1.2 Proteins Flashcards
(35 cards)
What is the proteome?
The proteome is the entire set of proteins expressed by a genome
Why is the proteome larger than the genome?
More than one protein can be produced from a single gene as a result of alternative RNA
splicing
What is the primary structure of a protein and what type of bond is it made from?
A sequence of a chain of amino acids that have bonded through a condensations reaction.
Bonding: peptide bond
What is the secondary structure of a protein?
Structure: Alpha helix and Beta sheets
Bonding: hydrogen bonds
What is the tertiary structure of a protein?
Hydrophobic side chains folded inwards
Bonding: disulphide bridges, ionic bonds, LDFs, hydrophobic interactions
What is the quaternary structure of a protein?
More than one polypeptide chain bonded together.
Can also have sub-units attached
Where does post translational modification take place and what are the forms of post translational modification?
Where: in the golgi
Forms of modification: addition of chemical groups, covalent modification
Name the 4 amino acid group categories and describe them
basic - positively charged
acidic - negatively charged
hydrophilic/polar - is attracted to water
hydrophobic/non-polar - isn’t attracted to water
What is the RER and how does it differ from the SER?
RER is covered in ribosomes
Describe the translation of the cytosolic proteins and secreted proteins
cytosolic protein - translation on cytosolic ribosomes
secreted proteins- translated on ribosomes on RER
Describe the pathway of a secreted protein?
Protein enters RER lumen, move in vesicles to Golgi apparatus, post translational modification, packaged in secretory vesicles, fuse with plasma, move along microtubules
What is a ligand?
A ligand is a substance that can bind to a protein
What are modulators?
Modulators bind with the allosteric site and bring about conformational change
What are negative modulators?
Negative modulators lock the enzyme into an inactive form i.e. decreasing the enzyme affinity for the substrate
What are positive modulators?
Positive modulators lock the enzyme into active form i.e. increases the enzyme’s affinity for the substrate
What are kinases?
Kinases add a phosphate group (phosphorylates)
What are phosphatases?
Phosphatases remove a phosphate group (dephosphorylates)
Which factors can affect the interactions between R-Groups?
Temperature, light
What type of covalent bond between R-groups containing sulfur?
Disufide bond
What is the name for a non-protein unit tightly bound to a protein?
Prosthetic group
Which organelle is the site of transmembrane protein synthesis?
Rough Endoplasmic Reticulum (RER)
Which organelle is the site of cytosolic protein synthesis?
Cytosolic Ribosomes
Which organelle is the site of lipid synthesis?
Smooth Endoplasmic Reticulum (SER)
Which organelle contains hydrolases that digest protein, lipids, nucleic acids and carbohydrates?
Lysosomes
