Biology 101 Chapter 17

Which of the following is true of a codon? It is the basic unit of protein structure. It never codes for the same amino acid as another codon. It can be either in DNA or in RNA. It can code for more than one amino acid.

It can be either in DNA or in RNA.

Which of the following statements correctly describes the function of a signal peptide? It helps target a protein to the ER. It directs an mRNA molecule into the lumen of the ER. It signals the initiation of transcription. It terminates translation of messenger RNA.

It helps target a protein to the ER.

Which of the following statements describes the effect of a nonsense mutation on a gene? It changes only one amino acid in the encoded protein. It has no effect on the amino acid sequence of the encoded protein. It alters the reading frame of the mRNA. It introduces a premature stop codon into the mRNA.

It introduces a premature stop codon into the mRNA.

Which of the following statements correctly describes a ribozyme? It is an enzyme that synthesizes RNA as part of the transcription process. It is an enzyme that catalyzes the association between the large and small ribosomal subunits. It is an RNA with catalytic activity. It is a catalyst that uses RNA as a substrate.

It is an RNA with catalytic activity.

Which of the following statements about the function of RNA polymerase is correct? It relies on other enzymes to unwind the double helix. It adds nucleotides to the 5′ end of the growing mRNA molecule. It unwinds the double helix and adds nucleotides to a growing strand of RNA. It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. All of the listed choices are correct.

It unwinds the double helix and adds nucleotides to a growing strand of RNA.

Use the scheme to answer the question. I −→−−−−enzymeX→enzymeX II −→−−−−enzymeY→enzymeY III The figure shows a simple metabolic pathway. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway? 5 3 2 It cannot be determined from the information provided.

2

Rank the following mutations with respect to their likelihood of affecting the structure of the polypeptide (from most likely to affect structure to least likely). 1. insertion mutation in the middle of an intron 2. deletion of 3 bases crossing an intron-exon border 3. substitution mutation at the third position of a codon 4. substitution mutation at the second position of a codon 3, 4, 2, 1 1, 2, 4, 3 2, 3, 4, 1 4, 3, 2, 1

2, 3, 4, 1

A particular triplet of bases in the template strand of DNA is 5'-AAA-3'. The anticodon on the tRNA that binds the mRNA codon is ________. 5'-TTT-3' 3'-UUU-5' 3'-AAA-5' 5'-UUA-3'

3'-AAA-5'

An mRNA molecule with the sequence 5'-CCG-ACG-3'is being read by a ribosome.During translation which of the following tRNA anticodons will be the first to productively bind with this mRNA? 5'-GGC-3' 5'-UGC-3' 3'-UGC-5' 3'-GGC-5'

3'-GGC-5'

Refer to the table. Which of the triplets below is a possible anticodon in a tRNA that transports proline to a ribosome? 5'-CCG-3' 5'-GGT-3' 3'-GGC-5' 3'-CCC-5'

3'-GGC-5'

Given a DNA molecule with the sequence of bases 5'-ATTGCA-3', what would be the sequence of the complementary strand? (It will be helpful to draw the DNA molecule when answering the question.) 3'-TAACGT-5' 5'-TAACGT-3' 5'-UAACGU-3' 3'-UAACGU-5'

3'-TAACGT-5'

A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. What would be the corresponding codon for the mRNA that is transcribed? 5'-AGT-3' 3'-ACU-5' 3'-UCA-5' 5'-UCA-3'

3'-UCA-5'

The direction of synthesis of an RNA transcript is _____.

5' —> 3'

Use this model of a eukaryotic primary transcript to answer the following question.E = exon and I = intron5'-UTR E1 I1 E2 I2 E3 I3 E4 UTR-3'If the primary transcript is processed and transported to the cytosol, which of the following molecules best represents the mRNA that will be produced? 5'-UTR E1 E2 E3 E4 UTR-3' 5'-E1 I1 E2 I2 E3 I3 E4-3'5 '-UTR I1 I2 I3 UTR-3' 5'-E1 E2 E3 E4-3'

5'-UTR E1 E2 E3 E4 UTR-3'

Life as we know it depends on the genetic code: a set of codons, each made up of three bases in a DNA sequence and corresponding mRNA sequence, that specifies which of the 20 amino acids will be added to the protein during translation. Imagine that a prokaryote-like organism has been discovered in the polar ice on Mars. Interestingly, these Martian organisms use the same DNA → RNA → protein system as life on Earth, except that there are only 2 bases (A and T) in the Martian DNA, and there are only 17 amino acids found in Martian proteins. Based on this information, what is the minimum size of a codon for these hypothetical Martian life-forms? 2 bases 3 bases 4 bases 5 bases 6 bases The answer cannot be determined from the information provided.

5.bases

Identify a 5′→3′5′→3′ sequence of nucleotides in the DNADNA template strand for an mRNAmRNA coding for the polypeptide sequence Phe-Pro-Lys. 5′-UUUCCCAAA-3′ 5′-AAACCCUUU-3′ 5′-CTTCGGGAA-3′ 5′-GAACCCCTT-3′

5′-CTTCGGGAA-3′

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true? DNA was the first genetic material. Different organisms have different types of amino acids. A gene from an organism can theoretically be expressed by any other organism. The same codons in different organisms translate into different amino acids.

A gene from an organism can theoretically be expressed by any other organism.

Which of the following statements about mutations is false? Addition and deletion mutations disrupt the primary structure of proteins. A deletion mutation results in the loss of a base in the DNA sequence. An addition mutation results in an added base in the DNA sequence. A knock-out mutation results in a total absence of the mutated protein.

A knock-out mutation results in a total absence of the mutated protein.

Which of the following statements best supports the one gene-one enzyme hypothesis? Multiple antibody genes can code for different related proteins, depending on the splicing that takes place post-transcriptionally. A mutation in a single gene can result in a defective protein. Alkaptonuria results when individuals lack multiple enzymes involved in the catalysis of homogentisic acid. Sickle-cell anemia results in normal hemoglobin.

A mutation in a single gene can result in a defective protein.

After transcription begins, several steps must be completed before the fully processed mRNA is ready to be used as a template for protein synthesis on the ribosomes. Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus? Coding sequences called exons are spliced out by ribosomes. A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA. Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. A translation stop codon is added at the 3' end of the pre-mRNA. A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA.

A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA. Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA.

Which of the following statements about ribozymes is/are correct? (select all) A ribosome can be regarded as one large ribozyme. Ribozymes are RNA molecules that function as enzymes. In some genes, intron RNA functions as a ribozyme and catalyzes its own excision. Submit

A ribosome can be regarded as one large ribozyme. Ribozymes are RNA molecules that function as enzymes. In some genes, intron RNA functions as a ribozyme and catalyzes its own excision. Submit

Which of the following describes the most likely effect that a single base substitution in the middle of gene's sequence will have on the protein the gene encodes? All amino acids following the substitution would be affected because the reading frame would be altered. A single amino acid would change because pairing of mRNA and tRNA in the ribosome would change. There would be no change because the genetic code is ambiguous. The protein would be shorter because the correct tRNA would not be able to interact with the ribosome.

A single amino acid would change because pairing of mRNA and tRNA in the ribosome would change.

During the elongation phase of translation, which site in the ribosome represents the first location where a codon pairs with an anticodon? the large ribosomal subunit P site E site A site

A site

Transcription begins at a promoter. What is a promoter? The same as a start codon Part of the RNA molecule itself A site in DNA that recruits the RNA Polymerase A site found on the RNA polymerase

A site in DNA that recruits the RNA Polymerase

At which site do new aminoacyl tRNAs enter the ribosome during elongation? P-site E-site B-site A-site

A-site

amino acid

AAA AUC CAC GCA ACU UGC

start/methionine

AUG

Which of the following shows the flow of genetic information? DNA to RNA to protein RNA to DNA to protein protein to RNA to DNA DNA to RNA to ribosomes

DNA to RNA to protein

Which of the following mutations would likely be most dangerous to a cell? Deletion of one nucleotide Deletion of three nucleotides Substitution of one nucleotide for another

Deletion of one nucleotide

targeting pathway of insulin protein

ER--golgi--outside cell

Which of these correctly illustrates the pairing of DNA and RNA nucleotides? GTTACG CAATCG GTTACG CAAUGC GTTACG GTTACG GTTACG ACCGTA GTTACG UAACAU

GTTACG CAAUGC

Which of the following statements correctly describes Archibald Garrod's hypothesis for how "inborn errors of metabolism" such as alkaptonuria occur? Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. Enzymes are made of DNA, and affected individuals lack DNA polymerase. Metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies. Certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors.

Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Which of the following properties is associated with a protein that will be secreted from a eukaryotic cell? Its signal sequence must be cleaved off as the polypeptide enters the ER. It must be translated by a ribosome that remains free within the cytosol. Its signal sequence must target it to the ER. Its signal sequence must target it to the plasma membrane

Its signal sequence must target it to the ER.

Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer that accomplishes this task in eukaryotes? DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place. RNA polymerase transfers information from the nucleus to tRNA synthase in the cytoplasm, where protein synthesis takes place. Messenger RNA is transcribed from a single gene and transfers information to the cytoplasm, where protein synthesis takes place.

Messenger RNA is transcribed from a single gene and transfers information to the cytoplasm, where protein synthesis takes place.

During translation, nucleotide base triplets (codons) in mRNA are read in sequence in the 5' → 3' direction along the mRNA. Amino acids are specified by the string of codons. What amino acid sequence does the following mRNA nucleotide sequence specify? 5′−AUGGCAAGAAAA−3′ **Express the sequence of amino acids using the three-letter abbreviations, separated by hyphens (e.g., Met-Ser-Thr-Lys-Gly).**

Met-Ala-Arg-Lys

What amino acid sequence does the following DNA nucleotide sequence specify? 3′−TACAGAACGGTA−5′3′−TACAGAACGGTA−5′ **Express the sequence of amino acids using the three-letter abbreviations, separated by hyphens (e.g., Met-Ser-His-Lys-Gly).**

Met-Ser-Cys-His

Which of the following best describes the redundancy in the genetic code? More than one codon can specify the addition of the same amino acid. A single codon can specify the addition of more than one amino acid. The genetic code is universal (the same for all organisms). The genetic code is different for different domains of organisms.

More than one codon can specify the addition of the same amino acid.

Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? One addition and two deletion mutations. One addition mutation. One deletion mutation. One addition and one deletion mutation.

One addition and one deletion mutation.

Which of the following statements is true about protein synthesis in prokaryotes? Translation can begin while transcription is still in progress. Extensive RNA processing is required before transcripts can be translated. Translation requires no initiation or elongation factors. Protein targeting to cellular organelles requires recognition of signal sequences.

Translation can begin while transcription is still in progress.

stop codon

UAA UAG UGA

Part complete Suppose that a portion of double-stranded DNA in the middle of a large gene is being transcribed by an RNA polymerase. As the polymerase moves through the sequence of six bases shown in the diagram below, what is the corresponding sequence of bases in the RNA that is produced? 3'CCGAGT5' 5'GGCTCA5' Enter the sequence of bases as capital letters with no spaces and no punctuation. Begin with the first base added to the growing RNA strand, and end with the last base added.

UGAGCC

What is a ribozyme? a biological catalyst consisting of DNAa mutated ribosome an enzyme that holds open the DNA double helix while RNA polymerase adds nucleotides a DNA sequence near the promoter that assists in the binding of RNA polymerase a biological catalyst made of RNA

a biological catalyst made of RNA

What does a mutagen cause? problems with mitosis a reduction in the number of tRNA molecules available for protein synthesis decreased permeability of the nuclear envelope decreased enzyme activity throughout the cell a change in the sequence of DNA

a change in the sequence of DNA

A single base substitution mutation is likely to have a less harmful effect when the base change results in which of the following? an amino acid substitution that alters the tertiary structure of the protein a stop codon an amino acid substitution at the active site of an enzyme a codon that specifies the same amino acid as the original codon

a codon that specifies the same amino acid as the original codon

While characterizing an error-prone organism, researchers found that each of the following types of mutations occurred immediately downstream of the translation start site. Which type of mutation is likely to have the most serious effect on the function of the polypeptide product? a deletion of two nucleotides a substitution of the third nucleotide in an ACC codon a substitution of the first nucleotide of a GGG codon a deletion of a codon

a deletion of two nucleotides

Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene? a base substitution at the beginning of the gene a base substitution at the end of the gene a frameshift deletion at the beginning of the gene a frameshift deletion at the end of the gene

a frameshift deletion at the beginning of the gene

Which of these is currently considered the best definition of a gene? a gene codes for a single polypeptide a gene codes for a particular ribozyme a gene codes for a single protein a gene codes for a single enzyme a gene codes for either a polypeptide or an RNA molecule

a gene codes for either a polypeptide or an RNA molecule

During RNA processing a(n) _____ is added to the 3' end of the RNA. 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

a long string of adenine nucleotides

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation? a polypeptide missing an amino acid a frameshift mutation a base-pair substitution a polypeptide missing its N-terminus

a polypeptide missing an amino acid

Which of the following mutations would be most likely to have a harmful effect on an organism? a deletion of three nucleotides near the middle of a gene a single nucleotide deletion in the middle of an intron a single nucleotide deletion near the end of the coding sequence a single nucleotide insertion downstream of, and close to, the start of the coding sequence

a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Translation termination occurs when a ribosome interacts with which of the following structures? the end of the mRNA molecule. the 5' cap a stop codon the poly-A tail

a stop codon

Post-translational modifications of proteins may include which of the following processes? addition of a 5' cap removal of introns addition of carbohydrates to form a glycoprotein synthesis of peptide bonds

addition of carbohydrates to form a glycoprotein

Polypeptides are assembled from _____. hexoses glycerol nucleotides proteins amino acids

amino acids

2. Amino acids are attached to tRNA by enzymes called _______ tRNA aminoacyl-tRNA synthease translation initiation termination

aminoacyl-tRNA synthease

Accuracy in translation of mRNA into the primary structure of a polypeptide depends on specificity in the ________. attachment of amino acids to tRNAs attachment of amino acid's carboxyl group with the amine of the next amino acid. binding of ribosomes to the mRNA binding of the anticodon to small subunit of the ribosome

attachment of amino acids to tRNAs

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? Covalently bound Complementary Identical Permanently base-paired

complementary

The anticodon of a particular tRNA molecule is complementary to the corresponding mRNA codon. complementary to the corresponding triplet in rRNA. catalytic, making the tRNA a ribozyme. the part of tRNAtRNA that bonds to a specific amino acid.

complementary to the corresponding mRNA codon.

Translation occurs in the _____. cytoplasm lysosome nucleus Golgi apparatus nucleoplasm

cytoplasm

targeting pathway of PFK protein

cytoplasm only

If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred? Both addition and deletion. Deletion. Addition. None

deletion

The RNA segments joined to one another by spliceosomes are _____. caps exons snRNPs tails introns

exons

True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated.

false

True or false? A codon is a group of three bases that can specify more than one amino acid.

false

Original: 3' TACGCAGGTACGATC 5' 5' ATGCGTCCATGCTAG 3' 3' TAC*C*GCAGGTACGATC 5' 5' ATG*G*CGTCCATGCTAG 3'

frameshift mutation

Part complete A section of DNA has the base sequence shown in #1. A mutation in this DNA strand results in the base sequence shown in #2. What type of mutation does this change represent? #1 5' - AGCGTTACCGT-3' #2 5'-AGGCGTTACCGT-3' frameshift mutation a missense mutation a silent mutation a point mutation

frameshift mutation

The flow of information in a cell proceeds in what sequence? from DNA to RNA to protein from DNA to protein to RNA from RNA to protein to DNA from protein to RNA to DNA from RNA to DNA to protein

from DNA to RNA to protein

Which of the following terms associated with transcription describe regions of nucleic acid? gene promoter terminator RNA polymerase

gene promoter terminator

What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure? hydrogen bonding between base pairs peptide bonding between amino acids van der Waals interactions between hydrogen atoms ionic bonding between phosphates

hydrogen bonding between base pairs

Which answer correctly compares prokaryotic and eukaryotic codons? Organisms utilize codons that are nearly universal among all organisms. Prokaryotic codons usually specify different amino acids than those of eukaryotes. Prokaryotic codons usually contain different bases than those of eukaryotes. Organism within a phylum share codons that are distinct from organisms in other phyla.

Organisms utilize codons that are nearly universal among all organisms.

If a bacteria contained a mutant aminoacyl-tRNA synthetase that attaches a lysine instead of the normal phenylalanine to tRNAs with the anticodon AAA which of the following would occur? Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. The cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. The ribosome will skip a codon every time a UUU is encountered. None of the proteins in the cell will contain phenylalanine.

Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

Which of the following processes occurs as part of transcription? mRNA attaches to ribosomes proteins are synthesized DNA is replicated RNA is synthesized

RNA is synthesized

In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a protein? RNA polymerase III RNA polymerase II RNA polymerase I primase

RNA polymerase II

Which of the following molecules is/are produced by translation? Include molecules that are subject to further modification after initial synthesis. (select all) RNA polymerase The amino acid glycine Aminoacyl-tRNA synthetase

RNA polymerase and Aminoacyl-tRNA synthetase

Which of the following statements best describes the termination of transcription in prokaryotes? RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript. RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome and releases. RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA.

RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

What name is given to the process in which pre-mRNA is edited into mRNA? RNA processing gene expression polypeptide formation transcription translation

RNA processing

Which of the following statements about RNA processing is correct? Exons are removed before mRNA leaves the nucleus. Ribozymes may function in RNA splicing. A primary transcript is often much shorter than the final RNA molecule that leaves the nucleus. RNA splicing can be catalyzed by tRNA.

Ribozymes may function in RNA splicing.

Which of the following steps occurs last in the initiation phase of translation? An aminoacyl tRNA binds to the start codon. A peptide bond is formed between two adjacent amino acids. The small subunit of the ribosome binds to the 5' cap on the mRNA. The large ribosomal subunit joins the complex.

The large ribosomal subunit joins the complex.

Which of the following is most likely to occur if a researcher removes the 5' cap and poly-A tail of an mRNA and inserts the mRNA molecule into a eukaryotic cell? The mRNA will attaches to a ribosome and be translated, but more slowly. The cell will add a new poly-A tail to the mRNA. The molecule will be degraded by enzymes. The mRNA will be quickly converted into a ribosomal subunit.

The molecule will be degraded by enzymes.

Which of the following statements best describes the promoter of a protein-coding gene? The promoter is a site found on RNA polymerase. The promoter is part of the RNA molecule itself. The promoter is a nontranscribed region of a gene. The promoter is a site at which only RNA polymerase will bind.

The promoter is a nontranscribed region of a gene.

Use the scheme to answer the question. I −→−−−−enzymeX→enzymeX II −→−−−−enzymeY→enzymeY III −→−−−−enzymeZ→enzymeZ IV Refer to the metabolic pathway illustrated. If I, II, III and IV are all required for growth, a bacterial strain that does not make enzyme Y would be able to grow on medium supplemented with which of the following compounds? nutrient A only nutrient C only nutrients A and C only nutrients B and D only

nutrients A and C only

DNA does not store the information to synthesize which of the following? Organelles DNA Messenger RNA Proteins

organelles

Which of the following processes is an example of a post-translational modification? Phosphorylation Elongation Peptide bond formation Initiation

phosphorylation

primary, secondary, tertiary, or quaternary? amino acid sequence

primary

Where does translation take place? Golgi apparatus Nucleus Ribosome Endoplasmic reticulum

ribosome

Which component is directly involved in translation? RNA polymerase ribosome spliceosome DNA

ribosome

primary, secondary, tertiary, or quaternary? α helix beta pleated sheet results from hydrogen bonding between the backbone constituents of the polypeptide

secondary

In eukaryotic cells, transcription cannot begin until the DNA introns are removed from the template. the 5′ caps are removed from the mRNA. several transcription factors have bound to the promoter. the two DNA strands have completely separated and exposed the promoter.

several transcription factors have bound to the promoter.

A _______ mutation does not change the wild-type amino acid sequence.

silent

Original: 3' TACGCAGGTACGATC 5' 5' ATGCGTCCATGCTAG 3' 3' TACGC*C*GGTACGATC 5' 5' ATGCG*G*CCATGCTAG 3'

silent mutation

Which of the following processes occurs in prokaryotes but not in eukaryotes? translation in the absence of a ribosome simultaneous transcription and translation of the same mRNA removing introns from pre-RNA translocation into the ER

simultaneous transcription and translation of the same mRNA

Spliceosomes are composed of _____. small RNAs and proteins polymerases and ligases introns and exons the RNA transcript and protein

small RNAs and proteins

RNA plays important roles in many cellular processes, particularly those associated with protein synthesis: transcription, RNA processing, and translation. transcription/RNA processing snRNA pre-mRNA mRNA translation rRNA tRNA not used in protein synthesis RNA primers

snRNA pre-mRNA mRNA

1. The RNA that has an amino acid attached to it, and that binds to the codon on the mRNA, is called a ______ tRNA aminoacyl-tRNA synthease translation initiation termination

tRNA

tRNA, mRNA, or rRNA? contains an anticodon has amino acids covalently attached

tRNA

_______of translation happens when the ribosome hits a stop codon on the mRNA. tRNA aminoacyl-tRNA synthease translation initiation termination

termination

primary, secondary, tertiary, or quaternary? results from interactions between side chains(R groups) of amino acids the overall shape of a polypeptide

tertiary

After an RNA molecule is transcribed from a eukaryotic gene, what are removed, and what are spliced together, to produce an mRNA molecule with a continuous coding sequence? introns, exons silencers, enhancers exons, introns operators, promoters promoters, operators

introns, exons

Where does RNA polymerase begin transcribing a gene into mRNA? transfer RNA acts to translate the message to RNA polymerase it starts after a certain nucleotide sequence called a promoter the ribosome directs it to the correct portion of the DNA molecule it starts at one end of the chromosome it looks for the AUG start codon

it starts after a certain nucleotide sequence called a promoter

According to the central dogma, which of the following intermediate molecules correctly completes the flow chart describing the flow of information in a cell blank? DNA - ________ - Proteins tRNA mRNA rRNA enzymes

mRNA

RNA processing converts the RNA transcript into _____. a protein DNA a eukaryotic cell mRNA a polypeptide

mRNA

Which nucleic acid is translated to make a protein? rRNA mRNA DNA tRNA

mRNA

Which of the following molecular structures contains codons? rRNA tRNA a protein mRNA

mRNA

tRNA, mRNA, or rRNA? contains exons specifies the amino acid sequence for a protein

mRNA

Which of the following molecules directly participates in the process of translation? mRNA, tRNA, DNA, and rRNA mRNA, tRNA, and DNA mRNA, tRNA, and rRNA mRNA, DNA, and rRNA

mRNA, tRNA, and rRNA

RNA plays important roles in many cellular processes, particularly those associated with protein synthesis: transcription, RNA processing, and translation. not used in protein synthesis snRNA pre-mRNA mRNA translation rRNA tRNA not used in protein synthesis RNA primers

not used in protein synthesis RNA primers

Use the scheme to answer the question. I −→−−−−enzymeX→enzymeX II −→−−−−enzymeY→enzymeY III −→−−−−enzymeZ→enzymeZ IV Refer to the metabolic pathway illustrated. If I, II, III, and IV are all required for growth, a bacterial strain that does not make enzyme X would be able to grow on medium supplemented with which of the following nutrient(s)? nutrient A only nutrient B only nutrients A and B only nutrients B, C, and D only

nutrients A and B only

In eukaryotes which of the following is the first step in translation? binding of the larger ribosomal subunit to smaller ribosomal subunits the small subunit of the ribosome recognizes and attaches near the 5' cap of mRNA base pairing of activated methionine-tRNA to AUG of the messenger RNA the ribosome reaches a stop codon

the small subunit of the ribosome recognizes and attaches near the 5' cap of mRNA

Which of the following characteristics is directly related to the coding of a single amino acid during the process of translation? the amino acetyl tRNA synthase used the base sequence at the tRNA 5' end the three-base sequence of mRNA the complementary binding of DNA with RNA

the three-base sequence of mRNA

In the structure of many eukaryotic genes, individual exons parallel which of the following? the number of start sites for transcription the various domains of the protein product the sequence of the intron that immediately precedes each exon the number of polypeptides making up the functional protein

the various domains of the protein product

A codon consists of __________ bases and specifies which __________ will be inserted into the polypeptide chain. three, nucleotide three, amino acid four, fatty acid four, amino acid two, nucleotide

three, amino acid

What is the process called that converts the genetic information stored in DNA to an RNA copy? Replication Transcription Translocation Translation

transcription

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA? RNA processing gene expression polypeptide formation transcription translation

transcription

Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase? aminoacyl-tRNA synthetase anticodons ribosomes and tRNA transcription factors

transcription factors

mRNA first plays a role in___ replication, transcription/RNA processing, or translation

transcription/RNA processing

3. The process, performed by the ribosome, of reading mRNA and synthesizing a protein is called ______ tRNA aminoacyl-tRNA synthease translation initiation termination

translation

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein? RNA processing gene expression polypeptide formation transcription translation

translation

______of translation always happens at the start codon of the mRNA. tRNA aminoacyl-tRNA synthease translation initiation termination

translation

tRNA and rRNA first play a role in_____ replication, transcription/RNA processing, or translation

translation

If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein? None. Two. Three. One.

two

Which of the following clues would tell you if a cell is prokaryotic or eukaryotic? whether the cell contains DNA or RNA the presence or absence of ribosomes the presence or absence of a rigid cell wall whether or not the cell is compartmentalized by internal membranes

whether or not the cell is compartmentalized by internal membranes

How is translation initiated? the start codon signals the start of translation the large ribosomal subunit binds to the small one the small ribosomal subunit binds to the mRNA the tRNA bearing methionine binds to the start codon All of the listed answers are correct.

All are correct

If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred? An addition mutation and a deletion mutation. A deletion mutation. An addition mutation None.

An addition mutation and a deletion mutation.

What determines which base is to be added to an RNA strand during transcription? Base pairing between the two DNA strands The previous base The order of the chemical groups in the backbone of the RNA molecule Base pairing between the DNA template strand and the RNA nucleotides

B) Base pairing between the DNA template strand and the RNA nucleotides

Which codon on the mRNA strand codes for the amino acid carried by the aminoacyl-tRNA represented in the figure? 5'-UGG-3' 5'-UUC-3' 3'-GUG-5' 5'-GUA-3'

D) 5′-UUC-3′

What is the function of the release factor during translation in eukaryotes? It supplies a source of energy for termination of translation. It releases the ribosome from the ER to allow polypeptides into the cytosol. It binds to the stop codon in the A site in place of a tRNA. It releases the amino acid from its tRNA to allow the amino acid to form a peptide bond.

It binds to the stop codon in the A site in place of a tRNA.

Which of the following processes correctly describes alternative RNA splicing? It can allow the production of similar proteins from different RNAs. It increases the rate of transcription. It can allow the production of proteins of different sizes and functions from a single mRNA. It is a mechanism for increasing the rate of translation.

It can allow the production of proteins of different sizes and functions from a single mRNA.

What happens to RNA polymerase II after it has completed transcription of a gene? It begins transcribing the next gene on the chromosome. It is degraded. It joins with another RNA polymerase to carry out transcription. It is free to bind to another promoter and begin transcription.

It is free to bind to another promoter and begin transcription.

Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes? It is the recognition site for ribosomal binding during translation. It is the recognition site for the binding of a specific transcription factor. It is the recognition site for ribosomal binding during transcription. It sets the reading frame of the mRNA during translation.

It is the recognition site for the binding of a specific transcription factor.

The average length of a transcription unit along a eukaryotic DNA molecule is about 27,000 nucleotide pairs, whereas an averaged-sized protein is about 400 amino acids long. What is the best explanation for this fact? Many genes are subject to alternative RNA splicing. Each amino acid in a protein is encoded by a triplet of nucleotides. Most eukaryotic genes and their RNA transcripts have long noncoding stretches of nucleotides that are not translated.

Most eukaryotic genes and their RNA transcripts have long noncoding stretches of nucleotides that are not translated.

Which one of the following statements is true of tRNAs? tRNAs are double-stranded. Each tRNA binds a particular codon. tRNAs carry special sequences known as codons. There are four types of tRNA. None of the listed answers are correct.

None of the listed answers are correct.

Which of the following is true of RNARNA processing? Nucleotides are added at both ends of the RNA. RNA splicing adds a poly-A tail to the mRNA. R Ribozymes may function in the addition of a 5′5′ cap. Exons are cut out before mRNA leaves the nucleus.

Nucleotides are added at both ends of the RNA.

Your body contains tens of thousands of different proteins, each with a specific structure and function. The unique three-dimensional shape of each of these diverse proteins is based on several superimposed levels of structure. Which of the following is an accurate statement about proteins? The primary structure of a protein is the order of amino acids in a polypeptide, as coded for by the DNA of a gene. Quaternary structure is only found in proteins that have four polypeptide subunits. Tertiary structure is the combining of several polypeptide subunits to form a functional protein; tertiary structure may be stabilized by hydrophobic interactions, hydrogen bonds, ionic bonds, and peptide bonds. Secondary structure, which includes αα helices and ββ pleated sheets, results from interactions between R groups.

The primary structure of a protein is the order of amino acids in a polypeptide, as coded for by the DNA of a gene.

What is meant by translocation? The polypeptide chain grows by one amino acid. The completed polypeptide is released from the ribosome. The ribosome slides one codon down the mRNA. The two ribosomal subunits are joined in a complex.

The ribosome slides one codon down the mRNA.

Which of the following best explains the observation that in bacteria, there are 61 mRNA codons that specify an amino acid, but only 45 tRNAs? The DNA codes 61 tRNAs, but some are destroyed after transcription. The rules for base pairing between the third base of a codon and tRNA are flexible. Some tRNAs have anticodons that recognize four or more different codons. Many codons are never used, so the tRNAs that recognize them are dispensable.

The rules for base pairing between the third base of a codon and tRNA are flexible.

Which of the following statements is the most current description of a gene? a discrete unit of hereditary information that consists of a sequence of amino acids a DNA sequence that is expressed to form a functional RNA or polypeptide product a unit of heredity that causes formation of a phenotypic characteristic a DNA subunit that codes for a single complete protein

a DNA sequence that is expressed to form a functional RNA or polypeptide product

Which of the following changes in an exon is most likely to result in a nonfunctional protein product? an addition of three nucleotides a codon deletion a substitution in the last base of a codon a base-pair deletion

a base-pair deletion

Which of the following molecules are produced by transcription? (select all) Messenger RNA Ribosomal proteins Ribozymes

messenger RNA and ribozymes

A _________ mutation causes a wild-type amino acid to be replaced by a different amino acid.

missense

Original: 3' TACGCAGGTACGATC 5' 5' ATGCGTCCATGCTAG 3' 3' TACGCA*A*GTACGATC 5' 5' ATGCGT*T*CATGCTAG 3'

missense mutation

During RNA processing a(n) _____ is added to the 5' end of the RNA. 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

modified guanine nucleotide

exon 1--exon 2--intro 2--exon 3

mutation in a splicing signal sequence in intron 2

no mRNA produced

mutation in the gene's promoter sequence

exon 1--intro 1--exon 2-- intron 2--exon 3

mutations in splicing signal sequences in both intron 1 and intron 2

exon 1--exon 2--exon 3

no mutation in any splicing signal sequence

A _________ mutation causes an early Stop codon to occur.

nonsense

Original: 3' TACGCAGGTACGATC 5' 5' ATGCGTCCATGCTAG 3' 3' TACGCAGGTAC*T*ATC 5' 5' ATGCGTCCATG*A*TAG 3'

nonsense mutation

Use the following information to answer the question. An mRNA molecule with the sequence 5'-CCG-ACG-3' is being translated at a ribosome. The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form. tRNA Anticodon Amino Acid GGC Proline CGU Alanine UCG Threonine CCG Glycine ACG Cysteine CGG Alanine Which of the following dipeptides will form from this mRNA? cysteine-alanine alanine-alanine proline-threonine glycine-cysteine

proline-threonine

primary, secondary, tertiary, or quaternary? the aggregation of multiple polypeptide subunits

quaternary

tRNA, mRNA, or rRNA? is a component of ribosomes is the most abundant form of RNA

rRNA

RNA plays important roles in many cellular processes, particularly those associated with protein synthesis: transcription, RNA processing, and translation. translation snRNA pre-mRNA mRNA translation rRNA tRNA not used in protein synthesis RNA primers

rRNA tRNA

During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3'→5' direction. However, for any given gene, either strand of the double-stranded DNA may function as the template strand. For any given gene, what ultimately determines which DNA strand serves as the template strand? which of the two strands of DNA carries the RNA primer the location along the chromosome where the double-stranded DNA unwinds the base sequence of the gene's promoter the location of specific proteins (transcription factors) that bind to the DNA

the base sequence of the gene's promoter

Which answer correctly compares the primary transcript in the nucleus of a eukaryotic cell with the functional mRNA? both the primary transcript and mRNA contain introns the primary transcript is the same size as the mRNA the primary transcript is larger than the mRNA the primary transcript is smaller than the mRNA

the primary transcript is the same size as the mRNA Submit