11 Questions
Which type of mutation results in a change of an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein?
Nonsense mutation
What is the result of frameshift mutations?
Extensive missense and premature termination
Ribosomes require less than a minute to translate an average-sized mRNA into a polypeptide.
True
During termination, a release factor binds to the start codon and hydrolyzes the bond between the polypeptide and its tRNA in the P site.
False
Translocation of tRNA involves the ribosome moving the tRNA with the attached polypeptide from the A site to the P site.
True
During transcription, RNA polymerase adds nucleotides to the 5' end of the growing RNA strand.
False
The 5' cap added to the pre-mRNA molecule protects mRNA from hydrolytic enzymes and serves as a translation start point for ribosomes.
True
Eukaryotic cells modify pre-mRNA by adding a poly(A) tail to the 5' end of the molecule.
False
What is the function of DNA ligase in DNA replication?
Joining Okazaki fragments to form a continuous DNA strand
What is the role of helicase in DNA replication?
Breaking the hydrogen bonds between the complimentary nitrogen bases
Why can't DNA polymerases add nucleotides to the 5' end of a growing DNA strand?
The 5' end lacks a free OH group for nucleotide attachment
Test your knowledge about the molecular chain of command in a cell, including DNA transcription, mRNA translation, and the genetic code's role in specifying amino acids. Understand the process of how genetic instructions for a polypeptide chain are written in DNA and transcribed into RNA.
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