Chapter 11

The significance of specific base pairing in DNA is that

it provides a method for making exact copies of DNA.

Housekeeping genes

are expressed by most of the cells in an organism.

Benzopyrene is a compound found in cigarettes that binds to the base guanine in DNA. This distorts the DNA double helix and causes changes in DNA sequence. Based on this information, benzopyrene is a

mutagen.

Assume a certain molecule of DNA is composed of exactly 22 percent adenine. How much cytosine would you expect to find in this molecule?

28 percent

Where in this diagram of the flow of genetic information of the cell would translation occur?

C

The hereditary genetic material present in all living cells is

DNA

How can a cell contain DNA molecules that are much longer than the cell?

DNA is very narrow and tightly packed.

Which of the following must occur for a mismatch error to be repaired?

DNA repair proteins identify damaged DNA.

Once a gene is turned on, it cannot be turned off.

False

Protein is the hereditary genetic material in human cells.

False

The process of DNA replication is error free.

False

Translation builds DNA from an RNA template.

False

Which of the following does NOT correctly state a difference between prokaryotic and eukaryotic DNA organization?

Eukaryotic DNA is usually arranged more simply than prokaryotic DNA.

At any given time, most of the genes in the genome of an organism are actively undergoing gene expression.

False

DNA is often damaged or may be replicated incorrectly. Which of the following is NOT true?

Humans have the most efficient DNA repair proteins.

Is a species that lacks DNA repair mechanisms likely to have more or fewer variations between individuals than a species that possesses repair mechanisms?

More, because more spontaneous mutations will go uncorrected.

One parent is a carrier for a recessive disease. The other parent is not a carrier and does not have the disease. Is it necessary for the fetus to undergo prenatal genetic screening to determine if she has the disease?

No, the fetus may be a carrier but will not have the disease.

Assume a cell present in your body has performed a mismatch error during the process of DNA replication. This error has resulted in the generation of a new allele for one of your genes. For this new allele to be inherited by your offspring, which of the following conditions must be true?

The error must occur in the germ line cells.

What is NOT true of the five different cell types from the individual shown in the following figure?

They express the same genes at the same time.

During DNA replication, the template strands of the original DNA molecule are complementary both to each other and to one of the new strands.

True

During replication, each "old" DNA strand serves as a template for a new strand

True

Enzymes proofread base pairing during DNA replication.

True

In eukaryotes, some genes with related functions are found on different chromosomes.

True

The 220 different cell types in the human body each contain all of the same DNA found in every other cell type.

True

To repair DNA, a protein cuts out the damaged section.

True

Bacterial cultures are sometimes exposed to ultraviolet (UV) light in order to generate organisms with new genetic traits. Why do microbiologists choose to use UV light for this purpose?

UV light has the ability to cause changes in DNA.

In plants, transposons are often the cause of variegation (the formation of white stripes of cells on a green leaf). Which of the following explains why a transposon might have this effect?

When a transposon "jumps" into the gene involved in the production of the green pigment in a plant, the gene no longer functions so the cells are all white.

Mismatch errors are

almost always corrected by DNA repair proteins.

Before a cell divides, it

copies its own genetic information.

Along one side of a DNA molecule, the nucleotides are connected to each other by

covalent bonds between phosphate groups and sugar molecules.

All cells in an organism contain a full copy of that organism's DNA. Your ears do NOT produce digestive enzymes because

different genes are expressed in different parts of an organism.

The order of the base pairs in a DNA molecule

differs from species to species.

One level of DNA packing involves the DNA being wound around

histone proteins.

The two strands of a DNA molecule are held together by ________ bonds between their base pairs.

hydrogen

A segment of DNA is present in a gene, is transcribed, but is not used in translation. This segment of DNA is a(an)

intron

The following figure illustrates DNA undergoing replication. The region indicated by the arrow in this image represents a

mismatch error.

Most eukaryotic DNA is

noncoding.

Estrogen is a hormone that binds to a receptor on the surface of some cells. This binding causes regulatory molecules in the nucleus to interact with a segment of DNA that precedes some genes. This interaction activates the gene and causes gene expression. The segment of DNA that the regulatory molecules bind to is called a

promoter.

Why is the expression of the rRNA gene so different from the expression of the other genes in the table?

rRNA is required for the proper functioning of all cells, but the products of the other genes are only essential to the function of one cell type.

A mistake during which of the following processes would have the most long-lasting effects on an organism and its offspring?

replication in germ line cells

Once replication in a DNA molecule is complete, each new DNA molecule contains one old strand and one new strand. This type of replication is called

semiconservative.

When examining the two complementary strands of nucleotides in one DNA molecule, you would expect to find that

the sum of Gs and Cs in one strand would be equal to the sum of the Gs and Cs in the other strand.

The difference between the different alleles of a gene is

their DNA base sequences.

Which of the following is NOT true? Organisms turn genes on and off

to switch from prokaryotic to eukaryotic status.

This figure shows a short sequence of DNA. During DNA replication, the piece of DNA depicted below will produce

two double-stranded molecules that look just like the image above