Structure and Function of DNA Test

1.  In his work with pneumonia causing bacteria and mice, Griffith found that

2.  Hershey and Chase’s experiment

3.  The main support to the DNA molecule is provided by two backbones which run along the two sides of the double helix. These backbones consist of

4.  In a just-discovered form of DNA, the distance between the bases is 0.58 nm. The molecule makes a complete helical turn every twelve base pairs. What length of the molecule is occupied by a complete helical turn?

5.  In their experiment that showed that DNA replication in E. coli was semi-conservative, Meselson and Stahl used

6. DNA replication is semi-conservative.  This means that

7. Chromatin, the protein-DNA complex, is wrapped around proteins called histones in the nucleus.  Packing of DNA around histones results in “beads” known as

8.  If the percentage composition of thymine in a DNA molecule is 22%, what is the percentage composition of cytosine? (Hint: Apply Chargaff’s rule)

9.  When DNA helicase is active, the result is

10.  During DNA replication, the function of RNA primers is to

11.  In what order do the following molecules become involved in DNA replication in E. coli?

1. single-stranded binding proteins
2. DNA polymerase III
3. primase
4. helicase

12.  A mutant form of E. coli has been discovered in which replication is unsuccessful because the RNA primer is not released from the template strand. Which enzyme do you think is nonfunctional?

13.  Complementary base pairing is the result of

14. In DNA, phosphodiester bonds join

15.  The lagging strand of DNA is synthesized

16.  A limitation of DNA polymerase III is that it cannot add nucleotides without the direct action/product of which enzyme?

17.  Which enzyme binds Okazaki fragments to the nucleotides that replace the RNA primers in the lagging strand?

18.  A deoxyribose sugar molecule has

19.  Noncoding nucleotide sequences at the end of eukaryotic chromosomes protect an organism’s genes from being eroded by rounds of DNA replication.  What are these noncoding nucleotide sequences “caps” called?

20.  What is the directionality of the two strands in a DNA molecule?

21.

22.  The following three activities were engaged in by three different scientists (or groups of scientists) who helped to determine the nature of the hereditary material

1. transformation in bacteria
2. research to identify what part of a bacteriophage is injected into a host bacterial cell
3. X-ray diffraction analysis of the DNA molecule

24. Which of the following is a correct representation of a segment of DNA?

25.  A biochemist isolates and purifies molecules needed for DNA replication.  When she adds some DNA, replication occurs, but each new DNA strand consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long.  What has she probably left out of the mixture?

26.  An eukaryotic cell lacking active telomerase would

27  Which of these is (are) pyrimidines?

28.  DNA polymerase is the protein that adds new nucleotides to the elongating DNA strand during replication. In order for DNA polymerase to bind the template and add new nucleotides, a free 3’hydroxyl group must be exposed to accept the first nucleotide.

29.  During DNA replication, one of the new strands of DNA is synthesized continuously, while the other is synthesized as a number of separate fragments of DNA that are subsequently linked by DNA ligase. This is because

30.  The percentage composition of a nucleic acid molecule found in bacterial cells is

32.3% adenine 
30.7% thymine 
19.1% cytosine 
17.9% guanine 

The molecule is most likely to be 

33.  Imagine that you are a geneticist and are investigating a species of bacteriophage about which little is known. How might Hershey and Chase’s experiment be modified to discover whether the nucleic acid in the bacteriophage is DNA or RNA?

32. The DNA of prokaryotes normally has only one origin of replication, whereas replication starts at many points on the chromosomes of eukaryotes. Hypothesize why this is the case.

31.