Chapter 18: Regulation of Gene Expression

Chemotherapeutic treatment for breast cancer depends on the absence or overexpression of the __________ gene(s). ERa, PR, and HER2 p53 ras APC p21

ERa, PR, and HER2

Which of the following best describes the makeup of the human genome? Genes for noncoding RNA make up the majority of meaningful genetic information in the human genome. Most of the genome consists of protein-coding DNA. Most of the genome does not contain meaningful genetic information and is not transcribed. The amount of DNA that consists of genes for ribosomal RNA and transfer RNA is slightly greater than the protein-coding DNA. None of the listed responses is correct.

Genes for noncoding RNA make up the majority of meaningful genetic information in the human genome.

What gene has been called the "guardian angel of the genome?" The BRCA1 gene The p53 gene The ras gene The myoD gene The p21 gene

The p53 gene

In the lac operon, the inducer is __________. allolactose, the isomer of lactose β-galactosidase lactose catabolic activator protein tryptophan

allolactose, the isomer of lactose

Post-transcriptional processing of a pre-mRNA allows for differential cell expression by a process called __________. combinatorial control enhanced transcription protein processing alternative splicing capping and tailing

alternative splicing

In prokaryotic genomes, groups of functionally related genes along with their promoters and operators are found together in __________. an operon a regulatory gene a transcription factor an enhancer a repressor

an operon

The trp (tryptophan) operon is an example of a(n) __________ that is controlled by __________. catabolic pathway; positive feedback catabolic pathway; feedback inhibition anabolic pathway; feedback inhibition anabolic pathway; positive feedback None of the listed responses is correct.

anabolic pathway; feedback inhibition

In Drosophila development, the anterior-posterior axis of the embryo is determined by __________. segmentation genes egg-polarity genes oncogenes myoD homeotic genes

egg-polarity genes

In a eukaryote, activating transcription factors may stimulate gene expression by binding to a DNA site called a(n) __________. silencer enhancer promoter histone operon

enhancer

In Drosophila development, pattern development in the late embryo, larva, and adult is controlled by __________. homeotic genes segmentation genes myoD oncogenes egg-polarity genes

homeotic genes

The lac operon is an example of a(n) __________ operon. activated eukaryotic inducible repressible suppressed

inducible

Specific cells that appear undifferentiated under the microscope but are already fated to become muscle cells are called __________. muscle cells myoblasts meristematic cells bicoids myocytes

myoblasts

In eukaryotes, histone acetylation __________. marks genes for destruction promotes transcription imprints genes inactivates genes reduces the size of the genome

promotes transcription

What two genes are often mutated in colon cancer? ras and myoD BRCA1 and BRCA2 APC and myoD ras and p53 p21 and p53

ras and p53

The trp (tryptophan) operon is an example of a(n) __________ operon. suppressed activated repressible eukaryotic inducible

repressible

In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway (such as the trp operon) are __________, and those encoding the enzymes of a catabolic pathway (such as the lac operon) are __________. inducible; repressible permanently off; permanently on repressible; inducible easily mutated; resistant to mutations permanently on; permanently off

repressible; inducible

In the trp (tryptophan) operon, the __________ binds to the product of the trp operon synthesis pathway, called __________, forming the __________. operator; lactose; inactive corepressor operator; tryptophan; inactive corepressor repressor protein; lactose; inactive corepressor operator; tryptophan; active corepressor repressor protein; tryptophan; active corepressor

repressor protein; tryptophan; active corepressor

In an inducible operon, the inducer is often the __________ in the pathway being regulated; the inducer binds to the __________, thus rendering it __________. substrate; corepressor; inactive substrate; repressor; inactive end product; repressor; inactive end product; corepressor; inactive substrate; repressor; active

substrate; repressor; inactive

Both repressible and inducible operons control gene expression at the level of __________. post-translational processing translation transcription DNA packing post-transcriptional processing

transcription

What is the role of proteasomes? - They are segments of noncoding DNA that help regulate transcription by binding certain proteins. - None of the listed responses is correct. - They inject double-stranded RNA into a cell, turning off a gene with the same sequence. - They are giant protein complexes that recognize ubiquitin and degrade the tagged proteins. - They encode for products that help prevent uncontrolled cell growth.

- They are giant protein complexes that recognize ubiquitin and degrade the tagged proteins.

Although the number of genes in the human genome is surprisingly low compared to less complex organisms, the number of possible products from those genes is greatly amplified by __________. - differential activation of genes in different cell types - each gene being activated by a unique combination of control elements and activator molecules - alternate arrangements of exons from a primary transcript - the congregation in specific sites in the nucleus of genes involved in related metabolic processes, but on different chromosomes - coordinate control of genes on different chromosomes

- alternate arrangements of exons from a primary transcript

Cytoplasmic determinants __________. - are RNAs, proteins, and other substances produced by the mother and deposited in the egg - are found in both eggs and sperm - are important in later embryonic stages - None of the listed responses is correct. - are RNAs, proteins, and other substances produced by the father and deposited in the egg when fertilized

- are RNAs, proteins, and other substances produced by the mother and deposited in the egg

Cell type-specific transcription is accomplished __________. - by specific enhancer control elements interacting with cell type-specific transcription factors - by blocking the binding of RNA polymerase II - by specific enhancer control elements shutting down transcription factors for the gene that is not needed - by using a corepressor - by specific enhancer control elements that activate splicing of the DNA

- by specific enhancer control elements interacting with cell type-specific transcription factors

Gene expression in bacteria is regulated primarily by __________. - controlling gene packing and unpacking - controlling the translation of mRNA into protein - controlling the transcription of genes into mRNA - transcription factors encoded for by mitochondrial DNA - selectively breaking down the proteins encoded by the genes

- controlling the transcription of genes into mRNA

A cancer cell __________. - does not respond to the chemical signals that control cell division - usually does not contain a nucleus - All of the listed responses are correct. - requires less nutrients than a normal cell -is typically more than 10 times larger than a normal cell

- does not respond to the chemical signals that control cell division

The control of gene expression is more complex in multicellular eukaryotes than in prokaryotes because __________. - the genes of eukaryotes provide information for making proteins - prokaryotes are restricted to stable environments - in a multicellular eukaryote, different cells are specialized for different functions - eukaryotic chromosomes have fewer nucleotides; therefore, each nucleotide sequence must do several jobs - eukaryotic cells are much smaller

- in a multicellular eukaryote, different cells are specialized for different functions

Small noncoding RNAs (ncRNAs) called piwi-interacting RNAs, or piRNAs, __________. - modify histones - induce the formation of heterochromatin and block the expression of movable DNA elements called transposons - induce shorter mRNA expression by reducing introns - induce the formation of euchromatin and block the expression of movable DNA elements called transposons - enhance transposon expression

- induce the formation of heterochromatin and block the expression of movable DNA elements called transposons

In addition to a promoter, eukaryotic genes have control elements called __________. - proximal control elements and distal enhancers - both proximal enhancers and proximal control elements - proximal enhancers and distal control elements - distal control elements and distal enhancers - operators

- proximal control elements and distal enhancers

MicroRNAs binding to complementary sequences on an mRNA __________. - enhances translation of the message - increases the half-life of the message so that more protein can be produced - results in either blocking translation or degrading the targeted mRNA - are signals for the ribosome to form a protein complex - None of the listed responses is correct.

- results in either blocking translation or degrading the targeted mRNA

MyoD promotes muscle cell development by __________. - turning on the expression of multiple muscle-related genes - enhancing apoptosis of non-muscle cells - stimulating the production of muscle-specific splicing variants of certain mRNAs - increasing the translation of muscle-related genes - stimulating a receptor on the surface of muscle cells, thus activating a signal-transduction pathway that promotes muscle development

- turning on the expression of multiple muscle-related genes