Mastering microbiology exam 2

When a frameshift mutation occurs, it causes changes in many bases downstream and can affect many of the amino acids in the protein.

Frameshift mutations can be very severe. What is one reason why they are often so serious?

phospholipids

Genetic information in the cell is held by information molecules, including all EXCEPT which of the following? DNAs polypeptides RNAs phospholipids

When replication occurs, complementary base pairing may fail because the base analog may not be treated in the same way as the base that it replaced.

One group of chemical mutagens includes the base analogs. How do these lead to mutations?

a high fidelity in the copying of DNA is necessary for good heredity

Proofreading of newly-synthesized DNA is important because __________.

middle and laye

Viral structural proteins and proteins involved in the release of new viral particles that are synthesized after genomic replication begins would be considered __________. View Available Hint(s) Viral structural proteins and proteins involved in the release of new viral particles that are synthesized after genomic replication begins would be considered __________. late proteins middle and late proteins early proteins middle proteins

capsid and genome

What component(s) make up the structure of a virion? View Available Hint(s) What component(s) make up the structure of a virion? capsid, genome, envelope capsid capsid and genome genome and envelope

Stabilizing proteins

What ensures that the single strands of DNA do not come back together?

all

What structure can the viral genome take? View Available Hint(s) What structure can the viral genome take? ss-DNA ds-RNA ds-DNA All of the listed responses are correct.

conservative transposition

When a transposon is cut from one location in genome and pasted into a new location, it is called __________.

DNA helicase

Which enzyme breaks the hydrogen bonds during replication?

RNA viruses

Which of the following groups contains some representatives with genomes that are so small that they may have as few as two genes? View Available Hint(s) Which of the following groups contains some representatives with genomes that are so small that they may have as few as two genes? bacteria DNA viruses eukaryotes RNA viruses

Viruses are obligate parasites and no living organisms are obligate parasites.

Which of the following is NOT a way in which viruses are different from living organisms? View Available Hint(s) Which of the following is NOT a way in which viruses are different from living organisms? Viruses are acellular and all living things are made up of cells Viruses depend on their host to synthesize the essential components of new viruses (e.g., genetic material and proteins), while living organisms are capable of synthesizing these components even if they require a host for food, shelter, or other necessities. Viruses have DNA or RNA, not both Viruses are obligate parasites and no living organisms are obligate parasites.

significantly smaller

A plasmid differs from the bacterial chromosome in that it is __________. circular always found as a single copy of DNA in a cell double-stranded significantly smaller

prokaryotes

As nutrients cycle in the biosphere, __________ can participate in every transformation from one chemical form of a nutrient to another. View Available Hint(s) As nutrients cycle in the biosphere, __________ can participate in every transformation from one chemical form of a nutrient to another. fungi animals plants prokaryotes

methane hydrates (0.014%)

Carbon dioxide and methane are potent greenhouse gases, with methane having 20 times more warming potential in the atmosphere than CO2. As global warming progresses, there is the real possibility that increased temperatures on land and in the oceans will lead to a positive feedback effect leading to accelerated warming. From the carbon reservoirs listed below with their percentage of the total carbon on Earth, what would be the most dangerous potential source of C that could be released to potentiate further warming? methane hydrates (0.014%) rocks and sediments (99.5%) fossil fuels (0.006%) oceans and terrestrial biosphere (0.053%)

Synthesis of one complementary DNA strand lags behind the synthesis of the other strand. DNA replication requires both DNA polymerase III and DNA polymerase I. Primase must synthesize an RNA primer before DNA synthesis can begin.

DNA polymerase can only add nucleotides to a free 3(-hydroxyl group on a nucleic acid strand. As a consequence what statements are true of DNA replication?

Chaperonins aid in the correct folding of proteins, as well as refolding partially denatured proteins.

Explain why chaperonins are critical to a cell's survival.

The rRNA recognizes the correct start codon with the aid of an upstream Shine-Dalgarno sequence.

How do prokaryotes determine where to begin translation so the correct protein is synthesized?

They bind to the single-stranded DNA.

How do stabilizing proteins work on the DNA?

increasing the anthropogenic carbon dioxide released in the atmosphere may significantly decrease the amount of calcium carbonate in the deep ocean

Human influences on the carbon cycle may cause major upsets in the balance of the ecosystem because __________. View Available Hint(s) Human influences on the carbon cycle may cause major upsets in the balance of the ecosystem because __________. increasing the anthropogenic carbon dioxide released in the atmosphere may significantly decrease the amount of calcium carbonate in the deep ocean increasing the anthropogenic carbon dioxide released in the atmosphere may significantly increase the amount of ozone in the atmosphere increasing the anthropogenic carbon dioxide released in the atmosphere is decreasing the temperature of the oceans increasing the anthropogenic carbon dioxide released in the atmosphere is significantly increasing the pH of the oceans

They differ in their genotype and in their phenotype.

In a culture of bacteria, there are some individuals that are unable to synthesize histidine. What is the best and most likely description of how these individuals differ from the other bacteria in the culture in regards to their genotypes and phenotypes?

It moves ahead of the newly synthesized DNA.

In which direction does the replication fork move?

the formation of carbonate rocks building the shells and frustules of microscopic algae and some animals

Increases in atmospheric carbon dioxide concentrations leads to acidification of the oceans as CO2 dissolves in the water and forms carbonic acid. This acidification is predicted to have a major effect on the carbon cycle, as well as the calcium and silica cycles, due to the roles of Ca+ and Si in __________. View Available Hint(s) Increases in atmospheric carbon dioxide concentrations leads to acidification of the oceans as CO2 dissolves in the water and forms carbonic acid. This acidification is predicted to have a major effect on the carbon cycle, as well as the calcium and silica cycles, due to the roles of Ca+ and Si in __________. mercury oxidation the formation of fossil fuels the formation of carbonate rocks building the shells and frustules of microscopic algae and some animals

transformation

Increasing genetic variability by the uptake of DNA from the environment is __________.

You discover a new type of archaeon. After analyzing its genome in the lab, you realize that it is missing the genes needed for glycolysis. What might you guess about this organism based on that information? View Available Hint(s) You discover a new type of archaeon. After analyzing its genome in the lab, you realize that it is missing the genes needed for glycolysis. What might you guess about this organism based on that information? It is an extremophile. It is a halophile. It is an obligate symbiont. It must be photosynthetic.

It is an obligate symbiont.

Methylmercury accumulates in animal muscle and is biomagnified in the food chain.

Some microbial transformations of mercury yield more toxic forms of mercury, including the most toxic form, methylmercury (CH3Hg+). Which of the following properties of methylmercury in an aquatic ecosystem would be most problematic for humans? View Available Hint(s) Some microbial transformations of mercury yield more toxic forms of mercury, including the most toxic form, methylmercury (CH3Hg+). Which of the following properties of methylmercury in an aquatic ecosystem would be most problematic for humans? Methylmercury absorbs readily through the skin. Methylmercury is water-soluble. Methylmercury accumulates in animal muscle and is biomagnified in the food chain. Methylmercury is a neurotoxin.

AUU, AUC, and AUA all code for Ile

The genetic code has many important characteristics. For example, a specific codon always means the same thing in a particular species. Codons mean the same thing in most species (even though there are some exceptions). In some cases, a particular amino acid can be specified by more than one codon (the genetic code is degenerate). Which of the following answers describes an example of the degenerate nature of the code? AUU, AUC, and AUA all code for Ile AUU codes for Ile in a wide variety of species The sequence "AUGCCGAUU" is read as three codons, AUG, then CCG, then AUU. There are no pauses or commas in the code.

C. several genes, next to each other in prokaryotic DNA, that are transcribed as a single piece of mRNA

Which statement best describes an operon? A. several genes, next to each other in eukaryotic DNA, that are transcribed as a single piece of mRNA B. a single gene in prokaryotic DNA that is transcribed as a single piece of mRNA C. several genes, next to each other in prokaryotic DNA, that are transcribed as a single piece of mRNA D. several genes, at different locations in prokaryotic DNA, which are transcribed as a single piece of mRNA

When runoff enters the body of water, the nitrogen level significantly increases, which increases the activity of the microorganism there and upsets the balance of the ecosystem.

Why would using nitrogenous fertilizer near a body of water affect the organisms in the body of water? View Available Hint(s) Why would using nitrogenous fertilizer near a body of water affect the organisms in the body of water? When runoff enters the body of water, the nitrogen level significantly decreases, which increases the activity of the microorganisms there and upsets the balance of the ecosystem. It would not affect the organisms in the water, only those in the soil where the fertilizer is applied. When runoff enters the body of water, the nitrogen level significantly increases, which increases the activity of the microorganism there and upsets the balance of the ecosystem. When runoff enters the body of water, the nitrogen level significantly increases, which decreases the activity of the microorganisms there and upsets the balance of the ecosystem.

You need to dehydrate some tissues and have several solutions available. Which solution would be the best choice to dehydrate the tissues as quickly as possible? View Available Hint(s) You need to dehydrate some tissues and have several solutions available. Which solution would be the best choice to dehydrate the tissues as quickly as possible? a 1 M solution of NaCl a 2 M solution of glucose a 1 M solution of CaCl2 a 1 M solution of glucose

a 1 M solution of CaCl2