Biochemistry

Biochemistry & Molecular Biology Practice Problems

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1.     DNA sequences are shown below:

  • For each of these write the complementary strand
  • Next transcribe the correct strand
  • Next translate this into a protein sequence

#1— 5’-CTTTTTTGCCAT-3’

#2— 5’-A C A T C A A T A A C T-3’

2.     Matching

1) sigma factor   2) poly A tail   3) TATAAT   4) exons   5) RNA polymerase III   6) intron   7) snRNA   8) RNA polymerase I    9) CAAT box

  • nucleotide sequence interrupting eukaryotic genes
  • used to remove introns; made of RNA molecules
  •  E.coli sequence (-10) of nontemplate strand of the promoter; helps unwind DNA so RNA polymerase can bind
  • helps make the rRNAs except for the 5S rRNA
  • part of prokartyoic RNA polymerase used to start transcription at promoters
  • helps make transfer RNA and small nuclear RNAs
  • 20-200 nucleotides at the 3’ end of many eukaryotic mRNAs
  • transcribes genes that encode proteins
  • sequence of eukaryotic 80 nucleotides up from where transcription begins on nontemplate strand
  • eukaryotic gene segments that make RNA transcripts

3.     Here’s a bacterial DNA sequence (promoter is not present, but upstream)

       5’-CAATCATGGACTGCCATGCTTCATATGAATAGTTGACAT-3’

3’-GTTAGTACCTGACGGTACGAAGTATACTTATCAACTGTA-5’

  • Write the mRNA sequence below.
  • Write the amino acid sequence for the protein.
  • If there’s a mutation where the arrow is located of the C there to be deleted, then write the polypeptide from this mutation.

4.     Label the figure below: terms list options: 1) potential wobble; 2) 3’end of mRNA; 3) ribosome 4) 5’-AUG-3’ ; 5) codon; 6) amino acid; 7) 5’ UTR; 8) anticodon; 9) N terminus; 10) 5’ end tRNA; 11) hydrogen bond; 12) 3’ end of tRNA; 13) nucleotide; 14) mRNA cap; 15) peptide bond; 16) P site; 17) name of this process is?

5. This is a gene expression model of simultaneous transcription/translation with multiple proteins being translated. The arrow indicates directional movement left to right of the process where there’s a protein attached to the DNA.

a)     Which end of the DNA (5’ or 3’) is letter A closest?

  • Which nucleic acid is closest to letter B?
  • To which end (5’ or 3’) is letter B closest?

d)     If D is closest to the amino acid MET, then is MET most likely closest to letter E also?

  • Does this particular process occur in prokaryotes, eukaryotes or both?
  • What is the name of the transcriptional protein closest to F?
  • What structure is closest to G?

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Categories: Biochemistry