Chemistry of Biomolecules

Most biological compounds are ORGANIC – compounds of CARBON The study of these compounds is ORGANIC CHEMISTRY.

Carbon! Why it’s cool, and what it can do

6 electrons 2 - 4

ORGANIC = 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: when 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) units

Very large polymers made from Carbon- based chains are called MACROMOLECULES “Macro” = giant (so, “giant molecule”)

How do monomers come together to form a polymer? Dehydration Synthesis: Chemical reaction where two monomers join together and release water.

How do polymers break down into monomers? Hydrolysis: Chemical reaction in which water is added and splits a polymer back into monomers

Hydrolysis of a disaccharide

MACROMOLECULES come in different varieties 4 important groups: –Carbohydrates –Proteins –Lipids –Nucleic Acids

What type of macromolecule is shown here?

Carbohydrates 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 carbs Carbohydrates include C. H, and O in a 1:2:1 ratio, such as in glucose C 6 H 12 O 6. 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 C 6 H 12 O 6 – a monosaccharide

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

Lactose – milk sugar

Polysaccharides – many monosaccharides linked together, such as in glycogen, starch, and cellulose

Types 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 cells

Plant starch in potato cells

Cellulose fibers in plant cells

Models of carbohydrates

Test for Sugars the Benedict’s Test

Test for starch - iodine

What type is shown here? (Okay, there are a few “hints”.)

Proteins Monomer = amino acid (20 of them) Functions 1.Structure – muscle proteins 2.Fight disease - antibodies 3.Control rates of reaction - enzymes 4.Transport substances in & out of the cell - hormones, channel proteins

An Amino Acid

The structure of an amino acid AMINO GROUP ACID GROUP The R groups is any atom or group of atoms. It makes each amino acid unique.

Structure of an Amino Acid

There are 20 different amino acids with different R groups.

Amino acids are held together by peptide bonds

Peptide Bond Formation Notice the loss of a water molecule.

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

Proteins have complex shapes that determine their function.

The 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 protein insulin? Quaternary – Two chains

If the primary structure is disrupted,then the protein may not be shaped correctly and will not be able to function as in hemoglobin in the disease sickle cell anemia.

Test for protein the Biuret test

What type of macromolecule is shown here?

Lipids Function: –C–Chemical messengers (steroids) –I–Insulation and cushioning –L–Long lasting energy source Examples: –F–Fats and oils –P–Phospholipids (cell membrane fats) –S–Steroids (cholesterol) –c–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 glycerol molecule, three water molecules are lost. Glycerol Fatty Acids Lipids

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

Saturated fats have only C TO C single bonds in their fatty acid “tail”. Unsaturated fats have one or more C = C double bonds in their fatty acid tail.

Fats 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.

Polyunsaturated more than one C-C double bond

Is there a shorter way to represent these BIG molecules?

Short-hand way to write a fatty acid. The end away from the acid end is the Omega end. Omega end

An 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.

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

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

Phospholipids – used in cell membranes They have a phosphorus atom in their structure. The Polar Part is attracted to water so HYDROPHILIC Tails are HYDROPHOBIC.

The Polar Part is attracted to water so HYDROPHILIC Tails are HYDROPHOBIC.

Another type of lipid that makes up cell membranes is cholesterol. It is a steroid and exists as fused rings.

Cell membranes and lipids

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

Nucleic Acids Monomer = nucleotide Function: –In heredity – DNA makes up genes –Direct production of proteins Examples: DNA and RNA

Can you identify this type of macromolecule?

A nucleotide is made of a sugar, phosphate group, and a Nitrogen base. The Nitrogen Bases have Four different Ones.

DNA’s main job To code for the amino acids that make a PROTEIN RNA helps.

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

1, How many bonds go to each Carbon?

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

3. Is this fat saturated or unsaturated?

4. This is a phospholipid found in cell membranes. Which part (color) is hydrophobic?

5. What is this a model of?