Chapter 4- Carbon and the Molecular Diversity of Life

organic chemistry is the key to the origin of life

• organic compounds- contain carbon and usually hydrogen

  • carbon can form large, complex, and diverse molecules

• CHNOPS- the major elements of life (carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur)

  • overall percentage is uniform from one organism to another

  • differences (diversity of life) due to variation in organic molecules

origin of organic molecules (life)

• stanley miller (1953)

  • set up a closed system to mimic conditions thought to have existed on early earth

    • see figure in BILL

  • results- identified variety of organic molecules common in living organisms

  • conclusion- organic molecules can be synthesized abiotically (these molecules can be made without the involvement of living organisms)

  • this experiment shifted mainstream biological thought from vitalism to mechanism

    • vitalism- theory that the origin and phenomena of life are dependent on a force or principle distinct from purely chemical or physical forces

    • mechanism- a system of casually interacting parts and processes that produce one of more effects

carbon diversity

• electron configuration determines the kinds/#s of bonds an atom forms with other atoms

  • valence electrons (ones on the outer shell) form bonds with other atoms

    • valence= the number of covalent bonds an atom can form

carbon bonding

• carbon can form single, double, or triple covalent bonds

• carbon chains form the skeletons of most organic molecules

  • molecules can be straight, branched, or ring shaped

    • see graphic in chapter 4 notes

hydrocarbons

• organic molecules consisting of only hydrogen and carbon

• carbon is the basis for the 4 groups of macromolecules

• many of a cells organic molecules have regions consisting of only carbon and hydrogen

  • fats; long hydrogen tail attached to a nonhydrocarbon component

isomers

• isomers are organic compounds with the same chemical formula but different structural formulas

  • isomers of one substance have different properties

• They are important because they exhibit different physical and chemical properties due to their unique structures, allowing for diverse applications in fields such as chemistry, biology, and materials science.

• 3 types of isomers (see graphic in chapter 4 notes)

  • structural, geometric (cis-trans), and enantiomers (mirror images)

    • structural isomers differ in the arrangement of covalent bonding partners

    • cis-trans isomers differ in arrangement about a double bond

    • enantiomers differ in spacial arrangement around an asymmetric carbon. This results in molecules that are mirror images, like left and right hands

functional groups

• characteristic chemical groups attached to the carbon skeleton

• there are 6 functional groups

  • they are all hydrophilic (water loving)

  • increase solubility of organic compounds in water

    • see flashcards in BILL

• hydroxyl group

  • consists of oxygen and hydrogen (-OH)

    • called alcohols, name ends in ~Ol

    • polar and soluble in water

• carbonyl group

  • consists of a carbon double bonded to an oxygen (>CO)

    • increases reactivity

• carboxyl group

  • consists of a carbon double bonded to an oxygen and also attached to a hydroxyl group (-COOH)

    • called carboxylic acids or organic acids

    • tend to release H+, becoming a carboxylate ion (-COO-)

• amino group

  • consists of a nitrogen atom bonded to two hydrogens (-NH2)

    • called aminos

    • can act as bases, picking up H+ ions and becoming -NH3+

• sulfhydryl group

  • consists of a sulfur atom bonded to a hydrogen (-SH)

    • called thiols; crosslinks in 3-D protein conformation

• phosphate group

  • consists of an oxygen attached to a phosphorus atom that is bonded to 3 other oxygen atoms (-OPO3 2-)

    • an ion contributes negative charge to organic phosphates

    • used in energy transfer

ATP= Adenosine Triphosphate

• the energy molecule of your cells

• consists of organic molecule adenosine with 3 phosphate groups attatched

• connections between structure and function

  • when ATP reacts with water the hatred phosphate is split off and energy is released