Biology Chapter 14

When a cell divides by mitosis:

each daughter cell receives a nearly perfect copy of the parent cell's genetic information.

Semiconservative DNA replication means that:

each new DNA molecule has half of its parent molecule.

"Bulking up" muscles primarily involves:

enlarging muscle cells.

The necessary "ingredients" for DNA replication do NOT include:

enzymes for translating DNA sequences to amino acid sequences.

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

The two polynucleotide chains in a DNA molecule are attached to each other by:

hydrogen bonds between bases.

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent _____.

leading strands and Okazaki fragments

Given what is known about the inheritance and variation of genetic traits, which of the following is NOT a required characteristic of the chemical serving as genetic material?

many unique subunits

In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?

nuclease, DNA polymerase I, DNA ligase

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

nucleosome, 30-nm chromatin fiber, looped domain

Semiconservative replication involves a template. What is the template?

one strand of the DNA molecule

Telomere shortening is a problem in which types of cells?

only eukaryotic cells

Each person has a unique:

sequence of DNA bases.

In Figure 10-01, the alternating five-sided and circular molecular groups making up the "backbone" of each strand of DNA are, respectively:

sugar and phosphate.

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has 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.

A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in the figure above would you expect if the DNA was replicated in a conservative manner?

B

Which of the following does NOT happen during the normal development of a multicellular organism?

Cells change their DNA content.

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

DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed?

DNA polymerase

In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5' → 3' direction?

DNA polymerase III

One of the two parental DNA strands is replicated in pieces because:

DNA polymerase can only move toward the "free phosphate" end of the parental strand.

The hereditary material that is present in all cells is:

DNA.

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

Which of the following statements describes chromatin?

Heterochromatin is highly condensed, whereas euchromatin is less compact.

Who performed classic experiments that supported the semiconservative model of DNA replication?

Meselson and Stahl

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?

No replication fork will be formed.

What are at the two ends of a DNA strand?

One end has a free sugar, the other has a free phosphate.

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

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

What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?

Prokaryotic chromosomes have a single origin of replication, while eukaryotic chromosomes have multiple origins of replication.

Which of the following is NOT associated with DNA replication?

RNA polymerase

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions?

Replication is not conservative.

Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging?

Telomerase eliminates telomere shortening and retards aging.

If a cell were unable to produce histone proteins, which of the following would be a likely effect?

The cell's DNA couldn't be packed into its nucleus.

Which of the following is TRUE about the accuracy of DNA replication?

The few errors made by DNA polymerase are usually corrected by repair enzymes.

In a DNA molecule, base pairing occurs between:

adenine and thymine.

If a cell has one DNA molecule containing only radioactive nitrogen, and the cell is placed in culture medium containing only regular nitrogen, how many cells will contain some DNA with radioactive nitrogen after four rounds of cell replication?

2

The DNA of a certain organism has guanine as 30% of its bases. What percentage of its bases would be adenine?

20%

If cytosine makes up 22% of the nucleotides in a sample of DNA from an organism, then adenine would make up ________ % of the bases.

28

Which of the following help(s) to hold the DNA strands apart while they are being replicated?

Which of the following help(s) to hold the DNA strands apart while they are being replicated?

Would you expect there to be strand complementarity in the Europan genetic material?

Yes, possibly. Instead of base pairing as in DNA, there could be two possible sets of subunit triplets.