BIOS260 Chapter 10 Questions and Answers 100%
Solved
What are the three basic stages of transcription? Describe what takes place at each stage.
Correct Ans-(1) Initiation:
Transcription proteins assemble at the promoter to form the basal transcription apparatus
and begin synthesis of RNA.
(2) Elongation:
RNA polymerase moves along the DNA template in a 3' to 5' direction, unwinding the DNA
and synthesizing RNA in a 5' to 3' direction.
(3) Termination:
Synthesis of RNA is terminated, and the RNA molecule separates from the DNA template.
What are the three principle elements in mRNA sequences in the bacterial cells? Correct
Ans--The 5' untranslated region, which contains the Shine-Dalgarno sequence;
-the protein-encoding region;
-the 3' untranslated region
, BIOS260 Chapter 10 Questions and Answers 100%
Solved
What is the function of the Shine-Dalgarno consensus sequence? Correct Ans-The Shine-
Dalgarno consensus sequence functions as a the ribosome-binding site on the mRNA
molecule.
What is the 5' cap? Correct Ans-The 5' end of eukaryotic mRNA is modified by the addition
of the 5' cap. The cap consists of an extra guanine nucleotide (linked 5' to 5' to the mRNA
molecule) that is methylated at postion 7 of the base and at adjacent bases whose sugars are
methylated at the 2' -OH group.
What is the function of the spliceosome? Correct Ans-The spliceosome consists of five
snRNPs. The splicing of pre-mRNA nuclear introns takes place within the spliceosome.
What is alternative splicing? How does it lead to the production of multiple proteins from a
single gene? Correct Ans--most genes in eukaryotes include one or more introns that must
be removed from the initial product of transcription, which is called a pre-mRNA molecule.
-As the introns are removed, the exons ( which carry the information needed to encode the
polypeptide product) are spliced together. -Alternative splicing allows for pre-mRNA
Solved
What are the three basic stages of transcription? Describe what takes place at each stage.
Correct Ans-(1) Initiation:
Transcription proteins assemble at the promoter to form the basal transcription apparatus
and begin synthesis of RNA.
(2) Elongation:
RNA polymerase moves along the DNA template in a 3' to 5' direction, unwinding the DNA
and synthesizing RNA in a 5' to 3' direction.
(3) Termination:
Synthesis of RNA is terminated, and the RNA molecule separates from the DNA template.
What are the three principle elements in mRNA sequences in the bacterial cells? Correct
Ans--The 5' untranslated region, which contains the Shine-Dalgarno sequence;
-the protein-encoding region;
-the 3' untranslated region
, BIOS260 Chapter 10 Questions and Answers 100%
Solved
What is the function of the Shine-Dalgarno consensus sequence? Correct Ans-The Shine-
Dalgarno consensus sequence functions as a the ribosome-binding site on the mRNA
molecule.
What is the 5' cap? Correct Ans-The 5' end of eukaryotic mRNA is modified by the addition
of the 5' cap. The cap consists of an extra guanine nucleotide (linked 5' to 5' to the mRNA
molecule) that is methylated at postion 7 of the base and at adjacent bases whose sugars are
methylated at the 2' -OH group.
What is the function of the spliceosome? Correct Ans-The spliceosome consists of five
snRNPs. The splicing of pre-mRNA nuclear introns takes place within the spliceosome.
What is alternative splicing? How does it lead to the production of multiple proteins from a
single gene? Correct Ans--most genes in eukaryotes include one or more introns that must
be removed from the initial product of transcription, which is called a pre-mRNA molecule.
-As the introns are removed, the exons ( which carry the information needed to encode the
polypeptide product) are spliced together. -Alternative splicing allows for pre-mRNA
