What’s so special about water?

It is a great solvent.

It holds heat very well.

It is the most importantinorganic molecule.

It is a polar compound

Water, pH and Biological Molecules

Water as a Solvent

Dissolving table salt (sodium chloride)

This means that ice forms an insulating blanket over water.

Water Is Lighter as Solid than as a Liquid

Water Has High Surface Tension

The attraction of one water molecule for another also accounts for its ability to hold huge amounts of heat.

Water is a Polar Compound

• Hydrogen ends holds slightly positive charges

• Oxygen end holds a slightly negative charge

p+ p+1H 1H(+) (+)

(--)

pH is a Big DealpH is a measure of proton (hydrogen ion or H+) concentration.

High pH (base) = few H+ ions ; more OH- ions

Low pH (acid) = lots of H+ ions

Acids and BasesAcid = H+ Donors Base = H+ Acceptors

ORGANIC COMPOUNDS

Making MoleculesBecause carbon contains 4 electrons in its outer shell, it can share electrons with many different atoms in an “attempt” to fill its outer shell.

Organic compounds are carbon compounds, made by living things

Carbon is the Central Atom of Life.

glucose

amino acids

fat

Some Useful

Nomenclature

In Biology, Shape Matters

Its not just chemical formula, it’s the shape of the molecule that lets it do its “job”.

Never forget the axiom – structure dictates function.

Some biological molecules.

Ah, That Smell!

Once again, shape matters. It’s the good fit between odorant and receptor molecule that lets us detect aromas.

Molecules of Life

Start with water, add lots of small carbon-containing molecules and …….

Four Major Classes of Biological Molecules

How do you build a cell?

Rules of the Game

Macromolecules are built by linking a set of building blocks (monomers) together into long chains (a polymer).

Each hexagon is this figure is a monomer, building blocks linked together to form a polymer.

Monomers – basic units that repeats over and over in organic compounds

Macromolecules Are Built By Linking a Set Of Building Blocks (Monomers) Together Into Long

Chains (A Polymer).

FOUR TYPES OF ORGANIC COMPOUNDS

• CARBOHYDRATES – SUGARS AND STARCHES

• LIPIDS– FATS

• PROTEINS– HAIR, FINGERNAILS, MUSCLES

• NUCLEIC ACIDS– DNA AND RNA (GENETIC MATERIAL)

CARBOHYDRATES• ELEMENTS – C, H AND O

• RATIO H:O = 2:1

• MONOMER = MONOSACCHARIDE

• EXAMPLES – SUGARS & STARCH

• MAIN FUNCTION – QUICK ENERGY

Glucose: A Simple Carbohydrate Used For Energy Production and as a Building Block

For Complex Carbohydrates

Linking Simple Sugars – the First Step to a Polymer and the Last Step to Some Familiar Compounds

MONOSACCHARIDES DISACCHARIDES

Some Familiar and Important Complex Carbohydrates

3 OR MORE REPEATING UNITS = POLYSACCHARIDE

Carbohydrates are Central Players in

Energy Production and Storage

LIPIDS

• ELEMENTS: C, H and O• RATIO OF H:O = More H than O• MONOMER = Glycerol and 3 Fatty Acids• EXAMPLES

– Fats, Oils and Waxes

• MAIN FUNCTION– Storage– Energy reserves– Cell membranes

Glycero

l

FA

FA

FA

Lipids are Hydrophobic Molecules That Exist In Three Primary Forms

Sterol

Fat

Phospholipid

Fats Are Made By Linking Fatty Acid Chains to Glycerol, a Three

Carbon Molecule

Space-filling model of a fat

A fatty acid

Fats are Used in Energy Storage and Production

The Degree Of Saturation In A Fat

Affects Its Physical

And Nutritional Properties

Where are the double bonds?

The Degree Of Saturation In A Fat Affects Its Physical And Nutritional Properties

Where are the double bonds?

saturated

monounsaturated

polyunsaturated

Sterols Are Part of Cellular Membranes and Act as Hormones

Note the four ring structure common to all sterols.

Sterols As HormonesEstrogen,

testosterone, progesterone,

and corticosteriods

(cortisol) are all steroid

hormones.

Sterols As Hormones

“Designer steroids” are major sporting news where they have been used illegally in track

and field, baseball, football and

countless other sports.

A heavily muscled Linford Christie who was disqualified from international competition after testing positive for a banned steroid.

Phospholipids are Building Blocks of Cellular Membranes

The hydrophilic head group and hydrophobic tails are the keys to phospholipid function.

Hydrophilic Head Group And Hydrophobic Tails Are The Keys To Phospholipid Function

Phospholipids have a Jekyll and Hyde personality.

Phospholipids Form Biological Membranes

THE CELL MEMBRANE

PROTEINS

• Basic building blocks of living material• ELEMENTS: C, H, O and N• MONOMER: Amino Acids

– 20 different amino acids

• USES– Hair, Muscles, Fingernails

– Enzymes – carry out chemical reactions

– Transport in cells

• FORMS PEPTIDE BONDS BETWEEN A.A.

Protein

Proteins are THE key elements of life. Forget DNA, proteins rule.

Remember the principle - Structure determines Function.

Since proteins are the key players of the cell, it follows that protein structure determines cell

function.

Some of the Diverse Functions of Proteins

Strands of the Protein Keratin Create Hair

Proteins are Linear Chains of Linked Amino Acids

A Common Thread and a

Unique Identity

R – Residual Group *side chain changes

Amino Group – NH2

Single Hydrogen - H

Acid or Carboxyl Group –C=O, OH

(Side chain)

PEPTIDE BONDS

• 1 amino acid

• 2 amino acids linked together – dipeptide

• 3 or more amino acids linked together - polypeptide

Peptide bonds

Amino Acids, Peptide Bonds, Polypeptides, Protein

Peptide bonds

Proteins are linear chains of 20 different building blocks called amino acids.

Amino acids are linked by peptide bonds – a form of covalent bond.

Proteins are Folded

Structures Whose Shape (and therefore

function) Depends on Amino Acid

Sequence

Nucleic AcidsThere are two kinds

of nucleic acids, DNA and RNA. Both are

involved in the storage and flow of information from

gene to gene product.

DNA

NUCLEIC ACIDS• ELEMENTS: C, H,

O, N P and S• MONOMER:

Nucleotides• USES: DNA and

RNA– Genetic material– Controls the cells

activities

NUCLEOTIDES

•SUGAR GROUP•DEOXYRIBOSE•RIBOSE (RNA)

•PHOSPHATE GROUP

•NITROGENOUS BASE•ADENINE•GUANINE•CYTOSINE•THYMINE•URACIL (RNA)

Nucleotides fuel the cell and

coordinate its metabolism.

Nucleotides are Important in Their Own Right

ATP, the cell’s primary energy

currency.

REACTIONS OF BIOLOGICAL COMPOUNDS• HYDROLYSIS REACTIONS

– Water is added to break apart molecules

• C12H22O11 + H2O C6H12O6 + C6H12O6

MALTOSE WATER GLUCOSE GLUCOSE

CONDENSATION / DEHYDRATION REACTIONS• CONDENSATION REACTIONS

(DEHYDRATION SYNTHESIS REACTIONS)– Joining molecules together by

removing water (-H and –OH are removed to make a water molecule)

• C6H12O6 + C6H12O6 C12H22O11 + H2O

GLUCOSE + GLUCOSE MALTOSE + WATER

CATALYST• SPEEDS UP THE NATURAL

RATE OF REACTIONS

• CAN BE ORGANIC OR INORGANIC

ENZYMES• A PROTEIN CATALYST

THAT CONTROLS THE RATE OF A REACTION

ENZYMES

• LOWER THE ACTIVATION ENERGY NEEDED TO CARRY OUT A REACTION

• INCREASES THE RATE OF REACTIONS

• ENZYME NAMES END IN –ase

• NAME IDENTIFIES A REACTING SUBSTANCE– LIPASE – REACTS WITH LIPIDS– SUCRASE – REACTS WITH SUCROSE

• NAME CAN IDENTIFY FUNCTION– OXIDASE – CATALYZES OXIDATION– HYDROLASE – CATALYZES HYDROLYSIS

SUBSTRATES

• Substance acted upon by an enzyme

ENZYME ACTION: LOCK & KEY MODEL

• AN ENZYME BINDS A SUBSTRATE IN A REGION CALLED THE ACTIVE SITE

• ONLY CERTAIN SUBSTANCES CAN FIT IN THE ACTIVE SITE

• ENZYME-SUBSTRATE COMPLEX FORMS

• SUBSTRATE REACTS TO FORM PRODUCT

• PRODUCT IS RELEASED

LOCK & KEY METHOD

ENZYME-SUBSTRATE COMPLEX

ACTIVE SITE

ENZYME FUNCTION

FACTORS AFFECTING ENZYME ACTION

• TEMPERATURE

– LITTLE ACTIVITY AT LOW TEMPS

– RATE INCREASES WITH TEMPERATURE

– MOST ACTIVE TEMP IN HUMANS (37ºC)

– ACTIVITY LOST WITH DENATURATION AT HIGH TEMPERATURE

TEMPERATURE AFFECTING ENZYME ACTION

RATE OF REACTION

TEMPERATURELOW HIGH

OPTIMUM TEMPERATURE

SUBSTRATE CONCENTRATION

AFFECTING ENZYME ACTION

RATE OF REACTION

SUBSTRATE CONCENTRATIONLOW HIGH

MAXIMUM ACTIVITY

pH AFFECTING ENZYME ACTION

RATE OF REACTION

pHLOW HIGH

OPTIMUM Ph

* Most enzymes lose activity in low or high pH