MCB*2050 Topic 1: Gene and Transcriptional Regulation
Questions With Complete Solutions
transcription activators
speed up transcription by binding to a region of DNA called an
enhancer; regulates the loading and release of RNA polymerase
operon
a group of genes that operate together and code for proteins that
function in one pathway (e.g. metabolism of lactose)
epigenetic regulation
changes in gene expression that are due to environmental effects
rather than to changes in the nucleotide sequence of the gene
(e.g. chromatin-mediated regulation)
chromatin-mediated regulation
in eukaryotes, genes can be activated and transcription can
proceed only when chromatin is open; genes are incapable of
being transcribed when chromatin is closed
pioneer transcription factors
Regulatory protein, which can bind to tightly packed chromatin
and open its structure so that other regulatory proteins can bind.
heterochromatin (closed chromatin)
regions of chromosomes that are more densely packed; rich in
repetitive DNA (transposons), centromeres, and telomeres, and
not accessible to transcriptional machinery
, euchromatin (open chromatin)
regions of chromatin that are less densely packed; these regions
are where active genes are found and where genes can be
transcribed
RNA polymerase I
transcribes rRNA in eukaryotes
RNA polymerase II
transcribes mRNA, as well as some snRNAs, siRNAs, and
miRNAs in eukaryotes
RNA polymerase III
transcribes tRNAs and other small stable RNAs in eukaryotes
small nuclear RNAs (snRNAs)
RNAs that come together with proteins to form a complex that
mediates RNA splicing; they do not get translated. They are
found in many cellular structures such as ribosomes
small interfering RNAs (siRNAs)
RNAs responsible for chromatin-mediated repression and
translation control; they do not get translated
microRNAs (miRNAs)
small, single-stranded RNA molecules that remain untranslated.
They associate with one or more proteins in a complex that can
degrade or prevent translation of an mRNA with a
complementary sequence.
pre-initiation complex
Questions With Complete Solutions
transcription activators
speed up transcription by binding to a region of DNA called an
enhancer; regulates the loading and release of RNA polymerase
operon
a group of genes that operate together and code for proteins that
function in one pathway (e.g. metabolism of lactose)
epigenetic regulation
changes in gene expression that are due to environmental effects
rather than to changes in the nucleotide sequence of the gene
(e.g. chromatin-mediated regulation)
chromatin-mediated regulation
in eukaryotes, genes can be activated and transcription can
proceed only when chromatin is open; genes are incapable of
being transcribed when chromatin is closed
pioneer transcription factors
Regulatory protein, which can bind to tightly packed chromatin
and open its structure so that other regulatory proteins can bind.
heterochromatin (closed chromatin)
regions of chromosomes that are more densely packed; rich in
repetitive DNA (transposons), centromeres, and telomeres, and
not accessible to transcriptional machinery
, euchromatin (open chromatin)
regions of chromatin that are less densely packed; these regions
are where active genes are found and where genes can be
transcribed
RNA polymerase I
transcribes rRNA in eukaryotes
RNA polymerase II
transcribes mRNA, as well as some snRNAs, siRNAs, and
miRNAs in eukaryotes
RNA polymerase III
transcribes tRNAs and other small stable RNAs in eukaryotes
small nuclear RNAs (snRNAs)
RNAs that come together with proteins to form a complex that
mediates RNA splicing; they do not get translated. They are
found in many cellular structures such as ribosomes
small interfering RNAs (siRNAs)
RNAs responsible for chromatin-mediated repression and
translation control; they do not get translated
microRNAs (miRNAs)
small, single-stranded RNA molecules that remain untranslated.
They associate with one or more proteins in a complex that can
degrade or prevent translation of an mRNA with a
complementary sequence.
pre-initiation complex
