Biological Molecules: Proteins Flashcards
(7 cards)
How are proteins made
All proteins in the cell are synthesised by the process of translation. The information coded within DNA is transmitted into a message RNA, which is translated into a sequence of amino acids, through the actions of tRNAs,
What are amino acids made up of?
Amino acids have a basic amino group (NH2) and a carboxylic acid group (COOH). Amino acids also possess a side chain called the ‘R’ group, which gives each amino acid its specificity. The R group is a different molecule in each amino acids, giving them their unique properties. This side chain can give the amino acid different 3D structures, charges or polarity.
What are the bonds in amino acids?
Amino acids are linked together to form a chain – the carboxy group of one amino acid is joined to the amino group of another, forming a peptide bond, (also called an amine bond).
When two amino acids are joined, the reaction releases a molecule of water. This is type of reaction is called a condensation reaction.
Describe the primary structure of a protein
The primary structure chain is made up of a particular order of amino acids with their unique properties, forming the initial polypeptide chain. This chain is dictated by genetic information.
Describe the secondary structure of a protein
The secondary structure involves the folding of a polypeptide chain. Commonly the alpha helix and the beta pleated sheet structure. Certain amino acid sequences tend to form particular secondary structures due to the properties of the peptide backbone. These structures are held together by hydrogen bonds.
Describe the tertiary structure of a protein
The tertiary structure refers to the 3D structure of a polypeptide chain.
Disulphide bonds act like a molecular safety pins keeping parts of the polypeptide chain together.
Ionic Bonds between positively charged R groups.
Hydrogen bonds, Polar R groups on the amino acids form bonds with other Polar R groups.
Describe the Quaternary structure of a protein
Protein consisting of more than one amino acid chain. Held together by noncovalent interactions (hydrogen bonds, ionic binds and hydrophobic interactions). Example is Haemoglobin.
