Module 1: Lesson 4 Flashcards
What is the largest consumer of energy during proliferation?
Protein synthesis
What plays a pivotal role in regulation of gene expression?
Control of mRNA translation
Where does transcription take place?
Nucleus
Where does translation take place?
Cytoplasm
What do the 5’ cap and 3’ PolyA tail do?
Increase stability of mRNA, facilitate mRNA export from the nucleus to the cytoplasm, and indicate that the RNA in mRNA (required for protein synthesis machinery to begin translation).
What components does “export ready” RNA have?
Cap binding complex, PolyA-binding proteins, proteins marking complete RNA splices, and a nuclear transport receptor.
What directs the synthesis of proteins?
Genetic information
What is a codon?
A nucleotide triplet
What is the state of the genetic code?
Degenerate/redundant
How many reading frames are possible for an mRNA molecule?
3 reading frames (organisms have different codon bias)
What is the molecular adaptor between codons and corresponding amino acids?
tRNA
What is an anticodon?
A set of three consecutive nucleotides on tRNA that pairs with the complementary codon on mRNA.
What is the 3’ end?
A short single-stranded region where the amino acid is attached to the tRNA.
What is the role of aminoacyl-tRNA synthetases enzymes?
Synthetases couple tRNAs to the correct amino acid. There is a different synthetase enzyme for each amino acid.
What end of the tRNA does a synthetase bind to?
3’ end
Where is protein synthesis performed?
Ribosome
What are the different binding sites of a ribosome?
Aminoacyl-tRNA (A), peptidyl-tRNA (P), exit (E)
What is the role of rRNA?
Ribosomal structure and catalytic function – peptide bond formation
What are the steps in protein synthesis?
Initiation, elongation, and termination
What is Charcot-Marie-Tooth (CMT) disease?
A peripheral neuropathy affecting both sensory and motor neurons through axonal degeneration or demyelination of neurons.
How many different mutations is CMT disease linked to, and where?
CMT disease is linked to six mutations in Aminoacyl-tRNA-Synthetase reactions (but are not the only mutations responsible for CMT).
How does a polypeptide chain grow?
Stepwise addition of amino acids to the C-terminal end
What is a svedberg (S)?
The sedimentation rate of a particle in the centrifuge
What are the steps to add an amino acid to the elongation chain?
tRNA binding, peptide bond formation, large subunit translocation, small subunit translocation
What is the role of tetracycline in protein synthesis blockage?
Blocks binding of aminoacyl tRNA to A site of ribosome
What is the role of chloramphenicol in protein synthesis blockage?
Blocks the peptide transferase reaction on ribosomes
What is the role of erythromycin in protein synthesis blockage?
Blocks the translocation step in translation
What are proteins synthesized on?
Polyribosomes
What are the different structures of proteins called?
Primary, secondary, tertiary, and quaternary
What is a primary structure?
A linear amino acid sequence
What are types of secondary structures?
Alpha helices and beta sheets
What is a tertiary structure?
Full three-dimensional structure formed by an entire polypeptide chain, including a-helices and b-sheets
What is a quaternary structure?
A protein molecule formed as a complex of more than one polypeptide chain
What non-covalent interact in proteins?
Electrostatic attractions, van der Waals attractions, and hydrogen bonds
What role do non-covalent bonds have on proteins?
Help the protein fold and stabilize its folded shape
What functional groups on proteins do hydrogen bonds use to form?
Amine (-NH) and carbonyl (C=O) groups in the backbone
What is the role of chaperone proteins?
To aid protein folding by binding to reversibly to misfolded proteins to prevent aggregation
What are intermediate folded proteins prone to?
Aggregation and misfolding
What are disulfide bonds and what is their role in protein synthesis?
Disulfide bonds are covalent bonds that stabilize extracellular proteins.
What is a ligand?
Any substance that can bind to a protein (ie. another protein, ion, small molecular, or other macromolecule)
What is a binding site?
The region of the protein that associates with a ligand.
What is specificity?
The ability of a protein to bind to just one or a few molecules out of many thousands of different molecules it encounters.
What are the criteria needed for protein binding?
Structural fit AND weak, non-covalent bonds interactions that form simultaneously
What is feedback inhibition?
Prevention of proteins acting due to activity produced later in the pathway.
What types of molecular switches are there?
GTPases and phosphates/kinases
