Proteins, Enzymes And Digestion. Flashcards
What is a micelle?
And emulsified lipid droplet, coated with bile salts to prevent reformation.
Proteins are large molecules. True/false?
True
How are polypeptides formed?
Joining amino acid monomer units.
What 4 groups is the central carbon in an amino acid attached to?
- amino group
- carboxyl group
- hydrogen
- R ( side group, variety of chemical groups )
How are dipeptides formed?
In a condensation reaction with amino acid monomers.
What happens during a condensation reaction between two monomers in reference to the 4 chemical groups attached to the central carbon?
- OH is removed from the carboxyl group of one amino acid.
- H removed from other amino acid
How can polypeptides be broken down?
Hydrolysis reaction
What is the primary structure of a protein?
A polypeptide
What does the primary structure of a protein do?
Determines the shape of the protein and its function
What bond joins monomers?
Peptide bond
Why are polypeptides able to form hydrogen bonds in the secondary structure of a protein?
There is an -NH and a -C=O group on either side of the peptide bond, the H is slightly electropositive, the O is slightly electronegative.
What shape is caused in the secondary structure of a protein as a result of the hydrogen bonds formed?
It becomes twisted into a 3D shape, e.g. A coil (alpha helix)
What re the two variations of proteins?
Fibrous and globular.
What is the tertiary structure of a fibrous protein?
Unbranched polypeptide chain that has been tightly wound and packed together closely by glycine, and then twisted into a second helix.
Name a fibrous protein.
Collagen
What us the quartenary structure of a fibrous protein?
3 polypeptide chains wound together similarly to fibres in a rope.
What does collagen do?
Joins muscles and bones.
Name examples of globular proteins and what they do.
Enzymes and haemoglobin
Carry out metabolic functions
What type of protein are enzymes?
Globular
What conditions must be present for a biochemical reaction to occur?
- for substrates to collide in order to react they require sufficient energy
- energy of products must be less than reactants
- activation energy
What does the protein biruet test detect?
Polypeptide bonds
What are the steps to the protein biruet test?
- place sample in test tube, add equal volume of sodium hydroxide at room temp.
- add a few drops of dilute copper sulphate solution and mix
What is the positive and negative result of a protein biuret test?
Positive - purple
Negative - blue
Which part of the enzyme is functional?
The active site
What is formed when the substate bonds with the enzyme’s active site?
Enzyme-substrate complex
How does the induced fit model work?
The enzyme is flexible and changes shape in the presence of the substate.
How does the induced fit model suggest the enzyme lowers the activation energy?
When altering in shape, it puts a strain on substate distorting a particular bond in the substrate, changing the activation energy.
What is the secondary structure of a protein?
Alpha helix of beta pleated sheets held together by hydrogen bonds.
What is the quaternary structure of a protein?
2 or more polypeptides held together.
What is an example of a quaternary globular protein?
Haemoglobin, chlorophyll.
What is the tertiary structure of a globular protein?
Secondary structure folded and held together by ionic, hydrogen and disulphide bonds?
