FROM QUIZLET: Old Exam 3

Serratia marscecens produces a red pigment at 25C but not at 35C. This is an example of a:

A. phenotypic change
B. missense change
C. allelic change
D. genotypic change

A. phenotypic change

Semi-conservative DNA replication means that

A. only half of the DNA strand is replicated
B. each daughter DNA molecule is composed of one original strand and one new strand

C. the cell can proofread its newly synthesized DNA part of the time
D. each strand of a double-stranded DNA molecule is replicated differently

B. each daughter DNA molecule is composed of one original strand and one new strand

What MUST be a feature of two strands of DNA to allow them to hydrogen bond to each other?

A. they must form A-T base pairs
B. they must bind to each other by covalent bonds
C. they must be complementary and anti-parallel
D. they must have identical sequences

C. they must be complementary and anti-parallel

Okazaki fragments are produced during

A. transformation
B. DNA repair
C. RNA transcription
D. DNA replication

D. DNA replication

In the Ames test:

A. reversion of mutations in a Staphylococcus strain are monitored
B. potential mutagens are identified
C. the ability/inability of a Salmonella strain to synthesize glutamine is monitored
D. B and C

B. potential mutagens are identified

All of the following are characteristic of inducible operons EXCEPT:

A. they are inactive in the absence of inducer
B. they are often involved in anabolic pathways
C. they are a way for bacterial cells to conserve energy
D. they are normally inactive

B. they are often involved in anabolic pathways

A particular genome of an organism has 200 base pairs; if there are 36 guanine residues, how many thymidine residues are there?

A. 128
B. 164
C. 64
D. 72

B. 164

Which is the strongest base pair?

A. A-U
B. C-G
C. A-T
D. C-C

B. C-G

Which of the following CORRECTLY identifies a similarity between RNA and DNA?

A. both are double-stranded
B. both are made from nucleotides which consist of a phosphate, 5-carbon sugar, and nitrogenous base
C. both contain an -OH group on the 3' carbon of the sugar
D. two of the above are correct

D. two of the above are correct

Bacteria genomes are considered to be:

A. diploid
B. haploid

B. haploid

Which enzyme is matched INCORRECTLY with its function?

A. DNA ligase - joins Okazaki fragments during DNA synthesis
B. RNA polymerase - transcribes mRNA

C. topoisomerase - relaxes DNA at replication fork; helps new strands of DNA separate
D. DNA polymerase - synthesizes RNA primer during DNA replication

D. DNA polymerase - synthesizes RNA primer during DNA replication

Conjugation differs from reproduction because conjugation

A. transfers DNA vertically, to new cells.
B. replicates DNA
C. transfers DNA horizontally, to cells in the same generation.
D. copies RNA to make DNA.

C. transfers DNA horizontally, to cells in the same generation.

The enzyme which carries out RNA transcription is:

A. reverse transcriptase
B. RNA polymerase
C. DNA polymerase
D. topoisomerase

B. RNA polymerase

If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?

A. the tertiary structure of the protein
B. the primary structure of the protein
C. the secondary structure of the protein
D. the quaternary structure of the protein

B. the primary structure of the protein

If the genetic code required only two nucleotides for incorporation of amino acids, the amino acid sequence of the transcript AUGAUGAUGAUG would be:

A. B-D-E-B-D-E
B. B-B-B-D-D-D
C. B-B-B-B-B-B
D. B-B-D-D-E-E

A. B-D-E-B-D-E

Consider an mRNA that has 30 nucleotide bases. During translation (e.g. after initiation when the ribosome is at the 15th nucleotide base), which of the following sequences show the correct order that tRNA will bind to sites on the ribosome?

A. E site, P site, A site
B. A site, E site, P site
C. A site, P site, E site
D. P site, A site, E site

C. A site, P site, E site

Bacteria cells are induced to form endospores when:

A. nitrogen or carbon levels are low
B. temperature is too low
C. water levels are low
D. the temperature gets too high

A. nitrogen or carbon levels are low

Which of the following must be removed from a eukaryotic mRNA molecule before it can be translated in eukaryotes?

A. cap
B. poly A tail
C. exon
D. intron

D. intron

In DNA replication, which strand of DNA is the source of the Okazaki fragments?

A. leading strand
B. primer
C. lagging strand
D. relaxed DNA

C. lagging strand

Which of the following causes of mutations is matched CORRECTLY with its result?

A. UV radiation - thymidine dimers
B. base analogs - insertion
C. X-rays - nucleotide substitutions
D. acridine - deletion

A. UV radiation - thymidine dimers

Which of the following processes increases the genetic diversity of bacteria?

A. transformation
B. conjugation
C. transduction
D. all of the above

D. all of the above

Protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotes

A. use formylmethionine as the "start" amino acid
B. have exons and have introns
C. use codons to determine polypeptide sequences
D. require snRNPS

C. use codons to determine polypeptide sequences

A particular bacterial gene encodes an mRNA which has 150 nucleotides; what is the maximum number of amino acids possible in the resulting polypeptide?

A. 450
B. 50
C. 150

A. 450

A permanent alteration in the DNA of an organism is called a(n):

A. hereditary marker
B. allele
C. mutation
D. vector

C. mutation

Which of the following is NOT associated with nucleic acid structure?

A. uracil
B. ribose
C. methionine
D. hydrogen bonds

C. methionine

The antibiotic streptomycin inhibits bacterial growth by binding to a protein in the 30S subuit of the ribosome. Based on this information, streptomycin inhibits:

A. transcription in eukaryotes
B. transcription in prokaryotes
C. translation in eukaryotes
D. translation in prokaryotes

D. translation in prokaryotes

Transformation is the transfer of DNA from a donor to a recipient cell

A. by cell-to-cell contact
B. by a bacteriophage
C. as naked DNA in solution
D. by sexual reproduction

C. as naked DNA in solution

If a DNA strand has a nitrogenous base sequence of CCCGAT, what is the sequence of the complementary RNA strand?

A. GGGCAU
B. GGGCTA
C. GGGCUA
D. GGGCUU

C. GGGCUA

The Ames test proves that a chemical is:

A. mutagenic in Salmonella
B. carcinogenic in bacteria
C. mutagenic in humans
D. carcinogenic in humans

A. mutagenic in Salmonella

In addition to coding for the amino acid methionine, what function does the codon AUG serve?

A. start codon for protein translation
B. termination signal
C. recognition site for RNA polymerase
D. splice site for intron removal

A. start codon for protein translation

What RNA is matched CORRECTLY with its description?

A. transfer RNA - contains the anticodon
B. messenger RNA - contains the E(jection) site

C. ribosomal RNA - its sequence is colinear with the amino acid sequence
D. A, B, and C

A. transfer RNA - contains the anticodon

If the codon AAA is changed to AAG, it still codes for the amino acid lysine; this is an example of a:

A. missense mutation
B. nonsense mutation
C. silent mutation
D. frameshift mutation

C. silent mutation

Which of the following would be an appropriate temperature for the first step in PCR?

A. 55°C
B. 94°C
C. 37°C
D. 65°C

B. 94°C

Which of the following are used to silence specific genes and hold promise for treating cancer or viral diseases, such as hepatitis B?

A. RNA interference (RNAi)
B. tumor-inducing plasmids (Ti plasmids)
C. complementary DNA (cDNA)
D. reverse transcriptase PCR (rtPCR)

B. tumor-inducing plasmids (Ti plasmids)

Assume you have discovered a cell that produces a lipase that works in cold water for a laundry additive. You can increase the efficiency of this enzyme by changing one amino acid. This is done by:

A. irradiating the cells
B. site-directed mutagenesis
C. selective breeding
D. enrichment

B. site-directed mutagenesis

Which of the following would NOT be required for PCR?

A. primers
B. deoxyribonucleotides
C. fluorescent probes
D. DNA polymerase

A. primers

Which of the following would NOT be a suitable use of DNA fingerprinting?

A. replacing defective genes with normal copies
B. determining whether or not the same strain of a microbe was causing a cluster of illnesses
C. linking crime scene specimens to suspects
D. identifying human remains

A. replacing defective genes with normal copies

You want to determine whether a person has a certain mutant gene. The process involves using a primer and a heat-stable DNA polymerase. This process is

A. restriction mapping
B. transformation.
C. translation
D. PCR

D. PCR

Self-replicating DNA used to transmit a gene from one organism to another is a

A. clone
B. Southern blot
C. vector
D. library

C. vector

Gene silencing blocks an undesirable product by

A. allosteric inhibition of an enzyme
B. blocking transcription
C. end-product repression
D. activating DICER which targets double-stranded RNA

D. activating DICER which targets double-stranded RNA

Which of the following statements is TRUE?

A. Circular DNA molecules are generally less stable than linear molecules.
B. A gene library is a bacterium or phage that contains all the genes from a particular organism

C. Any foreign DNA inserted into a cell will be inherited by that cell's progeny
D. Southern blotting can be used to identify microbes that cannot be cultured

D. Southern blotting can be used to identify microbes that cannot be cultured

The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar to

A. a combination of human and T. aquaticus DNA
B. human DNA
C. T. aquaticus DNA
D. human RNA

B. human DNA

Restriction endonucleases can be used in

A. genome mapping
B. creation of recombinant vectors
C. DNA fingerprinting
D. all of the above

D. all of the above

Restriction endonucleases are

A. animal enzymes that splice RNA
B. viral enzymes that destroy host DNA
C. bacterial enzymes that splice DNA.
D. bacterial enzymes that destroy phage DNA

D. bacterial enzymes that destroy phage DNA

If you have inserted a gene in the Ti plasmid, the next step in genetic engineering is

A. inserting the Ti plasmid into Agrobacterium
B. splicing Ti DNA into a plasmid
C. transformation of E. coli with Ti plasmid
D. transformation of an animal cell.

A. inserting the Ti plasmid into Agrobacterium

Of the following, which is MOST resistant to chemical biocides?

A. viruses with lipid envelopes
B. gram-positive bacteria
C. mycobacteria
D. fungal spores

C. mycobacteria

Which of the following will NOT preserve foods?

A. microwaves
B. high pressure
C. dessication
D. osmotic pressure

A. microwaves

Which concentration of alcohol is the MOST effective bactericide?

A. 100%
B. 70%
C. 50%
D. 25%

B. 70%

Which of the following is NOT used to preserve foods?

A. biguanides
B. potassium sorbate
C. nisin
D. sodium propionate

A. biguanides

Of the following, which is MOST resistant to chemical biocides?

A. naked viruses
B. bacterial endospores
C. gram-negative bacteria
D. enveloped viruses

B. bacterial endospores

Which of the following substances can sterilize?

A. phenols
B. soap
C. ethylene oxide
D. alcohol

C. ethylene oxide

Which of the following is a limitation of the autoclave?

A. cannot inactivate viruses
B. requires a long time to achieve sterilization
C. cannot be used with glassware
D. cannot be used with heat-labile materials

D. cannot be used with heat-labile materials

Which of the following pairs is MISMATCHED?

A. copper sulfate - algicide
B. alcohol - open wounds
C. silver - burns
D. hydrogen peroxide - open wounds

B. alcohol - open wounds

Which of the following BEST describes the patterns of microbial death?

A. the cells in a population die at a constant rate
B. the pattern of cell death varies depending on the species of microbe

C. the pattern of cell death varies depending on the antimicrobial agent
D. all the cells in a culture die at the same time

A. the cells in a population die at a constant rate

Which of the following substances is used for surgical hand scrubs?

A. chlorhexidine
B. phenol
C. soap
D. glutaraldehyde

A. chlorhexidine

A scientist treats a culture with an antimicrobial agent that kills 90% of the bacteria in 1 minute. If the initial concentration of cells in the culture is 100,000,000, how many minutes will it take before there are only 100 bacteria left?

A. 4 minutes
B. 20 minutes
C. 10 minutes
D. 6 minutes

D. 6 minutes

Which of the following does NOT achieve sterilization?

A. pasteurization
B. formaldehyde
C. dry heat
D. autoclave

A. pasteurization

Which of the following affects the elimination of bacteria from an object?

A. the number of bacteria present
B. the temperature
C. whether or not organic matter is present
D. all of the above affect the elimination of bacteria from an object

D. all of the above affect the elimination of bacteria from an object