chapter14

DNA polymerase can only add nucleotides to the free 3' end.

A new (daughter) DNA strand elongates only in the 5' to 3' direction because

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

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?

12

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?

E. 3'-GCCATG-5'

If one strand of DNA is 5'CGGTAC3', the corresponding strand would be

No replication fork will be formed.

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?

the particulate nature of the hereditary material

Mendel and Morgan did not know about the structure of DNA; however, which of the following of their contributions was (were) necessary to Watson and Crick?

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

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

the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagginc strand is synthesized in the opposhte direction.

The leading and the lagging strands differ in that

the nucleotide sequence of the template strand

What determines the nucleotide sequence of the newly synthesized strand during DNA replication?

assimilation of external DNA into a cell

What does transformation involve in bacteria?

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

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

It joins Okazaki fragments together.

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

DNA polymerase III

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

Alfred Hershey and Martha Chase

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.

Heterochromatin is highly condensed, whereas euchromatin is less compact.

Which of the following statements describes chromatin?

It consists of a single linear molecule of double-stranded DNA plus proteins.

Which of the following statements describes the eukaryotic chromosome?

primase

Which of the following synthesizes short segments of RNA?

Purines pair with pyrimidines.

Why does the DNA double helix have a uniform diameter?