Chapter 18 Review Quiz

* not completed

. A word or phrase which reads the same in both directions, such as "Able was I ere I saw Elba," is known as a/an:

Palomina correct incorrect

Palindrome correct incorrect

Hippodrome correct incorrect

Hippopotamus correct incorrect

River horse correct incorrect

* not completed

. Occasionally, segments of DNA may spontaneously move from one place to another region of the chromosome. Discovered by Barbara McClintock, these segments are called:

Jumping genes correct incorrect

Transcription elements correct incorrect

Transition elements correct incorrect

Introns correct incorrect

Exons correct incorrect

* not completed

. The structural features of DNA and RNA maximize their usefulness. The structural features of DNA improve its ability to:

Mutate rapidly correct incorrect

Store and transfer information correct incorrect

Avoid loss of introns correct incorrect

Maintain a steady supply of introns correct incorrect

Interact with repressor lipids correct incorrect

* not completed

. The leading strand of DNA being formed is continuous, but the lagging strand forms a number of small pieces of DNA. These are joined by enzymes called:

Lipases correct incorrect

Replicases correct incorrect

Topoisomerases correct incorrect

Nucleases correct incorrect

Ligases correct incorrect

* not completed

. A set of genes, along with the operator and promoter which regulate them are called a/an:

Opera correct incorrect

Aria correct incorrect

Operon correct incorrect

Spliceosome correct incorrect

Ring mechanism correct incorrect

* not completed

. We think of DNA as remarkably stable, but some species are believed to adapt to changing environments in part by a process called:

Genetic drift correct incorrect

Transposition correct incorrect

Genetic fragmentation correct incorrect

DNA recombination correct incorrect

Intron snipping correct incorrect

* not completed

. Eukaryotic genes are remarkable for the large amount of intron material present. In order to produce an active molecule of mRNA, the introns must be removed by structures called:

Reducasomes correct incorrect

snRPS correct incorrect

RNAsomes correct incorrect

CAPs correct incorrect

Promoters correct incorrect

* not completed

. In eukaryotes, messenger RNA is synthesized by an enzyme called:

DNA polymerase I correct incorrect

Phosphodiesterase correct incorrect

Pyrophosphorylase correct incorrect

RNA polymerase I correct incorrect

RNA polymerase II correct incorrect

* not completed

. The phenomenon called gene amplification describes the existence of more than one copy of a single gene. Why might the organism benefit from having more than one copy?

Some products of genetic expression are needed in larger amounts, and if one gene suffers a mutation, it's nice to have a backup correct incorrect

There really isn't a purpose for everything, and there's no possible purpose for this correct incorrect

Many genes mutate frequently and switch on and off correct incorrect

A larger animal needs more genes correct incorrect

This could never happen in an animal which was really worthless correct incorrect

* not completed

. Both strands of DNA are copied during replication, but only one strand of DNA is transcribed in vivo. Why wouldn't it be useful to transcribe the other strand?

The complementary strand would not code for useful information, and might even code for something dangerous. At the very least, it would be a waste of cellular resources. correct incorrect

It isn't necessary to use both strands; one is enough. correct incorrect

If both strands were copied, they would cancel each other. correct incorrect

The second strand is much shorter. Longer strands require complicated reactions and would probably result in mistakes of copying. In addition, Okazaki fragments would be destroyed correct incorrect

Sometimes, it's better to leave well enough alone. correct incorrect

* not completed

. Most biomolecules have a certain half-life, the average time the molecule exists before half the population of molecules has been destroyed. mRNA of organisms such as prokaryotes, which synthesize protein rapidly, has a much shorter half-life than that of organisms such as eukaryotes, which synthesize protein slowly. Suggest a reason why this might be so.

Eukaryotic cells are in relatively stable environments and do not have to respond as rapidly to changes. Organisms which replicate faster are more likely to successfully compete and therefore, more likely to multiply faster. correct incorrect

Smaller organisms always have an advantage correct incorrect

The big guys get everything correct incorrect

Organisms which replicate slowly transcribe faster to make up for it; those which transcribe most rapidly use fewer resources and less energy and are also able to transcribe using much smaller amounts of precursor molecules correct incorrect

Prokaryotes replicate faster because they only get to use the ribosomes for a short time correct incorrect

* not completed

. One strand of the original DNA pair is incorporated into each of the new strands during replication. This type of replication is described as:

Semiconservative correct incorrect

Conservative correct incorrect

Liberal correct incorrect

Reactionary correct incorrect

Fascist correct incorrect

* not completed

. A stationary structure composed of protein and nucleic acid synthesizes DNA in eukaryotes. This structure is known as the:

Replication factory correct incorrect

Chromosome correct incorrect

Chromatid correct incorrect

Chromonic mechanism correct incorrect

Replication fork correct incorrect

* not completed

. To begin transcription of the lac operon, RNA polymerase binds to a region of the DNA molecule called the promoter. A small homodimer aids in binding of the RNA polymerase. Name the homodimer protein.

Terminator correct incorrect

Operator correct incorrect

Catabolite activator protein correct incorrect

Instigator correct incorrect

Stop codon correct incorrect

* not completed

. Double-stranded DNA strands separate and replication occurs at a portion of the double helix called the:

Codon correct incorrect

Replication fork correct incorrect

Transition stage correct incorrect

Operator correct incorrect

Promoter correct incorrect

* not completed

. Regulation of genes in prokaryotes relies on protein-based structures called operons and RNA-based structures called:

Nucleophiles correct incorrect

Ribonucleotides correct incorrect

Ribonucleases correct incorrect

Riboswitches correct incorrect

Promoters correct incorrect

* not completed

. Mistakes in replication might result in mutations were it not for enzyme systems which recognize damaged bases, cut out the inappropriate nucleotides, and replace them with the correct versions. This type of repair is called:

Recombinational repair correct incorrect

Photoactivation repair correct incorrect

Excision repair correct incorrect

Light-induced repair correct incorrect

Spontaneous repair correct incorrect

* not completed

. Beautiful mushrooms of the Amanita species often contain dangerous toxins. One of the nastier toxins is α-amanitin, a protein which inhibits the activity of RNA polymerase II. A mouse given a small dose (say, one microgram per kilogram of body weight) dies in about 15 hrs. If the same animal were given a dose ten, a hundred, or a thousand times as large, it would still in about 15 hrs. Why doesn't the larger dose kill the mouse faster?

Once mRNA or proteins are formed, the toxin can't destroy them, no matter what quantity is present. About 15 hrs is required for the mouse to degrade the mRNA on hand or for the proteins coded for by the mRNA to be degraded correct incorrect

It takes about 15 hrs for the supply of DNA to be consumed, so once the mRNA or proteins are formed, the toxin can't wipe them out, no matter what quantity is present correct incorrect

Mice are tough and can take it for 15 hrs correct incorrect

Mice are small mammals and must eat frequently. A typical mouse has enough fat and carbohydrate stores to last for 15 hrs correct incorrect

A larger mammal would probably last a lot longer. The mice die rapidly because they are tiny and lose heat rapidly correct incorrect

* not completed

. Replication is faster in prokaryotes, which synthesize protein rapidly. What possible advantage could this provide the organism?

Organisms which make protein rapidly live in stable environments and often need to compete for food supplies correct incorrect

Cells which synthesize protein at a constant rate can count on existing in exciting environments correct incorrect

Rapid protein synthesis guarantees a stable environment correct incorrect

Cells which make DNA more slowly live in more stable environments and often need not divide rapidly correct incorrect

The organism which replicates faster moves faster correct incorrect

* not completed

. Some genes are turned on direct mRNA synthesis only upon demand, but other genes appear to be turned on at all times. These genes are called:

Replicary correct incorrect

Inducible correct incorrect

Constitutive correct incorrect

Reliquary correct incorrect

Reactionary correct incorrect

* not completed

. Telomeres are regions of repetitive DNA near the ends of chromosomes. DNA polymerase is not capable of replicating all the way to the end of the chromosome, and with each replication, the telomeres are shortened slightly. Shortening of the telomeres is associated with aging and with some diseases such as progeria. Certain cells possess an enzyme called telomerase which actually lengthens or maintains the length of telomeres. Which of the following seems a likely candidate for possession of the enzyme?

Nerve cells correct incorrect

Cancer cells correct incorrect

Kidney cells correct incorrect

Brain cells correct incorrect

Heart muscle cells correct incorrect

* not completed

. If replication is stopped before completion, small pieces of DNA are found. These are known as:

Telomeres correct incorrect

Okazaki fragments correct incorrect

RNA primers correct incorrect

ATP correct incorrect

Polymerases correct incorrect

* not completed

. Bacteriophages sometimes carry bacterial DNA into recipient cells inadvertently. This process may bring about genetic change and is called:

Transposition correct incorrect

Transduction correct incorrect

Reduction correct incorrect

Genetic rendition correct incorrect

Genetic drift correct incorrect