MICROBIOLOGY EXAM 1 - QUIZZES

If a researcher wanted to compare the enzymatic capacity to degrade compounds in a water column at various depths under a specific set of conditions, which would be the most useful approach? A) metagenomics B) metabolomics C) metaproteomics D) genomics

metaproteomics

Robert Koch received the 1905 Nobel Prize in Physiology or Medicine for A) making an effective rabies vaccine. B) identifying Mycobacterium tuberculosis as the causative agent of tuberculosis. C) developing a smallpox vaccination, identifying Mycobacterium tuberculosis as the causative agent of tuberculosis, and making an effective rabies vaccine. D) developing a smallpox vaccination.

identifying Mycobacterium tuberculosis as the causative agent of tuberculosis.

The evolutionary origin of mitochondria is demonstrated by which of the following key genomic characteristics? A) rRNA genes most closely related to Bacteria B) linear and circular genome structure in different organisms C) variable numbers of protein-encoding genes D) large stretches of AT-rich DNA

rRNA genes most closely related to Bacteria

Which of the following is NOT included in the genome? A) genes that encode RNAs B) coding regions of DNA C) proteins D) noncoding regions of DNA

proteins

Based on the table of attributes given below, which of the following statements are FALSE about the two organisms? Characteristic Bacterium A Bacterium B Endospore formation yes no Capsule no yes Type IV pili yes no Flagella no no Morphology bacillus bacillus A) Bacterium A is more resistant to heat and ultraviolet light. B) Bacterium B is likely to exhibit motility. C) Bacterium B likely forms a slime layer better than Bacterium A. D) Both bacteria may attach to surfaces.

Bacterium B is likely to exhibit motility.

Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea or Eukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes? A) Bacteria lack a nucleus. B) Archaea lack operons. C) Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases. D) Archaea and Eukarya have very similar ribosomes that are different than bacterial ribosomes.

Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.

Whether a molecule is oxidized or reduced in a redox reaction depends on its reduction potential relative to the available electron donors and acceptors present that the organism can utilize. Given the following reduction potentials for various redox half reactions, in a lithotroph capable of utilizing ammonia as an energy source, which substances would be potential terminal electron acceptors for respiration? NO2 -/NH3 +0.34 V NO3 -/NO2 - +0.43 V O2/H2O +0.82 V A) Both O2 and NO3 - are possible electron acceptors B) NO2 - C) O2 D) NO3 -

Both O2 and NO3 - are possible electron acceptors

What is the difference between a coenzyme and a prosthetic group? A) Coenzymes require additional ions to bind to enzymes but prosthetic groups are able to directly interact with enzymes. B) Coenzymes are essential for an enzymes function and prosthetic groups only enhance its reaction rate. C) Coenzymes are weakly bound whereas prosthetic groups are strongly bound to their respective enzymes. D) Coenzymes are organic cofactors and prosthetic groups are inorganic cofactors.

Coenzymes are weakly bound whereas prosthetic groups are strongly bound to their respective enzymes.

Automated sequencing techniques require only one lane on an electrophoresis gel rather than four. What is one method that makes this possible? A) Computers are able to recognize the different bases by their structure. B) Each base is identified with a different fluorescent color. C) The fragments of different lengths have different charges, meaning that they travel different distances in the electrophoresis gel. D) The different bases are recognized by their depth in the electrophoresis gel.

Each base is identified with a different fluorescent color.

Determine why some prokaryotes have less DNA but more genes than eukaryotes. A) Eukaryotes do not have introns in their chromosomes. B) Eukaryotes have more exons in their chromosomes. C) Eukaryotes have more introns in their chromosomes. D) Prokaryotes have more introns in their chromosomes.

Eukaryotes have more introns in their chromosomes.

T/F Molybdenum is a cofactor for nitrogenase, which means every nitrogen-fixing microorganism will not be able to fix nitrogen without Mo.

FALSE

Which is an example of a micronutrient? A) iron B) vitamin B12 C) inorganic phosphorous D) arginine

Iron

Predict why dipicolinic acid is only found in endospores and not vegetative cells. A) It binds to calcium ions to stabilize DNA at room temperatures. B) It binds free water and aids in transporting that water into vegetative cells, which would be detrimental to endospores. C) It binds to calcium ions to destabilize DNA at room temperature. D) It binds free water and aids in dehydration, which would be detrimental to vegetative cells.

It binds free water and aids in dehydration, which would be detrimental to vegetative cells.

In DNA replication in vivo, RNA primers are used. However, researchers used DNA primers instead in the lab because DNA primers are more stable. Why might this be the case? A) RNA molecules are shorter than DNA molecules, making them more stable. B) DNA has a more stable structure because the deoxyribose in DNA is a larger molecule than the ribose in RNA. C) RNA has a relatively short half-life compared with DNA and does not need to be as stable to perform its functions in the cell. D) RNA is usually single-stranded, and the double-stranded nature of DNA makes it more stable.

RNA has a relatively short half-life compared with DNA and does not need to be as stable to perform its functions in the cell.

Given the following DNA sequence (5' ( 3'), what would be the DNA sequence on the complementary strand (3' ( 5') of a double-stranded helix molecule? DNA sequence: AGTCCGA A) TCGGACT B) AGUCCGA C) TCAGGCT D) UCAGGCU

TCAGGCT

T/F Codon usage varies from one organism to the next.

TRUE

Which statement is TRUE regarding protein synthesis? A) The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain. B) Ribosomal proteins catalyze peptide bond formation in the growing polypeptide chain. C) Messenger RNA catalyzes peptide bond formation in the growing polypeptide chain. D) Transfer RNAs catalyze peptide bond formation in the growing polypeptide chain.

The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.

You experimentally change the DNA sequence directly upstream of a start codon of an operon in E. coli to investigate the function of this region of DNA. Analysis reveals that after the change the same amount of mRNA is made from the operon, but there are very few proteins made from the operon. What is the most likely function of the DNA sequence that you changed? A) The DNA sequence likely functions as a promoter. B) The DNA sequence likely functions as a ribosome-binding site. C) The DNA sequence likely functions as in transcriptional regulation. D) The DNA sequence likely functions as a termination sequence.

The DNA sequence likely functions as a ribosome-binding site.

The plaque (microbial biofilm) that forms between your teeth is a highly anaerobic (oxygen-free) environment, even though the mouth is one of the most aerobic habitats in the body and most of the bacteria living there can use oxygen if it is available. Why is there no oxygen in the plaque between your teeth? A) The teeth absorbed the oxygen. B) Bacteria cannot live in the absence of oxygen. C) The bacteria living between the teeth have used up the oxygen. D) The area between the teeth never had any oxygen.

The bacteria living between the teeth have used up the oxygen.

Researchers discover a new species of bacterium that has an unusual metabolism. However, it has biochemical and morphological similarities to other species. What is the most comprehensive and effective approach to determine how to classify these bacteria? A) The bacteria should be classified by using genomic analyses to construct phylogenies. B) The bacteria should be classified with the other bacteria that use the most similar biochemical pathways. C) Because of their unusual metabolic pathways, the bacteria should be classified in a new group. D) The bacteria should be classified with other bacteria that have the most similar morphology.

The bacteria should be classified by using genomic analyses to construct phylogenies.

Functional analysis of the genome of a prokaryote shows that 20% of the genome is for metabolism, 1 % for biosynthesis of amino acids, 8% for peptide ABC transporters, and 2% for replication. What can you determine about the environment in which this organism lives? A) The organism lives in an environment rich in sugars. B) The organism lives in an environment rich in hydrocarbons. C) The organism lives in an environment rich in lipids. D) The organism lives in an environment rich in organic material, particularly amino acids and proteins.

The organism lives in an environment rich in organic material, particularly amino acids and proteins.

Which response best explains why promoters for the same sigma subunit do not have identical sequences? A) The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit. B) Only the last 10 bases in the promoter region are needed for sigma subunit recognition. C) Different genes will have different DNA sequences. D) Only the first 35 bases in the promoter region are needed for sigma subunit recognition.

The sequences within the promoter region at -10 and -35 are the most important for recognition by the sigma subunit.

DNA polymerase can only add nucleotides to a free 3(-hydroxyl group on a nucleic acid strand. As a consequence, all EXCEPT which of the following statements are true of DNA replication? A) Primase must synthesize an RNA primer before DNA synthesis can begin. B) DNA replication requires both DNA polymerase III and DNA polymerase I. C) Uracil is not found in DNA. D) Synthesis of one complementary DNA strand lags behind the synthesis of the other strand.

Uracil is not found in DNA.

The replisome is a large complex of proteins that contains many enzymes involved in DNA replication. Hypothesize why these enzymes function best together. A) With the replisome, mRNA can be transcribed faster. B) With the replisome, it can replicate both strands of DNA at the same time. C) With the replisome, plasmids can be replicated along with the chromosome. D) With the replisome, the strands of DNA can be copied one at a time.

With the replisome, it can replicate both strands of DNA at the same time.

An operon is a useful genetic element, because it A) translates DNA sequence into amino acid sequence. B) encourages the binding of ribosomes in the correct location. C) encourages the binding of RNA polymerase. D) allows coordinated expression of multiple related genes in prokaryotes.

allows coordinated expression of multiple related genes in prokaryotes.

AT-rich DNA will denature/melt A) in accordance with the animal or plant from which it was taken. B) at a lower temperature than GC-rich DNA. C) at a higher temperature than GC-rich DNA. D) usually at the same temperature as GC-rich DNA, with some minor variations.

at a lower temperature than GC-rich DNA.

A chemoorganotroph and a photoautotroph in the same environment would NOT compete for A) carbon and oxygen. B) nitrogen. C) oxygen. D) carbon.

carbon and oxygen.

Chromosomal islands are similar to plasmids __________. A) because both elements contain nonessential genes B) because both elements replicate independently of the chromosome C) because both elements are found separate from the chromosome D) because both elements contain inverted repeats

because both elements contain nonessential genes

Teichoic acid molecules in Gram-positive cell walls include phosphate groups. Therefore, they will __________. A) bind other phosphate ions B) not bind any ions C) bind positive ions like Mg2+ and Ca2+ D) bind negative ions like Cl- and SO42-

bind positive ions like Mg2+ and Ca2+

Five-carbon sugars are used in the A) activation of pentoses to form glycogen for energy storage. B) biosynthesis of DNA and RNA. C) biosynthesis of DNA and RNA as well as catabolic pentose phosphate pathway. D) catabolic pentose phosphate pathway for carbon and energy.

biosynthesis of DNA and RNA.

The rising of bread dough is the result of A) biotin production. B) oxygen being released. C) carbon dioxide produced by fermentation. D) oxidative phosphorylation.

carbon dioxide produced by fermentation

The field of study that can reveal how genes function, reveal how organisms interact with the environment, and show evolutionary relationships is __________. A) proteomics B) comparative genomics C) transcriptomics D) genomics

comparative genomics

To ensure growth of a newly discovered bacterium with unknown nutritional requirements, it would be best to begin with a ________ medium rather than a ________ medium. A) complex / minimal B) selective / complex C) minimal / complex D) selective / differential

complex / minimal

Distinguish which list of structural properties and activities are true for ALL cells. A) cytoplasmic membrane, ribosomes, metabolism, evolution B) cytoplasmic membrane, ribosomes, growth, communication C) cytoplasmic membrane, ribosomes, metabolism, motility D) cytoplasmic membrane, ribosomes, growth, differentiation

cytoplasmic membrane, ribosomes, metabolism, evolution

Improperly functioning acyl carrier proteins (ACPs) would likely result in A) no harm to bacteria, because only archaeons and eukaryotes use ACPs for fatty acid biosynthesis. B) death for a bacterium due to poor lipid bilayer integrity. C) enhanced growth of a bacterium due to faster growth substrate uptake by a weakened membrane. D) a physiological shift to anaerobic metabolism where an energized membrane is less important for energy production.

death for a bacterium due to poor lipid bilayer integrity.

Transport proteins can become saturated with solute, have specificity for certain substances, undergo conformational (shape) changes, and are regulated by the cell. What other type of cellular proteins have these four general characteristics? A) ribosomes B) enzymes C) porins D) flagella

enzymes

By controlling the concentration of nutrients continuously added to a chemostat, cells can constantly be maintained at the A) exponential growth phase. B) death growth phase. C) lag growth phase. D) stationary growth phase.

exponential growth phase.

A bacterium running low on NADPH could ________ to generate more of this coenzyme. A) degrade a fatty acid B) degrade an amino acid or nucleic acid C) invoke the pentose phosphate pathway D) use a broad specificity phosphatase with inorganic phosphatase and NADH

invoke the pentose phosphate pathway

Like all forms of life on Earth, all microbial cells perform three major types of activities: A) growth, differentiation, and metabolism. B) metabolism, growth, and evolution. C) growth, genetic exchange, and evolution. D) metabolism, growth, and genetic exchange.

metabolism, growth, and evolution.

Hypothetically, if free electrons existed in sufficient numbers for enzymes to use in metabolic reactions A) Q-cycle reactions would no longer be necessary for electron transport, but the proton motive force would otherwise be unchanged. B) cytochromes would be unnecessary for cells and quinones would be more important. C) a higher diversity of cytochromes would likely be observed. D) most metabolic pathways for both anabolism and catabolism would have to be rewritten.

most metabolic pathways for both anabolism and catabolism would have to be rewritten.

A halotolerant facultative anaerobe would grow BEST in which of the following environments? A) oxygenated saline B) oxygenated non-saline C) oxygen depleted saline D) oxygen depleted non-saline

oxygenated non-saline

You want to know whether the virulence genes present in Bordetella pertussis are evolutionarily related to genes in the less pathogenic species B. bronchiseptica or if the virulence genes were acquired via horizontal gene transfer. What characteristic(s) would you compare to answer this question? A) genome size and number of introns B) ribosomal binding site and intron sequence C) number of genes in the pan genome D) percentage of GC content and codon usage

percentage of GC content and codon usage

All microorganisms require A) calcium, potassium, and magnesium. B) phosphorus, selenium, and sulfur. C) carbon, iron, and sodium. D) phosphorus, aluminum, and sodium.

phosphorus, selenium, and sulfur.

In Sanger sequencing and in many newer sequencing techniques, labeled precursors are used. What are these precursors? A) RNA B) fluorescent dyes C) primers or nucleotides that will be incorporated into the newly synthesized DNA D) DNA polymerase

primers or nucleotides that will be incorporated into the newly synthesized DNA

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, at different locations in prokaryotic DNA, which are transcribed as a single piece of mRNA D) several genes, next to each other in prokaryotic DNA, that are transcribed as a single piece of mRNA

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

Electron carriers used in electron transport chains are always found in membranes. Which one of the following statements is NOT a reason why electron transport chains are found in membranes? A) so that they can transport NADH out of the cell to the periplasm B) so that they can efficiently pass electrons in sequence from the carriers with the more negative reduction potentials to those with the more positive reduction potentials C) so that the electron carriers can be oriented within the membrane such that protons are passed from one side of the membrane to the other D) So that electron-only carriers can be arranged to alternate with electron-plus-proton carriers in the chain.

so that they can transport NADH out of the cell to the periplasm

Gene duplication is thought to have had a significant influence on the evolution of microbes because __________. A) the duplicated gene can be given away to another organism by conjugation B) the duplicated gene can allow for increased transcription and synthesis of the gene product C) the duplicated gene can be mutated, possibly leading to a useful new gene function or product, while the original copy can still perform its original (and possibly essential) genetic function D) the duplicated gene can serve as a "back-up" copy

the duplicated gene can be mutated, possibly leading to a useful new gene function or product, while the original copy can still perform its original (and possibly essential) genetic function

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that A) there are two termination sites in the mRNA. B) the protein is secreted and folds outside of the cell. C) you need to re-do the experiment because there should only be one form. D) the protein requires chaperonins to fold properly.

the protein is secreted and folds outside of the cell.

In E. coli, the consensus sequence for the Pribnow box (the -10 sequence) is TATAAT. Therefore, __________. A) this sequence will always be transcribed into RNA B) the sigma factor will only recognize this -10 sequence C) TATACT will be a very weak -10 promoter sequence D) this will be the strongest -10 promoter sequence

this will be the strongest -10 promoter sequence

The most abundant genes in prokaryotic genomes are A) those involved in transport. B) those involved in DNA replication. C) those involved in metabolism. D) those involved in translation.

those involved in metabolism.