Molecules of Life---Whoa!

Biology

9-9-10

Overview

• It’s all about the Carbon• Major Biological Molecules

Name Function

• Carbohydrates• Proteins• Lipids• Nucleic Acid

Organic vs. Inorganic

• Organics Contain CARBON Covalently bonded Large molecules Come from something that is now or once was

alive

Organic vs. Organic

• Inorganic No Carbon Ionic bonded Tiny Come from the earth’s crust

Carbon

Carbon atoms have four valence electrons, allowing them to form strong covalent bonds with many other elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen.

Carbon

Carbon atoms can also bond to each other, which gives carbon the ability to form millions of different large and complex structures.

Carbon Bonds

Carbon-carbon bonds can be single, double, or triple covalent bonds.

Macromolecules

• Organic molecules found in living cells

• Smaller molecules can combine to form VERY large chains: Polymerization

Macromolecules

• The smaller molecules are called monomers.

• Monomers in a polymer may be identical or different.

• Macromolecules are grouped according to their chemical composition.

Behind Door #1 We Have Our First Biological Molecule…

CARBOHYDRATES!!!

Carbohydrates

• What is the main function???

• ENERGY!!!

• Plants, some animals, and other organisms also use carbohydrates for structural purposes.

Carbohydrates

Carbohydrates are compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1 : 2 : 1.

Carbohydrates

• 2 different kinds: Simple Sugars: go right to bloodstream

after consumption Complex Carbohydrates: require

digestion; can be hours before body can use it.

Simple Sugars

• Monosaccharides• Relatively small in size• Glucose

Blood sugar

• Sucrose Table sugar

• Fructose Fruit sugar

• Lactose Found in milk

Complex Carbohydrates

• Polysaccharides: large macromolecules formed from monosaccharides.

• In animals….

• Glycogen: many animals store excess sugar here. Glycogen breaks down to glucose and is released into the blood when needed. In muscles, glycogen provides energy for contraction.

Complex Carbohydrates

• In plants…

• Excess sugar plants make is stored as starch.

• Plants also make cellulose which gives plants their strength and rigidity. indigestible for humans

Behind Door # 2…..

LIPIDS!!!

Lipids

• What are functions of lipids?• Protection: fat pads over heart, kidneys, etc. Serves

as cushions over organs.• Hormones and Steriods made by the body: estrogen,

testosterone• Cholesterol found in cell membranes• Lubrication (joints): act like gel packs between joints.• Energy Storage• Important part of biological membranes (cell

membranes)• Waterproof coverings

Lipids

• What are lipids made of?

• Mostly from carbon and hydrogen atoms

• Lipids are generally NOT soluble in water What is another word for that property?

• HYDRAPHOBIC

Lipids- Fatty Acids

• Fats- SATURATED

• Solids at room temperature; come from animals; single chain C molecules

• CH3-CH2-CH2-CH2-CH3

• Oils- UNSATURATED/ POLYUNSATURATED

• Liquid at room temperature; come from plants; multiple bond chains of C

• CH2=CH-CH=CH-CH=CH2

Lipids

• Hydrogenation

• Taking an unsaturated lipid and turning it into a saturated lipid by adding Hydrogen (H) to the lipid.

• Double bonds are broken and replaced by single bond H to Carbon.

• Tends to produce transfats.

Lipids

• Lipids can be formed when a glycerol molecule combines with fatty acids

Lipids

Behind Door #3….

Nucleic Acids!!!

Nucleic Acids

• What is their function?• To store and transmit hereditary/ genetic

information• DNA - • Deoxyribonucleic acid: biological blueprint• RNA - • Ribonucleic acid: carries out instructions from

DNA

Nucleic Acids

• Nucleotides: monomers that make up nucleic acids (polymers).

• Nucleotide structure:• 5-carbon sugar• Phosphate group

(-PO4)• Nitrogenous base

Nucleic Acids

• Main Nucleotides:

• Adenine (DNA and RNA)

• Guanine (DNA and RNA)

• Cytosine (DNA and RNA)

• Thymine (DNA only)

• Uracil (RNA only)

And Finally… Behind Door #4…

PROTEINS!!!

Proteins

• What are functions of Proteins??

• Structural: muscle, hair

• Enzymes--pure protein: catalysts which allow chemical reactions to take pace at normal body temperature.

• Transport: substances attach to protein to enter cells.

Proteins

• Proteins are made of compounds called amino acids.

• All proteins contain C, O, N, H• Amino acids are made up of an amino

group (-NH2) and a carboxyl group (COOH).

• How do amino acids differ?• R-group

Proteins

Proteins

• What is an R-group?

• This is a generic notation for some type of Carbon group.

• The R-group can also be a Hydrogen.

• In this case it is whatever is attached to the amino and carboxyl groups that make up the amino acid.

Proteins

Proteins

• How many amino acids exist in nature?

• More than 20 different types (because of R-group)

• Proteins are among the most diverse macromolecule because of all the possible arrangements of amino acids.

Proteins

• Proteins are polymers of amino acids.• Peptides/ polypeptides• Small, short strings of amino acids• Covalently bonded• Protein• A functional molecule built from one or

more polypeptides• Large; long chains of amino acids

Proteins

• Complete Proteins: Animal protein molecules contain repeated use of all 20 different amino acids.

• Incomplete Proteins: Most plant sources produce proteins that do not contain all 20 amino acids. Vegetarians need to eat a variety of plants in

order to get the amino acids they need for their own protein synthesis.

Proteins: Levels of Organization

• Proteins can have 4 different structural levels of organization.

• Primary Structure: is the sequence of its amino acids.

• Secondary Structure: the folding or coiling of a peptide chain. Typically done by hydrogen bonding.

Proteins:Levels of Organization

Proteins: Levels of Organization

• Tertiary Structure: the complete 3-D arrangement of the polypeptide chain.

• Fourth Level of Structure: proteins with more than one chain; fourth level describes the way the different polypeptide chains are arranged with respect to each other.