Bio Chapter 16

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

8%

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

A + C = G + T

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitroen of the DNa, rather than the phosphate. They reasoned that each nucleotide ahs only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins

Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiments in which E coli was infected by a T2 virus. Which molecular component of the T2 virus actually ended up inside the cell?

DNA

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

DNA contains phosphorus, whereas protein does not

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.

Erwin Chargaff

In his transformation experiments, what did Griffith observe?

Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form

How do we describe transformation in bacteria?

assimilation of external DNA into a cell

After mixing a heat-killed, phosphorescent (light-emitting) strain of bacteria with a living, nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observation(s) would provide the best evidence that the ability ot phosphoresce is a heritable trait?

phosphorescence in descendants of the living cells

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

sequence of bases