Unit 1- Protiens Flashcards
What is the proteome?
The entire set of proteins expressed by a genome.
What structures increase the surface area in cells?
Endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles.
What are the 2 types of ER?
Rough ER, Smooth ER.
Describe the functions of the different ERs.
RER- to synthesise proteins.
SER- to synthesise lipids.
Describe the Golgi apparatus.
A series of flattened membrane discs involved in the transport and modification of proteins.
Describe lysosomes.
Membrane bound organelles containing a variety of hydrolyses that digest proteins, lipids and carbs.
Describe vesicles.
Vesicles transport materials between membrane components.
Describe the synthesis of proteins.
RER has ribosomes on its cytosolic face. Lipids are synthesised on the SER and inserted into its membrane. The synthesis of all proteins begins in the cytosolic ribosome.
Describe the movement of proteins after the ER.
Ribosome on ER - Lumen - vesicle - Golgi apparatus (post translational modifications) - vesicle - other membrane.
Describe the secretory pathway.
Ribosome on ER - RER lumen - vesicle - Golgi apparatus - secretly vesicles - plasma membrane.
Describe an acidic R group.
Hydrophilic, -ve, CH2CO2
Describe a basic R group.
Hydrophilic, +ve, NH3
Describe a polar R group.
Hydrophilic, 0, OH
Describe a hydrophobic R group.
Hydrophobic, 0, long carbon chain.
Describe the primary structure.
Amino acids joined by peptide bonds to form polypeptides.
Describe secondary structure.
Aplha helix, B sheet, Turns.
Describe an alpha helix.
A spiral with the R groups sticking outwards, stabilised by hydrogen bonds.
Describe a Beta sheet.
Polypeptide is arranged in rows. Rows are parallel or anti parallel. Stabilised by hydrogen bonds.
Describe Turns.
They reverse the direction of the polypeptide chain and the chain folds back on itself.
Describe tertiary structure.
The final folded shape of the polypeptide.
Stabilised by hydrophobic interactions, Ionic bond, LDFs, Hydrogen bonds, disulphide bridges.
Describe quartanery structure.
Exists in proteins with two or more connected polypeptide subunits.
Describe a prosthetic group.
Non protein unit bound to the protein and necessary for its protein.
What is a ligand?
A substance that can bind to a protein.
What is an allosteric enzyme?
An enzyme whose activity is regulated by altering its conformation. It has an allosteric site elsewhere on the enzyme..
Describe a modulator?
Modulators regulate the activity of an enzyme when they bind to the allosteric site. The conformation changes after binding altering the affinity of the active site for the substrate.
Describe a positive modulator.
Positive modulators bind to allosteric site changing conformation shape increasing affinity and enzyme activity.
Describe a negative modulator.
Negative modulators bind to allosteric site changing conformation shape decreasing affinity and enzyme activity.
Describe cooperativity.
Allosteric proteins with multiple subunits show cooperativity in binding, in which changes in binding at one subunit alter the affinity of the remaining subunits.
Describe the cooperativity in haemoglobin.
Changing in binding of oxygen at one subunit, increases the affinity of the remaining subunits for oxygen.
Describe protein kinases.
They catalyse the transfer of a phosphate group from ATP to other proteins. Phosphorylation causes conformation changes.
Describe protein phosphatases.
They catalyse the transfer of a phosphate from proteins onto to ADP to create ATP
