Adv Bio Ch. 17
Place the events in the synthesis of a polypeptide in the proper order.
1) small sub unit binds to mRNA and an initiator tRNA 2) the larger unit attaches to the small sub unit wight he initiator tRNA in the P site 3)an amino acid acetyl tRNA matches its anticodon to the codon in the A site 4)a peptide bond forms 5)a tRNA translocates from the A to the P site and an unattached tRNA leaves the ribosome from the outside
Which point mutation would most likely to have a catastrophic effect on the function of a protein?
A base deletion near the start of a gene
What would be the DNA strand that would code for phe-leu-ile-val? UUU-CUU-AUU-GUU
AAA-GAA-TAA-CAA
What is the energy source for translation?
ATP and GTP
Termination
After polymerase transcribes past the signal sequence pre mRNA is cut and released
Frameshift
Base pair insertions or deletions that are not multiples of three nucleotides. Produce nonfunctional proteins
Nonsense
Base pair substitution that creates a stop codon
Silent
Base pair substitution that doesn't change. Amino acid translation
Missense
Base pair substitution that results in the insertion of a different amino acid
mRNA
Carries the codon from DNA to ribosomes
Four steps of polypeptide synthesis:
Codon recognition Peptide Bond formation Translocation Termination
The template for transcription is _____.
DNA
Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes what?
Excision of introns
A mutation in which part of a gene is likely to be the most damaging to a cell?
Exon
What are the coding segments of a stretch of eukaryotic DNA called?
Exons
What are polyribosomes?
Groups of ribosomes reading a single mRNA simultaneously
What type of bonding is responsible for maintaining the shape of the tRNA molecule?
Hydrogen bonding between base pairs
A frameshift mutation could result from either ____ or ____ of the base.
Insertion.Deletion
What is the effect of a nonsense mutation in a gene?
Introduces a premature stop codon into the messenger RNA
Small nuclear RNA
Part of spliceosomes and plays a catalytic role in splicing pre messenger RNA
rRNA
Performs catalytic functions at the binding site
What is the product of translation?
Polypeptide
What is the product of transcription?
Pre mRNA
During splicing, which molecular component of the spliceosome catalyzes the excision reaction?
RNA
The template for translation is _____.
RNA
Elongation
RNA polymerase II moves along the strong connecting RNA nucleotides
Explain the redundancy and the wobble phenomenon.
Redundancy- several triplets may code for the same amino acid to make sure one is available
What is the energy source for transcription?
Ribonucleoside triphosphate
Initiation
Transcription factors binded to a promoter factor and polymerase II separates DNA strands
tRNA
Transfer. Carries amino acid to its position on the polypeptide
If the triple of bases coding in DNA is AAA. What is the anticodon on tRNA?
UUU
What is a ribozyme?
an RNA with enzymatic activity
What is the most abundant type of RNA?
rRNA (ribosomal)
