AP Bio chapter 16

An Okazaki fragment has which of the following arrangements?

5' RNA nucleotides, DNA nucleotides 3'

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.

Alfred Hershey and Martha Chase

Replication in prokaryotes differs from replication in eukaryotes for which of these reasons?

Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

What kind of chemical bond is found between paired bases of the DNA double helix?

hydrogen

Which of the following covalently connects segments of DNA?

ligase

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

the diameter of the helix

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?

12

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

5' A C G U U A G G 3'

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

A + G = C + T

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, but protein does not.

Which of the following removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments?

DNA polymerase I

Which enzyme catalyzes the elongation of a DNA strand in the 5' 3' direction?

DNA polymerase III

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

DNA polymerase can join new nucleotides only to the 3' end of a growing strand.

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

G + C = T + A

Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach

Why do histones bind tightly to DNA?

Histones are positively charged, and DNA is negatively charged.

The following scientists made significant contributions to our understanding of the structure and function of DNA. Place the scientists' names in the correct chronological order, starting with the first scientist(s) to make a contribution. I. Avery, McCarty, and MacLeod II. Griffith III. Hershey and Chase IV. Meselson and Stahl V. Watson and Crick

II, I, III, V, IV

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.

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.

Oswald Avery, Maclyn McCarty, and Colin MacLeod

For a couple of decades, biologists knew the nucleus contained DNA and proteins. The prevailing opinion was that the genetic material was proteins, and not DNA. The reason for this belief was that proteins are more complex than DNA. What was the basis of this thinking?

Proteins have a greater variety of three-dimensional forms than does DNA.

Why does the DNA double helix have a uniform diameter?

Purines pair with pyrimidines.This answer is correct.

Use Figure 16.1 to answer the following questions. Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions?

Replication is not conservative

What is meant by the description "antiparallel" regarding the strands that make up DNA?

The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

When T2 phages infect bacteria and make more viruses in the presence of radioactive sulfur, what is the result?

The viral proteins will be radioactive

Which would you expect of a eukaryotic cell lacking telomerase?

a reduction in chromosome length

What does transformation involve in bacteria?

assimilation of external DNA into a cell

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

endonuclease, DNA polymerase I, DNA ligase

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

join Okazaki fragments together

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?

methylation and phosphorylation of histone tails