BIOL Ch. 14 Study

24 July 2022
4.7 (114 reviews)
56 test answers

Unlock all answers in this set

Unlock answers (52)
question
True or false? A codon is a group of three bases that can specify more than one amino acid.
answer
false
question
Which of the following statements about mutations is false? View Available Hint(s) Which of the following statements about mutations is false? Addition and deletion mutations disrupt the primary structure of proteins. An addition mutation results in an added base in the DNA sequence. A deletion mutation results in the loss of a base in the DNA sequence. A knock-out mutation results in a total absence of the mutated protein.
answer
A knock-out mutation results in a total absence of the mutated protein.
question
If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred? View Available Hint(s) If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred? None. Addition. Both addition and deletion. Deletion.
answer
Deletion
question
Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? View Available Hint(s) Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? One deletion mutation. One addition mutation. One addition and two deletion mutations. One addition and one deletion mutation.
answer
One addition and one deletion mutation.
question
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? View Available Hint(s) 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? Two. Three. One. None.
answer
two
question
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? View Available Hint(s) 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? A deletion mutation. An addition mutation None. An addition mutation and a deletion mutation.
answer
An addition mutation and a deletion mutation.
question
Examine the simple metabolic pathway in the figure. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway? 0 1 2 3 It cannot be determined from the pathway
answer
2
question
The flow of information in a cell proceeds in what sequence? View Available Hint(s) from RNA to DNA to protein from protein to RNA to DNA from DNA to protein to RNA from DNA to RNA to protein from RNA to protein to DNA
answer
from DNA to RNA to protein
question
A codon consists of __________ bases and specifies which __________ will be inserted into the polypeptide chain. View Available Hint(s) three ... amino acid four ... amino acid two ... nucleotide three ... nucleotide four ... fatty acid
answer
three....amino acid
question
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is 3' UGA 5'. 3' ACU 5'. 5' TCA 3'. 3' UCA 5'. either UCA or TCA, depending on wobble in the first base.
answer
3' UCA 5'
question
The genetic code is essentially the same for all organisms. Based on this information, one can logically assume which of the following statements to be correct? A gene from an organism can theoretically be expressed by any other organism. All organisms have experienced convergent evolution. The same codons in different organisms translate into the different amino acids. DNA was the first genetic material. Different organisms have different numbers of different types of amino acids.
answer
A gene from an organism can theoretically be expressed by any other organism.
question
In the diagram below, the gray unit represents _____. The figure shows a blue molecule arranged in the form of a double chain. The gray unit on this figure represents an oval structure which contains unwound and unpaired chains of this molecule. Before and after this unit, the molecule is wound in the form of a double helix. A green unit represents a part of the double helix before the gray unit. RNA DNA transcription factors RNA polymerase the promoter
answer
RNA polymerase
question
In the diagram below, the green unit represents _____. The figure shows a blue molecule arranged in the form of a double chain. The gray unit on this figure represents an oval structure which contains unwound and unpaired chains of this molecule. Before and after this unit, the molecule is wound in the form of a double helix. A green unit represents a part of the double helix before the gray unit. RNA DNA transcription factors RNA polymerase the promoter
answer
the promoter
question
In the diagram below, the two blue strands represent _____. The figure shows a blue molecule arranged in the form of a double chain. The gray unit on this figure represents an oval structure which contains unwound and unpaired chains of this molecule. Before and after this unit, the molecule is wound in the form of a double helix. A green unit represents a part of the double helix before the gray unit. View Available Hint(s) RNA DNA transcription factors RNA polymerase the promoter
answer
DNA
question
Which of these correctly illustrates the pairing of DNA and RNA nucleotides? GTTACG CAATCG GTTACG CAAUGC GTTACG GTTACG GTTACG ACCGTA GTTACG UAACAU
answer
GTTACG CAAUGC
question
The direction of synthesis of an RNA transcript is _____. 1' β€”> 5' 5' β€”> 3' 1' β€”> 3' 3' β€”> 5' 2' β€”> 4'
answer
5' β€”> 3'
question
Use the representation in the figure to answer the following question. DNA template strand 5'___________________________3' DNA complementary strand 3'___________________________5' Given the locally unwound double strand in the figure, in which direction does the RNA polymerase move? 3' β†’ 5' along the template strand 5' β†’ 3' along the double-stranded DNA 5' β†’ 3' along the template strand 3' β†’ 5' along the complementary strand 5' β†’ 3' along the complementary strand
answer
3' β†’ 5' along the template strand
question
Where does RNA polymerase begin transcribing a gene into mRNA? The ribosome directs it to the correct portion of the DNA molecule. It looks for the AUG start codon. It starts after a certain nucleotide sequence called a promoter. It starts at one end of the chromosome. Transfer RNA acts to translate the message to RNA polymerase.
answer
It starts after a certain nucleotide sequence called a promoter.
question
What is the function of RNA polymerase? View Available Hint(s) It relies on other enzymes to unwind the double helix. It unwinds the double helix and adds nucleotides to a growing strand of RNA. It adds nucleotides to the 5' end of the growing mRNA molecule. It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. All of the listed responses are correct.
answer
It unwinds the double helix and adds nucleotides to a growing strand of RNA.
question
Which of the following does not occur in prokaryotic gene expression, but does occur in eukaryotic gene expression? mRNA, tRNA, and rRNA are transcribed. RNA polymerase requires a primer to elongate the molecule. Transcription can begin as soon as translation has begun even a little. A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end. RNA polymerase binds to the promoter.
answer
A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.
question
Which of the following best describes the significance of the TATA box in eukaryotic promoters? It sets the reading frame of the mRNA. It is the recognition site for a specific transcription factor. It is the recognition site for ribosomal binding. It signals the end of the nucleotide sequence of the gene.
answer
It is the recognition site for a specific transcription factor.
question
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
answer
modified guanine nucleotide
question
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
answer
a long string of adenine nucleotides
question
Spliceosomes are composed of _____. small RNAs and proteins polymerases and ligases introns and exons the RNA transcript and protein
answer
small RNAs and proteins
question
The RNA segments joined to one another by spliceosomes are _____. caps exons snRNPs tails introns
answer
exons
question
Translation occurs in the _____. cytoplasm lysosome nucleus Golgi apparatus nucleoplasm
answer
cytoplasm
question
After an RNA molecule is transcribed from a eukaryotic gene, what is removed and what is spliced together to produce an mRNA molecule with a continuous coding sequence? View Available Hint(s) After an RNA molecule is transcribed from a eukaryotic gene, what is removed and what is spliced together to produce an mRNA molecule with a continuous coding sequence? promoters ... operators operators ... promoters silencers ... enhancers exons ... introns introns ... exons
answer
introns.....exons
question
Which of the following is a function of a poly-A tail in mRNA? It adds the modified guanine to the 3' end of the mRNA. It is a sequence that codes for the binding of RNA polymerase to the DNA. It indicates the site of translational termination. It helps protect the mRNA from degradation by hydrolytic enzymes.
answer
It helps protect the mRNA from degradation by hydrolytic enzymes.
question
Which of the following experimental procedures is most likely to speed up mRNA degradation in a eukaryotic cell? removal of one or more exons lengthening of the poly-A tail removal of the 5' cap removal of C nucleotides
answer
removal of the 5' cap
question
Which of these is a tRNA? The figure shows a process of translation. Each letter marks a definite structure. Letter A marks the thread, to which the ribosome is attached. This thread is the base of the translation. Letter B marks the structure, which is bonded with Gly and is located inside the ribosome. Letter C marks the structure, in which the translation happens. Letter D marks the thread, which is formed by the translation. Letter E marks the structures, which are constituent elements of the forming thread. A B C D E
answer
B
question
What enzyme catalyzes the attachment of an amino acid to tRNA? aminoacyl-tRNA synthetase rubisco dextrinase argininosuccinate lyase nuclease
answer
aminoacyl-tRNA synthetase
question
The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____. CAG CTG GAC CUG TCG
answer
CUG
question
What is the name of the process shown in the diagram? The figure shows a process which happens in the ribosome. During this process, a transport molecule which is localized in the central site of the ribosome binds to AUG sequence of the matrix molecule by its UAC site. This transport molecule also binds to Met molecule. initiation (of transcription) RNA processing initiation (of translation) elongation termination (of translation)
answer
initiation (of translation)
question
The initiator tRNA attaches at the ribosome's _____ site. A translocation E P Q
answer
P
question
The following information should be used for the next few questions. A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA). The charged transfer RNA molecules shown in the figure (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 UGC Threonine CCG Glycine ACG Cysteine CGG Alanine The anticodon loop of the first tRNA that will complement this mRNA is 3' UGC 5'. 5' GGC 3'. 5' UGC 3'. 5' ACG 3'. 3' GGC 5'.
answer
3' GGC 5'.
question
The figure shows secondary cloverleaf structure of tRNA. It has its 3 prime end called amino acid attachment site ACCA and an anticodon site with the sequence AAG. the figure the figure represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid? GUG GUA UGG UUC CAU
answer
UUC
question
Which one of the following is true of tRNAs? View Available Hint(s) There are four types of tRNA. tRNAs are double-stranded. tRNAs carry special sequences known as codons. Each tRNA binds a particular amino acid. All of the above.
answer
Each tRNA binds a particular amino acid.
question
important
answer
1. Initiation of translation always happens at the start codon of the mRNA. 2. Amino acids are attached to tRNA by enzymes called aminoacyl-tRNA synthetase. 3. The process, performed by the ribosome, of reading mRNA and synthesizing a protein is called translation. 4. The RNA that has an amino acid attached to it, and that binds to the codon on the mRNA, is called at RNA. 5. Termination of translation happens when the ribosome hits a stop codon on the mRNA.
question
A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. What would be a potential consequence for a cell in which this happens? Remember that phenylalanine may be encoded by multiple codons. Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. None of the proteins in the cell will contain phenylalanine. 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.
answer
Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.
question
Part complete There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that the rules for base pairing between the third base of a codon and tRNA are flexible. the DNA codes for all 61 tRNAs but some are then destroyed. many codons are never used, so the tRNAs that recognize them are dispensable. some tRNAs have anticodons that recognize four or more different codons. competitive exclusion forces some tRNAs to be destroyed by nucleases.
answer
the rules for base pairing between the third base of a codon and tRNA are flexible.
question
When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following sets of structures would you be able to isolate from the cell? separated ribosomal subunits, a polypeptide, and free tRNA an assembled ribosome with a polypeptide attached to the tRNA in the P site an assembled ribosome with a separated polypeptide separated ribosomal subunits with a polypeptide attached to the tRNA
answer
an assembled ribosome with a polypeptide attached to the tRNA in the P site
question
What must happen to a newly made polypeptide before it can be secreted from a cell? Its signal sequence must cause it to be encased in a vesicle as soon as it is translated. It must be translated by a ribosome that remains free of attachment to the ER. Its signal sequence must target it to the plasma membrane, where it causes exocytosis. Its signal sequence must be cleaved off before the polypeptide can enter the ER. Its signal sequence must target it to the ER, after which it goes to the Golgi.
answer
Its signal sequence must target it to the ER, after which it goes to the Golgi.
question
Which of these is currently considered the best definition of a gene? View Available Hint(s) A gene codes for a single protein. A gene codes for either a polypeptide or an RNA molecule. A gene codes for a single enzyme. A gene codes for a single polypeptide. A gene codes for a particular ribozyme.
answer
A gene codes for either a polypeptide or an RNA molecule.
question
Which of the following types of mutation, resulting in an error in the mRNA just after the 3 AUG start codon, is likely to have the most serious effect on the polypeptide product? a deletion of two nucleotides an insertion of a codon a deletion of a codon a substitution of the third nucleotide in an ACC codon a substitution of the first nucleotide of a GGG codon
answer
a deletion of two nucleotides
question
What is the effect of a nucleotide-pair substitution that results in a nonsense mutation in a gene? It alters the reading frame of the mRNA. It introduces a premature stop codon into the mRNA. It has no effect on the amino acid sequence of the encoded protein. It changes an amino acid in the encoded protein.
answer
It introduces a premature stop codon into the mRNA.
question
Which of the following types of mutations could result in a frameshift mutation? either an insertion or a deletion of a base a base insertion only a base deletion only deletion of three consecutive bases a base substitution only
answer
either an insertion or a deletion of a base
question
Which of the following DNA mutations is likely to have the most negative effect on the protein it specifies? a codon deletion a codon substitution a substitution in the last base of a codon a base-pair deletion
answer
a base-pair deletion
question
Which of the following statements is true about protein synthesis in prokaryotes? Translation can begin while transcription is still in progress. Prokaryotic cells have multiple mechanisms for targeting proteins to the appropriate cellular organelles. Extensive RNA processing is required before prokaryotic transcripts can be translated. Unlike eukaryotes, prokaryotes require no initiation or elongation factors.
answer
Translation can begin while transcription is still in progress.
question
Of the following, which is the most current and complete description of a gene? a discrete unit of hereditary information that consists of a sequence of amino acids a DNA-RNA sequence combination that results in an enzymatic product a DNA sequence that is expressed to form a functional product: either RNA or polypeptide a unit of heredity that causes formation of a phenotypic characteristic a DNA subunit that codes for a single complete protein
answer
a DNA sequence that is expressed to form a functional product: either RNA or polypeptide
question
In eukaryotic cells, transcription CANNOT begin until __________. the 5' caps are removed from the mRNA the DNA introns are removed from the template the two DNA strands have completely separated and exposed the promoter several transcription factors have bound to the promoter
answer
several transcription factors have bound to the promoter
question
Which of the following is NOT true of a codon? It never codes for more than one amino acid. It is the basic unit of the genetic code. It may code for the same amino acid as another codon. It extends from one end of a tRNA molecule.
answer
it extends from one end of a tRNA molecule
question
The anticodon of a particular tRNA molecule is __________. complementary to the corresponding triplet in rRNA catalytic, making the tRNA a ribozyme complementary to the corresponding mRNA codon the part of tRNA that bonds with a specific amino acid
answer
complementary to the corresponding mRNA codon
question
Which of the following is NOT true of RNA processing? RNA splicing can be catalyzed by spliceosomes. Exons are cut out before mRNA leaves the nucleus. Nucleotides may be added at both ends of the RNA. Ribozymes may function in RNA splicing.
answer
Exons are cut out before mRNA leaves the nucleus.
question
Which component is NOT directly involved in translation? GTP DNA tRNA ribosomes
answer
DNA
question
Which of the following mutations would be MOST likely to have a harmful effect on an organism? 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 deletion in the middle of an intron a deletion of three nucleotides near the middle of a gene
answer
a single nucleotide insertion downstream of, and close to, the start of the coding sequence
question
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
answer
deletion of one nucleotide