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Problem Set 3
Chapter 5
BILD10 / Winter 2014
Traver
1) DNA is now often used as evidence in criminal trials. It is particularly useful because it can be found in:
a) hair.
b) saliva.
c) blood.
d) dead skin cells.
e) All of the above are correct.
2) Double-stranded DNA that contains a high G–C content requires a higher temperature in order to separate the two
DNA strands. This is because:
a) G–C base pairing involves three hydrogen bonds while A–T pairing involves only two.
b) high G–C content makes the DNA less flexible.
c) DNA with a high G–C content forms a tighter double helix.
d) All of the above are correct.
e) Only a) and b) are correct.
3) In any DNA molecule, the number of guanine bases is:
a) always equal to the number of thymine bases.
b) always equal to the number of cytosine bases.
c) equal to the total number of cytosine and adenine bases.
d) sometimes equal to the number of thymine bases and sometimes equal to the number of adenine bases.
e) always equal to the number of adenine bases.
4) The complementary base pairs in a DNA molecule are stabilized by:
a) the electrostatic interactions of the charged backbone.
b) a covalent bond.
c) a salt bridge.
d) hydrogen bonds.
e) Both a) and b) are correct.
5) Most genes come in alternative forms called:
a) chromosomes.
b) gametes.
c) dominants.
d) alleles.
e) recessives.
6) In humans, genes make up ______ of DNA.
a) less than 5%
b) about 75%
c) about 50%
d) 100%
e) about 10%
Problem Set 3
Chapter 5
BILD10 / Winter 2014
Traver
7) Which of the following correctly describes the locations of transcription and translation within a eukaryotic cell?
a) DNA is transcribed in the nucleus, then the mRNA transcript is transported to the nucleosomes to be
translated into protein.
b) Both transcription and translation occur in the cytosol.
c) DNA is transcribed in the cytosol, then the mRNA transcript is transported into the nucleus to be translated
into protein.
d) Both transcription and translation occur in the nucleus.
e) DNA is transcribed in the nucleus, then the mRNA transcript is transported to the cytosol to be
translated into protein.
8) Genotype is to phenotype as:
a) cookie is to recipe.
b) fish is to bicycle.
c) cookie is to oven.
d) oven is to cookie.
e) recipe is to cookie.
9) During transcription, at the point where the DNA strand being copied has an adenine, _______________ is added
to the mRNA.
a) a cytosine
b) an adenine
c) a uracil
d) a thymine
e) a tRNA
10) The three nonsense codons that do not code for any amino acid—UAA, UAG, and UGA—are also known as:
a) stop codons.
b) antisense codons.
c) degenerate codons.
d) start codons.
e) secondary codons.
11) In the regulation of gene expression, anything that increases the binding of RNA polymerase to a gene’s promoter
region could be called:
a) positive translational control
b) negative translational control
c) negative transcriptional control
d) positive transcriptional control
e) a situation due to an inactive repressor
12) A frameshift mutation:
a) leaves the amino acid sequence unchanged.
b) results from an insertion or deletion in a DNA sequence.
c) substitutes a purine for a pyrimidine only.
d) is the result of an unequal crossing-over.
e) substitutes a pyrimidine for a purine, or vice versa.
Problem Set 3
Chapter 5
BILD10 / Winter 2014
Traver
13) Most genetic diseases result from mutations that cause a gene to produce a non-functioning ______________,
which in turn blocks the functioning of a metabolic pathway.
a) enzyme
b) codon
c) polysaccharide
d) tRNA
e) histone
14) Bacteria use restriction enzymes to:
a) destroy foreign protein.
b) synthesize RNA.
c) synthesize DNA.
d) destroy foreign DNA.
e) synthesize protein.
15) Golden rice:
a) could help the 250,000 children each year who are at risk of blindness due to vitamin A deficiency.
b) is an example of organic farming.
c) supplies more vitamin A in one serving than an individual needs in a full week.
d) can make vitamin A without beta-carotene.
e) grows without a husk, thereby reducing the processing required before it can be consumed.
16) Tomato plants that have pest-resistance genes inserted into the genome can be called:
a) cloned organisms.
b) genetically engineered organisms.
c) transgenic organisms.
d) Only b) and c) are correct.
e) All of the above are correct.
17) One of the possible concerns about genetically modified foods is that they might kill organisms that we don’t want
to kill. Which of the following is an example of this phenomenon?
a) Bears eating genetically modified corn may be poisoned by the Bt gene introduced to the corn to act as a
pesticide.
b) Featherless chickens look so ridiculous that other barnyard animals have died laughing at them.
c) The pollen from plants containing insect-killing Bt genes can be blown onto other plants. Insects that
we don’t want to kill, such as monarch butterflies, may be killed by such pollen.
d) Genetically modified super-sized salmon have been known to kill the bald eagles that generally feed on
them.
e) In the Irish Potato Famine, more than one million people died as a result of the lack of genetic diversity in
the potato crop.
18) Gene therapy involves:
a) the replacement, by transplant, of organs from patients with genetic disorders.
b) no controversial or ethical questions.
c) drug treatment of patients with genetic disorders at specific times that correspond with cell division.
d) introducing non-defective genes into the cells of an individual with a genetic disorder.
e) All of the above are correct.
Problem Set 3
Chapter 5
19)
BILD10 / Winter 2014
Traver
You amplify the same gene from two different people using PCR (polymerase chain reaction). When you
electrophorese the two samples on a gel, you see that two bands are present in the sample from Individual 1,
while only one band is present in the sample from Individual 2. What is a likely explanation for this outcome?
a) Individual 1 is homozygous, while Individual 2 is heterozygous.
b) Individual 1 is a man, while Individual 2 is a woman.
c) Individual 1 is a woman, while Individual 2 is a man.
d) Individual 1 is diploid, while Individual 2 is haploid.
e) Individual 1 is heterozygous, while Individual 2 is homozygous.
20) How similar are two people with respect to chromosomes, genes, and alleles?
Two people have the same number of chromosomes (46 for humans), and have the same genes arranged on
these chromosomes. However, they have different alleles of many of these genes.
21) In a few sentences, summarize the four steps of transcription, in which an mRNA copy of a gene is produced.
The enzyme RNA polymerase binds to the promoter region at the beginning of a gene, after which it proceeds to
assemble RNA nucleotides in an order dictated by the DNA sequence of the gene. This synthesis continues until
the enzyme encounters a termination sequence at the end of the gene and detaches from the DNA. The newly
synthesized mRNA molecule is then modified before being transported to the cytoplasm.
22) Describe the three ways in which an initial mRNA molecule is modified before transport to the cytoplasm.
The initial RNA transcript is modified in three ways. Extra pieces of non-coding RNA (introns) that are within
the gene are snipped out. Also, a cap is added to the beginning of the molecule, and a tail is added to the end of
the molecule. Both of these additions protect the transcript and assist with the next process: translation.