McMaster University

BIO 2EE3

CHAPTER 7

1)What did the experiment by Avery, MacLeod, and McCarty in 1944 with the R and S strains of Streptococcus pneumoniae demonstrate?

1. 1. That some strains of Streptococcus were not pathogenic
   2. DNA was the genetic material in cells
   3. Genetic material from one strain could be transferred to another strain
   4. The ability of these bacteria to kill mice
   5. R strain phenotype could spontaneously revert to S strain phenotype

2. The Watson and Crick model showed that in the DNA molecule
   1. Purines paired with pyrimidines, and the strands align anti-parallel to one another
   2. Purines paired with pyrimidines, and the strands align parallel to one another
   3. Pyrimidines paired with pyrimidines, and the strands align parallel to one another
   4. Purines paired with purines, and the strands align anti-parallel to one another
   5. Purines paired with purines, and the strands align parallel to one another

3. The main differences between Bacteria and Archaea chromosomal DNA when compared to Eukarya chromosomal DNA, is that the Bacteria or Archaea chromosome usually
   1. Consist of several chromosomes while Eukarya has a single chromosome
   2. Contains the base uracil while Eukarya has thymine in place of uracil
   3. Is diploid while Eukarya is haploid
   4. Is found in a non-condensed form while Eukarya DNA is highly condensed and packaged
   5. Is circular while Eukarya is linear

4. After the DNA is unwound at the site of DNA replication initiation, what binds to the unwound DNA to prevent it from reannealing?
   1. Single-stranded DNA binding protein
   2. DNA gyrase
   3. DNA polymerase
   4. DnaB
   5. DnaA

5. Which statement below is FALSE regarding replication of the bacterial chromosome?
   1. The incoming nucleotide triphosphate is covalently attached to the free 3’ hydroxyl
   2. DNA replication is a semi-conservative process, where one strand serves as a template for the synthesis of a complementary strand
   3. The leading strand is replicated in the 5’ to 3’ direction and the lagging strand in the 3’ to 5’ direction
   4. The primase adds a short RNA primer to serve as a starting point for the DNA polymerase to add new bases
   5. Replication occurs in a bidirectional manner from the origin of replication

6. Which enzyme removes the RNA primer and fills in the gap during DNA replication in bacteria?
   1. Primase
   2. Ligase
   3. DNA polymerase III
   4. DNA polymerase I
   5. DNAase

7. Term for a special sequence at the end of the chromosome in eukaryal cells
   1. Terminator
   2. Telomere
   3. Centromere
   4. Enhancer
   5. Antiorigin

8. Messenger RNA (mRNA) can best be described as a molecule that contains the code for a
   1. Polypeptide or regulatory RNA
   2. Polypeptide
   3. Polypeptide, tRNA, or rRNA
   4. Protein, rRNA, or tRNA
   5. Protein

9. For the initiation of transcription in bacteria, RNA polymerase binds to what region on the gene?
   1. Origin of replication
   2. Promoter
   3. Shine-Dalgarno sequence
   4. Operator
   5. Enhancer region

10. What does Rho-independent termination of transcription in bacteria involve?
    1. The formation of a hairpin loop followed by a poly A sequence
    2. The formation of a hairpin loop followed by a poly U sequence
    3. A poly U sequence followed by a poly A sequence
    4. The formation of a hairpin loop only
    5. A poly A sequence followed by a hairpin loop

11. Initiation of translation in bacteria starts with the binding of the 30S ribosomal subunit to the mRNA molecule. The ribosomal binding site is nearer the                                    end of the mRNA molecule and is called the                                 
    1. 5’; Rho sequence
    2. 3’; Pribnow box
    3. 3’; Shine-Dalgarno sequence
    4. 3’; Rho sequence
    5. 5’; Shine-Dalgarno sequence

12. After the translational process, the polypeptide folds into the appropriate conformation for proper functioning. What group of proteins aids in protein folding?
    1. Chaperonins
    2. Lipases
    3. Proteases
    4. Cytokines
    5. Peptidases

13. Which of these is a term for a point mutation that results in a change in the amino acid specificity of the codon?
    1. Missense
    2. Nonsense
    3. Frameshift
    4. Amber
    5. Silent

14. The Hershey and Chase experiment was able to conclusively demonstrate that DNA, not protein, was the genetic material. They were able to distinguish DNA from protein since labeled                             incorporated into DNA while labeled             incorporated into proteins
    1. Phosphorous; sulfur
    2. Sulfur; nitrogen
    3. Nitrogen; sulfur
    4. Nitrogen; magnesium
    5. Magnesium; nitrogen

15. The Watson-Crick model of DNA shows that the base adenine pairs with
    1. Guanine while cytosine pairs with thymine
    2. Either thymine or guanine, while cytosine pairs with either thymine or guanine
    3. Cytosine while guanine pairs with thymine
    4. Thymine while cytosine pairs with guanine
    5. Either thymine or cytosine while guanine pairs with either thymine or cytosine

16. What is the first protein to bind to the oriC region of the DNA molecule to start the replication process?
    1. DnaI
    2. Gyrase
    3. DnaA
    4. DNA polymerase
    5. Primase

17. What, in bacteria, is analogous to the autonomously replicating sequence (ARS) in yeast?
    1. Promoter
    2. Plasmid
    3. Transposon
    4. Prophage
    5. OriC

18. What are the main enzymes responsible for replication of DNA in eukaryal cells?
    1. DNA pol ε and DNA pol δ
    2. DNA pol I and DNA pol ε
    3. DNA pol α and DNA pol ε
    4. DNA pol III and DNA pol I
    5. DNA pol III and DNA pol α

19. Replication termination in E. coli involves which two proteins?
    1. Helicase and topoisomerase II
    2. Tus protein and DnaG
    3. Tus protein and helicase
    4. Tus protein and topoisomerase II
    5. Helicase and DnaG

20. A gene can be best described as a segment of DNA that
    1. Encodes for a protein
    2. Is transcribed as well as the associated regulatory regions
    3. Is transcribed
    4. Encodes for a protein as well as the associated regulatory regions
    5. Encodes for a protein or functional RNA

21. Most bacterial promoters consist of two regions:                         and                            
    1. Enhancer region and -35 region
    2. Enhancer region and operator
    3. -35 region and operator
    4. Pribnow box and operator
    5. Pribnow box and -35 region

22. The mRNA of bacterial cells is often polycistronic. What does this term mean?
    1. The translated protein may be modified in different ways
    2. It can be translated more than once
    3. It is transcribed from multiple sites on the chromosome
    4. It can be translated from either end
    5. It contains the code for multiple peptides

23. Which of these would a signal peptide be used for?
    1. To help regulate the activity of an enzyme
    2. To regulate translation
    3. To initiate DNA replication
    4. To help a protein fold correctly
    5. To move a protein to the outside of the cell

24. Which of these is a point mutation that results in changing a codon from an amino acid codon to a stop codon?
    1. Frameshift
    2. Missense
    3. Nonsense
    4. Deletion
    5. Silent

25. How do nucleotides connect to adjacent nucleotides in the Watson-Crick model of DNA?
    1. Via a covalent bond between the 3’ hydroxyl of one nucleotide and the 2’ deoxyribose of the other
    2. Via a hydrogen bond between the nitrogenous base of one nucleotide and the nitrogenous base of the other
    3. Via a hydrogen bond between the nitrogenous base of one nucleotide and the 5’ phosphate of the other
    4. Via a covalent bond between the 3’ hydroxyl of one nucleotide and the 5’ phosphate of the other
    5. Via a covalent bond between the 3’ hydroxyl of one nucleotide and the nitrogenous base of the other

26. Replication of the bacterial chromosome begins at how many locations?
    1. One
    2. Two
    3. Three
    4. Four
    5. Five

27. Which statement below is FALSE regarding replication of the bacterial chromosome?
    1. The incoming nucleotide triphosphate is covalently attached to the free 3’ hydroxyl
    2. The primase adds a short RNA primer to serve as a starting point for the DNA polymerase to add new bases
    3. The leading strand is replicated in the 5’ to 3’ direction and the lagging strand in the 3’ to 5’ direction
    4. Replication occurs in a bidirectional manner from the origin of replication
    5. DNA replication is a semi-conservative process, where one strand serves as a template for the synthesis of a complementary strand

28. Which enzyme is responsible for adding the final bases to the end of a chromosome during DNA replication in eukaryal cells?
    1. Telomerase
    2. DNA pol δ
    3. DNA primase B
    4. DNA pol α
    5. Topoisomerase

29. Which of these best differentiates DNA and RNA?
    1. RNA is single-stranded and DNA is double stranded
    2. RNA contains ribose and DNA contains deoxyribose
    3. RNA contains uracil in place of thymine, which is in DNA
    4. Both a and b are true
    5. a, b, and c are true

30. What is the sigma factor of the RNA polymerase holoenzyme responsible for?
    1. Ribosome binding
    2. Transcription termination
    3. Initiation of transcription
    4. Transcription elongation
    5. Recognition of the promoter region

31. What is a codon?
    1. 4 bases on the mRNA that is read by the ribosome in the 3’ to 5’ direction
    2. 2 bases on the mRNA that is read by the ribosome in the 5’ to 3’ direction
    3. 3 bases on the mRNA that is read by the ribosome in the 3’ to 5’ direction
    4. 3 bases on the mRNA that is read by the ribosome in the 5’ to 3’ direction
    5. 4 bases on the mRNA that is read by the ribosome in the 5’ to 3’ direction