ADV CH 9 LECTURE

Which are components of an operon in a sequence of DNA? Multiple select question.(2) inducer RNA polymerase structural genes operator repressor

structural genes operator

A(n) ______ operon, such as the lac operon, is usually in the "off" position, but can be turned on when the appropriate substrate is present.

Blank 1: inducible

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

False

Which type of operon is typically in the "off" position until the appropriate substrate is present? Constitutive operon Inducible operon Repressible operon

Inducible operon

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

Regulatory

________ of positive-strand ssRNA requires the synthesis of a negative strand which becomes a master template to create new daughter strands.

Replication

Transcription of the structural genes of the lac operon will be greatest when glucose is present in high concentrations but lactose is absent. both lactose and glucose are present in high concentrations. lactose is present in high concentrations but glucose is absent. both lactose and glucose are present but in low concentrations.

lactose is present in high concentrations but glucose is absent.

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

oncogenic

Gene expression in prokaryotes is regulated through _______. mutation enzymatic regulation feedback inhibition operons

operons

The ________ of an operon is the location where RNA polymerase binds, whereas the _________ acts as the on/off switch for transcription of the structural genes. operator/ligaser operator/promoter promoter/operator promoter/ligaser

promoter/operator

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

Blank 1: repressor

Retroviruses contain the enzyme __________ _________.

Blank 1: reverse Blank 2: transcriptase

Which type of organisms have their DNA arranged into operons? Eukaryotes Prokaryotes

Prokaryotes

_______ operons are usually turned on by the substrate of the enzyme for which the structural genes code.

Blank 1: Inducible

__________ genes code for proteins.

Blank 1: Structural

Viral DNA inserted into the host genome may cause the transformation of the host cell into a ________ cell.

Blank 1: cancer or cancerous

Lactose acts as an ________ in the lactose operon.

Blank 1: inducer

Which viruses insert their DNA into the host genome increasing the risk of cancer? Multiple select question.(2) Hepatitis B virus Herpesvirus Ebola virus

Hepatitis B virus Herpesvirus

Which part of the control locus acts as an on/off switch for transcription? Corepressor Promoter Inducer Operator

Operator

Prokaryotic DNA is arranged into systems called ________.

Operons

Which of the following is the genetic pattern of viral genomes? Single or double stranded DNA or RNA Single stranded DNA only Double stranded DNA only Single or double stranded DNA only

Single or double stranded DNA or RNA

Which kind of gene encodes a protein? Ribosomal Structural Regulatory

Structural

True or false: The promoter of an operon is the location where RNA polymerase binds, whereas the operator acts as the on/off switch for transcription of the structural genes.

True

Which of the following are true of RNA viruses compared to DNA viruses? Multiple select question.(3) Virus cycle occurs in cytoplasm. Enter host cell in RNA form. Smaller genomes. Virus cycle occurs in nucleus.

Virus cycle occurs in cytoplasm Enter host cell in RNA form Smaller genomes

The arg operon is usually transcriptionally active because the repressor is ______ until the levels of arginine ______. inactive; build up active; build up inactive; fall

inactive; build up

The _______ section of the control locus acts as an on/off switch for transcription.

operator

The ssRNA of positive-strand viruses come ready to be ______ into proteins. replicated translated transcribed

translated

_______ operons often contain genes coding for anabolic enzymes and are usually turned off by the end product of the reactions catalyzed by these enzymes.

Repressible

The _______ is the gene that codes for a protein capable of repressing the operon.

Regulator

What is the term for the gene that codes for a protein capable of repressing the operon? Corepressor Promoter Operator Regulator

Regulator

Control mechanisms ensure that _____ are active only when their products are required. ribosomes tRNAs genes codons

genes

What is the inducer of the lactose operon? Galactose Fructose Lactose Glucose

Lactose

Transcription of the structural genes of the arg operon is inhibited when arginine builds up and binds to and inactivates the repressor. levels fall so that arginine is released from the repressor. builds up and binds to and activates the repressor.

builds up and binds to and activates the repressor.

Transcription of the structural genes of the lac operon will be inhibited when lactose concentration is high and glucose concentration is high. lactose concentration is high and glucose concentration is low. lactose concentration is low and glucose concentration is high.

lactose concentration is low and glucose concentration is high.

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

Blank 1: environmental Blank 2: development

Several DNA viruses are known to be initiators of cancers and are thus termed ________.

Blank 1: oncogenic or oncoviruses

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

Blank 1: operator Blank 2: structural

The ______ protein is capable of repressing an operon.

Blank 1: repressor

The enzyme _______ ______ synthesizes a single strand DNA from the viral RNA template.

Blank 1: reverse Blank 2: transcriptase

RNA virus genomes are usually ________ than DNA virus genomes.

Blank 1: smaller

Which are parts of the lactose operon? Multiple select question.(3) Corepressor Control locus Regulator Structural locus

Control locus Regulator Structural locus

What binds with an inactive repressor to make an active repressor? Corepressor Promoter Inducer Repressor

Corepressor

The lactose operon is composed of the regulator, the ______ locus, and the structural locus. promoter elongation control

control

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

corepressor