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53) HIV does the greatest damage to
A) the adrenal glands.
B) pancreatic cells.
C) nervous tissue.
D) white blood cells.
54) How do viroids harm the plants that are infected with them?
A) by increasing the plants' metabolic rate
B) by altering the plants' growth
C) by reducing the plants' seed production
D) by destroying the root system
55) Which of the following statements about treatment or prevention of a prion infection is true?
A) Antibiotic therapies such as penicillin are very effective cures.
B) High doses of anti-inflammatory drugs such as ibuprofen reduce the symptoms of prion
infections.
C) Preventative vaccines have recently been shown to be effective in preventing prion infections.
D) There is no known treatment or cure for prion infections.
56) In the 1920s, Frederick Griffith conducted an experiment in which he mixed the dead cells of
a bacterial strain that can cause pneumonia with live cells of a bacterial strain that cannot. When
he cultured the live cells, some of the daughter colonies proved able to cause pneumonia. Which
of the following processes of bacterial DNA transfer does this experiment demonstrate?
A) transduction
B) conjugation
C) transformation
D) transposition
57) Transduction
A) is the direct transfer of DNA from one bacterium to another.
B) occurs when a bacterium acquires DNA from the surrounding environment.
C) occurs when a phage transfers bacterial DNA from one bacterium to another.
D) requires DNA polymerase.
58) Conjugation
A) is the direct transfer of DNA from one bacterium to another.
B) occurs when a bacterium acquires DNA from the surrounding environment.
C) is the result of crossing over.
D) occurs when a phage transfers bacterial DNA from one bacterium to another.
59) Conjugation, transformation, and transduction are all ways that bacteria
A) reduce their DNA content.
B) increase the amount of RNA in the cytoplasm.
C) increase their genetic diversity.
D) alter their oxygen requirements.
60) A friend accidentally sends an email to you that contains a computer virus from his
computer. Without knowing it, you infect your computer with the virus when you open the
email. This process of spreading the computer virus via email is most like which of the following
processes?
A) binary fission
B) conjugation
C) transduction
D) transformation
61) When a bacterial cell with a chromosome-borne F factor conjugates with another bacterium,
how is the transmitted donor DNA incorporated into the recipient's genome?
A) It is substituted for the equivalent portion of the recipient's chromosome by the process of
crossing over.
B) It circularizes and becomes one of the recipient cell's plasmids.
C) The genes on the donor DNA of which the recipient does not have a copy are added to the
recipient chromosome; the remainder of the donor DNA is degraded.
D) The donor and recipient DNA are both chopped into segments by restriction enzymes, and a
new, composite chromosome is assembled from the fragments.
62) In many bacteria, genes that confer resistance to antibiotics are carried on
A) factors.
B) R plasmids.
C) transposons.
D) exons.
63) Conjugation between a bacterium that lacks an F factor (F-) and a bacterium that has an F
factor on its chromosome (F+) could produce which of the following results?
A) The F- bacterium ends up carrying one or more plasmids from the F+ bacterium; the F+
bacterium is unchanged.
B) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the
F- bacterium, and the F- bacterium ends up with an unaltered chromosome.
C) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the
F- bacterium, and the F- bacterium ends up with a chromosome that lacks those genes.
D) The F- bacterium ends up with a recombinant chromosome that carries some genes from the
F+ bacterium, and the F+ bacterium ends up with an unaltered chromosome.
64) Which of the following human activities has contributed to an increase in the number of
bacteria having R plasmids?
A) nitrogen fixation by genetically engineered plants
B) improper use of restriction enzymes in research and medical facilities
C) increased carcinogen exposure from excessive fossil fuel burning
D) heavy use of antibiotics in medicine and in agriculture
65) What is the transcription product of the sequence GCTAGCGATGAC?
A) CGTUCGCUTCUG
B) CGAUCGCUACUG
C) CAGTAGCGATCG
D) CGUTCGCUTCUG
66) A eukaryotic cell has a nuclear envelope that allows tRNA molecules, but not mRNA
molecules, to leave the nucleus. Which of the following processes will not be able to take place
in this cell?
A) DNA replication
B) tRNAs binding to codons
C) RNA being made from DNA
D) tRNAs binding to amino acids
67) A single base mutation occurs in a gene that codes for a protein due to an error in DNA
replication. Which of the following outcomes would possibly not occur?
A) The mutation results in improved, the same, or diminished protein function.
B) The mutation results in a longer or shorter protein or a protein of the same length.
C) The mutation results in a human disease such as sickle-cell disease.
D) The mutation results in mRNA being made from the protein.
68) Below are three statements. Which of the following choices properly matches the statements
with the correct biological processes?
I. This occurs in the nucleus of eukaryotic cells.
II. Transfer RNAs bind amino acids in the cytoplasm.
III. A polymerase enzyme is required.
A) I: replication; II: translation; III: transcription
B) I: translation; II: translation; III: replication
C) I: transcription; II: translation; III: translation
D) I: replication; II: transcription; III: replication
69) It is possible to synthesize proteins in vitro (in a test tube) without the use of living cells. If
starting from a mature mRNA transcript, which of the following components would not be
needed to do this?
A) adenine molecules
B) amino acids
C) tRNAs
D) ribosomes
70) If Hershey and Chase had used radioactive oxygen in their experiments instead of
phosphorus and sulfur, what results would they have likely obtained?
A) They would have observed a radioactive signal in the pellet only.
B) They would have observed a radioactive signal in the liquid only.
C) They would have observed a radioactive signal in both the pellet and the liquid.
D) They would have not observed radioactivity anywhere.
71) You are interested in designing an experiment to test the hypothesis that frogs use the same
genetic code as humans. Which of the following experiments would not give you useful data to
test this hypothesis?
A) Purify tRNAs from frog cells and human cells and compare their structures.
B) Insert a human gene into a frog cell and see if the correct protein is produced.
C) Insert a frog gene into a human cell and see if the correct protein is produced.
D) Compare nucleotide sequences of promoters from similar frog and human genes.
72) Normal genes have a promoter followed by a start codon. In a mutant gene, the "A" in the
start codon has been deleted. Which of the following is not a possible outcome?
A) The normal protein will be produced.
B) A shorter protein will be produced.
C) A longer protein will be produced.
D) No protein will be produced.
10.2 Art Questions
1) What nucleotide sequence would be found on the partner DNA strand of the strand shown?
A) ACTGT
B) UGAGA
C) TGACA
D) TGUGU
2) If the left end of the daughter strand indicated by the arrow in the figure is being synthesized
in one continuous piece, then
A) the DNA at point A is being synthesized in one continuous piece.
B) the DNA at point B is being synthesized in small pieces.
C) the DNA at point C is being synthesized in one continuous piece.
D) the DNA at point D is being synthesized in one continuous piece.
3) Using the genetic code below, what protein sequence does the RNA sequence
CUAGCUCGAUAUCUC code for?
A) Asp - Ala - Arg - Ile- Leu
B) Val - Arg - Ala - Phe - Stop
C) Leu - Gly - Tyr - Ala — Leu
D) Leu - Ala - Arg - Tyr - Leu
4) Examine the following two DNA sequences.
Sequence 1: ATGCGATGCTAGCAT
Sequence 2: ATGCGATGATAGCAT
If both of these sequences code for proteins, how might the function of protein 2 differ from the
function of protein 1? Use the genetic code below for assistance.
A) Protein 1 and protein 2 will function exactly the same.
B) Protein 1 will be shorter than protein 2, so they will not function the same.
C) Protein 2 will be shorter than protein 1, so they will not function the same.
D) Protein 2 has a different sequence, so it will function differently from protein 1.
10.3 Scenario Questions
After reading the paragraphs below, answer the questions that follow.
Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some
people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National
Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect
against HIV infection. The mutation probably originated in Europe among survivors of the
bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes
and, therefore, from entering and infecting body cells.
Although the HIV virus is very different from the bacteria that causes the plague, both diseases
affect the exact same cells and use the same method of infection. The presence of the mutated
gene in descendants of plague survivors helps prevent them from contracting AIDS.
Pharmaceutical companies are using this information as the basis for a new approach to AIDS
prevention. This could be very important in areas of the world where the mutation is scarce or
absent, such as Africa.
1) The most likely method by which the mutated CCR5 gene prevents AIDS is by
A) covering the cell membrane.
B) rupturing the nuclear membrane.
C) attacking and destroying the HIV virus particles.
D) coding for a protective protein in the cell membrane.
2) Which of the following shows the steps of a viral infection in the proper order?
A) virus locates host cell → enters nucleus → alters host cell DNA → destroys cell membrane
B) virus locates host cell → alters host cell DNA → host cell produces copies of virus → copies
enter host cell nucleus → nucleus leaves cell
C) virus locates host cell → penetrates cell membrane → enters nucleus → alters host cell DNA
→ host cell produces copies of virus
D) virus locates host cell → forms hydrogen bonds → changes DNA to RNA→ host cell
produces copies of virus
25
3) Imagine that a pharmaceutical company was successful at producing a drug based on the
CCR5 gene product that is effective at preventing the contraction of AIDS. However, shortly
after the drug has been in use, patients and doctors report that the drug is not as effective as it
once was. What is the most likely explanation for this result?
A) The people taking the drug have built up a tolerance to the drug.
B) Some HIV viruses have genetic variations in the RNA genome that provide resistance to the
actions of the drug.
C) The HIV virus gained mutations in its DNA genome in order to become resistant to the
actions of the drug.
D) The DNA of white blood cells of the people taking the drug have mutated to become resistant
to the drug.
After reading the paragraphs below, answer the questions that follow.
Diabetes mellitus is a metabolic disease that is characterized by the buildup of glucose in the
blood, or hyperglycemia. Diabetes results either from the pancreas not being able to produce the
hormone insulin (type 1 diabetes) or if the body's cells become resistant to insulin (type 2
diabetes). Insulin is a protein that binds to receptors on cell surfaces to allow glucose to enter the
cell.
In order to manage the disease, type 1 diabetics require frequent insulin injections. Until the
1970s, insulin was obtained from processing the pancreases of large mammals such as cows and
pigs; it was then purified for medicinal use. This all changed in the 1970s with the advent of
recombinant DNA technology, which allows scientists to insert genes from other species into
bacterial plasmids and have bacteria produce proteins from these other species' genes. In 1978,
the gene that codes for human insulin was added to a bacterial plasmid and bacteria were used to
produce human insulin. These bacteria acted as mini-factories that produced human insulin for
type 1 diabetes patients. Today, the production of human insulin from bacteria is commonplace
and is a multibillion dollar market for pharmaceutical companies.
4) In order for bacterial cells to be able to produce the human insulin protein, which of the
following do not have to be true?
A) Bacteria and humans have to use the same genetic code.
B) Bacterial RNA polymerases have to recognize human promoters.
C) Bacterial ribosomes have to recognize human start and stop codons.
D) Bacteria have to have a gene for a bacterial form of insulin.
5) In order to add the gene for human insulin to a bacterial plasmid, the DNA molecules have to
be "cut" with enzymes called restriction endonucleases and then pasted back together with
enzymes called DNA ligases. Imagine that during this process, the first five nucleotides of the
human insulin gene were accidentally cut out before it was pasted into the bacterial plasmid.
What is the most likely outcome if this plasmid was added to bacterial cells?
A) Transcription would not take place because the RNA polymerase would not recognize the
promoter.
B) The human insulin protein would be produced as normal.
C) The human insulin protein would not be produced because the start codon is missing.
D) The human insulin protein would be shorter than normal because it will be missing one amino
acid.
6) Suppose that the human insulin protein that was produced by the bacteria was much shorter
than it should be. Upon further investigation, it was found that the DNA of the human insulin
gene had a mutation while in the bacterial cells. What type of mutation could not result in these
observations?
A) nucleotide insertion
B) silent mutation
C) nucleotide deletion
D) nonsense mutation
