Question 1

Early classification systems of the bacteria employed all of the following characteristics except
A)the ability to photosynthesize.
B)rRNA sequences.
C)motility.
D)colony or filament forming.
E)sporulation or binary fission.

Accepted Answer

Early classification systems for bacteria relied on observable characteristics such as the ability to photosynthesize, motility, colony or filament formation, and reproduction methods like sporulation or binary fission. The use of rRNA sequences for classification came later with advancements in molecular biology techniques.

Question 2

The fungus Penicillium produces a compound that blocks peptidoglycan assembly.Why is a fungus trying to kill bacteria?
A)Fungi eat bacteria.
B)Fungi and bacteria are both decomposers and compete for resources.
C)The compound produced by the fungus is used for nitrogen fixation,the antibacterial properties are accidental.
D)The fungal compound is produced in response to a bacterial invasion of the fungal hyphae.

Accepted Answer

Fungi and bacteria often inhabit the same environments and compete for similar resources, such as organic matter. By producing compounds that inhibit or kill bacteria, fungi like Penicillium can reduce competition for these resources, giving them an advantage in their shared environment.

Question 3

If the label on a slide reads Gram-positive bacillus,what would a students expect to see?
A)Pink helical cells
B)Purple rod shaped cells
C)Red spherical cells
D)Blue coiled cells

Accepted Answer

A Gram-positive bacillus would appear as purple rod-shaped cells under a microscope after being stained with Gram stain.

Question 4

The cells wall of bacteria Z contains high concentrations of phospholipids along with proteins and relatively low amounts of lipopolysaccharide.When bacteria Z is gram stained,it will most like be colored?
A)Purple
B)Pink
C)Blue
D)Clear,it does not retain any stain

Accepted Answer

The answer of The cells wall of bacteria Z contains...

Question 5

Genes abc and def have a high average cotransduction frequency.Genes abc and xyz have a very low average cotransduction frequency.What is the best explanation for this difference?
A)The genes abc and def are much closer to each other on the chromosome.
B)The genes abc and def must share a higher degree of sequence similarity.
C)Both genes have a high affinity for the viral binding sites.
D)Both genes code for gene products that are necessary for viral replication.

Accepted Answer

The high average cotransduction frequency between genes abc and def suggests that they are located closer to each other on the chromosome, as genetic linkage decreases with distance. In contrast, the low average cotransduction frequency between genes abc and xyz suggests that they are located farther apart on the chromosome.

Question 6

Many cells of the immune system have receptors that detect peptidoglycans and lipopolysaccharides.How do pathogenic bacteria avoid detection?
A)Pathogenic bacteria lack cell walls.
B)Pathogens often encase themselves in a gelatinous capsule.
C)Peptidoglycans are absent from pathogenic bacteria.
D)Disease is only possible if the immune system has been compromised by some other event.

Accepted Answer

Pathogenic bacteria often encase themselves in a gelatinous capsule, which helps them to avoid detection by the immune system. This capsule can mask the presence of peptidoglycans and lipopolysaccharides, which are common components of bacterial cell walls that can be recognized by immune cells.

Question 7

Phil has chronic ulcers,he has been taking acid blockers and drinking vast amounts of liquid antacids.These help relieve the symptoms but he still suffers from ulcers.What would be the best course of action to treat the source of his ulcers?
A)Taking several different antacids
B)Increasing the dosage of acid blockers
C)Taking a course of antibiotics
D)Reducing the stress in his daily life
E)Changing his diet to include more fiber

Accepted Answer

Chronic ulcers are often caused by an infection of the bacteria Helicobacter pylori. Antibiotics are the best course of action to treat the source of the ulcers. While antacids and acid blockers can help relieve symptoms, they do not address the underlying cause. Reducing stress and changing the diet may also be helpful in preventing ulcers, but they will not be enough to treat existing ulcers caused by an H. pylori infection.

Question 8

Vibrio cholerae produces a toxin that destroys the intestinal epithelium.This leads to massive diarrhea; the diarrhea can kill the human via dehydration but helps the bacteria spread and colonize other humans.What is this relationship?
A)Mutualistic
B)Commensalistic
C)Symbiotic
D)Atavistic

Accepted Answer

The relationship is symbiotic because it involves interaction between two different organisms, where the bacteria benefit by spreading and colonizing, while the host is harmed.

Question 9

Irregular dental hygiene and a high sugar diet may led to tooth decay.Why?
A)Bacteria consume calcium.
B)Lactic acid fermentation is used to generate ATP under anaerobic conditions.
C)Plaque degrades the tooth's protective mucosal layers.
D)Glucose forms a weak acid when dissolved in saliva.
E)High concentrations of sugar soften the tooth enamel.

Accepted Answer

Lactic acid fermentation is used by bacteria in the mouth to generate ATP under anaerobic conditions. These bacteria metabolize sugars present in food, producing lactic acid as a byproduct. The acid then contributes to the demineralization of the tooth enamel, leading to tooth decay.

Question 10

Amanda is a microbiologist who studies the pathogenic bacteria Streptococcus pyogenes.In what ways are they (Amanda and the bacteria)similar?
A)Both have cell walls.
B)Both have linear chromosomes.
C)Both have mitochondria for ATP production.
D)Both are capable of sexual reproduction.
E)Both obtain carbon from consuming organic molecules.

Accepted Answer

The answer of Amanda is a microbiologist who studies the...

Question 11

Bacteria typically use binary fission,but under special circumstances sexual reproduction is possible via horizontal gene transfer.

Accepted Answer

The answer of Bacteria typically use binary fission,but under special...

Question 12

Current classification of prokaryotes is based on
A)morphology of flagella.
B)sequencing of proteins,DNA,and RNA.
C)occurrence of transverse binary fission.
D)type of colony formation.
E)ability to stain the cell wall with Gram stain.

Accepted Answer

Current classification of prokaryotes is mostly based on the sequencing of proteins, DNA, and RNA, which provides a more accurate and detailed understanding of evolutionary relationships between different species. Other factors such as morphology and staining properties are useful in identifying and grouping prokaryotes, but they do not provide as much information about genetic relationships. Transverse binary fission and colony formation are important physiological characteristics, but they do not provide enough information for classification purposes. The ability to stain the cell wall with Gram stain is primarily used to differentiate between two major groups of bacteria, Gram-positive and Gram-negative, but it is not sufficient for classification at the species or genus level.

Question 13

A researcher observed a reduction in the number of chromosomes during cell division for a microbe,he concludes that the microbe must be
A)Eukaryotic
B)Prokaryotic
C)An archaean
D)a virus

Accepted Answer

Reduction in the number of chromosomes during cell division is a characteristic of eukaryotic cells undergoing meiosis. Prokaryotes, archaea, and viruses do not undergo meiosis and do not have chromosomes in the same sense as eukaryotes.

Question 14

A high concentration of chlorophyll imbedded in the plasma membrane fold of a newly discovered species of bacteria suggests a:
A)Chemolithoautotrophic metabolism
B)Chemoheterotrophic metabolism
C)Photoautotrophic metabolism
D)Photoheterotrophic metabolism

Accepted Answer

Chlorophyll is used in the process of photosynthesis, which is characteristic of organisms that use a photoautotrophic metabolism. Therefore, the high concentration of chlorophyll suggests that this newly discovered bacteria species likely uses a photoautotrophic metabolism.

Question 15

An oil spill occurs,and Greg (a member of the clean up team)suggests adding fertilizer.Why is he making this suggestion?
A)The fertilizer encourages the growth of microbes that can break down the oil.
B)The chemicals in the fertilizer digest the oil residues.
C)The fertilizer interacts with the oil droplets and renders them harmless.
D)The fertilizer volitizes the oil.

Accepted Answer

Fertilizer contains nutrients that promote the growth of microorganisms, such as bacteria, that can break down the oil into harmless byproducts. This process is known as biodegradation and is a common method for cleaning up oil spills.

Question 16

Why is chlamydia much more common than syphilis?
A)Chlamydia is spread via droplet inhalation.
B)Syphilis can penetrate a condom whereas chlamydia cannot.
C)Many chlamydia infections are asymptomatic.
D)Chlamydia is viral,and viral diseases spread much quicker.
E)Chlamydia is resistant to most antibiotics.

Accepted Answer

Many chlamydia infections are asymptomatic, meaning that people may not know they are infected and can unknowingly transmit the infection to others. This is not the case with syphilis, which typically presents with noticeable symptoms such as sores or rashes.

Question 17

Are transformation and transduction the same process?
A)Yes; they both involve the acquisition of viral genes.
B)No; only transformation passes on genes for pathogenicity.
C)Yes; both processes transfer specific gene products to a specific bacterium.
D)No; although both involve gene transfer the sources of the genetic material differ.

Accepted Answer

Transformation and transduction are not the same process. Transformation involves the uptake of naked DNA from the extracellular environment, while transduction involves the transfer of genetic material via a bacteriophage (a virus that infects bacteria). Although both processes involve gene transfer, the sources of the genetic material differ.

Question 18

Why are children often told that if they eat too much candy their teeth will fall out?
A)Sugar attacks tooth enamel.
B)Sugars gradually replace the tooth enamel.
C)Bacteria use the sugar to make ATP.This fermentation process produces acids as a by-product.
D)Bacteria secrete acids in order to digest the sugar molecules.

Accepted Answer

The answer of Why are children often told that if...

Question 19

Farmers often practice crop rotation to help enrich agricultural fields.Why are beans and other legumes often used in the rotations?
A)Beans fix nitrogen.
B)Bacteria in legume root nodules are nitrifiers.
C)Legumes enrich the soil by forming heterocysts.
D)Legumes remove toxins from the soil.
E)Less carbon dioxide.

Accepted Answer

The answer of Farmers often practice crop rotation to help...

Question 20

DNA replication and gene expression in archaeans more closely resemble eukaryotic cells than the same processes in bacteria.However both Bacteria and Archaea are prokaryotic.What does this suggest?
A)Eukaryotic cells are descended from modern Archaeans.
B)Bacterial cells are not related to Archaeans.
C)Eukaryotic cells shared a more recent common ancestor with Archaeans than with bacterial cells.
D)There must have been 2 origin events,one producing the bacteria and the other producing Archaeans and eukaryotic cells.

Accepted Answer

The fact that DNA replication and gene expression in archaeans more closely resemble eukaryotic cells than the same processes in bacteria suggests that eukaryotic cells shared a more recent common ancestor with archaeans than with bacterial cells, indicating the possibility of a single origin event for archaeans and eukaryotic cells.

Quiz 27: Prokaryotes

Early classification systems of the bacteria employed all of the following characteristics except

The fungus Penicillium produces a compound that blocks peptidoglycan assembly.Why is a fungus trying to kill bacteria?

If the label on a slide reads Gram-positive bacillus,what would a students expect to see?

The cells wall of bacteria Z contains high concentrations of phospholipids along with proteins and relatively low amounts of lipopolysaccharide.When bacteria Z is gram stained,it will most like be colored?

Genes abc and def have a high average cotransduction frequency.Genes abc and xyz have a very low average cotransduction frequency.What is the best explanation for this difference?

Many cells of the immune system have receptors that detect peptidoglycans and lipopolysaccharides.How do pathogenic bacteria avoid detection?

Phil has chronic ulcers,he has been taking acid blockers and drinking vast amounts of liquid antacids.These help relieve the symptoms but he still suffers from ulcers.What would be the best course of action to treat the source of his ulcers?

Vibrio cholerae produces a toxin that destroys the intestinal epithelium.This leads to massive diarrhea; the diarrhea can kill the human via dehydration but helps the bacteria spread and colonize other humans.What is this relationship?

Irregular dental hygiene and a high sugar diet may led to tooth decay.Why?

Amanda is a microbiologist who studies the pathogenic bacteria Streptococcus pyogenes.In what ways are they (Amanda and the bacteria) similar?

Bacteria typically use binary fission,but under special circumstances sexual reproduction is possible via horizontal gene transfer.

Current classification of prokaryotes is based on

A researcher observed a reduction in the number of chromosomes during cell division for a microbe,he concludes that the microbe must be

A high concentration of chlorophyll imbedded in the plasma membrane fold of a newly discovered species of bacteria suggests a:

An oil spill occurs,and Greg (a member of the clean up team) suggests adding fertilizer.Why is he making this suggestion?

Why is chlamydia much more common than syphilis?

Are transformation and transduction the same process?

Why are children often told that if they eat too much candy their teeth will fall out?

Farmers often practice crop rotation to help enrich agricultural fields.Why are beans and other legumes often used in the rotations?

DNA replication and gene expression in archaeans more closely resemble eukaryotic cells than the same processes in bacteria.However both Bacteria and Archaea are prokaryotic.What does this suggest?