Bio unit 2 Homework Questions

Consider Griffith's experiment. If he observed healthy mice after injecting these animals with dead virulent and live non-virulent bacteria, what could he have concluded? A. Genetic information cannot be transferred between bacteria. B. Genetic information is transferrable. C. Genetic information cannot be transferred between mice. D. None of the other answer options is correct. E. The RNA of the bacteria used in this experiment was degraded.

A

Why did scientists many years ago believe that protein was the storage molecule for genetic information, instead of DNA? A. All of these choices are correct. B. Proteins carry out a great range of cellular functions. C. Proteins have a wider variety of three-dimensional shapes than DNA. D. There are more building blocks for protein than there are for DNA.

A

In the Avery, MacLeod, and McCarty experiment, the transforming extract from virulent bacteria was treated with DNase, RNase, or protease before being mixed with nonvirulent bacteria. The appropriate control for this experiment is to treat the transforming extract from heat-killed virulent bacteria with A. nothing. B. protease alone. C. None of the other answer options are correct. D. RNase alone. E. DNase alone.

A. Control variables typically involve minimal or no change to the system. In order to determine if the system is working, the researchers needed a positive control where the heat-killed virulent bacteria would always transform the non-virulent bacteria. This positive control is adding "nothing" to the heat-killed virulent bacteria prior to adding the bacteria to the non-virulent bacteria.

If Avery, MacLeod, and McCarty had treated the transforming extract from virulent bacteria with various mixtures of DNase, RNase, and protease before being mixed with nonvirulent bacteria, which of these treatments would not destroy the transforming activity A. DNase and RNase B. DNase and protease C. RNase and protease D. DNase, RNase, and protease

C. RNase degrades RNA. Protease degrades protein. Because the transforming factor is DNA, as long as there is still intact DNA, the transformation will occur. By contrast, if DNA is degraded (by DNAse), then no transformation will occur.

Which statement is true regarding Frederick Griffith's experiments? A. His experiments relied on RNase and DNase to identify the genetic/hereditary material. B. He demonstrated that proteins serve as the genetic/hereditary material. C. He demonstrated that (only) dead virulent bacteria cause pneumonia in mice. D. He demonstrated that DNA serves as the genetic/hereditary material. E. He demonstrated that some unknown substance can transform a nonvirulent strain of bacteria to a virulent one.

E Griffith didn't use any techniques that would allow him to identify which molecule(s) carried information that cause virulence

In the experiments conducted by Avery, McCarty, and MacLeod, which hypothetical result would indicate that protein, not nucleic acid, was Griffith's transforming substance (note: it may help to read the description of this experiment in Ch. 3.1 of the textbook)? A. None of the extracts from heat-killed cells is able to transform nonvirulent bacteria. B. All of the extracts from heat-killed cells are able to transform nonvirulent bacteria. C. Only the extracts from heat-killed cells treated with DNase are unable to transform nonvirulent bacteria into virulent bacteria. D. Only the extracts from heat-killed cells treated with RNase are unable to transform nonvirulent bacteria into virulent bacteria. E. Only the extracts from heat-killed cells treated with protease are unable to transform nonvirulent bacteria into virulent bacteria.

E. Proteases cleave proteins and make them nonfunctional.