MCB3023 Exam 2

What are micro RNAs?

a. tRNAs

b. small regulatory RNAs

c. rRNAs

d. small mRNAs

e. mRNAs that encode for regulatory proteins

b. small regulatory RNAs

Replication of the bacterial chromosome begins at how many locations?

a. One

b. Three

c. Four

d. Two

e. Five

a. one

Which of these best differentiates DNA and RNA?

a. RNA contains ribose and DNA contains deoxyribose

b. RNA is single-stranded and DNA is double stranded

c. All statements are true

d. RNA contains the base uracil in place of thymine, which is in DNA

c. All statements are true

Which enzyme is responsible for adding the final bases to the end of a chromosome during DNA replication in eukaryal cells?

a. DNA polδ

b. DNA primase B

c. topoisomerase

d. DNA polα

e. Telomerase

e. Telomerase

Term for cells that can naturally take up extracellular DNA

a. primed

b. susceptible

c. conjugant

d. porous

e. competent

e. competent

Suppose a mutant strain of Escherichia coli K12 contains a mutation in the trpE gene and is no longer able to make tryptophan. What is this mutant called?

a. A phenotroph

b. An auxotroph

c. A lithotroph

d. A prototroph

e. An autotroph

b. An auxotroph

Which term applies to the transfer of genes from mother to daughter cell?

a. horizontal gene transfer

b. meiosis

c. transduction

d. vertical gene transfer

e. lateral gene transfer

d. vertical gene transfer

The process of molecular cloning was mainly brought about through the discovery of these

a. bacteriophages

b. restriction enzymes

c. transformations

d. conjugation events

e. transposons

b. restriction enzymes

Bacterial mutants have been very useful for studying and understanding:

a. capsule production

b. carbon metabolism

c. antibiotic resistance

d. all of these choices

e. biosynthetic pathways

d. all of these choices are correct

What is metagenomics?

a. A culture-dependent method that may be used to determine protein sequences

b. A culture -independent method that may be used for the isolation of different organisms

c. A culture-dependent method that may be used to study groups of microbes in an ecosystem

d. A culture-independent method that may be used to document microbial community pools of genetic material

e. A culture-dependent method that may be used to find new enzymes

d. A culture-independent method that may be used to document microbial community pools of genetic material

The sequencing method which uses detection of pyrophosphate liberated when nucleotides are added to a growing DNA chain is called:

a. Sanger dideoxy sequencing

b. Ion torrent sequencing

c. Pyrosequencing

d. PacBio sequencing

e. Plus-minus sequencing

c. Pyrosequencing

Which of these is another term for the Sanger method of DNA sequencing?

a. chemical degradation method

b. restriction method

c. dideoxy sequencing

d. gel method

e. label method

c. dideoxy sequencing

Genes which confer invasiveness to a pathogen and whose GC content varies significantly from that of the total genome constitute:

a. Symbiosis islands

b. Pathogenicity islands

c. SSU rRNA genes

d. Paralogs

e. Orthologs

b. Pathogenicity islands

Which of these would a signal peptide be used for in bacteria?

a. To regulate translation

b. To move a protein to the outside of the cell

c. To help a protein fold correctly

d. To help regulate the activity of an enzyme

e. To initiate DNA replication

b. To move a protein to the outside of the cell

Bacteriophages vary in their ability to infect different strains of bacteria. This is because some bacteria contain _________ __________ that cut the phage DNA after it enters the cell.

a. restriction endonucleases

b. DNA topoisomerases

c. general nucleases

d. DNA helicases

e. DNA gyrase

a. restriction endonucleases

Compared to the eukaryal genome, the bacterial genome:

a. contains usually one chromosome and most genes occur in a single copy

b. contains genes that are usually present in multiple copies

c. is difficult to manipulate

d. is diploid in number

e. is more complex

a. contains usually one chromosome and most genes occur in a single copy

Most bacterial promoters consist of two regions _____ and _______.

a. Enhancer region and operator

b. 35 region and operator

c. Pribnow (TATA) box and - 35 region

d. Pribnow (TATA) box and operator

e. Enhancer region and -35 region

c. Pribnow (TATA) box and - 35 region

. What is a transcriptome?

a. The coding region on the chromosome plus the control regions

b. The mount of mRNA in the cell

c. The coding region on the chromosome

d. The transcripts encoded for by the genes within a genome

e. The coding region on the chromosome minus the introns

d. The transcripts encoded for by the genes within a genome

The Sanger method of sequencing uses ALL of the following EXCEPT:

a. dideoxynucleotides

b. restriction enzymes

c. a short oligo primer

d. DNA polymerase

e. Deoxynucleotides

b. restriction enzymes

You insert a gene for tetracycline resistance into one plasmid and a gene for ampicillin resistance into another plasmid. You successfully introduce both plasmids into a sample of E. coli cells, but the E. coli cells do not grow in culture medium with both antibiotics present in it. What could best explain the problem?

a. A phage has neutralized one of the plasmids

b. The plasmid(s) have integrated into the bacterial chromosome

c. Random mutation has inactivated the antibiotic resistance genes

d. Plasmid incompatibility will not allow both plasmids to persist

e. E. coli cannot maintain two plasmids

d. Plasmid incompatibility will not allow both plasmids to persist

The main differences between Bacteria and Archaea chromosomal DNA when compared to Eukaryal DNA, is that bacteria or archaea chromosome is usually:

a. Contains the base uracil while eukarya has thymine in the place of uracil

b. Is circular while eukarya is linear

c. Is diploid while eukarya is haploid

d. Is found in a non-condensed form while eukaral DNA is highly condensed and packaged

e. Consists of several chromosomes while eukarya is a single chromosome

b. Is circular while eukarya is linear

Which statement below is false regarding replication of the bacterial chromosome

a. The leading strand is replicated in the 5' to 3' direction and the lagging strand in the 3' to 5' direction

b. DNA replication is a semi-conservative process, where one strand serves as a template for the synthesis of a complementary strand

c. The primase adds a short RNA primer to serve as a starting point for the DNA polymerase to add new bases

d. The incoming nucleotide triphosphate is covalently attached to the free 3' hydroxyl

e. Replication occurs in a bidirectional manner from the origin of replication

a. The leading strand is replicated in the 5' to 3' direction and the lagging strand in the 3' to 5' direction

. Which of these results from a deletion of base pairs such that the amino acid sequence is disrupted from that point downward?

a. Trans version mutation

b. Frameshift mutation

c. Nonsense mutation

d. Missense mutation

e. Transition mutation

b. Frameshift mutation

Initiation of translation in bacteria starts with the binding of the ribosome to the mRNA molecule. The ribosomal binding site is nearer the ___ end of the mRNA molecule and is called the ___.

a. 3' end; Pribnow box (TATA box)

b. 3' end; rho sequence

c. 5' end; rho sequence

d. 5' end; Shine-Dalgarno sequence

e. 3' end; Shine-Dalgarno sequence

d. 5' end; Shine-Dalgarno sequence

The Watson-Crick model of DNA shows that the base adenine pairs with:

a. Either thymine or cytosine while guanine pairs with either thymine or cytosine

b. Guanine while cytosine pairs with thymine

c. Thymine while cytosine pairs with guanine

d. Cytosine while guanine pairs with thymine

e. Either thymine or guanine while cytosine pairs with either thymine or guanine

c. Thymine while cytosine pairs with guanine

The Hershey and Chase experiment was able to conclusively demonstrate that DNA, not protein, was the genetic material. They were able to distinguish DNA from protein since labeled ___ incorporated into DNA while labeled ___ incorporated into proteins.

a. Phosphorus; sulfur

b. Nitrogen; magnesium

c. Nitrogen; sulfur

d. Sulfur; nitrogen

e. Magnesium; nitrogen

a. Phosphorus; sulfur

Genetic elements that are able to "jump" around on the chromosome

a. Resolvase

b. Chromatin

c. Conjugate

d. Transposons

e. Transductants

d. Transposons

You are searching for a mutant strain of E. Coli which is antibiotic resistant. What approach is most likely to be successful?

a. Replica plating on selective and non-selective media

b. Toothpick pick-and-patching

c. RNAseq analysis of the E. Coli strain

d. Environmental searching for a new population

e. DNA sequencing of cells within a population

a. Replica plating on selective and non-selective media

. What is an organism's complete collection of alleles called?

a. Wild-type

b. Prototype

c. Phenotype

d. Genotype

e. Histotype

d. Genotype

DNA microarray analysis may be used to study:

a. Gene expression in cells grown under different conditions

b. Protein expression in cells grown under different conditions

c. Rate of chromosomal replication in cells

d. Growth rate of cells when grown under different conditions

e. Enzyme activity in cells

a. Gene expression in cells grown under different conditions

Messenger RNA (mRNA) can best be described as a molecule that contains the code for a:

a. Protein, rRNA, or tRNA

b. Polypeptide, tRNA, or rRNA

c. Polypeptide

d. Proteins

e. Polypeptide or regulatory RNA

c. Polypeptide

For the initiation of transcription in bacteria, RNA polymerase binds to what region on the gene?

a. Origin of replication

b. Promoter

c. Operator

d. Shine-Dalgarno sequence

e. Enhancer region

b. Promoter

What is the first protein to bind to the oriC region of the DNA molecule to start the replication process?

a. DnaA

b. The primase

c. Dna

d. DNA polymerase

e. Pyrase

a. DnaA

You are searching for a mutant strain of E. coli which is antibiotic resistant. What approach is most likely to be successful?

a. DNA sequencing of cells within a population

b. Environmental searching for a new population

c. RNAseq analysis of the E. coli strain

d. Toothpick pick and patching

e. Replica plating on selective and non-selective media

e. Replica plating on selective and non-selective media

Term for the direct transfer of DNA from a living donor bacterium to a recipient bacterium/

a. Transduction

b. Conjugation

c. Transfection

d. Transformation

e. Electroporation

b. Conjugation

What is a proteome?

a. The mount of mRNA in the cell

b. The translated products encoded by the genes within a genome

c. The coding region on the chromosome minus the introns

d. The coding regions on the chromosome plus the control regions

e. The coding region on the chromosome

b. The translated products encoded by the genes within a genome

What did experiment by Avery, MacLeod, and McCarty in 1944 with the R and S strains of Streptococcus pneumoniae demonstrate?

a. That some strains of Streptococcus were not pathogenic

b. R strain phenotype could spontaneously revert to S strain phenotype

c. DNA was the genetic material in cells

d. Genetic material from one strain could not be transferred to another strain

e. The ability of these bacteria to kill mice

c. DNA was the genetic material in cells

Initiation of translation in bacteria starts with the binding of the ribosome to the mRNA molecule. The mRNA binds with its _____ to the 3' end of the ____

a. Pribnow box (TATA box), 23S rRNA

b. Rho sequence, 30S ribosomal subunit

c. Shine-Dalgarno sequence, 16S rRNA

d. Shine-Dalgarno sequence, ribosomal protein 23

e. Rho sequence, 16S rRNA

c. Shine-Dalgarno sequence, 16S rRNA

The mRNA of bacterial cells is often polycistronic. What does this term mean?

a. Tt can be translated from either end

b. It contains the code for multiple peptides

c. Tt is transcribed from multiple sites on the chromosome

d. It can be translated more than once

e. The translated protein may be modified in different ways

b. It contains the code for multiple peptides

Term for the uptake of extracellular DNA into a bacterial cell and incorporation into its genome.

a. Reversion

b. Conjugation

c. Transduction

d. Transformation

e. Transfection

d. Transformation

What is considered a bacterial strain's genome?

a. Everything except chromosome

b. Chromosome and plasmids, but not prophage DNA

c. Chromosome, plasmids, and lysogenic phage DNA

d. Genes that are actively transcribe

c. Chromosome, plasmids, and lysogenic phage DNA

Escherichia coli strain K12 is considered a wild-type strain and does not have any nutritional vitamin requirements. What term applies to this strain?

a. An auxotroph

b. A lithotroph

c. A phototroph

d. A prototroph

e. An autotroph

d. A prototroph

The ___ protein is important in the process of recombination

a. LacZ

b. RecA

c. TpnB

d. TpnC

e. TpnZ

b. RecA

DNA microarray analysis may be used to study:

a. Growth rate of cells when grown under different conditions

b. Protein expression in cells grown under different conditions

c. Enzyme activity in cells

d. Rate of chromosomal replication in cells

e. Gene expression in cells grown under different conditions.

e. Gene expression in cells grown under different conditions.

Suppose it is observed that a small section of a microorganism's chromosome varies significantly in GC content from the majority of the chromosome. What likely caused this?

a. Vertical gene transfer

b. Site-directed mutagenesis

c. Induced mutations

d. Horizontal gene transfer

e. Spontaneous mutations

d. Horizontal gene transfer

After the translational process the polypeptide folds into appropriate conformation for proper functioning. What group of proteins aids in protein folding?

a. Proteases

b. Chaperonins

c. Lipases

d. Cytokines

e. Peptidases

b. Chaperonins

In eukaryal cells, what does RNA polymerase II transcribe?

a. tRNA genes

b. Small regulatory RNAs

c. mRNA genes

d. the 55 and 18S rRNAs

e. rRNA genes

c. mRNA genes

In bacteria the replication of the chromosome is initiated by binding of which protein to the origin of replication?

a. DNA polymerase

b. Single-stranded DNA binding protein

c. DNA gyrase

d. DnaA

e. DnaB

d. DnaA

What is the sexual transfer of genes in bacteria called?

a. Transduction

b. Coupling

c. Conjugation

d. Transfection

e. Transformation

c. Conjugation

Term for a special sequence at the end of the chromosome in eukaryal cells?

a. Telomere

b. Centromere

c. Terminator

d. Enhancer

e. Antiorigin

a. Telomere

Which of these is TRUE regarding horizontal gene transfer?

a. It does not alter the genome of the organism

b. It doesn't play a role in microbial evolution

c. It does not result in any significant consequences for the organism involved

d. It occurs commonly in nature

e. It does not result in permanent change

d. It occurs commonly in nature

DNA micro array analysis may be used to study

a. Protein expression in cells grown under different conditions

b. Rate of chromosomal replication in cells

c. Enzyme activity in cells

d. Growth rate of cells when grown under different conditions

e. Gene expression in cells grown under different conditions

e. Gene expression in cells grown under different conditions

What are paralogs?

a. Genes that arise from a duplication event in the organism

b. Mutant genes in an organism

c. Genes that are expressed at a high level in an organism

d. Genes that have no function in an organism

e. Genes that are seldom expressed in an organism

a. Genes that arise from a duplication event in the organism

Which autoinducer is used by many Gram-negative bacteria?

a. a repressor protein

b. an activator protein

c. a metabolic intermediate

d. allolactose

e. a type of homoserine lactone

e. a type of homoserine lactone

Which of these is required for transcription that is regulated by positive control?

a. Activator Protein

b. DNA Polymerase

c. Attenuator protein

d. Repressor protein

e. Inducer protein

a. Activator Protein

A repressor protein binds to:

a. Operator

b. Sigma-70

c. -35 nucleotides upstream of promotor sequence

d. TATA box

e. Before each structural gene

a. Operator

Expression of genes that are constitutive is:

a. regulated by activation

b. Unregulated

c. regulated by repression

d. regulated by attenuation

e. regulated by induction

b. Unregulated

During negative regulation of gene expression, the repressor protein binds to the operator to inhibit transcription. What is the effector molecule that controls the activity of the repressor protein called?

a. Repressor

b. Corepressor or coactivator

c. Activator

d. Corepressor or inducer

e. Operator

d. Corepressor or inducer

What is an effector molecule?

a. A protein that binds to an operator region of a gene

b. A small molecule that binds to an enzyme/protein to regulate its activity

c. A small RNA molecule that inhibits translation of mRNA

d. An activator protein for gene expression

e. A small molecule that binds to the operator region of a gene

b. A small molecule that binds to an enzyme/protein to regulate its activity

The term for a large group of genes whose expression is under the control of a single regulatory system

a. Operon

b. Super operon

c. Regulon

d. Biome

e. Transcriptome

c. Regulon

Which component of the two component regulatory system frequently senses changes in the external environment?

a. Histidine kinase

b. Repressor protein

c. Response regulator

d. Transport protein

e. Activator protein

a. Histidine kinase

Translated type of RNA include:

a. sRNA

b. xRNA

c. rRNA

d. mRNA

e. tRNA

d. mRNA

The most commonly observed promotor sequence seen in an organism is known as the:

a. Consensus sequence

b. -35 region

c. TATA box

d. None is a correct choice

e. Shine-Delgarno sequence

a. Consensus sequence

Post initiation control of gene expression can be accomplished by:

a. All are correct

b. dsRNA

c. Small RNAs

d. tRNA

e. rRNA

c. Small RNAs

Once the autoinducer excreted by Vibrio fischeri reaches a critical concentration, it is able to diffuse back into the cell. What is its next action?

a. Be cleaved by a protease to produce luminescence

b. Bind to the promoter to enhance transcription of the lux genes

c. Inactivate a transcriptional repressor to allow transcription of the lux genes

d. Bind to the bacterial luciferase to produce luminescence

e. Bind to a transcriptional activator protein to activate transcription of the lux genes

e. Bind to a transcriptional activator protein to activate transcription of the lux genes

Small noncoding RNA molecules (sRNA) affect gene expression at the level of

a. transcription termination

b. protein activity

c. transcription initiation

d. transcription activation

e. transcription elongation

e. transcription elongation

Identify a mechanism that can switch off gene expression

a. Phosphorylation

b. Acetylation

c. translation activation

d. Methylation

e. mRNA synthesis inhibition

e. mRNA synthesis inhibition

During negative regulation of gene expression the repressor protein binds to the operator to inhibit transcription. What is the effector molecule that controls the activity of the repressor protein called?

a. Repressor

b. Activator

c. Corepressor or coactivator

d. Operator

e. Corepressor or inducer

e. Corepressor or inducer

What is diauxic growth?

a. Slow growth of auxotrophic mutants

b. Sequential use of different carbon sources leading to different growth rates

c. Inhibition of growth due to catabolite repression

d. Rapid growth due to simultaneous metabolism of multiple carbon sources (e.g. sugars)

e. Type of growth behavior used to identify nutritional mutants

b. Sequential use of different carbon sources leading to different growth rates

The term for a large group of genes whose expression is under the control of a single regulatory system

a. transcriptome

b. operon

c. regulon

d. super operon

e. biome

c. regulon

Which of these controls the expression of thelacoperon?

a. An attenuation mechanism

b. Both repression and attenuation mechanisms

c. A repressor protein only

d. Both repression and activation mechanisms

e. An activator protein only

d. Both repression and activation mechanisms

Which of these is required for transcription that is regulated by positive control?

a. attenuator protein

b. repressor protein

c. activator protein

d. inducer protein

e. DNA polymerase

c. activator protein

Which component of the two-component regulatory system frequently senses changes in the external environment?

a. activator protein

b. transport protein

c. histidine kinase

d. repressor protein

e. response regulator

c. histidine kinase

How will E. coli growing in a medium containing both lactose and glucose react?

a. Neither compound will be utilized for growth

b. By preferentially utilizing lactose first

c. By preferentially utilizing glucose first

d. By utilizing both at the same time

e. One will sometimes be utilized over the other

c. By preferentially utilizing glucose first

When glucose and lactose are present, which substrate is used by microbes:

a. glucose metabolism is repressed until lactose is used up

b. lactose inhibits glucose uptake

c. glucose and lactose are used simultaneously

d. glucose stimulates lactose uptake

e. lactose metabolism is repressed until glucose is used up

e. lactose metabolism is repressed until glucose is used up

How is chemotaxis regulated?

a. By allosteric enzymes

b. By a series of signal transduction events

c. By an induction-type mechanism

d. By increased gene expression

e. By decreased gene expression

b. By a series of signal transduction events

Post-initiation control of gene expression can be accomplished by:

a. small RNAs

b. all are correct

c. dsRNA

d. tRNAs

e. rRNA

a. small RNAs

Once the autoinducer excreted by Vibrio fischeri reaches a critical concentration, it is able to diffuse back into the cell. What is its next action?

a. Inactivate a transcriptional repressor to allow transcription of the lux genes

b. Be cleaved by a protease to produce luminescence

c. Bind to the bacterial luciferase to produce luminescence

d. Bind to the promoter to enhance transcription of the lux genes

e. Bind to a transcriptional activator protein to activate transcription of the lux genes

e. Bind to a transcriptional activator protein to activate transcription of the lux genes

Identify a mechanism that cannot reduce functional enzyme levels without changes in transcription or translation

a. Acetylation

b. Phosphorylation

c. Dephosphorylation

d. Methylation

e. translation inhibition

e. translation inhibition

Which of the following is not an example of a regulon?

a. SOS system

b. All are examples of regulons

c. lac operon

d. Catabolite repression

e. Heat shock protein activation

c. lac operon

Identify a mechanism that can switch off gene expression

a. translation activation

b. Phosphorylation

c. Methylation

d. Acetylation

e. mRNA synthesis inhibition

e. mRNA synthesis inhibition

Which of these is a term for a point mutation that results in a change in the amino acid specificity of the codon and the synthesized polypeptide?

a. silent

b. missense

c. amber

d. nonsense

e. frameshift

b. missense

Which of these would a signal peptide be used for in bacteria?

a. To help a protein fold correctly

b. To regulate translation

c. To help regulate the activity of an enzyme

d. To move a protein to the outside of the cell

e. To initiate DNA replication

d. To move a protein to the outside of the cell

The mRNA of bacterial cells is often polycistronic. What does this term mean?

a. It can be translated more than once

b. The translated protein may be modified in different ways

c. It contains the code for multiple peptides

d. Tt can be translated from either end

e. Tt is transcribed from multiple sites on the chromosome

c. It contains the code for multiple peptides

Suppose a microbe has died and lysed, exposing its DNA to the environment. Some of this DNA was taken up by another unrelated microbe and incorporated into its genome. This is an example of which process?

a. endocytosis

b. horizontal gene transfer

c. vertical gene transfer

d. transduction

e. conjugation

b. horizontal gene transfer

What is an open-reading frame?

a. A gene that no longer has a function

b. an unknown gene

c. The protein encoding sequence of a gene

d. The intron region of a gene

e. A non-translated region on the chromosome

c. The protein encoding sequence of a gene

The ___ protein is important in the process of recombination

a. LacZ

b. RecA

c. TpnB

d. TpnC

e. TpnZ

b. RecA

DNA microarray analysis may be used to study:

a. Growth rate of cells when grown under different conditions

b. Protein expression in cells grown under different conditions

c. Enzyme activity in cells

d. Rate of chromosomal replication in cells

e. Gene expression in cells grown under different conditions.

e. Gene expression in cells grown under different conditions.

Suppose it is observed that a small section of a microorganism's chromosome varies significantly in GC content from the majority of the chromosome. What likely caused this?

a. Vertical gene transfer

b. Site-directed mutagenesis

c. Induced mutations

d. Horizontal gene transfer

e. Spontaneous mutations

d. Horizontal gene transfer

After the translational process the polypeptide folds into appropriate conformation for proper functioning. What group of proteins aids in protein folding?

a. Proteases

b. Chaperonins

c. Lipases

d. Cytokines

e. Peptidases

b. Chaperonins

In eukaryal cells, what does RNA polymerase II transcribe?

a. tRNA genes

b. Small regulatory RNAs

c. mRNA genes

d. the 55 and 18S rRNAs

e. rRNA genes

c. mRNA genes

The mRNA of bacterial cells is often polycistronic. What does this term mean?

a. Tt can be translated from either end

b. It contains the code for multiple peptides

c. Tt is transcribed from multiple sites on the chromosome

d. It can be translated more than once

e. The translated protein may be modified in different ways

b. It contains the code for multiple peptides

Term for the uptake of extracellular DNA into a bacterial cell and incorporation into its genome.

a. Reversion

b. Conjugation

c. Transduction

d. Transformation

e. Transfection

d. Transformation

What is considered a bacterial strain's genome?

a. Everything except chromosome

b. Chromosome and plasmids, but not prophage DNA

c. Chromosome, plasmids, and lysogenic phage DNA

d. Genes that are actively transcribed

e. Chromosome only

c. Chromosome, plasmids, and lysogenic phage DNA

. What is a "reporter gene"?

a. A gene whose product can easily be measured

b. The fusion of two different structural genes

c. The fusion of a gene of interest to a regulatable promoter

d. A gene that is expressed under adverse environmental conditions

e. The fusion of a promoter region of interest to a gene whose product can easily be measured

e. The fusion of a promoter region of interest to a gene whose product can easily be measured

How is quorum sensing, a type of cell to cell communication, mediated?

a. By direct cell contact

b. By global regulation

c. By transfer of genetic information

d. By chemical signaling

e. By an induction mechanism

d. By chemical signaling

Which of these controls the expression of the lac operon?

a. An activator protein only

b. Both repression and attenuation mechanisms

c. Both repression and activation mechanisms

d. A repressor protein only

e. An attenuation mechanism

c. Both repression and activation mechanisms

You are analyzing a ~20,000 bp long DNA fragment that is part of a metagenome. Based on your experience in identifying microorganisms, what gene would you look for to best identify the organism that the DNA fragment might have come from?

a. DNA polymerase

b. tRNA gene

c. 16S rRNA gene

d. Cytochrome gene

e. Dehydrogenase gene

c. 16S rRNA gene

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) separates proteins based on what property?

a. Size and charge

b. Charge

c. Hydrophobicity

d. Size and hydrophobicity

e. Size

a. Size and charge

What did the experiment by Fred Griffith in 1928 with the R and S strains of Streptococcus pneumoniae demonstrate?

f. RNA was the genetic material in cells

g. Genetic material from one strain could be transferred to another strain

h. That all strains of streptococcus were pathogenic

i. The ability of these bacteria to kill mice

j. R strain phenotype could spontaneously revert to S strain phenotype

g. Genetic material from one strain could be transferred to another strain