Practice Test

Front 1

What is the reason that closely linked genes are typically inherited together?

Back 1

the likelihood of a crossover event between these two genes is low

Front 2

All female mammals have one active X chromosome per cell instead of two. What causes this?

Back 2

activation of the XIST gene on the X chromosome that will become the Barr body

Front 3

In his transformation experiments, what did Griffith observe?

Back 3

Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells intothe pathogenic form

Front 4

In trying to determine whether DNA or protein is the genetic material of phage using radioisotopes, Hershey and Chase made use ofwhich of the following facts?

Back 4

DNA contains phosphorus, whereas protein does not

Front 5

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

Back 5

DNA polymerase can assemble DNA only in the 5' to 3' direction

Front 6

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotidesin this sample will be thymine?

Back 6

8%

Front 7

DNA replication is said to be semiconservative. What does this mean?

Back 7

each new double helix consists of one old and one new strand

Front 8

What are the repetitive DNA sequences present at the ends of eukaryotic chromosomes called?

Back 8

A) Okazaki fragmentsB) origins of replicationC) supercoiled DNAD) centromeresE) none of the above

E

Front 9

Genomic imprinting, DNA methylation, and histone acetylation are all examples of

Back 9

epigenetic phenomena

Front 10

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced doublestrandedRNA is called

Back 10

RNA interference

Front 11

The following enzyme is necessary to generate a complementary DNA library:

Back 11

A) complementaraseB) reverse complementaraseC) libraseD) restriction enzymeE) none of the above

E

Front 12

Agent Scully was able to complete the following technique (in under two hours) combining gel electrophoresis of DNA fragmentswith nucleic acid hybridization in order to demonstrate the existence of alien DNA which had integrated into her own DNA

Back 12

Southern Blot

Front 13

Scientists can utilize the following techniques in order to get DNA inside a target cell:

Back 13

electroporation

Front 14

The following technique requires heating, cooling, and replication in order to bring about a chain reaction that produces anexponentially growing population of identical DNA molecules

Back 14

polymerase chain reaction

Front 15

A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using

Back 15

reverse transcriptase to reconstruct the gene from its mRNA

Front 16

In order to insert a human gene into a plasmid, both must

Back 16

be cut by the same restriction enzyme

Front 17

Which of the following is true of embryonic stem cells but not of adult stem cells?

Back 17

They can give rise to all cell types in the organism

Front 18

Cold case detectives are investigating a homicide that took place 30 years ago. In reexamining the evidence, they find a tiny spot ofblood on the victim’s clothing that was likely left by the murderer. The DNA in the blood has partially degraded over time. Whattechnique would the blood lab technicians use in their examination of this tiny, degraded blood sample?

Back 18

polymerase chain reaction to amplify the DNA

Front 19

DNA microarrays have made a huge impact on genomic studies because they

Back 19

allow the expression of many or even all of the genes in the genome to be compared at once

Front 20

Relatively short DNA fragments can be sequenced using

Back 20

dideoxyribonucleotides tagged with a distinct fluorescent label

Front 21

What methodology is normally utilized to insert a cloned gene into bone marrow cells from patients to correct a defective gene?

Back 21

infection with a retrovirus carrying the RNA version of the normal gene

Front 22

Gene function can be determined by disabling the gene using

Back 22

in vitro mutagenesis

Front 23

Which enzyme was used to produce the molecule in the figure to the right?

Back 23

a restriction enzyme

Front 24

Dr. Feuer would like to clone himself so that he can go surfing while his clone teaches BIOL 203. In the end, Dr. Feuer decidesagainst this foolish plan for the following reasons:

Back 24

A) ethical and moral considerationsB) telomere shortening may contribute to disease if the donor nucleus is removed from somatic cells for cloning purposesC) only a small percentage of cloned embryos have developed normally to birth most likely since epigenetic changes must bereversed in the donor nucleusD) Dr. Feuer is concerned that his clone may be a better surfer than himselfE) all of the above

E

Front 25

A particular triplet of bases in the template strand of DNA is 5' CTA 3'. The corresponding codon for the mRNA transcribed is

Back 25

3' GAU 5'

Front 26

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:

3' C C T A G G C -T- C G A A T G G 5'

An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

Back 26

5' A G C U U A C C 3'

Front 27

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

Back 27

bonding of the anticodon to the codon and the attachment of amino acids to tRNAs

Front 28

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA insteadof the normal phenylalanine. The consequence of this for the cell will be that

Back 28

proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Front 29

When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by

Back 29

a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane

Front 30

Which of the following DNA mutations is the least likely to be damaging to the protein it specifies?

Back 30

a substitution in the last base of a codon

Front 31

The figure below demonstrates the outcome of the following type of mutation:

Back 31

frameshift causing extensive missense

Front 32

Which of the following does not occur in prokaryotic gene expression, but does in eukaryotic gene expression?

Back 32

A) RNA polymerase requires a primer to elongate the moleculeB) RNA polymerase binds to the promoterC) mRNA, tRNA, and rRNA are transcribedD) transcription can begin as soon as translation has begun even a littleE) none of the above

E

Front 33

The average length of a transcription unit along a eukaryotic DNA molecule is about 27kb nucleotide pairs, whereas an averagedsizedprotein is about 400 amino acids long. What is the best explanation for this fact?

Back 33

most eukaryotic genes and their RNA transcripts have long noncoding stretches of nucleotides that are not translated

Front 34

The tryptophan operon is a repressible operon that is

Back 34

turned off whenever tryptophan is added to the growth medium

Front 35

If you were to observe the activity of methylated DNA, you would expect it to

Back 35

have turned off or slowed down the process of transcription

Front 36

In eukaryotes, general transcription factors

Back 36

bind to other proteins or to a sequence element within the promoter called the TATA box

Front 37

Which of the following best describes siRNA?

Back 37

a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

Front 38

The product of the bicoid gene in Drosophila provides essential information about

Back 38

the anterior-posterior axis

Front 39

Which of the following statements describes proto-oncogenes?

Back 39

They are cellular genes responsible for normal cell growth and division

Front 40

A student wants to clone a DNA sequence of ~200 kb in length. Which vector would be appropriate?

Back 40

A) a bacteriophageB) a large polypeptideC) a plant virusD) a plasmidE) none of the above

E

Front 41

Mutations in the ras gene may lead to

Back 41

production of a hyperactive Ras protein and increased cell division

Front 42

BRCA1 and BRCA2 are considered to be tumor-suppressor genes because

Back 42

their normal products participate in repair of DNA damage