Chapter 10 - Virus Resources
a fragment of DNA is taken up from the environment and incorporated into bacterial DNA
Bacteria can quickly acquire new genes in a single generation through infection by a phage
reverse transcriptase
DNA polymerase enzyme that transcribes single-stranded RNA into DNA
white blood cells
HIV does the greatest damage to
viral genome that has been incorporated into a bacterial cell's chromosomes. The formation of this prophage is one of the events of the lysogenic cycle.
A prophage is a(an)
a fragment of DNA from the host bacterium is packaged into the phage's coat and injected into the next bacterium that the phage infects.
Bacteria can quickly acquire new genes in a single generation through infection by a phage. How does this happen.
R plasmids carry genes for enzymes that destroy antibiotics, and bacteria with such genes proliferate in the bacterial population
Conjugation is an effective process for spreading antibiotic resistance among bacterial populations. Which statement best explains how this occurs?
Prions are protein that are folded incorrectly. They lack nucleic acids.
Radiation is a frequent method of sterilization. It is effective because it causes damage to DNA. However, prions, the agents that cause diseases such as mad cow disease, are unaffected by these treatments because they lack DNA. What is the definition of a prion? Prions are proteins folded into the correct configuration. Prions are small RNA molecules that do not encode proteins. Prions are small carbohydrate molecules that do not encode DNA. Prions are proteins that are folded incorrectly.
lytic cycle
the _______ is a viral life cycle that results in bursting of the host cell
missense mutation, abnormal hemoglobin
Sickle-cell disease results from a _________ which causes _______
reverse transcriptase
What enzyme is important in a retrovirus such as HIV?
herpes virus
enveloped DNA virus that replicates in host cell nucleus
capsid
the protein coat that surrounds the nucleic acid of a virus is called
bacteriophage
A _____ is a virus that specifically infects bacteria
inhibit reverse transcriptase
A drug that could prevent the spread of HIV without harming the host cell would need to have which of the following characteristics.
the virus gets an envelope that contains host molecules when it leaves the host cell.
A microbiologist analyzed chemicals obtained from an enveloped RNA virus—similar to a mumps virus—that infects monkeys. He found that the viral envelope contained a protein characteristic of monkey cells. Which of the following is the most likely explanation? The virus is a prophage.The virus gets an envelope that contains host molecules when it leaves the host cell.The virus fools its host by mimicking its proteins.The virus forced the monkey cell to make proteins for its envelope.
prophage
A viral genome that has inserted itself into the genome of its host. Viral DNA incorporated into host cell DNA
virus
Although generally not considered to be alive, a ____________ is studied alongside microbes such as bacteria.
start codon on the mRNA molecule
At the start of translation, where does the initiator tRNA bind?
whole viruses leave the host cell to infect other cells
During the lytic cycle, but not the lysogenic cycle, __________
transfer RNA
During the process of translation, _________- matches an mRNA codon with the proper amino acid
spreading from a host species to humans
Emerging viruses that infect human cells can appear as the result of
a virus spreading from one host species to humans
Emerging viruses that infect human cells can originate from __________. lambda viruses that were previously confined to bacterial populations that can now spread due to technological changes a virus spreading from one host species to humans a rapidly mutating lytic phage lack of hygiene
integrate their DNA into the host's chromosomes
HIV and phage lambda both
They contain the enzyme reverse transcriptase
How do retroviruses such as HIV differ from other viruses? They contain DNA that is used as a template to make RNA. They can reproduce only inside living cells. They contain the enzyme reverse transcriptase. They have much simpler reproductive cycles than other RNA viruses.
by altering the plants growth
How do viroids harm the plants that are infected with them? by altering the plants' growth by reducing the plants' seed production by destroying the root system by increasing the plants' metabolic rate
the viral envelope fuses with the cell's membrane allowing the protein coded RNA to enter cytoplasm
How does the envelope of a mump's virus help the virus
the end of the line where the pieces are put together to make the final product
IF protein production were an assembly line, a ribosome would be
generally not produced. However, when the host cell divides, the daughter cells already possess the provirus.
In the lysogenic cycle, new viral particles are
Prions lack nucleic acid
In which of the following ways does a prion differ from both cellular life and viruses? Prions lack nucleic acid .Prions lack a cell membrane. Prions lack protein. Prions cause brain diseases.
They direct the synthesis of new viral proteins & act as templates for a new viral genome RNA
Once inside a host cell's cytoplasm, an animal RNA virus directs the manufacture of complementary strands of RNA. What two functions do these new RNA strands perform?
phage
One type of virus that infects bacteria is called a
RNA information is coped into DNA
Reverse transcription, carried out by retroviruses, is the process by which _____. DNA information is copied into RNA RNA information is "read" to form a protein molecule RNA information is copied into DNA DNA is duplicated
evolved through the genetic reshuffling of viruses that infect humans, birds, and pigs.
The 2009 H1N1 flu virus evolved through the genetic reshuffling of viruses that infect humans, birds, and pigs. killed over 50 million people worldwide. was an avian flu virus. was spread by mosquitoes.
lysogenic cycle
The ______ is a viral life cycle in which the virus inserts its genome into the host, where it may remain dormant for long periods.
inhibition of reverse transcriptase
The drug AZT was one of the first drugs used to treat HIV. Which of the following drug actions would prevent the spread of HIV without harming the host cell?destruction of amino acids that are vital to viral protein synthesis prevention of the formation of glycoproteins inhibition of all DNA polymerase enzymes inhibition of reverse transcriptase
helps the virus enter the cell.
The envelope of a mumps virus
single-stranded RNA
The genetic material of HIV consists of _____. single-stranded DNA single-stranded RNA double-stranded DNA double-stranded RNA none of the above
lytic
The phage reproductive cycle that kills the bacterial host cell is known as _________ cycle
genome
The pointer is indicating the virus's ____________
Transduction, transformation, conjugation
The three modes of gene transfer between bacteria are ________ which is transfer via a virus; ________ which is the uptake of DNA from the surrounding environment; and _____________ which is bacterial "mating."
prophage
Viral DNA incorporated into host cell DNA is known as a(n) envelope capsid prophage phage.
transcription
Viral DNA make mRNA by the process of __________. It co-opts the cell's reproductive machinery.
an RNA virus that reproduces by means of a DNA molecule. Retroviruses are so named because they reverse the usual DNA→RNADNA→RNA flow of genetic information. These viruses carry molecules of an enzyme called reverse transcriptase, which catalyzes reverse transcription: the synthesis of DNA on an RNA template.
What is a retrovirus
retrovirus
What kind of virus is HIV
transfer RNA, ribosomes, AUG codons
Which of the following are necessary, but not sufficient for translation?
AIDS
Which of the following diseases is NOT caused by a prion?kuru in humans Creutzfeldt-Jacob disease in humans mad cow disease AIDS
reverse transcriptase
Which of the following enzymes does HIV use to synthesize DNA on an RNA template? DNA convertase reverse transcriptase RNA polymerase ligase
they kill their host cells by lysing them.
Which of the following is an INCORRECT statement about viruses that reproduce using lysogenic cycles
prions are proteins folded into the correct configuration, but present in lethally high concentrations.
Which of the following is not an accurate description of prions
whole viruses leave the host cell and infect other cells.
Which of the following occurs during a lytic, but not a lysogenic, viral replication cycle
Each tRNA molecule adds its amino acid to the growing polypeptide chain, moves from the A to the P site, then leaves the ribosome.
Which of the following sequence of events occurs during the elongation phase of translation
herpesviruses reproduce inside the host cell's mitochondria
Which of the following statements about herpesviruses is false? 1. herpesviruses acquire their envelopes from the host cell nuclear membrane 2. herpesviruses may remain dormant for long periods of time which inside the host cell nucleus. 3. herpesviruses may cause cold sores or genital sores to appear during times of physical or emotional stress. 4. herpesviruses reproduce inside the host cell's mitochondria
There are many successful ways to rid infected plants of a virus.
Which of the following statements about plant viruses is false? 1. the genetic material in most plant viruses is RNA 2. Preventing infections and breeding resistant plants can control viral infection in plants. 3. There are many successful ways to rid infected plants of a virus. 4. Once in a plant, a virus can spread from cell to cell through plasmodesmata.
The cycle typically leads to the lysis of the host cell.
Which of the following statements characterizes the lytic cycle of a viral infection? The cycle typically ends when the host bacterium divides .The virus reproduces outside of the host cell. The viral genes typically remain inactive once they are inside the host cell. The cycle typically leads to the lysis of the host cell.
Very few new human diseases have originated in other animals because the genetic differences are too great.
Which of the following statements regarding viral diseases is false? RNA viruses tend to have an unusually high rate of mutation because their RNA genomes cannot be corrected by proofreading. Very few new human diseases have originated in other animals because the genetic differences are too great. AIDS was around for decades before becoming a widespread epidemic. New viral diseases often emerge when a virus infects a new host species.
Ebola
Which of these is classified as an emerging virus that can have a direct impact on human health? Ebola pneumonia lambda tobacco mosaic virus
frameshift (insertion)
Which type of mutation is represented here. Normal "gene": the big red fly had one eye. Mutated "gene":the fbi gre dfl yha don eey e
is an infectious particle consisting of little more than "genes in a box": a bit of nucleic acid wrapped in a protein coat called a capsid and, in some cases, a membrane envelope. Unlike the genomes of all living cells, a viral genome may consist of DNA or RNA, and may be single- or double-stranded. Viral genomes usually consist of a single molecule of nucleic acid, which may be linear or circular.
describe the basic structure of a virus
In the lysogenic cycle
viral DNA is replicated along with host DNA
