Proteins Flashcards
What is the primary structure?
Amino acid sequence
What is the secondary structure?
α helixes, beta sheets, beta turns
What is the tertiary structure?
3D shape
What is the quaternary structure?
Protein forms complexes with other proteins
What are proteins made up of?
Polypeptide chains
What are the 6 functions of proteins?
Enzymes Signalling Transport Antibodies Structural Transcription factors
What do enzymes do?
catalyse chemical reactions
What is signalling?
Required for information processing within cells
What is a proteins function determined by?
It’s structure
Explain the example of the Ras protein?
It is a signalling enzyme called GTPase
It converts GTP (on) to GDP (off)
The active site of GTPase binds to GTP and Mg2+
Which techniques can you use for protein purification?
- Ultracentrifugation
- Gel filtration chromatography
- Ion-exchange chromatography
- Affinity chromatography
- Gel electrophoresis
What is ultracentrifuation?
Seperates biological macromolecules based on their relative buoyancy by spinning them at high speeds
What are proteins separated by in gel filtration chromatography?
Seperated on the basis of their size
How does gel-filtration chromatography work?
The protein mixture is run through a column contatining beads of a hydrophilic polymer
Large proteins do not enter the pores in the beads and so pass through quickly
Smaller proteins pass through the beads and so run much more slowly
What are proteins separated by in affinity chromatography?
Separated on the basis of a specific interaction with another molecule bound to a column of beads
