chapter 16

3' UTR

3' untranslated region; region just downstream of the protein-coding region in an RNA molecule that is not translated

5' UTR

5' untranslated region; region just upstream of the protein-coding region in an RNA molecule that is not translated

5' cap

a methylated guanosine triphosphate (GTP) molecule that is attached to the 5' end of a messenger RNA to protect the end from degradation

poly-A tail

a series of adenine nucleotides that are attached to the 3' end of an mRNA to protect the end from degradation

The binding of what is required for transcription start? a protein DNA polymerase RNA polymerase a transcription factor

a transcription factor

If glucose is absent but lactose is present, the lac operon will be: activated repressed partially activated mutated

activated

tryptophan

amino acid that can be synthesized by prokaryotic cells when necessary

operon

collection of genes involved in a pathway that are transcribed together as a single mRNA in prokaryotic cells

Which of the following are involved in post-transcriptional control? control of RNA splicing ubiquitination proteolytic cleavage phosphorylation

control of RNA splicing

post-transitional

control of gene expression after a protein has been created

post-transcriptional

control of gene expression after the RNA molecule has been created but before it is translated into protein

Binding of an RNA binding protein will change the stability of the RNA molecule in what way? increase decrease neither increase nor decrease either increase or decrease

either increase or decrease

guanine triphosphate (GTP)

energy-providing molecule that binds to eIF-2 and is needed for translation

dicer

enzyme that chops the pre-miRNA into the mature form of the miRNA

Control of gene expression in eukaryotic cells occurs at which level(s)? only the transcriptional level epigenetic and transcriptional levels epigenetic and transcriptional and translational levels epigenetic and transcriptional, translational, and post-translational levels

epigenetic and transcriptional, translational and post-translational levels

histone acetylation

epigenetic modification that leads to gene expression; commonly found in cancer cells

DNA methylation

epigenetic modification that leads to gene silencing; commonly found in cancer cells

epigenetic

heritable changes that do not involve changes in the DNA sequence

Which of the following statements about epigenetic regulation is false? Histone protein charge becomes more positive when acetyl groups are added. DNA molecules are modified within CpG islands. Methylation of DNA and histones causes nucleosomes to pack tightly together. Histone acetylation results in the loose packing of nucleosomes.

histone protein charge becomes more positive when acetyl groups are added

RNA stability

how long an RNA molecule will remain intact in the cytoplasm

A mutation in the 5'UTR that prevents any proteins from binding to the region will: increase or decrease the stability of the RNA molecule prevent translation of the RNA molecule prevent splicing of the RNA molecule increase or decrease the length of the poly-A tail

increase or decrease the stability of the RNA molecule

The addition of a ubiquitin group to a protein does what? increases the stability of the protein decreases translation of the protein increases translation of the protein marks the protein for degradation

marks the protein for degradation

guanine diphosphate (GDP)

molecule that is left after the energy is used to start translation

What are epigenetic modifications? the addition of reversible changes to histone proteins and DNA the removal of nucleosomes from the DNA the addition of more nucleosomes to the DNA mutation of the DNA sequence

mutation of the DNA sequence

myc

oncogene that causes cancer in many cancer cells

What are cancer-causing genes called? transformation genes tumor suppressor genes oncogenes protooncogenes

oncogens

lac operon

operon in prokaryotic cells that encodes genes required for processing and intake of lactose

inducible operon

operon that can be activated or repressed depending on cellular needs and the surrounding environment

proteasome

organelle that degrades proteins

A drug designed to switch silenced genes back on in cancer cells would result in what? prevent methylation of DNA and deacetylation of histones prevent methylation of DNA and acetylation of histones prevent deacetylation of DNA and methylation of histones prevent acetylation of DNA and demethylation of histones

prevent methylation of DNA and deacetylation of histones

gene expression

processes that control the turning on or turning off of a gene

initiation complex

protein complex containing eIF2-2 that starts translation

RISC

protein complex that binds along with the miRNA to the RNA to degrade it

eukaryotic initiation factor-2 (eIF-2)

protein that binds first to an mRNA to initiate translation

activator

protein that binds to prokaryotic operators to increase transcription

RNA-binding protein (RBP)

protein that binds to the 3' or 5' UTR to increase or decrease the RNA stability

transcription factor

protein that binds to the DNA at the promoter or enhancer region and that influences transcription of a gene

repressor

protein that binds to the operator of prokaryotic genes to prevent transcription

catabolic activator protein (CAP)

protein that complexes with cAMP to bind to the promoter sequences of operons that control sugar processing when glucose is not available

positive regulator

protein that increases transcription

negative regulator

protein that prevents transcription

operator

region of DNA outside of the promoter region that binds activators or repressors that control gene expression in prokaryotic cells

small 40S ribosomal subunit

ribosomal subunit that binds to the RNA to translate it into protein

large 60S ribosomal subunit

second, larger ribosomal subunit that binds to the RNA to translate it into protein

enhancer

segment of DNA that is upstream, downstream, perhaps thousands of nucleotides away, or on another chromosome that influence the transcription of a specific gene

untranslated region

segment of the RNA molecule that are not translated into protein. These regions lie before (upstream or 5') and after (downstream or 3') the protein-coding region

transcription factor binding site

sequence of DNA to which a transcription factor binds

trp operon

series of genes necessary to synthesize tryptophan in prokaryotic cells

transcriptional start site

site at which transcription begins

microRNA (miRNA)

small RNA molecules (approximately 21 nucleotides in length) that bind to RNA molecules to degrade them

What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator? In the presence of lactose, the lac operon will not be transcribed. In the absence of lactose, the lac operon will be transcribed. The cAMP-CAP complex will not increase RNA synthesis. The RNA polymerase will not bind the promoter.

the RNA polymerase will not bind the promoter

Gene A is thought to be associated with color blindness. The protein corresponding to gene A is isolated. Analysis of the protein recovered shows there are actually two different proteins that differ in molecular weight that correspond to gene A. What is one reason why there may be two proteins corresponding to the gene? One protein had a 5' cap and a poly-A tail in its mRNA, and the other protein did not. One protein had a 5' UTR and a 3' UTR in its RNA, and the other protein did not. The gene was alternatively spliced. The gene produced mRNA molecules with differing stability.

the gene was alternatively spliced

In a new cancer treatment, a cold virus is genetically modified so that it binds to, enters, and is replicated in cells, causing them to burst. The modified cold virus cannot replicate when wildtype p53 protein is present in the cell. How does this treatment treat cancer without harming healthy cells? The modified virus only infects and enters cancer cells. The modified virus replicates in normal and cancer cells. The modified virus only infects and enters normal cells. The modified virus replicates only in cancer cells.

the modified virus only infects and enters cancer cells

A mutation is found in eIF-2 that impairs the initiation of translation. The mutation could affect all but one of the following functions of eIF-2. Which one would not be affected? The mutation prevents eIF-2 from binding to RNA. The mutation prevents eIF-2 from being phosphorylated. The mutation prevents eIF-2 from binding to GTP. The mutation prevents eIF-2 from binding to the 40S ribosomal subunit.

the mutation prevents eIF-2 from binding to RNA

Which of the following is true of epigenetic changes? They only allow gene expression. They allow movement of histones. They change the DNA sequence. They are always heritable.

they allow movement of histones

trans-acting element

transcription factor binding site found outside the promoter or on another chromosome that influences the transcription of a particular gene

cis-acting element

transcription factor binding sites within the promoter that regulate the transcription of a gene adjacent to it