Carbon & the Molecular Carbon & the Molecular Diversity of LifeDiversity of Life

• All living things are made of & produce molecules based on carbon atoms

MAIN POINTS to REMEMBER!

1. The structure of organic molecules gives it some of its properties

2. The behavior of an organic molecule is dependent on the functional groups it has

3. You need to know the 7 functional groups & 1 or 2 examples of each

Properties of CarbonProperties of Carbon

• Can covalently bond w/ 4 other atoms

• Can form ring-shaped

molecules:

In aqueous solutions

*Forms single, double or triple bonds*Forms long chains of carbon-to-carbon molecules (hydrocarbon chains)

Organic CompoundsOrganic Compounds• These are compounds that have:

1. Carbon atoms bonded to each other and to hydrogen, oxygen, nitrogen, sulfur, phosphorous, chlorine or fluorine (most common= CHNOPS)

2. Covalent bonds• Can be natural (ex. sugar) or synthetic (ex.

(plastic)

Quick Think

• Why is carbon such a versatile molecule?Try to come up with at least 2 reasons

Origin of organic molecules

• 1953 – (just 55 years ago!) Stanley Miller – was able to make organic compounds in the lab from inorganic molecules found on earth (water, ammonia, etc)

• Showed that the origin of organic compounds was possible on early earth

Quick Think

• What is the significance of the work done by Miller?

Try to think of the themes of biology (see your student handbook)

Form & FunctionForm & Function• Shape often determines chemical or physical

characteristics• Isomers are compounds with the same

elements & number of atoms, but different structures

- Examples:mirror-images=enantiomers

Asymmetric carbons

• Carbons attached to 4 different atoms or groups of atoms

X X

X

X

Geometric isomers…differ in their arrangement around a double bond

cis molecule because the 2 variables, X, are on the same side

trans molecule because the 2 variables, X, are on the opposite side

Structural isomers…differ in their covalent partners

All are different arrangements of the same atoms

Important Examples of Structural Isomers

• Glucose

• Fructose

• Galactose

• All have chemical formula C6H12O6

glucose

•Each type of organic molecule has a unique three-dimensional shape that defines its function in an organism

–The molecules of your body recognize one another based on their shapes

Quick Think

• Research suggests that side effects from Ritalin, the drug used to treat attention deficit disorder, may be caused by contamination of enantiomers. What are enantiomers and why might enantiomers of the molecules in Ritalin pose a problem to the body?

Functional GroupsIn addition to geometric shape, properties of organic molecules depend on functional groups, groups of atoms attached to a carbon skeleton

Functional Groups• Usually found at end of carbon

chain or regularly interspersed

‘R’ represents any variation of a hydrocarbon chain

‘R’ represents any variation of a hydrocarbon chain

Functional Groups –

know these!

Phosphate group

Hydroxyl group

• Important properties:– Alcohols– Polar because O

is electronegative– Attracts water– Hydrocarbon

chain with –OH functional group

Carbonyl

• Ketone – if C is within the hydrocarbon skeleton

• Aldehyde - if C is at the end of the skeleton

• Ketones and aldehydes may be structural isomers of each other, and have very different properties

Carboxyl

• Carboxylic acids

• A source of hydrogen ions

• Strongly polar so it generally ionizes

Amino

• Amines

• Strongly polar - acts as a base (will accept hydrogen ions)

• Usually ionized (positive)

Sulfhydryl• Thiols

• Help stabilize the 4-D structure of proteins by forming a disulfide bond (covalent)

Amino acid cysteine

Phosphate group

• Organic phosphates

• Makes the molecule it is a part of negative (an anion) because it ionizes in water

• Can transfer energy between organic molecules

Quick Think

• What 2 groups are found in amino acids?

Functional Group DiceDirections: Form groups of 4

1 person is the judge and scorer for round 1

Other 3 players take turns rolling their dice and giving an answer

If correct with notes (judge decides), 1 pt

If correct without notes, 2 pts.without notes, 2 pts.

After 1 round, new judge

All players take a turn as the judge