PROTEINSBiology 30

Similar to lipids and carbohydrates, proteins are composed of carbon, hydrogen and oxygen. However, proteins also contain nitrogen

WHAT MAKES UP PROTEIN? All proteins are made up of tiny

structures called amino acids All amino acids have a basic structure:

A hydrogenA central carbonAn amino group(NH3)An acid group (COOH)

AMINO ACIDS Each amino acid has a unique R group,

or side group. This group is what distinguishes each amino acid from the next

There are 20 common amino acids

There are 9 essential amino acids. This means that the body CANNOT make these amino acids, so therefore you must get these amino acids from your diet.

FORMATION OF PROTEIN Amino acids are linked together in a

variety of ways to form thousands of different proteins.

Amino acids are linked together through a peptide bond

Amino acids are connected to form peptide bonds through DEHYDRATION SYNTHESIS

Dipeptide- two amino acids bonded together

Tripeptide- three amino acids bonded together

Polypeptide- Many amino acids bonded together

ROLES OF PROTEINS Proteins are the building materials for

muscles, skin, blood, bone, and almost every other body structure.

Collagen- is a type of protein that is the foundation for bones and teeth, as well it makes up connective tissue (tendons, ligaments, scars)

Proteins are needed daily in your body:Muscle cells need protein to grow larger and

stronger in response to exerciseNew proteins are used to synthesis hair and

fingernailsA lifespan of a skin is usually about 30 days,

therefore new cells are required, which are mostly made of proteins

Cells in the GI tract are replaced every 3 days!

Many proteins are used as transporters of lipids vitamins, minerals and oxygen

Other proteins act as antibodies Some proteins are hormones Proteins also play a vital role in chemical

reactions within the body. They act as enzymes- which help to make reactions occur more quickly and efficiently

HYDROLYSIS When the body needs specific amino

acids, peptide bonds will be broken to release an amino acid.

This process is called hydrolysis- since there is an addition of a water molecule.

PROTEIN SHAPE AND FOLDING Depending on the sequence of amino

acids, the polypeptide chain will twist and turn into various shapes.

The unique R group of each amino acid gives it characteristics that either attract or repel certain amino acids to each other.

Protein folding is critical, as is the sequence of amino acids!

If a protein has incorrect amino acids, this may prevent the protein from working properly.

For example, people who have sickle cell anemia have one incorrect amino acid in the chain for hemoglobin. This leads to curved shaped red blood cells, which carry oxygen