohesive
● Uneven electron distribution creates polarity
● Hydrogen bonds (H-bonds) are 1/10th as strong as covalent bonds
● Changes in heat energy in/out system affect hydrogen bonds first
● Excellent solvent
● Hydrophilic molecules interact with H2O (ex. Sugars, nucleic acids, soluble proteins)
● Hydrophobic molecules “separate” from H2O (lipids, insoluble proteins)
Solvent: fluids in which solutes dissolve
Macromolecules often made by repeating smaller, single units
Monomer: building blocks (simple sugars, amino and nucleic acids)
Polymer chain: store energy, carry out tasks, contain information
Order of monomers in a polymer chain may be carefully chosen (ex. Sequence of amino acids
linked to form a protein)
Monomers in some regions of chain may be attracted to those in others due to their uneven
electrostatic charges.
These interactions are non-covalent (weaker than atomic bonds)
,Polymer can spontaneously fold on itself as a result (such as insulin)
Selectively permeable membranes:
● Cells need membranes to keep contents in and materials out
● Cannot be totally impenetrable - some exchange must take place
● Cell membranes are amphipathic - made of phospholipids and proteins
Five molecular principles on Earth:
● Water
● Water
● Selectively permeable membranes
● Synthesis by polymerization
● Self - assembly
Polymers: Large strings of repeating smaller single units that, together, make a macromolecule
Macromolecules are often made by repeating smaller, single units
Monomer: building block (simple sugars, amino and nucleic acids)
Polymer chains: store energy, carry out tasks, contain information
Chains can be broken down, monomers recycled into new chains
Small organic molecules: glucose, amino acids, nucleotides, etc.
Macromolecules: Cellulose, protein, DNA, etc.
4 Main macromolecules:
● Polysaccharides
● Proteins
● Nucleic acids
, ● Lipids
Atoms always seek better bonds to calm the motion of their electrons.
Opportunities to break/reform better bonds creates complex molecules from simple ones.
Energy to break those starting bonds comes from contact with other biomolecules shoving or
giving off energy.
Polymers are chains of discrete units
Individual monomers have functions of their own
Chained monomers are used for:
● Energy storage
● Structural support
● Small machines
● Information storage
● Membranes
, Polymers are assembled by stepwise condensation.
Monomers(M1) is activated by binding to a carrier molecule ( C ) that can be a protein. This can
occur if a high energy bond of ATP is broken, favoring formation of lower energy M1-C bond.
Condensation occurs when activated M1 and M2 join, releasing H2O.
Bond between M1 and C is favorable and not broken.
Polymerization is continued process of adding additional M to growing chain