BIO 2100 Exam 5 questions and
answers rated A+
Operator - correct answer ✔✔ The on-off switch of DNA
Operon - correct answer ✔✔ Entire stretch of DNA required for enzyme production
Repressor - correct answer ✔✔ Binds to the operator and blocks attachment of RNA
polymerase to the promoter, preventing transcription of the genes
Regulatory Gene - correct answer ✔✔ Encodes repressor proteins
Corepressor - correct answer ✔✔ A small molecule that cooperates with a repressor protein to
switch an operon off ex: tryptophan
Repressible Operon - correct answer ✔✔ An operon whose transcription is usually on but can
be inhibited when a specific small molecule binds allosterically to a regulatory protein ex: trp
operon
Inducible Operon - correct answer ✔✔ An operon whose transcription is usually off but can be
stimulated to be on when a specific small molecule interacts with a different regulatory protein
ex: lac operon
Inducer - correct answer ✔✔ A specific small molecule that binds to an active repressor to
inactivate it and stimulate transcription ex: allolactose
, Cyclic AMP (cAMP) - correct answer ✔✔ An organic molecule that accumulates when glucose is
scarce
Activator - correct answer ✔✔ A protein that binds to DNA and stimulates transcription of a
gene
cAMP Receptor Protein (CRP) - correct answer ✔✔ A regulatory protein and activator. When
cAMP binds to this protein it assumes its active shape and attaches to a specific site at the
upstream end of the lac promoter
Differential Gene Expression - correct answer ✔✔ The expression of different genes by cells
with the same genome, allows for differences between cell types
Histone Acetylation - correct answer ✔✔ The addition of an acetyl group to an amino group to
an amino acid in a histone tail. This action promotes transcription by opening up the chromatin
structure
DNA Methylation - correct answer ✔✔ The addition of methyl groups to histones leading to the
condensation of chromatin and reduced transcription
Epigenetic Inheritence - correct answer ✔✔ Inheritance of traits transmitted by mechanisms
not involving the nucleotide sequence itself
Control Elements - correct answer ✔✔ Segments of noncoding DNA that serve as binding sites
for the proteins called transcription facotrs
Enhancers - correct answer ✔✔ More distant distal control elements which may be thousands
of nucleotides upstream or downstream of a gene or even within an intron. A gene may have
several of these but each one of these is generally only associated with one gene
answers rated A+
Operator - correct answer ✔✔ The on-off switch of DNA
Operon - correct answer ✔✔ Entire stretch of DNA required for enzyme production
Repressor - correct answer ✔✔ Binds to the operator and blocks attachment of RNA
polymerase to the promoter, preventing transcription of the genes
Regulatory Gene - correct answer ✔✔ Encodes repressor proteins
Corepressor - correct answer ✔✔ A small molecule that cooperates with a repressor protein to
switch an operon off ex: tryptophan
Repressible Operon - correct answer ✔✔ An operon whose transcription is usually on but can
be inhibited when a specific small molecule binds allosterically to a regulatory protein ex: trp
operon
Inducible Operon - correct answer ✔✔ An operon whose transcription is usually off but can be
stimulated to be on when a specific small molecule interacts with a different regulatory protein
ex: lac operon
Inducer - correct answer ✔✔ A specific small molecule that binds to an active repressor to
inactivate it and stimulate transcription ex: allolactose
, Cyclic AMP (cAMP) - correct answer ✔✔ An organic molecule that accumulates when glucose is
scarce
Activator - correct answer ✔✔ A protein that binds to DNA and stimulates transcription of a
gene
cAMP Receptor Protein (CRP) - correct answer ✔✔ A regulatory protein and activator. When
cAMP binds to this protein it assumes its active shape and attaches to a specific site at the
upstream end of the lac promoter
Differential Gene Expression - correct answer ✔✔ The expression of different genes by cells
with the same genome, allows for differences between cell types
Histone Acetylation - correct answer ✔✔ The addition of an acetyl group to an amino group to
an amino acid in a histone tail. This action promotes transcription by opening up the chromatin
structure
DNA Methylation - correct answer ✔✔ The addition of methyl groups to histones leading to the
condensation of chromatin and reduced transcription
Epigenetic Inheritence - correct answer ✔✔ Inheritance of traits transmitted by mechanisms
not involving the nucleotide sequence itself
Control Elements - correct answer ✔✔ Segments of noncoding DNA that serve as binding sites
for the proteins called transcription facotrs
Enhancers - correct answer ✔✔ More distant distal control elements which may be thousands
of nucleotides upstream or downstream of a gene or even within an intron. A gene may have
several of these but each one of these is generally only associated with one gene
