lec 4: genetic management pt. 2 Flashcards
Where is the site of protein synthesis?
cytoplasm, specifically in ribosome
What is the process of translating the nucleotide sequence of the bases on the mRNA into an amino acid sequence of a protein called?
Translation / Protein Synthesis
What is the enzyme that will activate amino acids?
Aminoacyl transferase (AAT)
the bond between amino acid in forming protein
peptide bonds
what are the requirements in translation?
ribosomes, mRNA, initiator tRNA, protein factors
it carries the first amino acid in the protein, which is almost always methionine (Met)
initiator tRNA
it acts as a template or a messenger to determine which amino acids will be included in the protein
sequence
mRNA
what are the key players in translation
tRNA, mRNA, rRNA
three parts of translation
▪ Chain Initiation
▪ Chain Elongation
▪ Chain Termination
the rules that specify how the nucleotide sequence of an mRNA is translated into the amino acid sequence of a polypeptide.
genetic code
The nucleotide sequence is read as triplets called
codons
T/F: Each amino acid is specified by one or more codons in the DNA
T
each group of nucleotide in the sequence of mRNA
codon
T/F: codons in the codon chart can specify more than 1 amino acid
F
T/F: there are no spaces or commas between codon in mRNA
T
role of tRNA in translation
it decodes the information in the mRNA
this enzyme recognizes the correct amino acid and covalently links it to the 3’ end of the tRNA
aminoacyl tRNA synthetase
it is complementary to the codon on the mRNA that specifies a particular amino acid
anticodon sequence
the charge form or activated tRNA. It is needed before the translation to begin.
aminoacyl tRNA
when aminoacyl-AMP is charged in the 2’ hydroxyl group of the tRNA
Class I
when aminoacyl-AMP is charged in the 3’ hydroxyl group of tRNA
Class II
what are the initiation factors
mRNA
small and large ribosomal subunits
initiator tRNA (aminoacyl tRNA)
it recognizes the AUG codon and carries the amino acid methione
aminoacyl tRNA
2 sites of ribosome for binding tRNA
peptidyl, aminoacyl
holds the peptidyl tRNA, the growing peptide bound to a tRNA molecule
peptidyl site (p-site)
holds the aminoacyl tRNA carrying the next amino acid to be added to the peptide chain
aminoacyl site (a-site)
the first stage in translation
initiation
in elongation, these steps are repeated until protein synthesis is complete:
- aminoacyl-RNA binds to A-site GTP
- peptide bond forms
- Translocation
this enzyme catalyzes the formation of peptide bond, located in the large unit
peptidyl transferase
the stage of translation where completed protein is released from ribosome
termination
when does translation terminates?
when one of the stop codons are encountered
what are the 3 stop codons?
UAA, UAG, UGA
removal of incorrect nucleotides after they are added
proofread
In translation, ______ _________ has a proofreading activity.
aminoacyl transferase
Any permanent, heritable change in the DNA base sequence of an organism
mutation
2 origins of mutation
spontaneous, induced
this mutation occur naturally during normal genetic & metabolic functions in the cell.
spontaneous mutation
origin of mutation that do not occur spontaneously
induced mutations
a type of mutagen that can be caused by the sun’s radiation
ultraviolet light
It can directly damage the DNA by breaking the double strand or single strand break
ionization radiation
The UV light and Ionizing radiation are example of
physical mutagen
Insert themselves between the DNA base pairs
intercalating agents
example of base analogs
5-bromouracil (the homologue of thymine)
point mutation where only 1 base can be changed
single base alteration
2 types of single base alteration
transition, transverstion
a type of single base alteration that replaces a purine-pyrimidine base pair with a different purine pyrimidine pair
transition
a type of single base alteration that replaces a purine-pyrimidine base pair with a pyrimidine-purine base pair
transversion
4 variety of mutations
- silent
- missense
- non-sense
- frameshift
New codon specifies the same amino acid
silent mutation
New codon specifies the different amino acid
missense mutation
the substitution of a new base pair results in a premature stop codon
non-sense mutation
a type of point mutation where the nucleotides of a DNA sequence are altered in a way that changes one or more codons
frameshift mutation
involves the removal of the portion of a newly synthesized strand of recently replicated DNA that contains a pair of mismatched bases.
mismatch repair
the repair mechanism that is common for
DNA lesions caused by UV or chemical means
nucleotide excision repair
present enzyme in nucleotide excision repair that will detect the rror
ABC exinuclease
this mechanism is used to detect and remove certain types of damaged bases
base excision repair
