MACROMOLECULES - PROTEINS

BIG Molecules – Part IV

MACROMOLECULES In Biology, macromolecules are known as large

molecules. A macromolecule can also be referred to as a

polymer. A polymer is a large molecule or complex form

that is made up of many smaller units called monomers.

Monomers are the individual units or a simple form.

MACROMOLECULES There are four types of macromolecules:

Carbohydrates Fruits, vegetables, grains, breads, pastas, sugars,

potatoes Proteins

Meat, chicken, fish, beans, peas, nuts, seeds, eggs, milk

Lipids (fats) Butter, oil, meat, fish, cheese, avocado, milk

Nucleic Acids RNA, DNA

PROTEINS Proteins are important molecules that have

many uses in living organisms. Humans can store energy in the form of

protein in our muscles. Plants can store energy in the form of

protein in seeds. Proteins can be used for transport

molecules. For example, hemoglobin, a protein found in blood, is used to carry oxygen molecules throughout our circulatory system.

PROTEINS Proteins can be used as structural

components in cells. Proteins can be hormones in our bodies.

For example, insulin, a protein that is a hormone, regulates blood sugar level.

Proteins can be enzymes. Enzymes are used by the body to speed up chemical reactions.

CHEMISTRY OF PROTEINS Proteins are mostly made of five

elements:HydrogenOxygenCarbonNitrogenSulfur (only found in some proteins)

These elements combine to form the simplest unit of a protein, the monomer, or the amino acid.

Amino Acids are the building blocks of proteins.

AMINO ACIDS Amino acids are the monomers of

proteins. All amino acids have the same basic

structure with the following 5 parts:Amino group (-NH2)Carboxyl group (-COOH)Side chain (-R)Hydrogen (-H)All attached to a

central carbon (-C-)

AMINO ACIDS There are 20 different amino acids. Each amino acid is different because of

its unique “Side Chain” or “R” group.

AMINO ACIDS Amino acids join together to form

polypeptide chains. Polypeptide chains are the polymer of

proteins. The longest known polypeptide chain

contains 30,000 amino acids. It is found in a muscle protein called Titin.

POLYPEPTIDE CHAINS Polypeptide

polymer chains join with other polypeptide chains to form proteins.

Most proteins consist of more than 1 polypeptide chain.

POLYPEPTIDE CHAINS For example,

hemoglobin, a protein that is found in blood, is composed of 4 polypeptide chains.

DEHYDRATION SYNTHESIS Dehydration means to lose a water

molecule. Synthesis means to join units together. When an amino acid bonds with another

amino acid, two amino acids are joined together. In the process a dipeptide molecule is synthesized and dehydration or a loss of a water molecule occurs.

DEHYDRATION SYNTHESIS The bond that connects the two amino

acids is called a peptide bond. Amino acid monomers continue to be

added to the polypeptide polymer chain. Each time another amino acid monomer

is added to the chain, another water molecule is lost.

HYDROLYSIS Dipeptides can be split by the process of

hydrolysis. Hydro means water. Lysis means to split units apart.

HYDROLYSIS When a dipeptide is split apart, the

dipeptide is split into 2 amino acids. In this process, a water molecule is required for the reaction to occur.

Hydrolysis is the opposite of dehydration synthesis.