Exam 15: Genes and How They Work

A scientist makes three artificial mRNA strands: (x)5' AAAUUUAAAUUUAAAUUUAAAUUUAAA 3' (y)5' UUUCCCUUUCCCUUUCCCUUUCCCUUU 3' (z)5' AUAUAUAUAUAUAUAUAUAUAUAUAU 3' When he analyzes the polypeptides produced,he finds that: X produces a polypeptide that is 50% phenylalanine and 50%lysine. Y produces a polypeptide that is 50% phenylalanine and 50% proline. Z produces a polypeptide that is 50% isoleucine and 50% tyrosine. Based on these results only,the best conclusion to make is that

Why are there fewer tRNA anticodons than the 61 needed to match each mRNA codon that codes for an amino acid?

The A,P,and E sites are progressively occupied by amino acids being assembled into a polypeptide.These sites are part of

What is the likely consequence of a mutation that alters the branch point within an intron?

How many unique mRNA codons can be constructed from the four different RNA nucleotides?

DNA affects the traits of an organism by providing the instructions for synthesizing _______.

During the splicing reaction,the intron-exon junctions are recognized by

During protein synthesis in eukaryotes,what happens during RNA splicing?

If the sequence of bases in the template strand of a DNA molecule is 3' ATCGCTCC 5',what is the sequence of bases in the RNA that is transcribed from this molecule?

The genetic code uses ________ nucleotide(s)to specify one amino acid.

During translation,uncharged tRNA molecules leave the ribosome from the ________ site.

To begin transcription,RNA polymerase must bind to a segment of DNA called the ________.

In eukaryotic cells,transcription occurs

You are working to characterize a novel protein in mice.Analysis shows that high levels of the primary transcript that codes for this protein are found in tissue from the brain,muscle,liver,and pancreas.However,an antibody that recognizes the C-terminal portion of the protein indicates that the protein is present in brain,muscle,and liver,but not in the pancreas.What is the most likely explanation for this result?

Two 6-base sequences are present in bacterial promoters: TATAAT (located 10 nt upstream from the start site)and TTGACA (located 35 nt upstream from the start site).What is the significance of the fact that these two base sequences are different?

Which statement about the genetic code is false?

Specific amino acids are attached to tRNA molecules by

Within the transcription bubble,the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand.How might transcription be affected if helix formation did not occur?

During ________,nucleotide sequence information is changed into amino acid sequence information.

Although 61 different codons code for amino acids,cells contain fewer than 61 different tRNAs.Why?