BS 161 Exam 4 Practice Questions
If the genetic code were read in groups of two bases, how many different codons would be possible?
16
Analysis of a bacterial gene indicates that 24% of the nucleotides in the coding strand contain the base A, 18% contain the base T, 26% contain the base G, and 32% contain the base C. What percent of the nucleotides in the mRNA transcribed from this gene will contain the base U? (Enter your answer as a number only without the percent sign, e.g. enter 5 not 5%.)
18
The complementary messenger RNA strand that would be synthesized from the DNA base sequence of 5' CTGAC 3' would be 3' GACTG 5' 5' UGACU 3' 3' AGTUG 5' 3' GACUG 5' 5' GACGU 3'
3' GACUG 5'
How many unique mRNA codons can be constructed from the four different RNA nucleotides? four 12 16 61 64
64
New amino acids (other than the initial f-Met) enter at which site? E P A Any of the choices
A
Translation is terminated when a stop codon is presented at the ________ site. A P E either A or P either A or E
A
Which of the following statements about eukaryotic mRNA is TRUE? A cap is added to their 5' end. A poly-A tail is added to their 3' end. Each usually specifies only a single protein. A cap is added to their 5' end and a poly-A tail is added to their 3' end. A cap is added to their 5' end, a poly-A tail is added to their 3' end, and each usually specifies only a single protein.
A cap is added to their 5' end, a poly-A tail is added to their 3' end, and each usually specifies only a single protein.
Translation is terminated when a stop codon is presented at the A site. P site. E site. either the A or P site. either the A or E site.
A site
The ribosome moves along the mRNA so that the tRNA that was in the _ site is now in the P site and the tRNA that was in the P site is now in the E site. The movement of the ribosome is called ___.
A, translocation
A particular tRNA molecule includes the anticodon sequence: AUG. What would be the corresponding sequence in the non-coding strand of the DNA molecule that encodes the mRNA that this tRNA would pair with? TAC ATG AUG UAC
ATG
You are working to characterize a novel protein in mice. Analysis shows that high levels of the primary transcript that codes for this protein are found in tissue from the brain, muscle, liver, and pancreas. However, an antibody that recognizes the C-terminal portion of the protein indicates that the protein is present in brain, muscle, and liver, but not in the pancreas. What is the most likely explanation for this result? The gene that codes for this protein is not transcribed in the pancreas. There is no modification of the primary transcript in the pancreas. There is no modification of the primary transcript in the brain, muscle, and liver. Alternative splicing in the pancreas yields a protein that is missing the portion that the antibody recognizes. Alternative splicing in the brain, muscle, and liver increases the level of translation.
Alternative splicing in the pancreas yields a protein that is missing the portion that the antibody recognizes.
A large region of a promoter has been deleted upstream of a gene. What effect will this have on transcription of the gene? Basal transcription factors won't bind to the template DNA, so RNA polymerase will not bind to the template DNA, so transcription will not occur. RNA polymerase will have to bind to a different region on the template DNA, so the rate of transcription will decrease Basal transcription factors will be able to bind to the template DNA, but RNA polymerase will not be able to bind, so transcription will not occur. RNA polymerase will not be regulated by repressors, so it will continually to bind to the template DNA, and the rate of transcription will be increased Transcription will continue as normal, but the 5' end of the gene will be truncated
Basal transcription factors won't bind to the template DNA, so RNA polymerase will not bind to the template DNA, so transcription will not occur.
Cells conserve energy and resources by making active proteins only when they are needed. If a protein is not needed, which of the following methods of control would be the most energy-efficient? Block transcription Degrade the mRNA after it is made Prevent translation of the mRNA Degrade the protein after it is made
Block transcription
Which of the following best describes transcription? DNA -> DNA DNA -> RNA DNA -> Protein RNA -> DNA RNA -> Protein
DNA -> RNA
You are studying the affects of transcription factors on the activation of gene expression. However, when first starting your study you notice that some of the transcription factors bind further away from the DNA that it is aiming to transcribe. What description best explains this? The transcription factor transcribes small RNAs that then bind to the promoter and activate the gene's expression. Signals originate via inducers from the transcription factor to the site of promotion that activate transcription of the gene. DNA looping transports the transcription factor closer to the promoter and initiates gene transcription. The assistance of RNA looping moves the transcription factor closer to the promoter.
DNA looping transports the transcription factor closer to the promoter and initiates gene transcription
DNA is used as a template to make a complementary strand of DNA. DNA replication Transcription Translation None of these
DNA replication
The best description of how regulatory proteins recognize and bind to the correct sequences without unwinding the DNA double helix is DNA-binding domains can recognize the chemical groups that protrude from the base-pairs into the major groove. DNA-binding domains can recognize the chemical groups that protrude from the base-pairs into the minor groove. DNA-binding domains can recognize the chemical groups that protrude from the sugar-phosphate backbone into the major groove. DNA-binding domains can recognize the chemical groups that protrude from the sugar-phosphate backbone into the minor groove. Regulatory proteins have DNA-binding domains that are inserted into the major groove and can recognize the shape of each nitrogenous base.
DNA-binding domains can recognize the chemical groups that protrude from the base-pairs into the major groove.
The Central Dogma of biology can be stated as proteins→ RNA→ DNA. RNA→ DNA→ proteins. DNA→ proteins→ RNA. DNA→ RNA→ proteins.
DNA→ RNA→ proteins.
During translation, uncharged tRNA molecules leave the ribosome from this site. E P A termination release
E
The tRNA in the _ site is ejected.
E
A gene that codes for a protein was removed from a eukaryotic cell and inserted into a prokaryotic cell. Although the gene was successfully transcribed, the protein translated from this transcript was different from the protein produced in the eukaryotic cell. What is the most likely explanation? There are slight differences in the genetic code for prokaryotes and eukaryotes. Unlike eukaryotes, which have three different RNA polymerases, prokaryotes have a single RNA polymerase. Eukaryotic genes often contain introns while prokaryotic genes do not. Eukaryotic transcripts have a 5' cap while prokaryotic transcripts do not.
Eukaryotic genes often contain introns while prokaryotic genes do not.
The coding strand of a particular DNA molecule has the following sequence: ATCCCTGCA. Assuming that this sequence is part of an exon, and represents three codons, what sequence would be found on the tRNA anticodon loop used to translate the second codon? CCU CCT GGA CGU GCA
GGA
Why might a chromosomal duplication be a positive evolutionary force? If an organism make twice as much protein, it will be better suited to its environment. If there are two genes, one is free to mutate and take on a different function that may make it more fit. Organisms with more DNA are better able to cope with environmental change. Organisms that are able to survive chromosomal mutations, like duplications, must already be highly fit. None of these are true, duplications are mutations and all mutations are detrimental to an organism.
If there are two genes, one is free to mutate and take on a different function that may make it more fit.
What is a difference between DNA replication and RNA transcription? Synthesis occurs in the 3' to 5' direction in DNA replication but in the 5' to 3' direction in RNA transcription. In DNA replication the helix is never closed after it is opened by helicase, but once RNA polymerase has finished transcribing a region the double helix closes. DNA replication produces a fundamentally different type of molecule than is produced by RNA transcription. DNA replication occurs in the nucleus, and RNA transcription occurs in the cytoplasm. All of these are differences between DNA replication and RNA transcription.
In DNA replication the helix is never closed after it is opened by helicase, but once RNA polymerase has finished transcribing a region the double helix closes.
How is GTP used during elongation? It aids in the binding of the incoming tRNA to the A site of the ribosome. It provides energy for the formation of the peptide bond. It aids in translocating the ribosome one codon down the mRNA. It provides energy for the formation of the peptide bond AND it aids in translocating the ribosome one codon down the mRNA. It aids in the binding of the incoming tRNA to the A site of the ribosome AND It aids in translocating the ribosome one codon down the mRNA.
It aids in the binding of the incoming tRNA to the A site of the ribosome AND It aids in translocating the ribosome one codon down the mRNA.
Which of the following statements about peptidyl transferase is TRUE? (multiple answers) It catalyzes the formation of peptide bonds. It is present in the 50S ribosomal subunits. It is a protein. It catalyzes the formation of peptide bonds and It is present in the 50S ribosomal subunits. It catalyzes the formation of peptide bonds, It is present in the 50S ribosomal subunits, and It is a protein.
It catalyzes the formation of peptide bonds and it is present in the 50S ribosomal subunit
Suppose a mutation changes the amino acid that an aminoacyl-tRNA synthetase enzyme recognizes without changing the tRNA molecule that it recognizes. How is this likely to affect the process of protein synthesis? Check all that apply. It will alter the location of the start sites during transcription It will alter the sequence of bases in the mature mRNAs It will alter the location of splice sites in the pre-mRNAs It will alter the location of the start codons during translation It will alter the sequence of amino acids in the polypeptide chains It will cause premature termination of translation, resulting in shortened polypeptide chains It will affect the synthesis of only one or a few types of protein produced by the cell It will affect the synthesis of most or all of the proteins produced by the cell
It will alter the sequence of amino acids in the polypeptide chains, it will affect the synthesis of most or all of the proteins produced by the cell
Bicyclomycin is an antibiotic that is effective against many gram negative bacteria. It works by inhibiting Rho. What direct effect would this have on a bacteria? It would prevent transcription of RNA. It would prevent RNA polymerase from binding to the proper promoter sites. It would prevent termination of RNA transcription, causing mRNA transcripts to be abnormally long. It would prevent proper intron splicing of mRNA, so that some exonic regions are removed and some intronic regions remain. It prevents the transport of mRNA out of the nucleus
It would prevent termination of RNA transcription, causing mRNA transcripts to be abnormally long
A peptide bond forms between the amino acid attached to the tRNA in the A site and the growing polypeptide chain attached to the tRNA in the _ site.
P
The initiating transfer RNA, carrying formylmethionine, binds to which site? E site P site A site E, P, and A sites P and A sites
P site
Which of the following best describes translation? DNA -> DNA DNA -> RNA DNA -> Protein RNA -> DNA RNA -> Protein
RNA -> protein
Ribosomes are complex aggregates of RNA and DNA. RNA and proteins. RNA and sugars. DNA and proteins. nucleosomes and RNA.
RNA and proteins
The enzyme that accomplishes transcription is termed DNA polymerase. RNA polymerase. DNA ligase. RNA ligase. RNA replicase.
RNA polymerase
Transcription is carried out by the enzyme DNA polymerase. RNA polymerase. RNAse. topoisomerase. reverse transcriptase.
RNA polymerase
Which of the following is not involved in the initiation of translation? mRNA ribosomal subunits initiator tRNA RNA polymerase all of these choices are involved
RNA polymerase
What would happen if the sigma factor didn't bind to the RNA polymerase? RNA polymerase would not bind to the template DNA RNA polymerase would not move off the promoter and begin transcription The proper nucleotides would not be used to make the new RNA molecule The terminator sequence would not be recognized The stem-loop structure would not be formed
RNA polymerase would not bind to the template DNA
Why is RNA synthesis called 'transcription' and protein synthesis called 'translation?' RNA synthesis happens in the nucleus and protein synthesis happens in the cytoplsam. RNA synthesis makes an exact copy of the DNA molecule and protein synthesis makes a complementary copy of the RNA. RNA synthesis produces nucleic acid from nucleic acid and protein synthesis produces polypeptides from nucleic acid. RNA synthesis makes a complementary copy of the entire DNA molecule and protein synthesis only uses a short piece of the RNA molecule. Because that's one someone named them a long time ago.
RNA synthesis produces nucleic acid from nucleic acid and protein synthesis produces polypeptides from nucleic acid.
combines with protein to form particles that help ribosomes attach to the endoplasmic reticulum in eukaryotes.
SRP RNA
The following sequence of DNA is the normal, wild-type gene. 5' ATG CGG GTA GTT AGC CGA TAG 3' A deletion occurs during DNA replication, causing the guanine shown in red to be removed from the nucleotide strand. What effect will this have on the final protein? The deletion of the G will cause a single amino acid substitution in the codon in which it occurs. The deletion of the G will cause a frame shift, so that all the amino acids after the mutation will change. The protein will be a normal number of amino acids. The deletion of the G will cause a frame shift, resulting in a premature stop codon and a truncated protein. The deletion of the G will cause a frame shift, resulting in the loss of the normal stop codon and an abnormally long protein with an altered amino acid sequence. The deletion of the G will not have an effect on the final protein.
The deletion of the G will cause a frame shift, resulting in a premature stop codon and a truncated protein.
A mutation occurred in the third codon position of a gene, but the protein still functions normally. How is this possible? DNA polymerase's proofreading function fixed the mistake in the nucleus. RNA polymerase detected the mutation and transcribed the gene with the proper nucleotide. The ribosome recognized the mutated codon and bound the tRNA that carried the proper amino acid rather than the one specified after the mutation. The genetic code is redundant, so that mutations in the third position of the codon often result in the same amino acid being specified. Proteins still function normally if only one amino acid is substituted.
The genetic code is redundant, so that mutations in the third position of the codon often result in the same amino acid being specified.
What happens during RNA splicing in eukaryotes? The product of translation, called the primary transcript, is cut and some pieces are joined back together to form the mature mRNA. The product of transcription, called the primary transcript, is cut and some pieces are joined back together to form the mature tRNA. The product of transcription, called the secondary transcript, is cut and some pieces are joined back together to form the mature mRNA. The product of transcription, called the primary transcript, is cut and some pieces are joined back together to form the mature mRNA. The product of transcription, called the primary transcript, is cut and all pieces are joined back together to form the mature mRNA.
The product of transcription, called the primary transcript, is cut and some pieces are joined back together to form the mature mRNA.
You are studying a eukaryotic gene that codes for the alpha-subunit in hemoglobin. What is the most likely result if base substitutions occur in the first nucleotide at the 5' end of an intron and also in the last nucleotide at the 3' end? There will be no change in the polypeptide coded by this gene because introns are not expressed. A change in reading frame will alter all amino acids in the polypeptide past the point of the first substitution. A change in reading frame will alter all amino acids in the polypeptide past the point of the second substitution. This intron will not be removed during pre-mRNA splicing because the spliceosome will not recognize the intron-exon junctions. Each base substitution is likely to alter only one amino acid in the final polypeptide chain.
This intron will not be removed during pre-mRNA splicing because the spliceosome will not recognize the intron-exon junctions.
RNA is used as a template to make a polypeptide. DNA replication Transcription Translation None of these
Translation
In eukaryotes, specific transcription factors have two distinct domains: a DNA-binding domain and a RNA-binding domain. a DNA-binding domain and an activation domain. a DNA-binding domain and a repressor domain. a DNA-binding domain and an enhancer domain. a DNA-binding domain and an operator domain
a DNA-binding domain and an activation domain
What mutation in the ribosome would have the most detrimental effect on peptide bond formation? A mutation in the A-site that allowed non-specific binding of t-RNA. A mutation in the P-site causing a loss of function of peptidyl transferase. A mutation in the E-site causing a delay in the release of tRNA molecules. A mutation in the A-site preventing the binding of the release factor protein. All of these would be equally detrimental to peptide bond formation
a mutation in the P-site causing a loss of function of peptidyl transferase
Initiation of transcription differs from initiation of DNA replication in several ways. One difference is that initiation of transcription does not require a promoter. enzymes. a primer. a DNA template strand.
a primer
If a protein in the coactivator complex does not function properly, what would be a consequence? RNA polymerase will not bind to the template DNA RNA will not bind to the template at the promoter, but instead at an improper location on the template DNA Activators and repressors will not be able to properly effect the rate of transcription RNA polymerase will not be able to leave the promoter to begin transcription of the gene All of these would occur
activators and repressors will not be able to properly effect the rate of transcription
When preparing a presentation on the addition of methyl groups to DNA, the major points to include are (multiple answers) addition of methyl groups does not affect base pairing. methylation blocks transcriptional activators. direct inactivation of the genes occurs. methylation ensures a gene is turned off. chromatin can be methylated to alter the structure of histones.
addition of methyl groups does not affect base pairing, methylation blocks transcriptional activators, methylation ensures a gene is turned off
One or a few base pairs are gained.
addition/insertion
Specific amino acids are attached to tRNA molecules by aminoacyl-tRNA synthetases. hydrogen bonds. anticodons. deactivating enzymes. initiation factors.
aminoacyl-tRNA synthetases
What protein would be the most likely to be expected to contain a signal sequence? An antibody SRP Aminoacyl-tRNA synthetase Sigma subunit Phosphofructokinase
an antibody
A charged tRNA with the _____ that is complementary to the codon in the A site enters and binds to the A site.
anticodon
The tRNA nucleotide sequence that pairs with bases on the mRNA is called a(n) intron. exon. codon. initiation factor. anticodon.
anticodon
A nucleotide deletion in DNA replication A nucleotide deletion in DNA replication causes one amino acid of the protein to be incorrect. causes all of the amino acids of the protein to be incorrect. causes the amino acids inserted after the deletion to be incorrect. causes the amino acids inserted before the deletion to be incorrect. has no effect on the resulting protein.
causes the amino acids inserted after the deletion to be incorrect
The p300/CBP (CREB-binding protein) coactivator proteins are histone acetyltransferases that help regulate the transcription of many genes. Based on this information you can conclude that these proteins are involved in DNA acetylation. chromatin remodeling. recruitment of RNA pol II. formation of the transcription initiation complex.
chromatin remodeling
The strand of DNA that is not transcribed is called the ______. coding strand non-coding strand template strand complementary strand
coding strand
Crick and his colleagues proposed that the genetic code consists of a series of blocks of information, each corresponding to one amino acid in an encoded protein. What were these blocks of information called? alleles codons genes polypeptides
codons
One or a few base pairs are lost.
deletion
Segments of a chromosome that are lost are called
deletions
Which of the following causes an extra copy of a chromosomal region to occur? Inversion Duplication Deletion Simple translocation Reciprocal translocation
duplication
Segments of a chromosome that are repeated are called
duplications
T/F All codons code for amino acids
false
T/F Most codons code for more than one amino acid.
false
T/F Only 20 different codons are used to code for amino acids.
false
An addition or deletion that alters the codons downstream from the mutation
frameshift mutation
A defining characteristic of eukaryotic organisms is that they have their transcription occurring in the cytoplasm and translation in the nucleus. have their transcription occurring in the nucleus and translation in the cytoplasm. have only operons to assist in gene expression. carry out protein synthesis only in the presence of the cAMP molecule. use the leucine zipper primarily for the production of the amino acid tryptophan.
have their transcription occurring in the nucleus and translation in the cytoplasm
RNA polymerase is able to open the DNA double helix as it moves down the template. What type of enzymatic activity does this mean RNA polymerase must possess? Polymerase activity Exonuclease activity Helicase activity Primase activity Ligase activity
helicase activity
You and a group of scientists are mapping out gene regulation in a new species. Based on what is currently known about control of gene expression, the control point to begin your study at would be degradation of mRNA. splicing of mRNA. the passage of mRNA through the nuclear membrane. initiation of transcription. initiation of translation. posttranslational modification of proteins.
initiation of transcription
When a chromosome is broken in two places and reconnected so that a region is flipped from the normal order, this is called... inversion duplication deletion simple translocation reciprocal translocation
inversion
Segments of a chromosome that are broken in 2 places, reversed, and then put back together are called
inversions
What is unusual about the initiator tRNA? It carries a modified amino acid It does not bind to the ribosome at the A site Its anticodon is not complementary to the codon with which it associates It carries a modified amino acid AND it does not bind to the ribosome at the A site All of these are true
it carries a modified amino acid AND it does not bind to the ribosome at the A site
What is unusual about the initiator tRNA? It carries a modified amino acid. It does not bind to the ribosome at the A site. Its anticodon is not complementary to the codon with which it associates. It carries a modified amino acid AND it does not bind to the ribosome at the A site. All of these are TRUE.
it carries a modified amino acid AND it does not bind to the ribosome at the A site
Which of the following is correct regarding sigma factor? it is involved in the termination of replication it recognizes the promoter region it forms an open complex it forms mRNA none of these choices are correct
it recognizes the promoter region
A small ribosomal subunit binds to a molecule of ____ near its 5' end.
mRNA
During protein synthesis in eukaryotes, which molecule passes from the nucleus to the cytoplasm and specifies the sequence of amino acids in the new polypeptide? DNA RNA polymerase mRNA rRNA tRNA
mRNA
The Shine-Dalgarno sequence is found on the ________. small ribosomal subunit large ribosomal subunit initiator tRNA mRNA IF3
mRNA
is translated by the ribosomes and contains the code that specifies the sequence of amino acids in a polypeptide chain.
messenger RNA
All nascent proteins being with what amino acid? Methionine Guanine Phenylalanine Valine Different proteins begin with different amino acids
methionine
Vertebrate cells possess a protein that binds to clusters of 5-methylcytosine and ensures the gene will stay in the "off" position. This control of gene regulation is a result of translation. enhancer expression. methylation. promoter expression. operator suppression.
methylation
acts to cleave target mRNAs or inhibit the translation of target mRNAs present in the cytoplasm of eukaryotes.
micro RNA
Changes a codon for one amino acid into a codon for a different amino acid
missense mutation
During translation, translocation refers to releasing a tRNA molecule from the ribosome. joining an amino acid to a tRNA molecule. joining an amino acid to the next amino acid in the chain. joining a tRNA molecule to the ribosome. moving the ribosome along the mRNA molecule.
moving the ribosome along the mRNA molecule
Which of the following statements about termination is TRUE? No tRNA can recognize a stop codon. It is recognized by a release factor protein. Only a single release factor tRNA can recognize a stop codon. There are three release factor tRNAs that can recognize a stop codon. No tRNA can recognize a stop codon. After the ribosome stalls on the mRNA for a certain length of time, it falls off and termination occurs. All tRNAs can recognize stop codons, and so the last amino acid of all newly formed proteins is random
no tRNA can recognize a stop codon. it is recognized by a release factor protein
Changes a codon for one amino acid into a stop codon.
nonsense mutation
Histones that are tightly wound by DNA and are the basic unit of chromatin are called operons. nucleosomes. protein clusters. repressor genes. facilitators sites.
nucleosomes
The nucleic acid sequence in mRNA is determined by the order of amino acids in the protein. nucleotide sequence in DNA. nucleotide sequence in t-RNA. all of these choices are correct.
nucleotide sequence in DNA
Both DNA and RNA are made up of building blocks known as nucleotides. nucleic acids. amino acids. genes. codons.
nucleotides
In eukaryotes, translation takes place on the plasma membrane. inside the nucleus. on ribosomes. on the nuclear membrane. on spliceosomes.
on ribosomes
The location of translation in prokaryotic cells is in the nucleoid. on ribosomes. on the plasma membrane. on mesosomes. on chromosomes
on ribosomes
In vertebrates, DNA methylation - the addition of a methyl group to DNA nucleotides - ensures that the gene functions without interruption. no errors will be made during transcription. the nucleosome will quickly form, which assists in mRNA formation. once that gene is transcribed, the mRNA is saved and used over and over again. once a gene is turned off, it will remain off.
once a gene is turned off, it will remain off
How does DNA polymerase differ from RNA polymerase? Only RNA polymerase adds new nucleotides to the 3' end of a growing chain. Only RNA polymerase requires a primer. Only DNA polymerase uses a template DNA strand to direct synthesis of a new nucleotide strand. Only DNA polymerase has a proofreading ability.
only DNA polymerase has a proofreading ability
How does the ribosome recognize the proper tRNA to bind? An elongation factor recognizes the tRNA and aids its binding through GTP hydrolysis. Only a tRNA with an anticodon that is complementary to the codon will bind in the A-site. Only a tRNA carrying the amino acid that is complementary to the amino acid in the P-site will bind in the A-site. The ribosome recognizes only the proper tRNA that needs to bind in the A-site through GTP-hydrolysis. The enzyme peptidyl transferase allows only the appropriate tRNA to bind in the A-site.
only a tRNA with an anticodon that is complementary to the codon will bind in the A-site
When a polypeptide is being assembled, the bond that forms between a newly added amino acid and the previous amino acid in the chain is this type of bond. hydrogen hydrophobic terminal phosphodiester peptide
peptide
The amino acids carried by the transfer RNA are joined by ionic bonds. covalent bonds. polar bonds. peptide bonds. nonpolar bonds.
peptide bonds
The release factor breaks the covalent bond that links the newly synthesized _______ to the tRNA in the P site.
polypeptide chain
Messenger RNA molecules contain information that is used to synthesize ___________. nucleotides amino acids polypeptides fatty acids
polypeptides
You are working to identify enhancer regions of a particular gene. The best place to begin your search is immediately upstream of the promoter. immediately downstream of the promoter. primarily upstream of the promoter; distance from the promoter does not matter. primarily downstream of the promoter; distance from the promoter does not matter.
primarily upstream of the promoter; distance from the promoter does not matter
A site at the 5' end of a gene where RNA polymerase attaches to initiate transcription and control of gene expression occurs is called a(n). operon. repressor. promoter. operator. CAP.
promoter
RNA polymerase binds to the operator. promoter. regulator. terminator. enhancer.
promoter
The transcription enzyme first attaches to the ________ of the gene. coding region promoter operator regulator initiator
promoter
The segment of the DNA molecule where messenger RNA synthesis begins is called the promoter region. sigma factor. transcription terminator. polymerase. template.
promoter region
The segment of the DNA molecule where messenger RNA synthesis begins is called the... promoter region. sigma factor. transcription terminator. initiation site template.
promoter region
The connection that exists between genes and hereditary traits is based on using the information encoded in genes to synthesize codons. nucleotides. proteins. histones. complementary bases.
proteins
Translation is the synthesis of mRNA from DNA. mRNA from proteins. proteins from DNA proteins from mRNA proteins from tRNA
proteins from mRNA
Which molecule combines with proteins to form both the large and small ribosomal subunits? DNA RNA polymerase miRNA rRNA tRNA
rRNA
If two chromosomes are broken and they exchange non-homologous segments, this is called a ___ translocation.
reciprocal
The protein that promotes translation termination is called terminator. polypeptidase. release factor. doomsday factor. X factor.
release factor
When the ribosome encounters a stop codon, a _____ binds to the A site
release factor
Codons that serve as "stop" signals for translation are recognized by tRNA. release factors. anticodons. translation terminators. aminoacyl-tRNA synthetases
release factors
combines with protein to form the 2 ribosomal subunits.
ribosomal RNA
The polypeptide-making organelles, which consist of protein combined with RNA, are called ribosomes. Golgi bodies. lysosomes. centrosomes. mitochondria
ribosomes
The polypeptide-making organelles, which consist of protein combined with RNA, are called ribosomes. Golgi bodies. lysosomes. centrosomes. mitochondria.
ribosomes
Changes a codon for one amino acid into a different codon for the same amino acid
silent mutation
Which of the following occurs when a piece of one chromosome breaks off and is attached to another chromosome? Inversion Duplication Deletion Simple translocation Reciprocal translocation
simple translocation
A large ribosomal subunit associates with the ____ ribosomal subunit.
small
plays a key role in the splicing reaction that removes introns from eukaryotic pre-mRNA.
small nuclear RNA
During the splicing reaction, the intron-exon junctions are recognized by snRNPs. miRNAs. SRP RNAs. the lariat. the branch point.
snRNPs
Enhancers are the binding sites for the promoters of DNA synthesis. suppressor factors. co-activation factors. mediator factors. specific transcription factors.
specific transcription factors
During transcription of mRNA in eukaryotes, some sequences are cut out of the primary transcript and the remaining sequences are joined together. This processing of mRNA is called _________. termination translation splicing capping elongation
splicing
One or a few base pairs are replaced by different base pairs
substitution
A charged ___ molecule with a UAC anticodon binds to the first AUG codon in the mRNA strand.
tRNA
During translation, amino acids are carried to the ribosome by mRNA. tRNA. snRNA. rRNA. miRNA.
tRNA
If a duplication occurs directly next to the original segment, it is termed a ___ duplication.
tandem
The Rho protein is involved in the _____ stage of transcription. initiation elongation termination none of these choices are correct
termination
Evaluate the statements and determine which is the best explanation for why eukaryotes use so many regulatory elements, such as activators, repressors, coactivators, and basal transcription factors The complexity is a result of multiple gene duplication events. The complexity ensures that a single mutation cannot effect the function of the protein. The complexity allows specific control over the timing and quantity of the protein produced. The complexity allows more than one protein to be transcribed by a single RNA Polymerase. The complexity is necessary because RNA polymerase cannot efficiently bind to the DNA by itself.
the complexity allows specific control over the timing and quantity of the protein produced
A single point mutation has occurred a gene causing a stop codon to appear early in the translation of the protein. What effect will this have on the protein? A single point mutation will have only a minimal effect on the protein. The early stop codon will cause premature termination, and the protein will be abnormally short. Proofreading by the ribosome will recognize the abnormal stop codon and a random tRNA will bind at the A-site rather than the release factor. This will likely result in a single amino acid substitution. The protein will be produced in two pieces. One piece that occurs before the stop codon, and the second piece is the remainder of the protein after the stop codon. Chaperone proteins will then facilitate the proper assembly of the functional protein. This will require extra energy for the cell. None of these are true
the early stop codon will cause premature termination, and the protein will be abnormally short
A mutation causes an activator to be nonfunctional. Which of the following statements best describes the consequences? The gene will not be expressed. The gene will be expressed, but in less than optimal quantities. The gene will be over expressed. The gene will be expressed constitutively. The gene will be expressed as normal.
the gene will be expressed, but in less than optimal quantities
How do you know that the gene being transcribed in the animation is a prokaryote? The chromosome is circular. The enzyme involved is RNA polymerase. The initiation of transcription involves a promoter. The initiation of transcription involves a sigma factor. The termination of transcription involves a terminator.
the initiation of transcription involves a sigma factor
The A, P, and E sites are progressively occupied by amino acids being assembled into a polypeptide. These sites are part of DNA. the large ribosomal subunit. mRNA. tRNA. the spliceosome.
the large ribosomal subunit
A patient's liver has too much messenger RNA. Where would be a good place to start research as a means of enhancing a cell's natural mechanism of degrading mRNA? (multiple answers) The loss of poly-A tails by 3' to 5' RNA exonucleases. Removal of 5' cap by 5' to 3' RNA exonucleases. 3' end recognition sites for endonucleases. Recognition sites for endonucleases at both the 5' and 3' ends. Loss of both the 3' cap and poly-A tail by endonucleases.
the loss of poly-A tails by 3' to 5' RNA exonucleases, removal of 5' cap to 3' RNA exonucleases, 3' end recognition sites for endonucleases
If the Shine-Delgarno sequence was mutated, what might be a consequence? The mRNA would not bind to the small ribosomal subunit in the proper location. The initiator tRNA would not bind to the small ribosomal subunit in the P-site. The initiation factors would not bind to the ribosome, and initiation would not occur. The initiation factors would not be released from the ribosome, and elongation would not occur. The initiation factors would not be able to hydrolyze GTP, and the mRNA, initiator tRNA, and the ribosome would not form a strong association.
the mRNA would not bind to the small ribosomal subunit in the proper location
Within the transcription bubble, the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand. How might transcription be affected if helix formation did not occur? Rewinding the DNA molecule would be inhibited. Unwinding the DNA molecule would be inhibited. The position of the 5' end of the RNA would be unstable, inhibiting elongation. The position of the 3' end of the RNA would be unstable, inhibiting elongation. The position of the 5' end of the RNA would be unstable, stimulating elongation.
the position of the 3' end of the RNA would be unstable, inhibiting elongation
Within the transcription bubble, the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand. How might transcription be affected if helix formation did not occur? Rewinding the DNA molecule would be inhibited. Unwinding the DNA molecule would be inhibited. The position of the 5' end of the RNA would be unstable, inhibiting elongation. The position of the 3' end of the RNA would be unstable, inhibiting elongation. The position of the 5' end of the RNA would be unstable, stimulating elongation.
the position of the 3' end of the RNA would be unstable, inhibiting elongation.
If a frameshift mutation causes a stop codon to be inserted into the DNA sequence the resulting protein will not be affected. the phenotype will change but not the genotype. the resulting protein will be too short and non-functional. the resulting protein will be too long and non-functional.
the resulting protein will be too short and non-functional
Which of the following occurs as a result of translocation? The tRNA that was in the A site moves into the E site. The tRNA that was in the P site moves into the A site. The tRNA that was in the E site moves into the P site. The tRNA that was in the E site moves into the A site. The tRNA that was in the P site moves into the E site.
the tRNA that was in the P site moves into the E site
Which of the following occurs as the ribosome shifts down the mRNA by a distance of three nucleotides? the tRNA that was in the A site moves into the E site the tRNA that was in the P site moves into the A site the tRNA that was in the E site moves into the P site the tRNA that was in the E site moves into the A site the tRNA that was in the P site moves into the E site
the tRNA that was in the P site moves into the E site
If an aminoacyl-tRNA synthetase added the wrong amino acid to a tRNA, what would happen? The tRNA could not bind to the ribosome, and no amino acid would be added to the growing peptide The tRNA would associate with the wrong codon, and the wrong amino acid would be incorporate into the growing peptide. The tRNA would carry the wrong amino acid, and it would be incorporated into the growing protein The ribosome would not be able to recognize the stop codon, and translation would continue to occur when it should have been terminated The ribosome would not be able to recognize the start codon, and translation would not eb initiated.
the tRNA would carry the wrong amino acid, and it would be incorporated into the growing protein
Why are nucleotide triphosphates used to polymerize RNA? Nucleotide triphosphates are the structural building blocks of RNA. The triphosphate is a high energy molecule so that polymerization is spontaneous. RNA polymerase only recognizes nucleotide triphosphates, it cannot use a normal nucleotide as its substrate. Nucleotide triphosphates are more stable and less likely to degrade than normal nucleotides.
the triphosphate is a high energy molecule so that polymerization is spontaneous
Why are there fewer tRNA anticodons than the 61 needed to match each mRNA codon that codes for an amino acid? There is some flexibility in pairing between the 5' base of the codon and the 3' base of the anticodon. There is some flexibility in pairing between the middle base of the codon and the middle base of the anticodon. There is some flexibility in pairing between the 3' base of the codon and the 5' base of the anticodon. There is some flexibility in pairing between all 3 bases of the codon and all 3 bases of the anticodon.
there is some flexibility in pairing between the 3' base of the codon and the 5' base of the anticodon
The best summary of gene splicing mechanisms are that (multiple answers) they allow one coding sequence to be expressed differently according to each cell type. it offers gene plasticity to most eukaryotes. they change all gene types randomly. it adds yet another layer to gene regulation. slicing jumps genes to different locations in the genome.
they allow one coding sequence to be expressed differently according to each cell type, it offers gene plasticity to most eukaryotes, it adds yet another layer to gene regulation
What statement about basal transcription factors is true? Their binding prevents the binding of RNA polymerase to the promoter. They can increase the rate of transcription by themselves. They can decrease the rate of transcription by themselves. They are essential for transcription. They bind to sites that are distant from the promoter.
they are essential for transcription
What statement about enhancers is true? They are sequences to which activators bind. They are basal transcription factors. They are essential for transcription. They are proteins that link basal transcription factors to activators. They are found within the promoter of a gene
they are sequences to which activators bind
What changes would a scientist want to make to a eukaryotic gene before they insert it into a bacterial chromosome to be expressed? They should add many genes next to each other to form an operon. They should remove the introns. They should add a 5' cap and a poly-A tail. They should add a terminator sequence at the 3' end. All of these are necessary before inserting a eukaryotic gene into a prokaryote.
they should remove the introns
The genetic code uses how many nucleotide(s) to specify one amino acid. one two three four 64
three
DNA is used as a template to make a complementary strand of RNA. DNA replication Transcription Translation None of these
transcription
Gene expression involves two phases, translation and _____________. replication transcription initiation condensation
transcription
A bacterial cell has a nonsense mutation that prevents it from producing a functional sigma subunit for RNA polymerase. Inability to synthesize a functional sigma subunit would have the most direct effect on transcription initiation. transcription elongation. transcription termination. translation initiation. translation termination.
transcription initiation
The most efficient control of eukaryotic gene expression is achieved at the level of replication. transcription initiation. post-transcription. translation initiation. post-translation.
transcription initiation
Which of the following statements about a structural gene is TRUE? The gene itself is the only important region of a structural gene. Transcription of a structural gene results in a protein. Transcription of a structural gene could result in a tRNA molecule. Transcription of structural genes requires DNA sequences that are not part of the gene itself.
transcription of structural genes requires DNA sequences that are not part of the gene itself
The eukaryotic transcription initiation complex is (multiple answers) transcription of virtually all genes transcribed by RNA pol II requiring the same suite of general factors. responsible for highly regulated transcription levels. only associated with RNA polymerase I. interactive with activators through DNA looping. a basal factor associated with RNA pol II after positioning RNA pol II at the start site.
transcription of virtually all genes transcribed by RNA pol II requiring the same suite of general factors, responsible for highly regulated transcription levels, interactive with activators through DNA looping
The structure that causes the synthesis of RNA to cease is known as the promoter region. sigma factor. transcription terminator. polymerase. template.
transcription terminator
transports amino acids to the ribosomes for use in protein synthesis.
transfer RNA
At the E site transfer RNA is released anticodons match with codons peptide bonds are formed between amino acids transcription occurs
transfer RNA is released
A lack of amino acid availability would affect what stage in gene expression? transcription translation mRNA production gene replication
translation
During this process, a ribosome assembles a polypeptide whose amino acid sequence is specified by the nucleotide sequence in a molecule of mRNA. Transcription Translation Replication Posttranscriptional modification
translation
Which of these events occur as a prokaryotic mRNA is being transcribed? Splicing of introns Addition of a 5' cap Addition of a poly-A tail Translation of protein All of these
translation of protein
Ribosome movement along the mRNA is called transcription. initiation. replication. translocation. activation.
translocation
Segments of a chromosome that break off and attach to another chromosome are called
translocations
T/F In some cases, it is possible to change the sequence of bases in a codon and it will still code for the same amino acid.
true
T/F Most amino acids are specified by more than one codon.
true
T/F The start codon has a dual function because it also codes for an amino acid.
true
Your research project involves the characterization of a recently identified transcription factor. As part of your project, you want to determine if this transcription factor binds directly to any of the general transcription factors. Unfortunately, however, you are having trouble expressing and purifying the full length protein. An option that may help you achieve your research goal would be to abandon this experiment and try a vastly different approach to your question, since transcription domains cannot be separated. express large amounts of the general transcription factors. express and purify only the DNA-binding domain, since transcription domains can be separated. try to express and purify only the activation domain, since transcription domains can be separated.
try to express and purify only the activation domain, since transcription domainds can be separated
Splicing joins together two introns. two exons. two polypeptides. a DNA and an RNA molecule. an RNA molecule and a polypeptide.
two exons
The assembly of transcription factors begins upstream from the transcription start site. downstream from the transcription start site. upstream from the translation start site. downstream from the translation start site. downstream from the translation stop site.
upstream from the transcription start site
Which base in an anticodon will pair with the base adenine in a codon? Thymine Cytosine Guanine Uracil
uracil
At what point in gene expression do molecules go from being information storage molecules to metabolic and structurally functional molecules? When DNA is in the nucleus When DNA is transcribed into RNA When RNA moves out of the nucleus and into the cytoplasm When RNA is translated into protein The molecules are always only informational.
when RNA is translated into protein
