Genetics exam 3

Which component of the ribosome is able to detect when the wrong tRNA has inserted into the A site? 16S rRNA P site 23S rRNA Shine-Dalgarno sequence aminoacyl-tRNA synthetase snRNA

16s rRNA

RNA polymerase I in eukaryotes produces which type of RNA? 5S rRNA 18S rRNA tRNA snRNA

18s rRNA

The restriction enzyme BamHI recognizes the sequence: 5'-G/GATCC-3' 3'-CCTAG/G-5' It cuts between the G and G as noted by the slashes. Following the digestion of chromosomal DNA and vector DNA with BamHI, let's suppose that one fragment of chromosomal DNA gets inserted into a vector. No DNA ligase has been added. If both of the sticky ends holding the chromosomal DNA fragment are binding to the sticky ends of the vector, what is holding the two pieces of DNA together? 26 hydrogen bonds 10 hydro

20 hydrogen bonds -The DNA fragments are held together by the hydrogen bonds holding the nucleotides together. There are 4 nucleotides in the overhang on each end, GATC and CTAG. Each GC base pair is held together by 3 hydrogen bonds and each AT base pair is held together by 2 hydrogen bonds. 2x3 + 2x2 = 10. Because there two ends, there are 20 hydrogen bonds holding the molecules together.

Which component of the ribosome is part of the peptidyl transferase in the 50S subunit and acts as a ribozyme to catalyze peptide bond formation? nRNA 23S rRNA 16S rRNA aminoacyl-tRNA synthetase Shine-Dalgarno sequence P site

23s rRNA

The consensus sequences in a prokaryotic promoter are 5'TTGACA3' and 5'TATAAT3' at -35 and -10, respectively. What sequence would be most easily recognized by σ factor? 5'TAAATT3' 5'TTCAGA3' 5'TTGAAA3' 5'TATATA3'

5'TTGAAA3' The sequence 5'TTGAAA3' only has one difference from the -35 consensus sequence. The other sequences have more than one difference from either the -35 or -10 sequence. Therefore 5'TTGAAA3' would be most readily recognized.

You perform a cell free translation experiment like Nirenberg and Matthaei, but you forget to write down what nucleotides you added to make the mRNA. You precipitate the translated polypeptides and measure the relative amount of radiolabeled amino acids incorporated into them. You get 25% proline, 25% threonine, 12.5% glutamine, 12.5% lysine, 12.5% asparagine, and 12.5% histidine. What nucleotides and in what % did you add to make the mRNA? 50% C and 50% U 50% A and 50% G 50% C and 50% A 70% C

50% C and 50% A If the amounts of the NDPs in the phosphorylase reaction are controlled, the relative amounts of the possible codons can be predicted. e.g., if 50% C and 50% A are mixed together with polynucleotide phosphorylase, the predicted amounts of the codons within the random polymers would include 12.5% CCC & 12.5% CCA, both of which encode Pro, for an expected value of 25% proline.

Which of the following is an example of a base analog? 5BU EMS nitrous acid acridine dyes nitrogen mustards

5BU -Compounds such as 5-bromouracil (5BU) and 2-amino purine are base analogs that become incorporated into daughter strands during DNA replication. 5BU is a thymine analog that can be incorporated into DNA instead of thymine.

Regulation of gene expression may occur at which of the following levels? Multiple Choice transcription translation posttranslation All of the answers are correct.

All answers are correct

What would be the result if the U-rich sequence after the fourth stem loop in the trp operon was replaced by a UG-rich sequence? Multiple Choice Attenuation would occur if tryptophan was high. Attenuation would occur if tryptophan is low. Attenuation would not occur if tryptophan was high. None of the answers are correct.

Attenuation would not occur if tryptophan was high. -Attenuation occurs when tryptophan levels are high. The U-rich sequence is involved in rho-independent termination at the attenuator sequence. Recall that in rho-independent termination, a stem-loop forms in the RNA, which causes the RNA polymerase to pause. While the polymerase is paused, the RNA and the polymerase dissociate from the DNA due to the weak hydrogen bonding between U and A in the U-rich sequence. Therefore, we can surmise that if the U-rich sequence was replaced with a UG-rich sequence, the hydrogen bonding would be too strong for the RNA to dissociate, and attenuation would not occur.

What is the make up of the bacterial and eukaryotic SRP, respectively? Bacterial: 1 ncRNA, 1 protein; Eukaryotic: 1 ncRNA, 6 proteins Bacterial: 1 ncRNA, 6 proteins; Eukaryotic: 1 ncRNA, 6 proteins Bacterial: 6 ncRNAs, 1 protein; Eukaryotic: 1 ncRNA, 1 protein Bacterial: 1 ncRNA, 1 protein; Eukaryotic: 6 ncRNAs, 1 protein

Bacterial: 1 ncRNA, 1 protein; Eukaryotic: 1 ncRNA, 6 proteins

What gene(s) is/are encoded in the Xic? Xce Xist Tsix Both the Tsix and Xist are genes are in the Xic region

Both the Tsix and Xist are genes are in the Xic region

Most trinucleotide repeat expansion repeats involve expansion of which of the following? any codon containing three of the same bases GAA ATG CAG

CAG

Into which gene of the CRISPR-Cas system are fragments of bacteriophage DNA inserted? Cas9 Cas1 Cas2 tracr Crispr

Crispr

CpG islands are associated with which of the following? Multiple Choice termination of translation DNA methylation steroid hormone activity nucleosome location

DNA Methylation

Select the ncRNA that facilitates the binding of telomerase to the telomere and acts as a template for DNA replication. TERC snRNA SRP RNA Xist RNA

TERC

What general transcription factor is most often affected by regulatory transcription factors? TFIIE TFIIF TFIIB TFIID

TFIID

Translational regulatory proteins recognize specific areas of what molecule? Multiple ChoicetRNA Ribosome rRNA mRNA None of the answers are correct.

mRNA

An RNA molecule with catalytic activity is called a(n) ncRNA snRNA ribozyme miRNA.

ribozyme

In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated? Two One Zero Three

two -In the TPP riboswitch, transcription is attenuated when TPP is bound, and transcription occurs when TPP is not bound. Therefore, if TPP cannot bind to the mRNA, the operon will be transcribed completely.

Most eukaryotic genes are colinear. True False It is unknown at this time.

False

With which injection did Mello and Fire observe the lowest amount of mex-3 probe staining? Injected with double-stranded RNA Uninjected Injected with mex-3 antisense RNA

Injected with double-stranded RNA

Beechdrops is a parasitic plant that cannot perform photosynthesis but relies on its host the Beech tree. However, beechdrops still retains many if not all of the genes for photosynthesis. Snapdragons and gladiolas are common garden flowers that rely on their ability to perform photosynthesis. If you were to compare the gene sequences for these three plants for ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) a protein necessary for photosynthesis what would you predict? The differences

The differences between gladiolas and snapdragons would most likely be silent mutations while those in beechdrops may be silent or missense -Since the gene for ribulose-1,5-bisphosphate carboxylase/oxygenase is still functioning in snapdragons and gladiolas, you would expect very few mutations in these genes, or for the mutations to be silent. When looking at beechdrops, it is still likely to have some silent mutations, but may have missense mutations as well, since the plant doesn't carry out photosynthesis.

In eukaryotic organisms, the processing of the 45S rRNA into 5.8S, 18S, and 28S rRNA occurs where? in the endoplasmic reticulum in the nucleolus in the Golgi body throughout the cell in the cytoplasm

The nucleolus

What effect will a mutation in IRP that prevents it from binding to iron have on an individual? Ferritin will not be made, so iron intake must be maximized. There will be excess ferritin, so iron intake must be lowered. There will be excess transferrin, so iron intake must be lowered. Transferrin will not be made, so iron intake must be maximized.

There will be excess transferrin, so iron intake must be lowered. -The iron regulatory protein (IRP) binds to the IRE of the ferritin mRNA, preventing translation. When iron binds to the IRP, the IRP is released from the IRE and translation of ferritin proceeds. At the transferrin receptor mRNA, the IRP enhances the stability of the mRNA. When IRP binds iron, the IRP is released from the transferrin receptor mRNA, and the mRNA is degraded. At the ferritin mRNA, inability of the IRP to bind iron would mean the IRP would remain bound to the ferritin mRNA and ferritin would not be made, which would mean there would not be ferritin to store excess iron. In the case of the transferrin receptor mRNA, this mRNA would be extra stable because the IRP would remain bound to the mRNA. This would mean excess transferrin receptor would be made, which would lead to more iron being imported. This would especially be a problem in the absence of ferritin. Therefore iron intake would need to be lowered.

You are studying the DNA of a person who you know has two defective copies of the gene that encodes phenylalanine hydroxylase. You are surprised to find that this person also carries two defective copies of the gene for homogentisic acid oxidase. What disease symptoms will this person exhibit? (Assume pathway intermediates are not available from sources outside the phenylalanine breakdown pathway.) This person will exhibit symptoms of alkaptonuria. This person will exhibit symptoms of tyrosinosi

This person will exhibit symptoms of phenylketonuria. - The person would exhibit symptoms of phenylketonuria. Because phenylalanine hydroxylase works earlier in the pathway than homogentisic acid oxidase, the pathway would be blocked at the stage of phenylalanine conversion to tyrosine, and the intermediaries further in the pathway wouldn't be available.

If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario. Transcription would be difficult to repress in the presence of glucose. Transcription would be difficult to activate in the absence of glucose. Transcription would be difficult to activate in the presence of glucose. Transcription would be difficult to repress in the absence of glucose.

Transcription would be difficult to activate in the absence of glucose. -Normally cAMP binds to CAP in low glucose conditions, causing CAP to bind to the CAP site. Binding of RNA polymerase to the promoter is enhanced by CAP binding to the CAP site and transcription is activated to a higher level than if CAP isn't bound. If CAP can't bind to the CAP site, it would be difficult to activate transcription in the absence of glucose.

What gene is most responsible for X-chromosome inactivation? Xist Xce Tsix Xic

Xist

Which of the following forms of RNA encodes the sequence of amino acids for a functional protein? nRNA mRNA tRNA scRNA rRNA

mRNA

Combinatorial factors include activators and repressors as well as small effector molecules, proteins that alter the composition of nucleosomes, and DNA methylation. proteins that alter the composition of nucleosomes and DNA methylation, but not small effector molecules. small effector molecules, proteins that alter the composition of nucleosomes, DNA methylation, and basal transcription factors. small effector molecules, proteins that alter the composition of nucleosomes, but not DNA methylati

small effector molecules, proteins that alter the composition of nucleosomes, and DNA methylation.

Site-directed mutagenesis allows researchers to produce a mutation at a ______ within a cloned DNA segment. Multiple Choice random site semilocalized site that can later be identified by sequencing specific site

specific site

What are some of the steps in eukaryotic transcriptional control? A transcriptional repressor recruits general transcription factors and RNA polymerase II without affecting nucleosome positioning. A transcriptional repressor recruits nucleosome remodeling proteins that alter nucleosome positioning, modification, and composition. This allows for the formation of a closed chromatin complex, and binding of general transcription factors and RNA polymerase II. Histone cores remain on the gene as tran

A transcriptional activator recruits nucleosome remodeling proteins that alter nucleosome positioning, modification and composition. This allows for the formation of an open chromatin complex, and binding of general transcription factors and RNA polymerase II. Finally, as transcription elongation occurs, histone cores are evicted from the DNA to allow the RNA polymerase to transcribe the gene.

What are some types of the molecular changes that underlie epigenetic gene regulation? depurination and chromatin remodeling. DNA methylation and chromatin remodeling depurination of cytosine and thymidine residues DNA methylation and depurination of cytosine residues

DNA methylation and chromatin remodeling

Which technique uses dideoxynucleotides? Multiple Choice restriction digest gene cloning RT-PCR DNA sequencing

DNA sequencing

In Jacob, Monod, and Pardee's experiment, what would have been the conclusion if all four tubes produced a yellow color when β-ONPG was added? LacI provides the binding site for the repressor The researcher added too much β-ONPG Expression of the lac operon is constitutive whether lacI is functional or not LacI encodes a diffusible repressor

Expression of the lac operon is constitutive whether lacI is functional or not -The yellow color in Jacob, Monod, and Pardee's experiment indicated that beta-galactosidase had been produced. Beta-galactosidase is encoded by the lacZ gene. In their experiment, one of the tubes did not turn yellow. This tube contained the merozygote strain, and no lactose. This tube did not turn yellow because the lacI gene on the F' factor made enough repressor protein to bind to the operator on both the F' factor and the bacterial chromosome. Because the repressor bound to these operators, no beta-galactosidase was made, and no yellow color was produced in this tube. If yellow color had been produced when there was active repressor and no lactose present, this would indicate that expression of the lac operon was constitutive regardless of whether lacI was functional or not.

If a eukaryotic organism is missing the U5 snRNP, it will have trouble performing which step of splicing? Formation of the intron loop Binding of snRNPs to the branch site Exon degradation Binding of snRNPs to the 5' splice site

Formation of the intron loop U5 is involved in the formation of the intron loop so if it was missing the intron loop might not form.

The ncRNA HOTAIR recruits what type of proteins to target genes? Histone-modifying complexes Transcription factors Histone acetyltransferase RNA polymerase

Histone-modifying complexes

What is responsible for binding the initiator tRNA in prokaryotes and eukaryotes? EF-G / eEF2 RF3 / eRF3 IF2 / eIF2 EF-Tu / eEF1α

IF2 / eIF2

You are performing a mobility shift assay with a protein complex that is composed of proteins A, B, C, & D, each of which can bind to the DNA of interest. You run the gel with the lanes as follows: Lane 1: Protein A + DNA Lane 2: Proteins A + B + DNA Lane 3: Proteins A + B + C + DNA Lane 4: Proteins A + B + C + D + DNA In which lane will the DNA run closest to the top of the gel? Multiple Choice Lane 1 Lane 2 Lane 4 Lane 3

Lane 4 -The fragments closest to the top of the gel are the largest and migrate the most slowly. Therefore the DNA bound by all 4 proteins will run closest to the top of the gel.

What is the name of the type of chemical modification on anti-miRNA oligonucleotides used to inhibit miRNA function that involves ribose sugars with an extra bridge connecting the 2′ oxygen and the 4′ carbon? Locked nucleic acids Enoxacin RNaseMRP Antagomirs

Locked nucleic acids

Suppose you performed a triplet binding assay with the triplet 5′-UAA-3′. Among those listed below, what radiolabeled amino acids do you expect to find bound to the filter? Tyrosine Glycine Methionine None

None The triplet 5'-UAA-3' would not result in any of these amino acids bound to the filter. UAA is a stop codon.

You work in a lab that is studying PIWI proteins. You have isolated piRISCs and piRITSs from a cell. What would be one way to identify which complexes are piRISCs and which are piRITSs? One of the proteins in the piRITS should have nuclease activity. One of the proteins in the piRITS should have a nuclear localization signal. One of the proteins in the piRITS should function as a transcription factor. One of the proteins in the piRITS should have acetylation activity.

One of the proteins in the piRITS should have a nuclear localization signal. -piRITSs travel into the nucleus, whereas piRISCs function in the cytosol. Therefore one of the proteins in the piRITS should have a nuclear localization signal.

A scientist does not have an antibody to detect the protein of interest, but wants to know if the gene is expressed at low levels. What technique could the researcher use to detect, but not quantify the expression of the gene of interest? Multiple Choice Western Blotting Real-time PCR Cloning Reverse transcriptase PCR

Reverse transcriptase PCR -Without an antibody, the scientist cannot carry out western blotting. If the researcher simply wants to detect the presence of an mRNA, the best choice would be reverse transcriptase PCR. This technique does not quantify the amount of gene expression, but will tell the researcher if a mRNA product is made.

In eukaryotic organisms, a mutation in which of the following would result in a failure of the RNA polymerase to maintain an open complex? TFIID TFIIF TFIIB TFIIE TFIIH

TFIIE is involved in the formation or maintenance of the open complex. Without TFIIE the open complex could not be maintained.

Anticipation is associated with which of the following? Multiple Choice nonsense mutations intergenic suppressors TRNE mutations up-promoter mutations

TRNE mutations -Some TNRE disorders have the unusual feature of a progressively worsening severity in future generations—a phenomenon called anticipation. For example, a trinucleotide repeat of CAG could expand from 11 to 18 tandem copies.

What occurs during the annealing stage of a PCR reaction? Multiple Choice The reaction stops. The DNA strands separate The DNA polymerase copies the template DNA. The primers bind to the template DNA.

The primers bind to the template DNA.

Following mitosis, the two daughter cells usually have __________ pattern of facultative heterochromatin and __________ pattern of constitutive heterochromatin as was present in the mother cell. the same; a different a different; the same the same; the same a different; a different

The same:the same

if the Trp codons in the trpL gene were mutated to encode another amino acid, what would the result be? The trp operon would only be transcribed when tryptophan in the cell was high. The trp operon would always be transcribed. The trp operon would never be transcribed. The trp operon would only be transcribed when tryptophan in the cell was low.

The trp operon would never be transcribed If there were not Trp codons in the trpL mRNA, the ribosome would never pause within region 1 of the mRNA. Translation of the trpL mRNA would progress to its stop codon, where the ribosome would pause. This pausing prevents region 2 from forming a stem loop. Region 3 hydrogen bonds with region 4, which terminates transcription of the rest of the trp operon.

The Avy allele of the Agouti gene involves the insertion of a transposable element upstream from the normal Agouti promoter. The transposable element carries a promoter that causes the overexpression of the Agouti gene. Mice carrying this allele tend to have coat colors that are more yellow than mice that don't have this transposable element. If pregnant female mice are fed a diet that contains chemicals that increase DNA methylation, how would you expect that this diet would affect the coat c

Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed. -Methylation of the TE leads to inhibition of the overexpression of the Agouti gene and darker colored mice. If the mice are fed chemicals that increase DNA methylation we would expect darker colored mice because the Agouti gene would not be over expressed.

In trying to distinguish between the two models of eukaryotic transcriptional termination, you identify a drug that specifically blocks exonuclease activity. When you add it at the appropriate time to an in vitro system that carries out all the stages of eukaryotic transcription, you find that transcription proceeds normally, but transcription doesn't terminate. This experiment provides support for which model of eukaryotic transcriptional termination? Torpedo model Rho-dependent termination Al

Torpedo model Eukaryotic transcriptional termination occurs via the allosteric model or the torpedo model. Only the torpedo model employs an exonuclease, so this experiment lends support for the torpedo model.

What would be a set of anticipated results from a "Lederberg" experiment? Total number of colonies on a plate: 500Total number of resistant colonies on replica plate with T1: 1500 Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 1500 Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 15 Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 0

Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 15 -In the Lederberg experiment, we expect to see a greater number of colonies on the master plate compared to the replica plate with T1. Thererfore, the most likely result is that in which there are 1500 colonies on a plate, and only 15 on the T1 replica plate.

A gene that undergoes rho-dependent termination has a mutation in the rut site. How will this influence transcriptional activity? Transcription will terminate normally as Rho termination relies on the rut site to enhance termination; it is not essential for termination. Transcription will continue until another termination sequence is reached, either Rho-dependent or independent. Transcription will stop immediately because RNA polymerase will sense there is a mutation. There will be no transcrip

Transcription will continue until another termination sequence is reached, either Rho-dependent or independent. - The rut site is the site where the rho protein binds. Without rho binding termination will not occur in this location. Transcription will continue until another terminator sequence is reached.

What is the difference between the trithorax (TrxG) and polycomb (PcG) complexes of proteins? Methylation of H3 on lysine 27 can result in activation of transcription Methylation of lysine at position 4 on H3 results in silencing of gene expression TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3. TrxG proteins methylate lysine 27 on histone H3 while PcG complexes methylate lysine 4 on

TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3.

What genes appear to be controlled by the Xic? Xic TsiX Xist and Tsix Xist

Xist and Tsix

The C-terminus of a polypeptide always contains a stop codon. an amino group. carbon dioxide. a carboxyl group. Methionine. a stop amino acid.

a carboxyl group

A tRNA's anticodon is 5′GGC3′. What amino acid is attached to it? arginine glycine alanine proline

alanine If an anticodon is 5′GGC3′ the codon will be 5'GCC3'. This codon encodes alanine.

How does position effect influence gene expression? The movement of the genetic material on the chromosome by inversions or translocations may place a coding sequence near a new regulatory region, thus activating the expression of the gene. The movement of the gene may place it into a region that is highly condensed. The movement of a gene may remove it from its normal promoter, thus silencing the gene. All of the answers are correct.

all answers correct

Which environmental agent shown can induce mutations? UV radiation x-rays gamma rays All of the answers are correct.

all answers correct

Which of the following is found in an operon? Multiple Choice promoter terminator two or more genes operator All of the answers are correct.

all answers correct

Chromatin remodeling complexes alter nucleosomes, this occurs when complexes of ATP-dependent proteins may reposition, evict, or change nucleosome composition. complexes of ATP-dependent protein degrade histones and release the DNA from nucleosomes. remodeling proteins bind to TFIID to promote or inhibit nucleosome formation. remodeling proteins increase the supercoiling of the DNA, which can inhibit nucleosome formation.

complexes of ATP-dependent proteins may reposition, evict, or change nucleosome composition.

Which of the following is an example of a pluripotent cell? fetal heart cells umbilical cord blood nerve cells embryonic stem cells red blood cells

embryonic stem cells -ES cells are pluripotent, which means they can differentiate into almost every cell type of the body. However, a single ES cell has lost the ability to produce an entire, intact individual.

The origins of which of the following cell types creates the least amount of ethical debate? Multiple Choice embryonic germ cells hematopoietic stem cells embryonic stem cells All of the answers are equal.

hematopoietic stem cells -Bone marrow transplantation of hematopoietic stem cells derived from an adult donor is commonly used to treat patients with certain forms of cancers and does not require cells derived from an embryo.

Both the rho-dependent and rho-independent mechanisms of termination Multiple Choice involve the formation of a stem-loop structure. require a helicase to separate the DNA-RNA complex. end transcription immediately after the stop codon. involve a sequence rich with A-U base pairs.

involve the formation of a stem-loop structure.

What is the molecular mechanism for imprinting a gene? Acetylation Phosphorylation Methylation Nitration

methylation

Abnormal levels of miRNAs are associated with nearly all forms of what type of human disease? Neurological disorders Cancer Gastrointestinal disease Cardiovascular disease

neurological disorders

Which DNA repair process often leads to deletion in chromosome sequence? base excision repair mismatch repair nonhomologous end joining (NHEJ) homologous recombination repair nucleotide excision repair direct repair

nonhomologous end joining (NHEJ)

Which procedure is used to identify a specific RNA within a mixture of many RNA molecules? Southern blotting Western blotting Eastern blotting Northern blotting

northern blotting

Where are the ribosomal subunits assembled? Multiple Choice nucleoid nucleolus nuclear envelope nucleus

nucleolus

What process repairs damage from UV radiation? base excision repair mismatch repair nonhomologous end joining (NHEJ) nucleotide excision repair homologous recombination repair direct repair

nucleotide excision repair

The regulation of protein function, not gene expression is called ______ regulation. Multiple Choice posttranscriptional posttranslational transcriptional translational

posttranslational

A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause _____ in the expression of the gene. Multiple Choice an increase no change a reduction

reduction -A chromosomal rearrangement repositioning a gene from a less condensed, or euchromatic region, where it is active, to a very highly condensed, or heterochromatic region will cause the gene expression to be turned off (See Figure 19.2b for a schematic representation).

What effect would disabling exportin 5 have on RNA interference? miRNAs could still carry out RNA interference, but siRNAs would not be made. siRNAs could still carry out RNA interference, but miRNAs would not be made. In the absence of exportin 5 activity, no RNA interference could occur. RNA interference would be unaffected by the lack of exportin 5 function.

siRNAs could still carry out RNA interference, but miRNAs would not be made. -Exportin 5 binds to pre-miRNAs and exports them from the nucleus. If exportin 5 was not functional, pre-miRNAs would not be exported to the cytosol, and therefore miRNAs could not be made. Since siRNAs are made from pre-siRNAs that are either virally or experimentally put into the cytosol, RNA interference mediated by siRNAs would be unaffected by lack of exportin 5 function.

Which molecule contains an anticodon? snRNA rRNA tRNA DNA mRNA

tRNA

DNA ligase is needed in a cloning experiment for what reason? Multiple Choice to act as a selectable marker in the identification of cells that took up the vector to allow the vector to enter into the cell to proofread the vector for mistakes to covalently link the sugar-phosphate backbones of the two DNA fragments

to covalently link the sugar-phosphate backbones of the two DNA fragments

Riboswitches have been shown to affect regulation of ______. only transcription transcription and translation only RNA splicing only translation

transcription & translation