RNA: Protein Synthesis Flashcards
Usually double stranded
DNA
Stores genetic information, building blocks of DNA/RNA.
Nucleic acids
Usually single stranded
RNA
Three-letter code that specifies a particular AA found within mRNA. ex: 5’-AUG-3’
Codon
Basic unit of a protein
Amino Acid
Complimentary code for a codon found within tRNA. Ex: 3’-UAC-5’
Anti codon
A series of arranged codons which codes for an mRNA
Gene
A special type of RNA which codes for a protein
mRNA
Process of converting a nucleic acid(mRNA) into a protein product
Translocation
Multiple codons can code for the same Amino Acid. UUU, UUC both code for ________.
Degenerate. Phenylalanine.
A particular codon can only code for a single amino acid. GUU can only code for ________.
Unambiguous. Valine.
Genetic Code Characteristics
Unpunctuated, Non overlapping & Universal “UNU”
Genetic Code Characteristic: there is no overlap in reading codons
Non-overlapping
Genetic Code Characteristic: the genetic code is the same for all animal species
Universal
Genetic Code Characteristic: no punctuation exists between or within codons
Unpunctuated
Is the process of converting a coded message within a messenger RNA into a polypeptide structure. Include _________.
Protein synthesis. Translation.
Polypeptide structure
Protein
An adapter molecule. Bridges the gap between your mRNA & protein. Cloverleaf shaped. Each of this species holds a single _______.
Transfer RNA. AA.
Parts of tRNA: where the AA is attached
Acceptor arm
Parts of tRNA: recognition site for specific aminoacyl-tRNA synthetase. Rich in dihydrouridine.
D arm
Parts of tRNA: binds aminoacyl tRNA to ribosomal unit
Thymidine-Pseudouridine-Cytidine arm
Parts of tRNA: seven-letter code containing the anticodon
Anticodon arm
In tRNA Activation: special enzyme, ____________, bind specific AAs with their corresponding tRNAs, with the help of ____. AAs are attached via their _______ at the 3’ end of the tRNA with an _________, forming an _________.
Aminoacyl-tRNA synthetases. ATP. Carboxyl end. Ester bond. Aminoacyl tRNA.
Contains adenine & guanine
Purines
Contains thymine, cytosine & uracil
Pyrimidine
Phases of Translation
Initiation, Elongation & Termination
Translation Initiation Phase: Ribosomes dissociate into 40s and 60s subunits
Dissociation
Translation Initiation Phase: Delays reassociation, allows for other IFs to mingle with 40s
elF-3 & elF-1A
Translation Initiation Phase: elF-2 binds to
GTP
Translation Initiation Phase: elF-2 GTP complex binds to
Met-tRNA
Translation Initiation Phase: elF-2-GTP-met-tRNA complex binds to
40s
Translation Initiation Phase: eiF2 binds to GTP. elF-2 GTP complex bind to met-tRNA and elF-2-GTP-met-tRNA complex binds to 40s.
43S preinitiation complex
Translation Initiation Phase: mRNA binds to 43s preinitiation complex. Via __________________. Uses GTP. Cap-binding protein complex eIF-4F binds to the methyl cap. Cap only in eukaryotes.
48s initiation complex
Translation Initiation Phase: mRNA binds to 43s preinitiation complex via
Methyl-guanosyl triphosphate cap
Translation Initiation Phase: In 48 initiation comples, eIF-4F consists
eIF-4E & eIF-4G
Translation Initiation Phase: In 48s initiation complex, this is a scaffolding protein
elF-4G
Translation Initiation Phase: In 48s initiation complex, it is responsible for recognizing the mRNA cap. It is phosphorylated by ______ and ______ to enhance initiation. Its is bound by _____ to inhibit initiation.
elF-4E. Insulin & Mitogens. BP-1.
Translation Initiation Phase: In 48s initiation complex, insulin and mitogens ________ BP-1, preventing it from binding to _______ (which would enhance initiation)
Phosphorylate. eIF-4E.
Translation Initiation Phase: In 48s initiation complex, melts the secondary structure of the cap. The complex begins to scar for ____________. Purines at positions -3 and +4 of the AUG sequence.
elF-4A & elF-4B. Zosak concensus sequences.
Translation Initiation Phase: 48s initiation complex binds to 60s subunit. elF-5 hydrolyzes the GTP. this uses GTP as energy source. To remove all initiation factors. And to reassociate 60s & 40s.
80s initiation complex
Translation Initiation Phase: In 80s initiation complex, 48s initiation complex binds to
60s subunit
Translation Initiation Phase: In 80s initiation complex, hydrolyzes the GTP.
eIF-5
Translation Elongation Phase: elongation factor eEF-1a complexes with GTP. Complex binds with an entering aminoacyl tRNA. Charged aminoacyl tRNA then enters this site.
A-site Attachment
Translation Elongation Phase: In A-site attachment, complexes with GTP
eEF-1a
Translation Elongation Phase: a-amino group of the A-site aminoa cid attacks the carboxyl end of the growing P-site polypetide chain. Facilitated by __________, a ribozyme component of the 60s subunit.
Peptide Bond Formation. Peptidyltransferase.
Translation Elongation Phase: P-site tRNA is removed from the P-site. ________ facilitates the transfer of A-site tRNA to the P-site. Hydrolysis of the GTP will move ______ along the ribosome.
Translocation. eEF-2 + GTP. mRNA.
Translation Elongation Phase: Energy requirement for activation of tRNA
2 ATPs
Translation Elongation Phase: Energy requirement for entry of aminoacyl tRNA into A-site
1 GTP
Translation Elongation Phase: Energy requirement for translocation
1 GTP
Translation Elongation Phase: Total Energy requirement
4 high energy phosphate bonds
Translation Phase: Stop codons enter the A-site. Releasing factors eRF remove the growing polypeptide from the P-site tRNA. mRNA detaches from ribosomes. Ribosome complex dissociates into 40s and 60s subunits.
Termination phase
Translation Termination Phase: remove the growing polypeptide from the P-site tRNA together with GTP & Peptidyltransferase.
eRF
Translation Termination Phase: mRNA detaches from
Ribosomes
Releasing factor for UAA & UGA
eRF-2
Releasing factor for UAA & UAG
eRF-1
Releasing factor for binding of GTP
eRF-3
Happens after translation. To promote protein functionality. Include many processes.
Posttranslational Processing
In Posttranslational Processing: Some viral proteins: long __________ are cleaved to provide specific proteins.
Polycistronic proteins.
In Posttranslational Processing: prohormone is a single chain protein. ________ cleaves it into two polypeptide chains, forming the functional hormone.
Insulin. Protease.
In Posttranslational Processing: ______ molecules are translated. Three of these molecules align themselves. Enzymes _______ and _______ specific AAs. Amino terminal peptides are cleaved off.
Collagen. Procollagen. Hydroxylates & Oxidizes.
In Collagen life cycle, cleavage of extension peptides by
Amino/Carboxyproteinases
Segue to protein targeting
Translation
Multiple ribosome units translating the same mRNA are called
Polyribosomes/Polysomes
Polysomes are located either in free _______ or within _____.
Cytosol. RER.
Secretory Pathway occurs in the
ER
Tags aberrant proteins
Ubiquitin
Destroys aberrant proteins
Proteasome
Changes in the nucleotide sequence of a given DNA segment
Mutation
Purine to purine OR pyrimidine to pyrimidine
Transition mutation
Purine to pyrimidine OR pyrimidine to purine
Transversion mutation
Mutation: add something
Insertion mutation
Mutation: remove something
Deletion mutation
Mutation type: inherent degeneracy of the genetic code. CUC to _____.
Silent/Nothing mutation. CUG.
Mutation type: An amino acid is replaced with another AA. CUC to
Missense mutation. CCC.
Mutation type: A codon for an AA is replaced with a stop codon. Results in premature termination. (Truncated protein) UAU, UAC to
Nonsense mutation. UAA,UAG
Mutation type: error in reading the code due to either insertion or deletion. Occurs since the code is read 3 bases at a time.
Frame-shift mutation
Mutation types: change something “MSN”
Missense, Silent & Nonsense
Mutation types: add something
Frame-shift
Mutation types: remove something
Frame-shift mutation
Protein synthesis changes as a response to environmental threats. Excess iron in the blood triggers the synthesis of ________, which binds excess Fe2+.
Protein synthesis dysregulation. Ferritin.
Changes as a result of viral infection.
Protein synthesis