Unit Five Practice Exam

Unit 5 Practice Exam

1. A nucleotide consists of all of the following except

A. A phosphate group

B. A nitrogenous base

C. An amino acid

D. A ribose sugar

E. All of these are part of a nucleotide

2. A single strand of DNA contains nucleotides connected by

A. Hydrogen Bonds

B. Weak Bonds

C. Peptide Bonds

D. Phosphodiester bond

E. A and B

3. One strand of DNA is 5'-ACGTGCAT-3'. The complementary DNA strand is






4-8 use the following as answers. Each answer may be used once, more than once or not at all

A. DNA Polymerase

B. DNA ligase

C. Helicase

D. Primase

E. Telomerase

4. This enzyme seals together Okazaki fragments

5. This enzyme synthesizes new strands of DNA

6. This enzyme separates the 2 DNA strands

7. This enzyme proofreads DNA making sure no errors are made during DNA synthesis

8. This enzyme adds a short segment of RNA nucleotides to begin synthesis of a new strand

9. All of the following are true about errors in the DNA sequence except

A. Errors occur during synthesis of strands, but are corrected by proofreading

B. Errors occur when we are exposed to radiation, and are usually fatal

C. Errors are very rare during the replication of DNA

D. Deletions or additions of a nucleotide are much more serious than substitutions

E. Errors occur when we are exposed to x-rays, but are corrected by nucleases and other enzymes

10. How does transcription begin?

A. The separation of the 2 DNA strands by helicase

B. The unwinding of the DNA by topoisomerase

C. The binding of RNA polymerase to the promoter

D. The binding of DNA polymerase

E. With the synthesis of a primer

11. RNA processing includes all of the following except

A. Substitution of U nucleotides for T nucleotides

B. Addition of a 5' cap

C. Addition of a Poly A tail

D. Splicing of introns

E. All of the above occur during RNA processing

12. All of the following is true about introns except

A. Are found only in eukaryotes

B. Have no evolutionary purpose

C. Are interspersed with coding segments of a gene

D. Are transcribed but then removed

E. Are recognized by snRNPs

13. An mRNA transcript GCGAUGGGCATUUAGCGA enters a ribosome. How large will the peptide be?

A. 3 amino acids

B. 4 amino acids

C. 5 amino acids

D. 6 amino acids

E. Impossible to tell from this situation

14. Viruses

A. Can only reproduce inside of a host cell

B. Are more genetically similar to their host than to other viruses

C. Can contain RNA or DNA

D. Can have very serious effects on a host organism

E. All of the above

15. All of the following are ways bacteria cells recombine DNA except

A. Conjugation

B. Meiosis

C. Transformation

D. Transduction

E. All of the above are ways bacteria recombine DNA

16. Which of the following best describes a repressible operon?

A. The gene is normally expressed

B. Presence of a molecule can stop the transcription of that gene

C. The gene is normally not expressed

D. The gene is turned on but the presence of an activator molecule

E. A and B

17. A person has a defective gene for histone proteins. What level of DNA structure would be hindered?

A. The double helix

B. Nucleosomes

C. Chromatin Fibers

D. Looped domains

E. Chromosomes

18. Which of the following is not a common way of regulating gene expression?

A. DNA methylation

B. Control of transcription factors

C. Histone acetylation

D. Polypeptide modifications

E. These are all methods of regulation

19. Differences between prokaryotic and eukaryotic DNA include all of the following except

A. The presence of introns in eukaryotic DNA

B. The circular nature of prokaryotic DNA

C. The length of the DNA

D. The type of sugar in DNA

E. These are all differences between prokaryotic and eukaryotic DNA

20. Transcription factors are important in what step of transcription?

A. Initiation

B. Elongation

C. Termination

D. A and B

E. A, B and C

21. In prokaryotes RNA processing

A. In the nucleus

B. In the cytoplasm

C. In the ribosome itself

D. In the nucleolus

E. RNA processing doesn't occur in prokaryotes

22. Okazaki fragments are

A. Short mRNA strands

B. Primers used for the beginning of DNA replication

C. Short segments on the lagging strand during DNA replication

D. Segments of the leading strand during DNA synthesis

E. None of the above

23. Which of the following is not necessary for the pathway from gene to polypeptide to occur

A. Ribosomes

B. RNA polymerase


D. DNA polymerase

E. A promoter region in DNA

24. Which of the following is not true about ribosomes?

A. They are slightly different in prokaryotes and eukaryotes

B. They are found in the nucleus

C. They consist of two subunits

D. They are more abundant in cells that make many proteins

E. Many ribosomes can operate on one mRNA molecule at once

25. Which of the following is not necessary for cloning a gene?

A. A plasmid

B. A bacterial cell

C. Restriction Enzymes

D. A method of transforming bacterial cells

E. All of the above are necessary

26. A biologist has a short sequence of DNA from 3 individuals and wishes to match them with a sample of the same DNA segment. The easiest way for him to accomplish this is to

A. Use restriction enzymes and gel electrophoresis

B. Clone the genes

C. Perform a microassay

D. Sequence the DNA

E. None of the above

27. Differences between a genomic library and cDNA library include all of the following except

A. The genomic library includes introns

B. The genomic library includes satellite DNA

C. The genomic library includes non-coding regions

D. The genomic library is made using reverse transcriptase

E. The genomic library contains all genes in an organism

28. A biologist performed a microassay on brain tissue. She was most likely trying to discover

A. If the brain tissue was the same as a sample tissue she had

B. Sequence the DNA found in the brain tissue

C. Identify which genes are expressed in the brain tissue

D. Create a genomic library of the brain tissue

E. Create a cDNA library of the brain tissue

29. The benefit of PCR in identifying viruses is that

A. PCR is highly selective in which genes it copies due to the primer

B. PCR can make many copies of the virus, so that we can locate a small amount of HIV

C. PCR specifically targets viral DNA

D. A and B

E. A, B and C

30. Suppose all of the Thymine nucleotides in a cell were labelled with a fluorescent dye. We would find this dye

A. In all RNA strands that were transcribed

B. In all daughter DNA molecules after replication

C. In one of the two daughter DNA molecules after every replication

D. A and B

E. A and C

31. All of the following are transcribed from DNA except

A. Exons


C. Introns


E. All of the above are transcribed from DNA

32. A triplet segment of DNA is AAA. The anticodon on the tRNA that will carry the amino acid



C. Any anticodon beginning with UU

D. Any anticodon beginning with TT


33. Anticodons are found


B. in mRNA

C. in tRNA

D. in rRNA

E. in snRNPS

34. There are 61 mRNA codons that specificy an amino acid, but only 45 tRNAs. This is explained by the fact that

A. some tRNAs have anticodons that recognize two or more codons

B. The rules for base pairing of the 3rd nucleotide in a codon are more flexible than the rules for the first 2

C. The “wobbling” of tRNA anticodons

D. A and B

E. A, B and C

35. A single nucleotide is lost from the middle of a mRNA molecule during transcription

A. snRNPs will splice and remove the incorrect amino acid

B. nucleases will correct the error

C. One amino acid will be incorrect, but the polypeptide will most likely not be affected

D. The entire polypeptide will be dysfunctional

E. Depends on the gene


Questions 36-39 use the following as answers

A. Reverse transcriptase

B. Restriction enzymes

C. RNA polymerase

D. DNA polymerase

E. A and D

36. Used by retroviruses

37. Used in PCR

38. Used in cloning

39. Used in Southern Blotting

40. In the lytic cycle viruses do all of the following except

A. Incorporate themselves into the host's genome

B. Use the host's polymerases to copy their nucleic acid

C. Use the host's ribosomes to copy their proteins

D. Destroy the hosts

E. All of the above are done in the lytic cycle

41. Which of the following statements is true?

A. Animals can easily be regenerated from any animal cell grown in the right culture

B. Animal cells differentiate whereas plant cells do not

C. Differentiation of cells is mostly due to different genes being present

D. Plant cells can be regenerated from a single cell grown in the right medium

E. Stem cells are highly specialized and differentiated cells

42. The scientists who cloned Dolly had to find a way to

A. Un-differentiate the cells to be cloned

B. Make cells grow without the presence of an ovum

C. Sequence the sheep genome

D. Create a diploid sperm cell

E. Insert sheep DNA into bacteria

43. The most important control step in the differentiation of cells and the expression of genes is

A. The processing of RNA

B. Translation

C. Protein modifications

D. Transcription

E. DNA replication

44. Viruses

A. Evolved before bacteria

B. Are all related to each other

C. Most likely evolved from mobile elements in their host's genome

D. Can easily reproduce on their own

E. Cause syphillis


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