TOPIC 1- Proteins Flashcards
What are the monomers of proteins?
Amino acids
What is a dipeptide?
When two amino acids join together
A polypeptide
When two or more amino acids join together
What is the structure of an amino acid?
-A carbocyl group (COOH)
-Amine/aminogroup (NH2)
-R group attached to a carbon atom
Which is the only R group which does not contain carbon?
Glycine
What makes all living thing different?
Their R group
How many amino acids are there?
20
How are amino acids linked together to form dipeptides and polypeptides?
Condensation reactions
What is the bond formed between amino acids?
Peptide bonds
What reaction happens when dipeptides and polypeptides breakdown?
Hydrolysis
What is the primary structure?
The sequence of amino acids in the polypeptide chain
What is the secondary structure?
-Polypeptide chain chain does not remain flat and straight
-Hydrogen bonds form between the amino acids in the chain
-This makes it coil into an alpha helix or fold into a beta pleated sheat
What is tertiary structure?
-Coiled/folded chain of amino acids is coiled/folded futher
-More bonds form between different parts of the polypeptide chain including hydrogen and ionic bonds
-Disulfide bridges also form when two molecules of the amino acid cysteine come close together- the sulfur atom in one cysteine bonds to the sulfur atom in the other
-For proteins made from one polypeptide chain the tiertry structure forms tehir final 3D structure
What are ionic bonds?
Attractions between negative and positive charges on different parts of the molecule
What is quaternary structure?
-The way several polypeptide chains are assembled together with bonds
-Final 3D structure
A proteins 1_ determines its function
- Shape
How is an enzymes shape related to its function?
-Spherical due to tight folding of their polypeptide chains
-Soluble
-Have roles in metabalisism
How does an antibodies shape related to its function?
-Made up of two light (short) polypeptide chains and two heavy (long) polypeptide chains bonded togther
-They have variable regions
How does a transport proteins shape related to its function?
-Channel proteins contain hydrophobic and hydrophillic amino acids which cause the protein to fold up and form a channel
How do structural proteins shape relate to its function?
-Physically strong
-Long polypeptide chains lying parallel to each other with cross links between them
-Polypeptides coiled together
What si the test for proteins?
Biuret
What is the method for the Biuret test?
-The test solution needs to be alkaline so add a few drops of sodium hydroxide solution
-Add some copper (II) sulfatre solution
What will the resulst be?
Positive-purple
Negative-Blue
Do peptide bonds have all 3 structures?
Yes
What structures do hydrogen bonds have?
Secondary and tertiary
