Honors Biology Chapter 10 - Copley-Fairlawn City Schools



Honors Biology Chapter 10Name ________________________Date _____________ MOD _______Test Your KnowledgeMultiple ChoiceIn an important experiment, bacteriophages were allowed to infect bacteria. In the first trial, the phages contained radioactive DNA, and radioactivity was detected in the bacteria. Next, other phages containing radioactive protein were allowed to infect bacteria, and no radioactivity was detected in the bacteria. When the experimenters compared the results of these two trials, they concluded thatgenes are made of DNA.bacteriophages can infect bacteria.DNA is made of nucleotides.genes carry information for making proteins.genes are on chromosomes.An RNA or DNA molecule is a polymer made of subunits calledbases.amino acids.nucleotides.nucleic acids.pyrimidines.The information carried by a DNA molecule is inits amino acid sequence.the sugars and phosphates forming its backbone.the order of the bases in the molecule.the total number of nucleotides it contains.the RNA units that make up the molecule.A gene isthe same thing as a chromosome.the information for making a polypeptide.made of RNA.made by a ribosome.made of protein.DNA replication occurswhenever a cell makes protein.to repair gene damage caused by mutation.before a cell divides.whenever a cell needs RNA.in the cytoplasm of a eukaryotic cell.The flow of information in a cell proceedsfrom RNA to DNA to proteinfrom protein to RNA to DNA.from DNA to protein to RNA.from RNA to protein to DNA.from DNA to RNA to protein.Which of the following is not needed for DNA replication?ribosomesb. DNA c. nucleotides d. enzymes e. All are needed.Which of the following processes occur(s) in the cytoplasm of a eukaryotic cell?DNA replicationtranslationtranscriptionDNA replication and translationtranslation and transcriptionBeadle and Tatum showed that each kind of mutant bread mold lacked a specific enzyme. This experiment demonstrated thatgenes carry information for making proteins.mutations are changes in genetic information.genes are made of DNA.enzymes are required to repair damaged DNA information.cells need specific enzymes in order to function.During the process of translation (polypeptide synthesis), ______ matches a nucleic acid codon with the proper amino acid.a ribosomeDNA polymeraseATPtransfer RNAmessenger RNAHow does RNA polymerase “know” where to start transcribing a gene into mRNA?It starts at one end of the chromosome.Transfer RNA acts to translate the message to RNA polymerase.It starts at a certain nucleotide sequence called a promoter.The ribosome directs it to the correct portion of the DNA molecule.It looks for the AUG start codon.When RNA is being made, the RNA base _____ always pairs with the base _____ in DNA.U … TT … GU … AA … UT … AA mutagen isa gene that has been altered by a mutation.something that causes a mutation.an organism that has been changed by a mutation.the portion of a chromosome altered by a mutation.any change in the nucleotide sequence of DNA.How do retroviruses, such as HIV, differ from other viruses?They are much simpler than other viruses.They contain DNA that is used as a template to make RNA.They can reproduce only inside of living cells.They contain nucleic acids that code for the making of proteins.They contain RNA that is used as a template to make DNA.The primary difference between bacterial sex and sexual reproduction in plants and animals is thatbacterial sex involves more than two individuals.bacterial sex does not involve genetic recombination.bacteria exchange RNA, not DNA.bacterial sex does not produce offspring.eggs and sperm are different, but bacterial gametes are all alike.Sometimes a bacteriophage transfers a gene from one bacterium to another. This process is calledtransduction.conjugation.cloning.DNA splicing.transformation.Which of the following are arranged in the correct order by size, from largest to smallest?chromosome-gene-codon-nucleotidenucleotide-chromosome-gene-codoncodon-chromosome-gene-nucleotidegene-chromosome-codon-nucleotidechromosome-gene-nucleotide-codonA geneticist raised a crop of T2 bacteriophages in a medium containing radioactive phosphorus so that the DNA of the bacteriophages was labeled with radioactivity. The labeled phages were then allowed to infect nonradioactive bacteria. In a few hours, these bacteria burst open, releasing many bacteriophages. Some of these phages contained labeledDNA.RNA.protein.all of the above.DNA and protein only.A messenger RNA molecule for making a protein is made in the nucleus and sent out to a ribosome. The ribosome reads the mRNA message and makes a protein containing 120 amino acids. The mRNA consisted of at least how many codons?30b. 40 c. 120d. 360 e. 480The nucleotide sequence of a DNA codon is ACT. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a transfer RNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodone? (Careful-this one is harder than it appears.)TGAb. UGAc. ACTd. TGUe. ACUImagine an error occurring during DNA replication in a cell so that where there is supposed to be a T in one of the genes there is instead of G. What effect will this probably have on the cell?Each of its kinds of proteins will contain an incorrect amino acid.An amino acid will be missing from each of its kinds of proteins.One of its kinds of proteins might contain an incorrect amino acid.An amino acid will be missing from one of its kinds of proteins.The amino acid sequence of one of its kinds of proteins will be completely changed.A particular ______ carry the information for making a particular polypeptide, but ______ can be used to make any polypeptide.gene and ribosome … a tRNA and an mRNAgene and mRNA … a ribosome and a tRNAribosome and mRNA … a gene and a tRNAgene and tRNA … a ribosome and an mRNAtRNA and ribosome … a gene and an mRNAA sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show?The polypeptide chain moves over and bonds to the single amino acid.The tRNA with the amino acid leaves the ribosome.The amino acid moves over and bonds to the polypeptide chain.The tRNA with the polypeptide chain leaves the ribosome.A third tRNA with an amino acid joins the pair on the ribosome.A microbiologist analyzed chemicals obtained from an enveloped RNA virus (similar to a mumps virus) that infects monkeys. He found that the virus envelope contained a protein characteristic of monkey cells. Which of the following is the most likely explanation for this?The virus gets its envelope when it leaves its host cell.The virus forced the monkey cell to make proteins for its envelope.The virus has a lysogenic life cycle.The virus gets its envelope when it enters its host cell.The virus fools its host cell by mimicking its proteins.At one point as a cell carried out its day-to-day activities, the nucleotides G A T were paired with the nucleotides C U A. This pairing occurredin a double-stranded DNA molecule.during translation.during transcription.when an RNA codon paired with a tRNA anticodon.It is impossible to say, given this information.Which of the following does not take part in polypeptide synthesis?an exonmRNAan introntRNAa ribosomeA microbiologist analyzed the DNA of E. coli before and after conjugation. She found that both cells lost some genes and gained others.both cells gained genes but lost none of their original genes.one cell lost genes, and the other gained genes.one cell gained genes, and the genes of the other were unchanged.the genes of both cells remained unchanged.EssayExplain why in DNA T pairs only with A and not with C or G.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Why does it take a group of three DNA nucleotides to specify one amino acid in a protein? Wouldn’t it be simpler to have a one-to-one code, where one nucleotide specified one amino acid?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________What is a mutation? What causes mutations? Why are most mutations harmful? Why aren’t all mutations harmful?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Which type of mutation - a base substitution or a base deletion - is likely to have the greatest effect on the organism? Why?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Describe step by step, but in simple terms, the roles of mRNA, tRNA, ribosomes, and amino acids in making a polypeptide.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________E. coli bacteria are used in many genetic studies. Type A E. coli can live on a simple nutrient medium because they have all the genes necessary to produce the chemicals they need. Type V E. coli can live only on a nutrient medium to which a certain vitamin has been added because they lack a gene that enables them to make this vitamin for themselves. It has been found that bacteria can absorb genes from other dead, ground-up bacteria. Describe an experiment using type A and type V E. coli to demonstrate that genes are made of DNA and not protein. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________It is possible to extract DNA from cells and analyze it to determine the relative amounts of the four DNA bases. The DNA of a goldfish contains more T and less G than human DNA, but in both goldfish and human DNA the amount of T is equal to the amount of A. Explain why.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Eric said to Renee, “The amino acid sequence of the proteins in your hair determines how curly or straight your hair will be.” Renee replied, “I don’t think that is right. Your genes determine whether your hair is curly or straight. That’s why it’s inherited.” Who is right? Explain.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________The DNA base sequence for a short gene is:TATGATACCTTGATAGCTATCTGATTGWhat is the amino acid sequence of the polypeptide produced according to this DNA information? Use the genetic code chart (Figure 10.8A in the text) and your knowledge of transcription and translation to figure out the message.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________A biochemist found that a bacterium produced an mRNA molecule consisting of 852 nucleotides and translated this mRNA into a polypeptide containing 233 amino acids. How many nucleotides in the mRNA message would actually be needed to carry the message for the polypeptide, and how many were “extras”? How would the bacterium know which nucleotides made up the message?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________The virus that causes chickenpox can disappear for years and then reappear in a line of painful sores (“shingles”) where a nerve cell passes through the skin. How can viruses go away and then reappear like this? Where are the viruses during the intervening period of time?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________A gene can be removed from a eukaryotic cell and spliced into the DNA of a prokaryotic cell. The prokaryotic can transcribe the gene into mRNA and translate this mRNA into a polypeptide, but the polypeptide has an incorrect amino acid sequence, very different from the polypeptide normally produced by the eukaryotic cell. Why?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A mutant strain of E. coli bacteria will not grow unless they are supplied with the amino acid lysine. Another strain will not grow without a different amino acid, proline. When E. coli of the two strains are mixed, a few bacteria appear in the culture that are able to grow without either of the amino acids. Name and briefly describe three possible mechanisms that might account for this change.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Flu viruses and polio viruses are both RNA viruses. Normally flu viruses attack lung cells and polio viruses attack nerve cells. In the lab, virologists assemble a hybrid RNA virus that has the membranous envelope of a flu virus and the RNA of a polio virus. The researchers then try to infect lung cells and nerve cells with the hybrid. They find that the hybrid can only infect one of the kinds of cells. Which kind of cell would you expect that to be, a lung cell or a nerve cell? Why? After the viruses replicate and fill the infected cell, what kind of RNA would you expect them to contain, flu or polio virus RNA? Why? Which kind of proteins would you expect them to have, flu or polio proteins? Why?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________KEYHonors Biology Chapter 10Name ________________________Date _____________ MOD _______Test Your KnowledgeMultiple ChoiceIn an important experiment, bacteriophages were allowed to infect bacteria. In the first trial, the phages contained radioactive DNA, and radioactivity was detected in the bacteria. Next, other phages containing radioactive protein were allowed to infect bacteria, and no radioactivity was detected in the bacteria. When the experimenters compared the results of these two trials, they concluded thatgenes are made of DNA.bacteriophages can infect bacteria.DNA is made of nucleotides.genes carry information for making proteins.genes are on chromosomes.An RNA or DNA molecule is a polymer made of subunits calledbases.amino acids.nucleotides.nucleic acids.pyrimidines.The information carried by a DNA molecule is inits amino acid sequence.the sugars and phosphates forming its backbone.the order of the bases in the molecule.the total number of nucleotides it contains.the RNA units that make up the molecule.A gene isthe same thing as a chromosome.the information for making a polypeptide.made of RNA.made by a ribosome.made of protein.DNA replication occurswhenever a cell makes protein.to repair gene damage caused by mutation.before a cell divides.whenever a cell needs RNA.in the cytoplasm of a eukaryotic cell.The flow of information in a cell proceedsfrom RNA to DNA to proteinfrom protein to RNA to DNA.from DNA to protein to RNA.from RNA to protein to DNA.from DNA to RNA to protein.Which of the following is not needed for DNA replication?ribosomesb. DNA c. nucleotides d. enzymes e. All are needed.Which of the following processes occur(s) in the cytoplasm of a eukaryotic cell?DNA replicationtranslationtranscriptionDNA replication and translationtranslation and transcriptionBeadle and Tatum showed that each kind of mutant bread mold lacked a specific enzyme. This experiment demonstrated thatgenes carry information for making proteins.mutations are changes in genetic information.genes are made of DNA.enzymes are required to repair damaged DNA information.cells need specific enzymes in order to function.During the process of translation (polypeptide synthesis), ______ matches a nucleic acid codon with the proper amino acid.a ribosomeDNA polymeraseATPtransfer RNAmessenger RNAHow does RNA polymerase “know” where to start transcribing a gene into mRNA?It starts at one end of the chromosome.Transfer RNA acts to translate the message to RNA polymerase.It starts at a certain nucleotide sequence called a promoter.The ribosome directs it to the correct portion of the DNA molecule.It looks for the AUG start codon.When RNA is being made, the RNA base _____ always pairs with the base _____ in DNA.U … TT … GU … AA … UT … AA mutagen isa gene that has been altered by a mutation.something that causes a mutation.an organism that has been changed by a mutation.the portion of a chromosome altered by a mutation.any change in the nucleotide sequence of DNA.How do retroviruses, such as HIV, differ from other viruses?They are much simpler than other viruses.They contain DNA that is used as a template to make RNA.They can reproduce only inside of living cells.They contain nucleic acids that code for the making of proteins.They contain RNA that is used as a template to make DNA.The primary difference between bacterial sex and sexual reproduction in plants and animals is thatbacterial sex involves more than two individuals.bacterial sex does not involve genetic recombination.bacteria exchange RNA, not DNA.bacterial sex does not produce offspring.eggs and sperm are different, but bacterial gametes are all alike.Sometimes a bacteriophage transfers a gene from one bacterium to another. This process is calledtransduction.conjugation.cloning.DNA splicing.transformation.Which of the following are arranged in the correct order by size, from largest to smallest?chromosome-gene-codon-nucleotidenucleotide-chromosome-gene-codoncodon-chromosome-gene-nucleotidegene-chromosome-codon-nucleotidechromosome-gene-nucleotide-codonA geneticist raised a crop of T2 bacteriophages in a medium containing radioactive phosphorus so that the DNA of the bacteriophages was labeled with radioactivity. The labeled phages were then allowed to infect nonradioactive bacteria. In a few hours, these bacteria burst open, releasing many bacteriophages. Some of these phages contained labeledDNA.RNA.protein.all of the above.DNA and protein only.A messenger RNA molecule for making a protein is made in the nucleus and sent out to a ribosome. The ribosome reads the mRNA message and makes a protein containing 120 amino acids. The mRNA consisted of at least how many codons?30b. 40 c. 120d. 360 e. 480The nucleotide sequence of a DNA codon is ACT. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a transfer RNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodone? (Careful-this one is harder than it appears.)TGAb. UGAc. ACTd. TGUe. ACUImagine an error occurring during DNA replication in a cell so that where there is supposed to be a T in one of the genes there is instead of G. What effect will this probably have on the cell?Each of its kinds of proteins will contain an incorrect amino acid.An amino acid will be missing from each of its kinds of proteins.One of its kinds of proteins might contain an incorrect amino acid.An amino acid will be missing from one of its kinds of proteins.The amino acid sequence of one of its kinds of proteins will be completely changed.A particular ______ carry the information for making a particular polypeptide, but ______ can be used to make any polypeptide.gene and ribosome … a tRNA and an mRNAgene and mRNA … a ribosome and a tRNAribosome and mRNA … a gene and a tRNAgene and tRNA … a ribosome and an mRNAtRNA and ribosome … a gene and an mRNAA sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show?The polypeptide chain moves over and bonds to the single amino acid.The tRNA with the amino acid leaves the ribosome.The amino acid moves over and bonds to the polypeptide chain.The tRNA with the polypeptide chain leaves the ribosome.A third tRNA with an amino acid joins the pair on the ribosome.A microbiologist analyzed chemicals obtained from an enveloped RNA virus (similar to a mumps virus) that infects monkeys. He found that the virus envelope contained a protein characteristic of monkey cells. Which of the following is the most likely explanation for this?The virus gets its envelope when it leaves its host cell.The virus forced the monkey cell to make proteins for its envelope.The virus has a lysogenic life cycle.The virus gets its envelope when it enters its host cell.The virus fools its host cell by mimicking its proteins.At one point as a cell carried out its day-to-day activities, the nucleotides G A T were paired with the nucleotides C U A. This pairing occurredin a double-stranded DNA molecule.during translation.during transcription.when an RNA codon paired with a tRNA anticodon.It is impossible to say, given this information.Which of the following does not take part in polypeptide synthesis?an exonmRNAan introntRNAa ribosomeA microbiologist analyzed the DNA of E. coli before and after conjugation. She found that both cells lost some genes and gained others.both cells gained genes but lost none of their original genes.one cell lost genes, and the other gained genes.one cell gained genes, and the genes of the other were unchanged.the genes of both cells remained unchanged.EssayExplain why in DNA T pairs only with A and not with C or G.A single-ringed pyrimidine, such as T, must pair with a double-ringed purine, such as A. Two pyrimidines - A and C - would not be large enough to reach across the double helix. T specifically pairs with A and not G because T and A have complementary chemical side groups that form hydrogen bonds.Why does it take a group of three DNA nucleotides to specify one amino acid in a protein? Wouldn’t it be simpler to have a one-to-one code, where one nucleotide specified one amino acid?Twenty amino acids are used in building proteins. There are only four nucleotides in DNA, so a one-base code could specify only 4 amino acids. A two-base code could specify only 42, or 16 amino acids. In a triplet code, 43, or 64, combinations of bases are possible, more than enough to code for 20 amino acids.What is a mutation? What causes mutations? Why are most mutations harmful? Why aren’t all mutations harmful?A mutation is a change in the nucleotide sequence of DNA. Some mutations are spontaneous, but many are caused by X-rays, ultra-violet light, and chemicals. Most mutations are harmful because they alter protein amino acid sequences and impair the function of proteins. Some mutations do not alter amino acid sequence; others lead to an improved protein or one with new capabilities that enhance an organism’s success. Mutations create genetic diversity that makes evolution by natural selection possible. Which type of mutation - a base substitution or a base deletion - is likely to have the greatest effect on the organism? Why?A base substitution can reslt in no change to a protein or, most often, a change in one amino acid. Effects on the organism may be minimal. A base deletion shifts the sequence of triplet groupings in a gene, causing a drastic change in the amino acid sequence downstream from the deletion. This can have a profound effect on the protein and the organism.Describe step by step, but in simple terms, the roles of mRNA, tRNA, ribosomes, and amino acids in making a polypeptide.Messenger RNA (mRNA) is transcribed from a gene and carries the instructions for making a particular polypeptide. A ribosome is the site of translation, the process of making a polypeptide according to the mRNA message. Transfer RNAs act as translators, each kind matching a particular amino acid with a particular codon in the mRNA. The ribosome “reads” the mRNA one codon at a time, and tRNAs deliver their amino acids, which are added to the polypeptide chain one at a time.E. coli bacteria are used in many genetic studies. Type A E. coli can live on a simple nutrient medium because they have all the genes necessary to produce the chemicals they need. Type V E. coli can live only on a nutrient medium to which a certain vitamin has been added because they lack a gene that enables them to make this vitamin for themselves. It has been found that bacteria can absorb genes from other dead, ground-up bacteria. Describe an experiment using type A and type V E. coli to demonstrate that genes are made of DNA and not protein. Extract DNA from dead type A E. coli and mix it with live type V E. coli. If the type V E. coli absorb the DNA and genes are made of DNA, the type V bacteria will be able to grow on the simple medium without the vitamin. For comparison, extract protein from dead type A E. coli and mix it with live type V E. coli. If the type V E. coli absorb the protein and genes are made of protein, the type V bacteria will be able to grow on the simple medium without the vitamin. Prediction: DNA will transform the type V bacteria, but protein will not.It is possible to extract DNA from cells and analyze it to determine the relative amounts of the four DNA bases. The DNA of a goldfish contains more T and less G than human DNA, but in both goldfish and human DNA the amount of T is equal to the amount of A. Explain why.In the DNA double helix, T and A bases pair up; wherever there is a T nucleotide in one strand, there is a complementary A nucleotide in the other. Thus the amount of T is equal to the amount of A. The specific nucleotide sequences of goldfish and human DNA are different, so the number of A-T pairs is different in the two species.Eric said to Renee, “The amino acid sequence of the proteins in your hair determines how curly or straight your hair will be.” Renee replied, “I don’t think that is right. Your genes determine whether your hair is curly or straight. That’s why it’s inherited.” Who is right? Explain.They are both right. Eric is talking about phenotype and Renee about genotype. The nucleotide sequences of your genes - genotype - determine the amino acid sequences of proteins that cause your hair to be curly or straight - your phenotype.The DNA base sequence for a short gene is:TATGATACCTTGATAGCTATCTGATTGWhat is the amino acid sequence of the polypeptide produced according to this DNA information? Use the genetic code chart (Figure 10.8A in the text) and your knowledge of transcription and translation to figure out the message.Met-Glu-Leu-Ser-Ile-Asp. First you have to transcribe DNA base sequence into mRNA base sequence, then translate into amino acid sequence. Remember that translation always starts at the AUG start codon.A biochemist found that a bacterium produced an mRNA molecule consisting of 852 nucleotides and translated this mRNA into a polypeptide containing 233 amino acids. How many nucleotides in the mRNA message would actually be needed to carry the message for the polypeptide, and how many were “extras”? How would the bacterium know which nucleotides made up the message?Because a three-base codon specifies each amino acid, the message coding for the polypeptide would consists of 233 x 3, or 699 nucleotides (actually 702, if the stop codon is included). The rest of the nucleotides are extras. Translation of protein does not have to start and stop at the ends of the mRNA. It starts at a start codon (AUG) and stops at a stop codon (UAA, UAG, or UGA). The nucleotides from the start codon to the stop codon are the only ones that spell out the amino acid sequence of the polypeptide.The virus that causes chickenpox can disappear for years and then reappear in a line of painful sores (“shingles”) where a nerve cell passes through the skin. How can viruses go away and then reappear like this? Where are the viruses during the intervening period of time?The virus may be able to insert its genes into a nerve cell’s DNA and remain latent within the cell as a provirus. From time to time the provirus may begin producing complete viruses, causing disease symptoms.A gene can be removed from a eukaryotic cell and spliced into the DNA of a prokaryotic cell. The prokaryotic can transcribe the gene into mRNA and translate this mRNA into a polypeptide, but the polypeptide has an incorrect amino acid sequence, very different from the polypeptide normally produced by the eukaryotic cell. Why?In a eukaryotic cell, the RNA transcript is processed before translation. Noncoding introns are removed and exons are spliced together to produce the mRNA. A prokaryote does not process its RNA before translation, so the introns from the eukaryotic gene are not removed. When this unedited RNA is translated, the wrong polypeptide is produced. A mutant strain of E. coli bacteria will not grow unless they are supplied with the amino acid lysine. Another strain will not grow without a different amino acid, proline. When E. coli of the two strains are mixed, a few bacteria appear in the culture that are able to grow without either of the amino acids. Name and briefly describe three possible mechanisms that might account for this change.Some bacteria are combining their DNA with the DNA from the other strain, producing bacteria with the characteristics both strains. It could be that some bacteria are dying, and their DNA is being taken up from the medium by living bacteria-a process called transformation. Bacterial genes could be transferred from bacterium to bacterium by a bacteriophage - transduction. Or the bacteria could be undergoing conjugation - bacterial mating - in which DNA is transferred from one bacterium to another.Flu viruses and polio viruses are both RNA viruses. Normally flu viruses attack lung cells and polio viruses attack nerve cells. In the lab, virologists assemble a hybrid RNA virus that has the membranous envelope of a flu virus and the RNA of a polio virus. The researchers then try to infect lung cells and nerve cells with the hybrid. They find that the hybrid can only infect one of the kinds of cells. Which kind of cell would you expect that to be, a lung cell or a nerve cell? Why? After the viruses replicate and fill the infected cell, what kind of RNA would you expect them to contain, flu or polio virus RNA? Why? Which kind of proteins would you expect them to have, flu or polio proteins? Why?Thy hybrid virus would only be able to attack lung cells because its coat contains structures (like the glycoprotein spikes of the mumps virus or HIV) that “dock” with lung cells, not nerve cells. Once a cell is infected, the polio virus RNA replicates and directs the manufacture of polio virus proteins. Therefore the viruses that fill the infected cell would contain only polio virus RNA and protein, because only polio RNA instructions got in. ................
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