Proteins Flashcards
Draw and label a diagram of an amino acid
Must include:
- amine group NH2
- carboxyl group - COOH
- variable R group
- H
How many amino acids occur in life?
20
What elements do all proteins contain?
Carbon, hydrogen, oxygen, nitrogen
What are the 3 types of amino acids in life?
-5 non essential
Our body can make them from other amino acids
- 9 essential as they are only obtained by what we eat
- 6 conditionally essential
Only needed as children
Draw a labelled diagram demonstrating condensation and hydrolysis of peptide bonds
- must show the water molecule removed
- use textbook to check
Draw a dipeptide and label the bond
Use book to check
Explain why there is a range of dipeptides and lots of variety in polypeptide chains
There are 20 amino acids
20x20 = 400 dipeptides
This quickly leads to a hugeee number of polypeptides
Define polypeptide
Define protein
Polypeptide - a polymer of amino acids
Protein - one or more polypeptide chains arranged as a macromolecule with a specific function
Define primary structure and describe how it is held together
- this is the sequence of amino acids in the polypeptide chain
- this is decided by DNA
- it is put together on ribosomes
- peptide bonds
Define secondary structure
- what are the two types
- describe how it’s held in place
- chain folds or coils of polypeptide chain = secondary
- alpha helix or beta pleated sheets
- hydrogen bonds form between NH and CO of non adjacent amino acids
Define tertiary structure
- describe how it is held in place
- further folding caused by bonds and interactions between R groups
- the secondary structure pulls R groups of amino acids closer
- weak hydrophobic / Philic interactions
- hydrogen bonds
- ionic bonds - oppositely charged R groups
- disulphide bridges - covalent and strong, but only between R groups containing sulphur
Explain quaternary structure
- describe how it is held in place
Associations between separate polypeptide chains - uses all types of bonding Hydrophobic / Philic interactions Hydrogen bonds Ionic Disulphide bridges
Define globular protein
- properties
- compact
- water soluble
- spherical
- forms when hydrophilic R groups are on the outside of the protein, and hydrophobic are on the inside
Define fibrous proteins
- long
- insoluble
- strong
- 2D ish
- high proportion of hydrophobic R groups
- repetitive primary structure
Define prosthetic group
A non protein group that makes up the R group of an amino acid