Chemistry of BiomoleculesChemistry of Biomolecules

• Most biological compounds are ORGANIC – compounds of CARBON

• The study of these compounds is ORGANIC CHEMISTRY.

Carbon!Carbon!Why it’s cool, and Why it’s cool, and

what it can dowhat it can do

6 electrons

2 - 4

ORGANIC = CONTAINING CARBONORGANIC = CONTAINING CARBON

• The fact that Carbon has 4 electrons in its outer valence level, means it can make four covalent bonds with other atoms.

• It can also do neat things like:

• form long chains, branches, rings, and double bonds

Monomers & Polymers: Monomers & Polymers: when carbons get togetherwhen carbons get together

• Individual units called MONOMERS are linked together to form big molecules called POLYMERS.

monomer + monomer + monomer =

Polymer

A polymer of glucose (sugar) unitsA polymer of glucose (sugar) units

Very large polymers made from Carbon-based chains are called

MACROMOLECULES

“Macro” = giant

(so, “giant molecule”)

How do monomers come together How do monomers come together to form a polymer?to form a polymer?

Dehydration Synthesis:

Chemical reaction where two

monomers join together and

release water.

How do polymers break down into How do polymers break down into monomers?monomers?

Hydrolysis:Chemical reaction in which water

is added and splits a polymer back into monomers

Hydrolysis of a disaccharide

MACROMOLECULES come in MACROMOLECULES come in different varietiesdifferent varieties

4 important groups:

–Carbohydrates–Proteins–Lipids–Nucleic Acids

What type of macromolecule is shown here?

CarbohydratesCarbohydrates• Monomer = monosaccharide

– Ex: glucose, fructose, galactose

• Function: energy, structure• Example: Sugar, cellulose

(crunchy part of plants), starch, glycogen (glucose storage in the liver)

Facts about carbsFacts about carbs

• Carbohydrates include C. H, and O in a 1:2:1 ratio, such as in glucose C6H12O6.

• They exist as rings with an integral Oxygen and many H and OH groups.

• The simplest are monosaccharides, such as glucose, fructose, or galactose.

Glucose CGlucose C66HH1212OO6 6 – a monosaccharide– a monosaccharide

DisaccharidesDisaccharides

• Disaccharides have two rings, such as sucrose which is table sugar.

Lactose – milk sugarLactose – milk sugar

Polysaccharides – many Polysaccharides – many monosaccharides linked monosaccharides linked

together, such as in glycogen, together, such as in glycogen, starch, and cellulosestarch, and cellulose

Types of polysaccharidesTypes of polysaccharides

• a. Glycogen: Animal glucose storage in

the liver and muscles

• b. Starch: Plant energy storage.

• c. Cellulose: wood, plant material

Most abundant carbohydrate

Glycogen in liver cellsGlycogen in liver cells

Plant starch in potato cellsPlant starch in potato cells

Cellulose fibers in plant cellsCellulose fibers in plant cells

Models of carbohydratesModels of carbohydrates

Test for SugarsTest for Sugarsthe Benedict’s Testthe Benedict’s Test

Test for starch - iodineTest for starch - iodine

What type is shown here? (Okay, there

are a few “hints”.)

ProteinsProteins

• Monomer = amino acid (20 of them)• Functions

1. Structure – muscle proteins2. Fight disease - antibodies3. Control rates of reaction - enzymes4. Transport substances in & out of the cell

- hormones, channel proteins

An Amino Acid

The structure of an amino acidThe structure of an amino acid

AMINOGROUP

ACIDGROUP

The R groups is any atom or group of atoms. It makes each amino acid unique.

Structure of an Amino AcidStructure of an Amino Acid

There are 20 different amino acids There are 20 different amino acids with different R groups.with different R groups.

Amino acids are held together by peptide bondsAmino acids are held together by peptide bonds

Peptide Bond FormationPeptide Bond FormationNotice the loss of a water molecule.Notice the loss of a water molecule.

A Polypeptide is many amino A Polypeptide is many amino acids linked together…. acids linked together…. beginning of a proteinbeginning of a protein

Proteins have complex shapes that Proteins have complex shapes that determine their function.determine their function.

The levels of protein structureThe levels of protein structure

• Primary – chains of amino acids

• Secondary – folds• Tertiary –

compacting• Quaternary – two or

more chains

What level is shown here in the What level is shown here in the protein insulin?protein insulin?

Quaternary – Two chains

If the primary structure is disrupted,then If the primary structure is disrupted,then the protein may not be shaped correctly the protein may not be shaped correctly

and will not be able to function as in and will not be able to function as in hemoglobin in the disease sickle cell hemoglobin in the disease sickle cell

anemia.anemia.

Test for proteinTest for proteinthe Biuret testthe Biuret test

What type of macromolecule is shown here?

LipidsLipids• Function:

– Chemical messengers (steroids)– Insulation and cushioning– Long lasting energy source

• Examples:– Fats and oils– Phospholipids (cell membrane fats)– Steroids (cholesterol)– composed of: fatty acids on a

“glycerol backbone”

Are NOT SOLUBLE in water!

Joined to three fatty acid tails

composed of: fatty acids and a “glycerol backbone”

ACID group

Fatty acids have many C-H bonds - good energy source.

When three fatty acids join to the When three fatty acids join to the glycerol molecule, three water molecules glycerol molecule, three water molecules

are lost.are lost.

GlycerolFattyAcids

Lipids

To separate parts of the fat To separate parts of the fat molecules, you have to add 3 water molecules, you have to add 3 water molecules in a hydrolysis reactionmolecules in a hydrolysis reaction

Hydrolysis of a triglyceride

Saturated fats have only C TO C single bonds in their Saturated fats have only C TO C single bonds in their fatty acid “tail”.fatty acid “tail”.

Unsaturated fats have one or more C = C double bonds Unsaturated fats have one or more C = C double bonds in their fatty acid tail.in their fatty acid tail.

Fats and OilsFats and Oils

• Saturated fatty acids (butter, fats) are solid at room temperature

• Unsaturated fatty acids (oils) are liquid at room temperature and better for you and your arteries.

PolyunsaturatedPolyunsaturatedmore than one C-C double bondmore than one C-C double bond

Is there a shorter way to Is there a shorter way to represent these BIG molecules?represent these BIG molecules?

Short-hand way to write a fatty acid. The end awayfrom the acid end is theOmega end.

Omegaend

An Omega – 3 – fatty acidAn Omega – 3 – fatty acid

OMEGA END

• Omega 3 fatty acids are better for you than Omega 6 ones.

Trans Fats are not good for you.Trans Fats are not good for you.

Food labels help you decide if the Food labels help you decide if the food you are eating is healthy.food you are eating is healthy.

• Due to their chemical structure, lipids are not soluble in water.

Phospholipids – used in cell membranesPhospholipids – used in cell membranesThey have a They have a phosphorusphosphorus atom in their atom in their

structure. structure.

The Polar Part isattracted to water so HYDROPHILIC

Tails are HYDROPHOBIC.

The Polar Part isattracted to water so HYDROPHILIC

Tails are HYDROPHOBIC.

Another type of lipid that makes up Another type of lipid that makes up cell membranes is cell membranes is cholesterol.cholesterol. It is a It is a

steroidsteroid and exists as fused rings. and exists as fused rings.

Cell membranes and lipidsCell membranes and lipids

A test for fats is a “greasy” A test for fats is a “greasy” transparent spot on paper.transparent spot on paper.

Nucleic AcidsNucleic Acids

• Monomer = nucleotide• Function:

– In heredity – DNA makes up genes– Direct production of proteinsExamples: DNA and RNA

Can you identify this type of macromolecule?

A nucleotide is made of a sugar, A nucleotide is made of a sugar, phosphate group, and a Nitrogen phosphate group, and a Nitrogen

base.base.

The NitrogenBases haveFour differentOnes.

DNA’s main jobDNA’s main job

• To code for the amino acids that make a PROTEIN

• RNA helps.

So, hope you have it!So, hope you have it!Because this is a QUIZ!Because this is a QUIZ!

1, How many bonds go to each 1, How many bonds go to each Carbon?Carbon?

2. Is this a monosaccharide, 2. Is this a monosaccharide, disaccharide, or polysaccharide?disaccharide, or polysaccharide?

3. Is this fat saturated or unsaturated?3. Is this fat saturated or unsaturated?

4. This is a phospholipid found 4. This is a phospholipid found in cell membranes. Which part in cell membranes. Which part

(color) is hydrophobic?(color) is hydrophobic?

5. What is this a model of?5. What is this a model of?