1. A bacteriophage that reproduces only by a lytic cycle is said to be:
   a. retroviral
   b. temperate
   c. temporal
   d. virulent

2. Which of the following types of nucleic acid may serve as the core of a virus (ss=single-stranded, ds=double-stranded)?
   a. dsDNA only
   b. ssRNA or dsDNA
   c. glycoprotein
   d. dsDNA + prions
   e. ssRNA, dsRNA, ssDNA, or dsDNA

3. A lysogenic reproductive cycle is characterized by:
   a. integration of viral DNA into the host genome
   b. lysis of the host cell
   c. synthesis of viral capsids
   d. both b and c
   e. a, b and c are all correct

4. The protein coat surrounding the viral core is the:
   a. capsid
   b. envelope
   c. phage
   d. sheath

5. Retroviruses have a gene for reverse transcriptase that:
   a. uses viral RNA as a template for making complementary RNA strands
   b. protects viral DNA from degradation by restriction enzymes
   c. destroys the host cell DNA
   d. translates RNA into proteins
   e. uses viral RNA as a template for DNA synthesis

6. A virus has a base ratio of (A + G)/(U + C) = 1. What type of virus is this?
   a. a single-stranded DNA virus
   b. a single-stranded RNA virus
   c. a double-stranded DNA virus
   d. a double-stranded RNA virus

7. Nucleosomes, the basic unit of DNA packing, are made up of:
   a. DNA + RNA
   b. 30 nm chromatin fibers
   c. DNA + histone proteins
   d. nucleic acid + transcription factors

8. DNA that is always highly condensed and is never transcribed is known as:
   a. constitutive DNA
   b. euchromatin
   c. heterochromatin
   d. tense DNA

9. Tandemly-repetitive DNA is mainly located:
   a. at centromeres and telomeres
   b. dispersed throughout the genome
   c. in gene family clusters
   d. within centrioles

10. Non-functional genes with DNA sequences similar to functional genes but lacking sites necessary for expression are called:
    a. incompetent genes
    b. non-LTR retroposons
    c. pseudogenes
    d. suppressed factors

11. One example of a multigene family is the family of genes coding for:
    a. guanine
    b. Huntington's disease
    c. rRNA
    d. transposase

12. Which of the following statements regarding retrotransposons is false?
    a. they can insert in the middle of a gene's coding sequence
    b. they replicate by reverse transcription of an RNA intermediate
    c. they move using the enzyme telomerase
    d. both b and c
    e. none of the above

13. Prokaryotic cells use feedback inhibition to:
    a. control DNA packing
    b. regulate enzyme activity
    c. regulate gene expression
    d. synthesize DNA from RNA

14. The lac operon is an example of an inducible system. The inducer in the lac operon is:
    a. beta-galactosidase
    b. lactose
    c. lacZ
    d. RNA polymerase

15. Which of the following statements is true regarding the repressor of the lac operon?
    a. it is a constitutive protein
    b. when lactose is absent, it binds to the promoter
    c. when lactose is present, no repressor is produced

16. The lac operon is characterized by:
    a. negative control by lactose and positive control by glucose
    b. negative control by glucose and positive control by the repressor
    c. negative control by the repressor and positive control by CRP
    d. negative control by CRP and positive control by lactose

17. If a mutation resulted in a non-functional lacI gene (the gene coding for repressor), which of the following would be true?
    a. repressor would bind to the promoter when lactose is present
    b. transcription would take place in the absence of lactose
    c. transcription would take place only at high levels of glucose
    d. permease would bind with the promotor

18. Which of the following increases the rate of transcription in eukaryotes?
    binding of RNA polymerase to repressors
    DNA methylation
    histone acetylation
    RNA splicing

19. One example of coordinate gene expression in eukaryotes is the activation of a variety of genes by:
    a. RNA polymerase
    b. steroid hormones
    c. telomeres
    d. transposons

20. Which of the following DNA sequences is an example of a palindrome that might be recognized by a restriction enzyme?
    a. CGCAGC
    b. GAATTC
    c. TAGGAT
    d. TTAACC

21. When making recombinant DNA, DNA ligase is used to:
    a. cut DNA asymmetrically at restriction sites
    b. form covalent bonds between sticky ends of DNA fragments
    c. denature double-stranded DNA molcules
    d. break open bacterial cells to release foreign DNA

22. Which of the following is NOT required in the bacterial plasmid used in the cloning example we studied?
    a. a gene which confers resistance to the antibiotic ampicillin
    b. the lacZ gene which hydrolyzes lactose and X-gal
    c. a single restriction site located within the lacZ gene
    d. a gene which codes for the enzyme reverse transcriptase

23. Bacterial cell colonies which have taken up non-recombinant plasmids:
    a. turn blue because they have a functional lacZ gene
    b. die when grown on a medium containing ampicillin and X-gal
    c. produce hyphae with black sporangia
    d. leave exposures on X-ray film

24. Genetically engineered cloning vectors which are hybrids between viral and bacterial DNA (and are 30 - 45 kb in length) are called:
    a. bacmids
    b. cosmids
    c. phages
    d. plasmids

25. A method of making many copies of a specific DNA segment without cells is:
    a. nucleic acid hybridization
    b. polymerase chain reaction
    c. transduction
    d. Southern blotting

26. If a linear DNA segment containing four restriction sites is cut with the appropriate restriction enzyme, how many fragments should result?
    a. 3
    b. 4
    c. 5
    d. 8

27. If a circular plasmid containing three restriction sites is cut with the appropriate restriction enzyme, how many fragments should you get?
    a. 1
    b. 2
    c. 3
    d. 4

28. DNA produced by reverse transcription of mRNA is called:
    a. complementary DNA (cDNA)
    b. inverse DNA
    c. polycistronic
    d. RNA