Exam 16: The Molecular Basis of Inheritance

Which of the following investigators was/were responsible for the following discovery? Phage with labeled proteins or DNA was allowed to infect bacteria. It was shown that the DNA, but not the protein, entered the bacterial cells, and was therefore concluded to be the genetic material.

Which of the following investigators was/were responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.

To repair a thymine dimmer by nucleotide excision repair, in which order do the necessary enzymes act?

Which of the following represents the order of increasingly higher levels of organization of chromatin?

In an analysis of the nucleotide composition of DNA, which of the following will be found?

What is the function of topoisomerase?

About how many more genes are there in the haploid human genome than in a typical bacterial genome?

Use Figure 16.1 to answer the following questions. Figure 16.1 -In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (¹⁵N)and then transferred them to a medium containing ¹⁴N. Which of the results in Figure 16.1 would be expected after one round of DNA replication in the presence of ¹⁴N?

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

Which of the following investigators was/were responsible for the following discovery? Chemicals from heat-killed S cells were purified. The chemicals were tested for the ability to transform live R cells. The transforming agent was found to be DNA.

Use Figure 16.1 to answer the following questions. Figure 16.1 -In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?