Chapter 17 & 18 Exam
According to Beadle and Tatum's one gene one enzymes hypothesis, how, many gene(s) is (are) necessary for this pathway
2
If proteins were composed of only 12 different kinds of animo acids, what would be the smallest possible codon size in a genetic system with four different nucleotides?
2
A new form of life is discovered. It has a genetic code much like that of organisms on Earth except that there are five different DNA bases instead of four and the base sequences are translated as doublets instead of triplets. How many different amino acids could be accommodated by this genetic code
25
A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?
3' AAA-GGG-TTT-CCC-AAA-GGG
Choose the answer that has these events of protein synthesis in the proper sequence.
4,1,2,5,3
The enzyme polynucleotide phosphorylase randomly assembles a polymer of nucleotides. You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. The resulting artificial mRNA molecule would have __________ possible different codons if the code involved two-base sequences and __________ possible different codons if the code involved three-base sequences.
4;8
A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be
5' AUG- CTG-CAG-TAT 3'
a particular eukaryotic protein is 300 amino acids long. Which of the following could be the max number of nucleotides in the DNA that codes for the amino acids in this protein ?
900
Which of the following does NOT occur during the termination phase of translation?
A TRNA WITH THE NEXT AMINO ACID ENTERS THE P SITE
Which of the following is a characteristic of all viruses?
A and B only
What is the function of the single-stranded RNA in certain animal viruses?
A and C only are correct.
Which of the following is true of retroviruses? They
A and C only are correct.
Beadle and Tatum proposed the one gene-one enzyme concept. In its original form, this hypothesis could be restated in which of the following ways?
A given sequence of DNA nucleiods contains the information to make one enzyme
Double-stranded viruses can reproduce the lytic cycle and the lysogenic cycle. Which of the following is characterstic of the lytic cycle?
A large number of phages are released at a time.
One strain of a diploid organism is homozygous for a recessive allele coding for a defective enzyme a. Another strain is homozygous for a recessive allele coding for a defective enzyme b. Crossing those two strains will result in a strain that would grow on which of the following
A minimal medium supplemented with B
A portion of the genetic code is UUU = phenylalanine, GCC = alanine, AAA = lysine, and CCC = proline. Assume the correct code places the amino acids phenylalanine, alanine, and lysine in a protein (in that order). Which of the following DNA sequences would substitute proline for alanine?
AAA-GGG-TTT
The nitrogenous vase sdenjne is found in all members of which of the following groups?
ATP, RNA and genes
A mutation results in a defective enzyme a. Which of the following would be a consequence of mutation?
An accumulation of A and B and no production of C
RNA differs form DNA in that RNA
Both A and C are correct
As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs
Both A and C are corrected
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the
Both C and D are correct
During translation, chain elongation continues until
CHAIN TERMINATOR CODON OCCURS
All of the following are directly involved in translation except
DNA
The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except
DNA was the first genetic material.
which of the following are is not involved in transcription
Initiation factors
What are prions?
Misfolded versions of normal brain protein.
Which of the following represents a similarity between RNA and DNA?
Nucleotides consisting of a phosphate, sugar, and nitrogen base
Which of the following helps to stabilize mRNA by inhibiting its degradation
Poly A tail
Which of the following is true for both prokaryotic and eukaryotic gene expression? Which of the following is true for both prokaryotic and eukaryotic gene expression?
RNA polymerase binds to the promoter region to begin transcription
A particular triplet of bases in the coding sequence of DNA is AGT. The corresponding codon for the DNA transcribed is
TCA
Which of the above is analogous to a single substitution mutation?
THECATARETHERAT
Which of the above is analogous to a frameshift mutation?
THECATATTHERAT
A researcher lyses a cell that contains nucleic acid molecules and capsid units of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur?
The plants would develop symptoms typically produced by viroids.
Which of these statements represents a common misconception regarding point mutations?
They always produce a change in the amino acid sequence of a protein.
Which of the following is true of plant virus infections?
They have little effect on plant growth
which of the following is least related to the other items?
Translation
A particular triplet of bases in the coding sequence of DNA is AGT. The corresponding codon for the mRNA transcribed is
UCA
Figure 17.4 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?
UUC
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is
UUU
Of the following, which is least related to the others?
Viral envelope
Which of the following is a true statement about viruses
Viruses are classified below the cellular level of biological organization.
which of the following is a true statement
Viruses can cause diarrhea, colds, and measles
Which of the following represents a difference between viruses and viroids?
Viruses have capsid composed of protein, while viroids have no capsids
which point mutation would be most likely to have a catastrophic effect on the function of a protein?
a base deletion near the start of a gene
What is the relationship among DNA, a gene, and a chromosome?
a chromosome contains hundreds of genes which are composed of dna
When does translation begin in prokaryotic cells?
as soon as the DNA introns are removed from the template
The first event in translation of eukaryotes (starting with methionine) is the
base pairing of tRNA to AUG of the mRNA
Which of the following DNA mutations is the most likely to be damaging to the protein it specifies?
base-pair deletion
According to the signal hypothesis, ribosomes are directed to the ER membrane
by a signal recognition particle that brings ribosomes to a receptor protein in the ER membrane.
The function of the ribosome in polypeptide synthesis is to
catalyze the addition of amino acids from tRNAs to the growing polypeptide chain.
Viral envelopes are generally
composed of a lipid bilayer
A frameshift mutation could result from
either an insertion or a deletion of a base.
Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes
excision of introns
All of the following are transcribed from DNA except
exons
what are the coding segments of a stretch of eukaryotic DNA called?
exons
what are polyribosomes?
groups of ribosomes reading the same mRNA simultaneously
What type of bonding is responsible for maintaining the shape of the tRNA molecule?
hydrogen bonding between base pairs
which of the following is least related to the other items
inosine
All of the following are found in a prokaryotic messenger RNA EXCEPT
introns
DNA has two functions: it can self-replicate and it can make non-DNA molecules. Dna is capable of these because
its nucleotides will form base pairs with both ribose and deoxyribose nucleotides
Which of the following is not directly involved in the process of translation?
ligase
Virulent phages undergo a(n) __________ life cycle, whereas temperate phages are capable of undergoing a(n) __________ cycle.
lytic; lysogenic
What is the primary transcript of eukaryotic gens
mRNA
what are ribosomes composed of
mRNA, tRNA, rRNA and protein
A transcription unit that is 800 nucleotides long may use 1,200 nucleotides to make a protein consisting of 400 amino acids. This is best explained by the fact that
many noncoding nucleotides are present
Which of the following is correct about a codon? It
may code for the same amino acid as another codon
which of the following processes would never contribute to genetic variation within a bacterial population
meiosis
What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'
met-ser-ser-leu-ser-leu
A shrimp grower wants to create a new "green" shrimp. He plans on growing normal shrimp in green light because, he says, the green light will cause mutations that make the shrimp green. You tell him this is not a good idea because
mutations are random, and no agent (even green light) can cause a specific mutation like turning shrimp green
Where is eukaryotic ribosomal RNA transcribed?
nucleoli
when a ribosome first attaches to an mRNA molecule, on et RNA binds to the ribosome. The tRNA that recognizes the initiation codon binds to the
peptide site (p site) of the ribosome only
The phage DNA is not hydrolyzed with the host DNA because
phage DNA contains an urecognizable form of cytosine.
What is the sequence of a peptide based on the following mRNA sequence? 5' . . . UUUUCUUAUUGUCUU 3'
phe-ser-tyr-cys-leu
If the triplet UUU codes for the amino acid phenylalanine in bacteria, then in plants UUU should code for
phenylalanine.
Viruses have some of the properties of living organisms. Which of the following is a characteristic of all organisms, but not of viruses?
plasma membrane
Of the following types of mutations, which one is likely to be the most common?
point mutation
Sickle-cell disease is probably the result of which kind of mutation?
point only
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA). 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.
proline-threonine
Where is the attachment site for RNA polymerase
promoter region
Bacteriophage DNAs that have become integrated into the host cell chromosome are called
prophages.
which of the following is false
proteins are translated in the cytoplasm
What is the most abundant type of RNA?
rRNA
RNA viruses appear to have higher rates of mutation because
replication of their nucleic acid does not involve the proofreading steps of DNA replication.
Viruses that have a single strand of RNA that acts as a template for DNA synthesis are known as
retroviruses.
Suppose the following DNA sequence was mutated from 3' AGA-GAG-AGA-GAG-AGA-GAG 5' to 3' AGA-AGA-GAG-ATC-GAG-AGA 5'. What amino acid sequence will be generated based on this mutated DNA ?
ser-ser-leu
which of the following is least related to the other items
signal recognition particles
which of the following is least related to the other items
snRNP
Which of the following is not related to ribosomal activity?
spliceosome
what is an anticodon part of
tRNA
which of the following is least related to the other items
termination
when a nucleotide pair is lost from the middle of a gene during the process of transcription, what happens
the reading frame is shifted, producing a nonfunctional polypeptide
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.
From the following list, which is the first event in translation in eukaryotes?
the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA
For many bacteriophages, infections are self-limiting. Each phage that infects a cell produces hundreds of new phages, and eventually cells are infected by several phages at different times. This results in a competition for regulatory control over the cell, with the eventual result of the death of the cell without the production of new viruses. This phenomenon is called superinfection. Superinfection can be prevented by which of the following changes in the bacteriophage?
the virus becoming a prophage in the cell
Introns are significant to biological evolution because
their presence allows exons to be shuffled.
The host range of a virus is determined by
they use the host cell's nucleotides and enzymes to reproduce
What is one function of a signal peptide?
to translocate polypeptides across the ER membrane
Which of the following does not contribute to the emergence of viral disease?
transformation from lytic to lysogenic activity
What is the function of reverse transcriptase in retroviruses?
uses viral RNA as a template for making complementary RNA strands
The simplest infectious biological systems are
viroids
