Chemistry

Macromolecules

Macromolecules

• Small molecules linked together to create large molecules

– Have shape created by hydrogen bonding, sulfhydryl bonding, polarity, etc.

• FORM FITS FUNCTION

– Ex. Proteins do ‘everything’

Protein

Stanley Miller Linus Pauling

Carbon bonds 4 times in multiple ways

Creates great variety

Hydrocarbons

ISOMER

Isomers = molecules

with the same formula but

different structural

formulae; not isotope

AMP

ATP

GTP

Differences in functional groups

What is a functional group?

Ethane

Ethanol

Functional group

Functional groups -Create the necessary variety of shapes of macromolecules for life to exist

Dehydration synthesis =

enzymatically controlled

formation of large molecules by

removal of water

Macromolecules

• Monomers + monomers + monomers = polymers

• Produced by DEHYDRATION SYNTHESIS

• Hydrolysis – breakdown of macromolecules by the addition of water

• Enzymes

Macromolecules• What do you need to know for each

macromolecule important to life:

– Structure

– Monomers

– Function in organisms

Macromolecules

• Carbohydrates

• Lipids

• Proteins

• Nucleic acids

Carbohydrates

• Carbon + water (hydrate)

• Basic formula: CH2O(n)

• Monomers = monosaccharide (‘one sugar’)

• End in ‘ose’

Monosaccharides

• Glucose C6H12O6

• Many monomers form rings in aqueous solutions to become more stable

• Monomers may be functional:

– Glucose is primary source of energy for organisms

Carbohydrates• Monomer + monomer = dimer• Monosaccharide + monosaccharide = disaccharide • Glucose + glucose = maltose• Glucose + fructose = sucrose• Glucose + galactose = lactose

Polysaccharides

• Polymers of monosaccharides

• Type of monosaccharide and arrangement creates variation in polysaccharides

• Starch (Amylose, amylopectin) = plants

• Glycogen = energy storage for animals

• Cellulose = plant cell walls

• Chitin = exoskeleton of arthropods, some fungi

Carbohydrates: Function

• Energy; stored energy (which?)

• Structure – (which?)

• Cell-to-cell communication, identification (glycoproteins, glycolipids)

– Antigens /antibodies

Lipids • InsolubleInsoluble in water; (long, nonpolar

hydrocarbon chains) • Basic formula: C50H70O6

• Three types:– Fats, oils, waxes– Phospholipids – Steroids

Lipids: Fats

• Macromolecules of glycerol + 3 fatty acids

• Glycerol = glyc = ‘sugar’ C3H8O3

• Fatty acids = hydrocarbon chain (16-18 carbons)– Hydrocarbon chain is hydrophobic

Lipids: Fats

• Fats = triglycerides (3 fatty acids)

• Structure of the fatty acid chains creates variety in types of fats

– Saturated – full of hydrogen atoms; no double bonds

– Unsaturated – not full; double bond(s)

Types of Fats

• Saturated

• No double bonds• Saturated• Solids @ (200)• Animal fats• Bacon grease, lard,

butter

• Unsaturated • Double bond(s)• Unsaturated• Liquids @ (200)• Plant fats (oil)• Corn, peanut, olive

oils

Link between an acid and a sugar

Triglycerides

• Important to diet

• Limit amount of saturated fats

• Hydrocarbon chains are high in energy

• More difficult to breakdown

• Link to triglycerides and arteriosclerosis

Lipids: Phospholipids

• Glycerol + 2 fatty acids • 3rd position on the glycerol is taken by a phosphate

group (PO4)

Phospholipids

• Major component of cell membrane

• ‘head’ end (glycerol) is polar (term?)• Hydrophilic = “water loving”• ‘tail’ end is non-polar (term?)• Hydrophobic = “water fearing”

Phospholipids• Phospholipids in water form a micelle

• First prokaryotes evolved when phospholipids formed micelles in water (?)

• Abiogenesis

Steroids

• 4 fused carbon rings + functional group

• Insoluble in water

• Ex. Cholesterol

– Between fatty acids tails of phospholipids

– Help to moderate the effects of extreme temperatures

Steroids

• Precursors of sex hormones

• Too much causes atherosclerosis (?)

Importance

• Energy (?)• Padding (?)• Insulation (?)• Structure (?)• Hormones (?)

Proteins

• Many shapes = many functions

• ‘first place’

• Polymers of AMINO ACIDS

• Linked by PEPTIDE BONDS

• POLYPEPTIDES

• Proteins = folded, shaped polypeptides

Proteins: Amino Acids

• 2 carbon skeleton

– Amino group

– Carboxyl group

– H atom

• Side group (R group)

Proteins: Amino Acids

• R group determines properties of the aa– Some are polar, some are nonpolar– Polar may be acidic or alkaline

• 20 different amino acids• Essential = body cannot produce on its own

Proteins

• Peptide bonds are the result of dehydration synthesis

• Amino group reacts with carboxyl group of adjacent amino acid

• Polypeptide - string of polypeptide bonds

Proteins• Function depends upon shape

• Conformation – 3d shape caused by H-bonds

– Fold and twist the amino acids

• Globular

– Insulin, enzymes

• Fibrous = ‘stringy’

– Silk, muscle

Proteins

• Four levels of protein structure that give a protein its unique shape:

– Primary

– Secondary

– Tertiary

– Quaternary

Proteins: Primary Structure

• Sequence of amino acids

– Determined by genetic code

– ‘goof’ in sequence can have harmful or lethal effects

Secondary Structure

• Folds or twists created by H-bonding in the carbon backbone; NOT the R group

• 2 types: both may be in a protein – Alpha - helix – Beta - pleated sheet

Tertiary Structure• Irregular contortions caused

by bonding of R groups:– Ionic, hydrogen, disulfide

bridges (covalent)• Hydrophobic interaction -

nonpolar portions tend to line up in core of the protein

Quaternary Structure

• Multiple polypeptides in one giant protein

– Hemoglobin (heme + globin)

Protein Shape

• Primary – (?)• Secondary – (?)• Tertiary – (?) • Quaternary – (?)

Denaturation

• Alteration of conformational shape

• Caused by:

– pH, salinity, organic solvents (alcohols, carbon tetrachloride, acetone, etc.), heat, inorganic chemicals that dissolve bonds (HCl)

• Some change shape to function

– Receptor, contractile

Denatured proteins are the cause of….

Polypeptide to Protein

• Polypeptides are NOT proteins– Need to be folded into conformational

shape• Chaperonins = proteins that aid in the

folding into conformational shape• Knowledge of protein folding helps to

manufacture proteins

Determining the Structure of Molecules

• X-ray diffraction

• Electron density map

• Computer

Rosalind Franklin: X-ray diffraction of

DNA

Nucleic Acids

• DNA, RNA

• Polymers of nucleotides

• Nucleotide:

– Simple sugar (ribose or deoxyribose)

– Nitrogenous base

– Phosphate group (PO3)

4 nitrogenous bases: Purines Pyrimidines

Nucleic Acids

• Nitrogenous bases are complimentary

• A-T

• C-G

• Hydrogen bonds

• Sugar-phosphate backbone

H bonding

Relationship between

nucleic acids and proteins