HW 4 CH 11 + 13

In order for viruses to enter host cells, they must bind to receptors on the host cytoplasmic membrane. T/F?

False

Nitrifiers fix nitrogen gas, making it available to other organisms? T/F

False

Nitrifiers trap nitrogen gas, keeping it from other organisms T/F

False

Nitrifiers use sulfur as an energy source T/F

False

All viruses can infect any cell type or tissue type. T/F?

False

Which of the following is an example of lysogenic conversion? A. A lysogen that acquires new characteristics as a result of the prophage. B. A temperate phage that loses the ability to synthesize a repressor. C. A temperate phage that loses the ability to recognize a repressor. D. A lysogen in which the prophage excises from the chromosome and begins the lytic cycle. E. All of the answer choices are correct.

A a lysogen that acquires new characteristics as a result of the prophage

Which of the following is required for prion replication? A. Abnormal prion protein B. DNA-dependent DNA polymerase C. DNA-dependent RNA polymerase D. RNA-dependent RNA polymerase E. All of the answer choices are correct.

A abnormal prion protein

During viral infection of a host cell, which is the third step of the process? A. Release of nucleocapsid into host cytoplasm B. Uncoating and nucleic acid release C. Biosynthesis of virion components D. Entry (fusion or endocytosis) into host cell E. Attachment to host cell

A release of nucleocapsid into host cytoplasm

Removal of the capsid to release the virus nucleic acid into the host cytoplasm is called ______. A. uncoating B. endocytosis C. desynthesis D. decoating E. fusion

A uncoating

A positive (+) strand of RNA A. makes a minus (-) strand of RNA, which can then act as mRNA. B. can directly act as mRNA. C. must be converted back to DNA for gene expression. D. cannot function directly as mRNA. E. must be double-stranded.

B can directly act as mRNA

Select the FALSE statement regarding bacterial diversity. A. The Ti plasmid of Agrobacterium is used to genetically engineer plant cells. B. During unfavorable conditions, myxobacteria travel as a pack to a new location. C. Agrobacterium species are able to transfer a piece of DNA to plant cells, which then express that DNA. D. Myxobacteria are able to pile up to produce fruiting bodies. E. The nitrogen-fixing symbionts of legumes are genetically related to the plant pathogens that cause crown gall.

B during unfavorable conditions, myxobactera travel as a pack to a new location

The negative (-) sense strand of RNA A. is identical to the (+) sense strand. makes RNA replicase. B. is used to synthesize more (+) strands. C. acts as mRNA to make viral proteins. D. plays no role.

B is used to synthesize more (+) strands

Reverse transcriptase synthesizes A. viral protein from viral RNA. B. viral DNA from viral RNA. C. (+) RNA from (-) RNA. D. (+) RNA from protein. E. (+) DNA from (-) RNA.

B viral DNA from viral RNA

A microbiologist discovers a new infectious agent. In an effort to identify the type of agent, the microbiologist exposes the agent to the following: i. RNAse ii. DNAse iii. Protease iv. Heat v. Acid After the different treatments, the microbiologist determines that the agent is destroyed by treatments (i), (iv), or (v). This result leads the scientist to conclude that the agent likely is a(n) _____. A. prion B. viroid C. bacteriophage D. RNA virus E. retrovirus F. DNA virus

B viroid

In animal virus replication, an uncoating step is needed to release the nucleic acid from the capsid. Why is this step not needed in bacteriophage replication? A. Uncoating is also needed in the phage life cycle. B. Bacteriophages only contain RNA. C. Bacteriophages inject their DNA into the host cell. D. Bacteriophages only contain protein and lipids. E. Bacteriophages do not replicate.

C bacteriophages inject their DNA into the host cell

Please choose the statement that describes how cytopathic effects are detected in virally infected cells. A. Performing biochemical tests on infected cells. B. Growing infected cells in glass Petri dishes. C. Examining infected cells with a microscope. D. Performing immunological tests on infected cells. E. Growing infected cells in a variety of different media.

C examining infected cells with a microscope

What are the two entry mechanisms used by enveloped viruses? A. Fusion and uncoating B. Fusion and budding C. Fusion and endocytosis D. Fusion and exocytosis E. Endocytosis and uncoating

C fusion and endocytosis

Which of the following about hydrothermal vents is FALSE? A. Prokaryotes that thrive there are hyperthermophiles. B. Prokaryotes thriving in the region can withstand autoclave temperatures. C. Photosynthesis supports food production in the region. D. Many of the microbes in the vents live symbiotically with eukaryotes in the region. E. al of the statements are true

C photosynthesis supports food production in the region

In viral entry by endocytosis A. viral spikes fuse with the host cell's cytoplasmic membrane to form a vesicle. B. the host cell's cytoplasmic membrane surrounds only the viral nucleic acid. C. the host cell's cytoplasmic membrane surrounds the whole virion and forms a vesicle. D. the host's cells cytoplasmic membrane surrounds only the viral protein coat. E. lipases degrade the viral coat to release the viral nucleic acid.

C the host cell's cytoplasmic membrane surrounds the whole virion and forms a vesicle

Based on what you know about the myxobacteria, for which of the following could they serve as an experimental model? A. nitrogen and sulfur fixation B. growth at very high temps C. plasmid production and manipulation D. cell-to-cell communication and cooperation

Cell-to-cell communication and cooperation

Identify which of the following genera have members that are disease-causing facultative anaerobes. Corynebacterium escherichia Staphylococcus Mycobacterium Thermus

Corynebacterium escherichia staphylococcus

Deinococcus may be used to clean up environmental radioactive waste. A. Hemorrhagic B. Transforming C. Lytic D. Lysogenic E. Oncogenic

D lysogenic

Viral capsids are composed of ______. A. phosphates B. carbohydrates C. lipids D. protein E. nucleic acids

D protein

Which of the following is a potential future use of genetically engineered Deinococcus? A. Deinococcus may be used in the brewing industry because it produces ethanol. B. Deinococcus may be used as a source of UV radiation in a medical setting. C. Deinococcus may be used to produce radioactive compounds for research. D. Deinococcus enzymes may be put into detergents used at very high temperature. E. Deinococcus may be used to clean up environmental radioactive waste.

E Deinococcus may be used to clean up environmental radioactive waste.

Viral spikes A. are present in all viruses. B. are made of lipids. C. are composed of polysaccharides. D. attach non-specifically to host cell receptors. E. attach specifically to host cell receptors.

E attach specifically to host cell receptors

1. Every virus particle contains ______. A. DNA and RNA B. phospholipids C. DNA D. ribosomes E. either DNA or RNA

E either DNA or RNA

When present, what is the viral envelope composed? A. Carbohydrates B. Proteins and sugars C. Nucleic acid D. Mainly protein E. Mainly lipids

E mainly lipids

You are completing a research project for a Microbiology honors class. You are working with two bacteria: E. coli and Deinococcus radiodurans. You inoculate each organism onto tryptic soy agar plates, and you then expose the plates to ultraviolet (UV) radiation for a specified time. You then incubate the plates overnight at 37oC for 24 hours, after which you count the number of colonies on each plate. Your results are shown on the graph. Select the FALSE statement regarding D. radiodurans A. These bacteria have enzymes capable of DNA repair. B. Deinococcus species have an unusual cell wall. C. These bacteria can withstand high doses of UV radiation. D. Deinococcus obtains its energy from organic compounds. E. Members of this genus are obligate anaerobes.

E. members of the genus are obligate anaerobes

Almost immediately upon entry, the viral nucleic acid alters the gene expression of the host cell. T/F

True

Both enveloped and non-enveloped (naked) viruses can enter a cell by endocytosis. T/F?

True

More than one mechanism of viral entry into a host cell exists. T/F

True

Nitrifiers convert ammonium to nitrite T/F

True

Nitrifiers convert nitrite to nitrate T/F

True

Nitrogen-fixing cyanobacteria are critically important ecologically. True or false?

True