Proteins Flashcards
What are proteins? (also known as peptides)
Proteins are the major structural materials of animal tissue. For e.g, enzymes are proteins, which act as biological catalysts. Animals cannot make proteins, only plants can.
BBC Bitesize - Proteins are natural condensation polymers formed by joining together thousands of amino acid molecules.
How are proteins formed?
In condensation reactions between animo acids. The amine group (NH2) of one amino acid joins with the carboxyl group (COOH) of another. Water is also formed.
What are the two types of proeins?
Fibrous - long, spiral chains that are folded to form strong structures
Globular - spiral chains folded into spherical shapes.
What is the link between amino acids called?
The amide link or peptide link.
What is an alpha amino acid?
When both functional groups are bonded to the same carbon.
How does the human body get the proteins in needs (essentail animo acids)?
Proteins taken in can be broken down during digestion in a hydrolysis reaction. Stomach acids contain hydrogen, so can be used (acid hydrolysis), these amino acids can be used to make proteins needed. Essential amino acids need to be taken in from diet.
How are amino acids transferred around the body?
When they are broken down into amino acids, they are small enough to pass through the gut wall, they are then absorbed into the blood stream.
What happens when proteins are heated?
Chains are held with intermolecular bonding between the side chains and when they are heated up, these bonds are broken, so the proteins denature (change shape). This changes the texture of food.
