Ch. 2 – The Chemistry of Life

Section 2-3Carbon Compounds

orA Brief Introduction to

Organic Chemistry

Carbon

Why Carbon?

• What makes carbon (C) the basis of all living things?

Carbon has 4 valence electrons (remember that valence electrons are the ones available for bonding with other atoms).This means carbon (C) can bond with many elements including hydrogen (H), oxygen (O), phosphorus (P), sulfur (S), and nitrogen (N).

Why Carbon? (continued)

• What makes carbon (C) the basis of all living things?

Carbon can also bond to other carbon atoms giving them the ability to make chains that are almost unlimited in length.No other element has the versatility of carbon (it’s a kind of “Swiss Army knife”).

Why Carbon? (continued)

Carbon bonds are very stableCarbon bonds contain a lot of energy

Why Carbon? (continued)

Carbon-carbon bonds can be single, double, or triple bonds

C CSingle bond

C

C

C

C

+

Why Carbon? (continued)

Carbon-carbon bonds can be single, double, or triple bonds

C CDouble bond

C

C

C

C

+

Why Carbon? (continued)

Carbon-carbon bonds can be single, double, or triple bonds

C CTriple bond

C

C

C

C

+

Why Carbon? (continued)

Carbon compounds come in a wide variety of shapes – like chains, rings and sheets.

Acetylene Butadiene Benzene IsooctaneMethane

carbon rings

graphite

Fatty acids – carbon “chains”

Cellulose – carbon “sheet”

“Buckyballs”

Macromolecules

• Carbon is good at making macromolecules.– Macromolecules are “giant

molecules”. • Macromolecules are formed

by joining huge numbers of small units together.

• The small units are called monomers.– The monomers subunits may

be identical or different.

Macromolecules

• The giant molecules are polymers.

• The process of connecting the little monomers into huge macromolecules is known as polymerization.

Macromolecules (continued)

• There are four (4) main groups of organic macromolecules:– Carbohydrates– Lipids– Nucleic acids– Proteins

Carbohydrates

• Carbo- (carbon)

• Hydrate (water)

• CH20 units–1 C : 2 H : 1 O

Carbohydrates

• Living things use carbohydrates as their main source of energy.

• Plants and some animals also use carbohydrates for structural purposes.

Carbohydrates• The monomers (small

subunits) that make up large carbohydrates are called simple sugars (monosaccharides).

• Polysaccharides are large carbohydrate macromolecules made up of many monosaccharide monomers.

Monosaccharides

• Two of the most important and common monosaccharides are glucose and fructose.

• Both have the chemical formula C6H12O6, but

have different shapes.

Macromolecules (continued)

• There are four (4) main groups of organic macromolecules:– Carbohydrates– Lipids– Nucleic acids– Proteins

Lipids

• Common categories of lipids are:– Fats– Oils– Waxes

• Lipids can be used to store energy.

• Some lipids are important parts of biological membranes and waterproof coverings.

Lipids

• Lipids contain mostly C and H atoms.

Lipids• Many lipids are

formed when a glycerol molecule combines with fatty acids. (see pg. 46 in text)

Saturated Fats• Saturated fats are

those that contain the maximum number of H atoms (think “saturated with H”).– Another way of

thinking about saturated fats is that they have all single C-C bonds.

Lipids

• Unsaturated fats are those that contain at least one C=C double bond.

• Polyunsaturated fats are those lipids with multiple C=C double bonds.

Saturated vs. Unsaturated Fats

The chains in unsaturated fatty acids are “kinked”.

Fat

ver

sus

Oil

FAT Fully saturated Straight chains Solid at room temp.

OIL Unsaturated Kinked chains Liquid at room temp.

• Why do you think saturated fats are solids at room temperature while unsaturated fats are liquids at room temperature?

Are you pondering what I’m pondering?

• Do you think that all parts of a lipid molecule are equally attracted to water molecules?

Are you pondering what I’m pondering?

Macromolecules (continued)

• There are four (4) main groups of organic macromolecules:– Carbohydrates– Lipids– Nucleic acids– Proteins

Nucleic acids

• Nucleic acids contain O, N, C, and P.

• Nucleic acids are huge polymers assembled from small monomer units called nucleotides.

Nucleic acids

• Nucleic acids store and transmit hereditary, or genetic, information.

• There are two kinds of nucleic acids:– Ribonucleic acid

(RNA)– Deoxyribonucleic

acid (DNA)

Nucleic acids

• DNA and RNA have different sugar molecules at their core (deoxyribose, ribose). (structure pg. 47)

Macromolecules (continued)

• There are four (4) main groups of organic macromolecules:– Carbohydrates– Lipids– Nucleic acids– Proteins

Proteins

• Proteins are macromolecules that contain N (nitrogen), C, H, and O.

• Polymers of amino acids

Proteins

• Proteins are very diverse.

• This is because there are more than 20 different amino acids that can be arranged in any order in a protein.– See pg. 47 for amino

acid structures.• The varying part of

amino acids is called the R-group.

Amino Acid Structure

Amino group

Carboxylic acid group

Variable portion, “R” group

The structure of the twenty amino acids

amino acids

Types of proteins• Some proteins control the

rate of reactions and regulate cell processes (enzymes are biological catalysts).

• Some are used to form bones and muscles.

• Others transport substances into or out of cells

• Still others help to fight disease (antibodies).

Biological Macromolecules - Summary

CarbonCompounds

include

that consist of

which contain

that consist of that consist of that consist of

which contain which contain which contain

Carbohydrates Lipids Nucleic acids Proteins

Sugars and starches

Fats, oils, waxes Nucleotides Amino Acids

Carbon,hydrogen,

oxygen

Carbon,hydrogen,

oxygen

Carbon,hydrogen,oxygen, nitrogen,

phosphorus

Carbon,hydrogen,oxygen,

nitrogen,

End 2-3

Why Carbon? (continued)

• Carbon-carbon bonds can be single, double, or triple bonds

C CTriple bond

C

C

C

C

+

Sat

urat

ed &

Uns

atur

ated

F.A

.

Biological Macromolecules

CarbonCompounds

include

that consist of

which contain

that consist of that consist of that consist of

which contain which contain which contain

Carbohydrates Lipids Nucleic acids Proteins

Sugars and starches

Fats and oils Nucleotides Amino Acids

Carbon,hydrogen,

oxygen

Carbon,hydrogen,

oxygen

Carbon,hydrogen,oxygen, nitrogen,

phosphorus

Carbon,hydrogen,oxygen,

nitrogen,