Ch 9- An introduction to Microbial Genetics

Which term represents all of the genetic information within a cell? (genome, gene, chromosome)

genome

Genetic inheritance in microorganisms is best defined by which term? (phenotype, recombination, mutation, heredity)

heredity

_____ is another term for genetics-- the study of inheritance in living things.

heredity

What must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosomes? (replication, transformation, transcription, translation)

replication

The _____ protein is capable of repressing an operon.

repressor

The protein product of a repressor gene is the ____ which binds the operator to stop transcription.

repressor

Vancomycin-resistant enterococci (VRE) arise when, through genetic transfer, a MRSA strain acquires the _____ operon located within a ______

vanA; transposon

True or False: Bacterial conjugation is a sexual process.

False Bacterial have no exact equivalent to sexual reproduction, but use conjugation for gene exchange via pili.

The complete set of chromosomes and genes in an organism is referred to as the ______

genome

During semiconservative _____ the DNA is duplicated prior to binary fission.

replication

During semiconservative _________ the DNA is duplicated prior to binary fission.

replication

The protein product of a repressor gene is the ______ which binds the operator to stop transcription.

repressor

In a chromosome, the DNA is composed of ___ strands.

2

What is the name of the specialized plasmid that directs conjugation in gram-negative cells? (lambda, lac operon, pilus factor, f factor)

F factor

Conjugation in gram-negative cells is directed by a plasmid called the ____ factor.

F or fertility

True or False: Mutations are always harmful to cells.

False

True or False: Viral genomes are always composed of either single or double stranded DNA.

False viral genomes may be composed of single or double stranded DNA or RNA.

The three types of RNA are _____RNA, ______RNA, and ______RNA.

messenger (mRNA) transfer (tRNA) ribosomal (rRNA)

The mechanisms of _____ transformation involve genes that can regulate cellular genomes and control the onset of cell division.

oncogenic

Two components of an operon include the ____ that acts as an on/off switch, and the ____ gene sequences.

operator; structural

______ RNA may exert control on several levels in both prokaryotes and eukaryotes.

regulatory

Which of the following is the genetic pattern of viral genome?

single or double stranded DNA or RNA

What type of mutation is due to random mistakes in replication? (induced, spontaneous, nonspontaneous)

spontaneous

______ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.

spontaneous

Which term, synonymous with codon, describes a trinucleotide sequence coding an amino acid in DNA? (anticodon, inversion, triplet)

triplet

The ____ protein is capable of repressing an operon.

repressor

______ in bacteria refers to horizontal gene transmission via pili.

conjugation

Two components of an operon include the ____ that acts as an on/off switch, and the _____ gene sequence.

operator; structural

What is the purpose of the Ames test? - to determine is an operon is turned on of off. - to verify the DNA template sequence used in transcription - to demonstrate the effects of transformation on a bacterial species - to determine the carcinogenic potential of a chemical.

- to determine the carcinogenic potential of a chemical.

The term ______, or codon, is a sequence of 3 nucleotides in DNA that encodes an amino acid.

triplets

A _____ binds to an inactive repressor to make an active repressor.

corepressor

Which bet describes the flow of genetic information in a cell?

DNA encodes RNA which encodes protein

The flow of genetic information in a cell is a process starting with ____ which encodes ____ which encodes protein.

DNA; RNA/mRNA

What binds with an inactive repressor to make an active repressor? (corepressor, inducer, repressor, promoter)

corepressor

The main enzyme responsible for the transcription is (ligase, helicase, gyrase, DNA polymerase, RNA polymerase)

RNA polymerase During transcription, RNA is built using RNA polymerase. DNA polymerase is involved in replication of DNA.

Which term refers to the transfer of genes from donor to recipient microorganisms? (recombination, reproduction, mutation, heredity)

recombination

______ refers to the transfer of genes from donor to recipient strain shows a change in genetic makeup at the end.

recombination

What are components of an operon in a sequence of DNA? (structural genes, RNA polymerase, repressor, inducer, operator)

- structural genes - operator

Which of the following are functions of the RNA polymerase? - seals the fragmented piece of RNA together after synthesis - synthesizes an RNA molecule from DNA template - terminates the transcription process - unwinds the DNA so that transcription can take place

- synthesizes an RNA molecule from DNA template - unwinds the DNA so that transcription can take place

The _____ test is used to determine the carcinogenic potential of a chemical.

Ames

True or False: a mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.

TRUE

Genetic transfer of ____ to a methicillin-resistant Staphylococcus aureus (MRSA) strain produces vancomycin resistant enterococci (VRE).

a transposon containing the vanA operon

Which of the following is NOT a type of RNA? (dRNA, mRNA, tRNA, rRNA)

dRNA

The DNA of a chromosome is ____ stranded

double

In eukaryotic cells, gene expression is regulated in response to ____ stimuli such as nutrient and toxin levels, and also during growth and ______.

environmental; development

Proteins that remove incorrect bases and replace them with correct ones are termed _____ repair enzymes.

excision

Proteins that remove incorrect bases and replace them with correct ones are termed _____ repair enzymes. (deletion, ligase, excision, light)

excision

Which is the correct order of events when a protein is made in the process of translation?

initiation, elongation, termination

The first three events of translation in the correct order are _______, _______, ________ followed by protein folding and processing.

initiation; elongation; termination

Which DNA sequences are found within a gene but do not encode the protein specified by that gene? (exons, introns)

introns

______ are DNA sequences found within a gene that do not encode the protein corresponding to the gene.

introns

A permanent inheritable alteration in the DNA sequence of a cell is a _______

mutation

a small number of ______ are considered beneficial in that they provide the cell with a useful change in structure or physiology.

mutation

Several DNA viruses are known to be initiators of cancers are thus termed _____

oncogenic

Which process repairs DNA that has been damaged by Ultraviolet radiation using visible light? (photoactivation, photolysis, excision repair)

photoactivation

A _____ is a small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes.

plasmid

What is a small circular segment of DNA found in the cytoplasm of prokaryotes that is capable of independent replication and usually contains nonessential genes? (transposon, plasmid, chromsome, mutation)

plasmid

Mutations that involve the addition, deletion, or substitution of no more than a few bases are referred to as ______ mutations.

point

Mutations that involve the addition, deletion, or substitution of one or a few bases are referred to as _____ mutations. (frameshift, back, point, wild-type)

point

Mutations that involve the addition, deletion, or substitution of one or a few bases are referred to as ______ mutations. (frameshift, wild-type, point, back)

point

Which are components of an operon in a sequence of DNA? (repressor, inducer, structural genes, RNA polymerase, operator)

structural genes operator Repressor: is a protein that attaches to the operator region to block transcription. It is not part of the operon itself. Inducer: is a molecule that when it combines with the repressor, removes it and allows transcription to occur. RNA polymerase: transcribes the DNA of the operon.