The Chemistry of Life

Anatomy and Physiology

Hierarchy of StructuresHierarchy of Structures (Ex.)Rattlebox Moth Rattlebox Moth

• OrganOrgan– Ex. flight muscleEx. flight muscle

• TissuesTissues– Ex. muscle tissueEx. muscle tissue

• CellCell– Ex. muscle cellEx. muscle cell

• OrganellesOrganelles– Ex. myofibrilEx. myofibril

• MoleculesMolecules– Ex. actin and myosinEx. actin and myosin

So, what elements make up the molecules of life?

The Star of the Show

Why Study Carbon?• All of life is built on carbon

• Cells – ~72% H2O

– ~25% carbon compounds• carbohydrates• lipids• proteins • nucleic acids

– ~3% salts and trace elements • Na, Cl, K…

Chemistry of Life• Organic chemistry is the study of carbon

compounds• Carbon atoms are versatile building blocks

– Forms 4 stable covalent bonds– Can form large ring, chain, or branching chain

structures.– Can form double and triple bonds between two carbons

HHC

H

H

Valence electrons – are the electrons in the outermost shell of an atom.

Valence – refers to the number of covalent bonds an atom of an element can form:

C is 4 H is 1 O is 2 N is 3

Ex. H2O, CH4, C2H2, C2H4

• CarbohydratesCarbohydrates

• LipidsLipids

• ProteinsProteins

• Nucleic acidsNucleic acids

4 types of Macromolecules4 types of Macromoleculesand our body gets them/builds them from food and and our body gets them/builds them from food and

waterwater

Macromolecules Macromolecules compounds of lifecompounds of life

• carbon framework (carbon framework (organicorganic))

• they are they are polymerspolymers made of repeating made of repeating subunits called subunits called monomersmonomers..– polypoly means means manymany– merosmeros means means partpart– monomono means means singlesingle– So what do the words So what do the words polymerpolymer, , monomermonomer, and , and

macromoleculemacromolecule mean? mean?

– Like “pearls on a necklace”Like “pearls on a necklace”

Macro-Macro- means very, very LARGEmeans very, very LARGE

Carbohydrates are polysacharridesCarbohydrates are polysacharridesThese are all These are all SUGARSSUGARS

• Monomers (subunits)Monomers (subunits)– Simple sugars a.k.a monosaccharides

FUNCTIONS

1)1) quick energyquick energy

a) a) starchstarch in plants in plants

b) b) glycogenglycogen in animals in animals

2) 2) structures structures such as such as

1) 1) cellulosecellulose (plant cell walls) (plant cell walls)

2) 2) chitinchitin (exoskeleton of insects) (exoskeleton of insects)

Glucose – simple sugar made by plants during photosynthesis

Simple & complex sugars

• Monosaccharides– simple 1 monomer sugars– glucose

• Disaccharides– 2 monomers– sucrose

• Polysaccharides – large polymers– starch

OH

OH

H

H

HO

CH2OH

H

H

H

OH

O

Glucose

Some CarbohydratesSome Carbohydrates(polymer “necklaces” made of monomer glucose “pearls”)(polymer “necklaces” made of monomer glucose “pearls”)

• Monomer subunitsMonomer subunits– Amino acidsAmino acids– There are There are 20+

Here are a few of many, many functionsHere are a few of many, many functions: :

1) 1) Peptide HormonesPeptide Hormones regulate homeostasis regulate homeostasis

ex. Insulinex. Insulin

2) 2) StructuresStructures ex. bone, hair, muscle, horns, webs ex. bone, hair, muscle, horns, webs

3) 3) EnzymesEnzymes – – catalystscatalysts for biochemical reactions. for biochemical reactions.

(lowers energy needed for reactions to start)(lowers energy needed for reactions to start)

4) 4) Genetic regulation Genetic regulation (turns genes on and off)(turns genes on and off)

5) 5) TransportTransport ex. hemoglobin in rbc carries O ex. hemoglobin in rbc carries O22

ProteinsProteins

Proteins• Structure

– monomer = amino acids• 20 different amino acids

– polymer = polypeptide• protein can be one or more polypeptide chains

folded & bonded together• large & complex 3D molecules

hemoglobin

growthhormones

Nucleic AcidsNucleic Acidsthe information moleculesthe information molecules

• Monomer subunitsMonomer subunits– NucleotidesNucleotides

• FunctionFunction

Carries informationCarries information• HeredityHeredity• Genes provide directions Genes provide directions to make proteinsto make proteins

ExamplesExamplesDNA = deoxyribonucleic acidDNA = deoxyribonucleic acidRNA = ribonucleic acidRNA = ribonucleic acid

NucleotidesNucleotides have three parts: have three parts:a phosphate, sugar, and a basea phosphate, sugar, and a base

(A, G, C, T, or U)(A, G, C, T, or U)

proteinsproteins

DNADNA

Nucleic Acids• Function:

– genetic material• stores information

– genes– blueprint for building proteins

» DNA RNA proteins

• transfers information– blueprint for new cells– blueprint for next generation

Lipids

• Lipids are composed of C, H, O– long hydrocarbon chains (H-C)

• “Family groups”– fats– phospholipids– Steroids

• Do not form polymers– big molecules made of smaller subunits– not a continuing chain

LipidsLipids- all have - all have hydrophobic propertieshydrophobic properties “water fearing” “water fearing”

Functions / examples:Functions / examples:

1)1) Fats Fats STORE energySTORE energy(these have “long-tail” (these have “long-tail” fatty acids)fatty acids)

2) 2) SteroidsSteroids for hormonal regulation for hormonal regulationEx. estrogen and testosteroneEx. estrogen and testosterone

3) 3) StructuresStructuresEx.Ex. p phospholipids make up the cell membranemake up the cell membraneEx. Ex. waxeswaxes for waterproofing for waterproofing

- such as (a) cuticle on leaves (b) earwax- such as (a) cuticle on leaves (b) earwax

Saturated Fats

• All C bonded to H

• No C=C double bonds– long, straight chain– most animal fats – solid at room temp.

• contributes to cardiovascular disease (atherosclerosis) = plaque deposits

Unsaturated Fats

• C=C double bonds in the fatty acids– plant & fish fats – vegetable oils– liquid at room temperature

• the kinks made by doublebonded C prevent the molecules from packing tightly together

mono-unsaturated?poly-unsaturated?

saturated vs. unsaturatedsaturated unsaturated

Phospholipids make up the cell membrane

Phospholipids make up the cell membrane

• Hydrophilic heads “attracted” to H2O

- they will “flip” outward

• Hydrophobic tails “hide” from H2O

- they will flip inward

bilayer

Water (outside the cell)

Water (inside the cell)

Another lipid: Steroids• Structure:

– 4 fused C rings + ??• different steroids created by attaching different

functional groups to rings• different structure creates different function

– examples: cholesterol, sex hormones

cholesterol

MATCHINGMATCHINGWhich group Which group A A representsrepresents1) carbohydrates?1) carbohydrates?2) nucleic acids?2) nucleic acids?3) proteins?3) proteins? BB4) lipids?4) lipids?

CC

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