chapter 4: carbon & functional groups

why is carbon such a good building block

1. carbon is tetravalent: forms diverse complex molecules

2. forms covalent bonds

3. bonding ability allows for formation of larger interconnected molecules

4. its stable & doesn’t ionize easily

organic carbon molecules

associated with life — contain carbon covalently bonded to hydrogen

• ex. methane, hydrocarbons, carbohydrates, proteins, lipids & nucleic acid

inorganic compounds

do not have carbon-hydrogen bonds

• ex. carbon dioxide, carbon monoxide, carbonates, bicarbonates, cyanide

hydrocarbons

organic molecules only made of carbon & hydrogen

• backbone of many cell’s organic macromolecules

what causes molecular diversity

variation in carbon skeletons

• other element’s atoms can be bonded

• skeleton vary in length, straight or branched, vary in bonds, rings

importance of shape to function

3-d shape of organic molecules determines function

what is the problem presented with hydrocarbons

they are non-polar — are hydrophobic, cannot exist/function within a cell

functional group

chemical groups that replace one or more of the hydrogen atoms of the hydrocarbon skeleton

-increase the solubility of organic compounds

what are the seven functional groups

1. hydroxyl group (—OH)

2. carbonyl group (=O)

3. carboxyl group (—COOH)

4. amino group (—NH2)

5. sulfydryl group (—SH)

6. phosphate group (PO₄2-)

7. methyl group (CH3)

hydroxyl group

oxygen of group is bonded to carbon skeletons

carbonyl group

oxygen is double bonded to carbon atom in hydrocarbon

1. aldehydes: =O is at end of c-chain (ex. butanal)

2. ketones: =O in in c-chain (ex. butone)

carboxyl group

carbon atom at end of HC molecule is double bonded to an oxygen atom & hydroxyl group

• molecules called carboxylic acids

  • polar, can donate H ions

amino groups

carbon in HC molecule is bonded to an N atom which is bonded to two O atoms

• makes molecule basic (and polar)

  • can accept H ions

• organic compounds with amino groups are called amines

what do amino acids have

amino & carboxyl groups

sulfydryl group

sulfur atom bonded to carbon skeleton & hydrogen atom

• two groups can interact, forming disulfide bridge — stabilizes structure of proteins

phosphate group (charged)

phosphorus atom bonded to 4 oxygen, one bonded to a c & others to phosphorus — 2 are negatively charged

• used to transfer energy between molecule

methyl group

adds carbon with three hydrogens bonded to it — keeps molecule non-polar

adenosine triphosphate

organic molecules — adenosine attracted to string of 3 phosphate groups — reacts with water to produce usable energy

why is carbon dioxide important

is the source of carbon for all organic molecules found in organisms

what makes something saturated

if it has its max hydrogen bonds — if double bonds are present its unsaturated

structural isomer

same molecular formula — different arrangemet

geometric isomers/cis-trans

require presence of double bond

entantiomers

mirror image — carbon bonded to four different groups/atoms — creates left & right isomer