Make Connections: Bacterial Conjugation and Binary Fission

Which of the following statements about phylogenetic trees is true?

A paraphyletic group consists of a common ancestor and some of its descendants.

Which of the following statements best represents the effectiveness of teixobactin and vancomycin in reducing the number of MRSA colonies relative to the control?

Both antibiotics substantially reduced the number of MRSA colonies compared to the control. Further, at both the 1 mg/kg and 5 mg/kg doses, there was no significant difference in the number of MRSA colonies, suggesting that teixobactin and vancomycin are equally effective at controlling MRSA.

Bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. They use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. These bacteria are __________.

Chemoautotrophs use inorganic molecules (in redox reactions) for energy, and carbon dioxide for carbon.

The prokaryotic cells that were the first to add significant quantities of oxygen to Earth's atmosphere are classified as _____.

Cyanobacteria are aerobic photosynthesizers.

The prokaryotic cells that built stromatolites are classified as _____.

Cyanobacteria built stromatolites.

Which of the following statements about endotoxins is correct?

Endotoxins are released only when bacteria die and their cell walls break down. Endotoxins are components of the outer membrane of gram-negative bacteria.

According to this phylogenetic tree, which of these pairs of prokaryotic subgroups share the most recent common ancestor?

Euryarchaeota ... Crenarchaeota The branching pattern of the phylogenetic tree indicates that, of the pairs listed here, this is the one whose members are the most closely related.

Drag each phrase into the appropriate bin depending on whether it applies to an F+ cell, an Hfr cell, or an F- cell. (Remember that we are only considering conjugation involving the F factor here, and not other mechanisms for transferring genetic material.)

F+ cell: -Carries the F factor in a plasmid. -May donate a plasmid to another cell. *** Hfr cell: -Carries the F factor in its circular chromosome. -May donate genes from its chromosome to another cell. *** F- cell: -May become F+ after conjugation with an F+ cell. -May become recombinant after conjugation with an Hfr cell. -May receive genetic material, but cannot donate genetic material.

Which molecule did Carl Woese study to produce his tree of life?

Ribosomal RNA

Based on your results in Part A, which of the following statements most appropriately reflects the relative effectiveness of the vancomycin treatment, teixobactin treatment, and the control?

Teixobactin reduced the number of MRSA colonies about as effectively as did vancomycin relative to the control. Overall, the mean calculations demonstrate that teixobactin reduced the number of MRSA colonies about as effectively as did vancomycin. For example, at a dose of 1 mg/kg, teixobactin reduced the number of MRSA colonies by more than 10-fold compared to the control; vancomycin also reduced the number of MRSA colonies, but it did so by less than a 10-fold reduction. At a dose of 5 mg/kg, both vancomycin and teixobactin greatly reduced the number of MRSA colonies (roughly 10,000-fold) compared to the control.

Which of the following statements about obligate anaerobes is correct? a.) They live exclusively by cellular respiration or by anaerobic respiration. b.) They obtain energy by oxidizing ferrous ions. c.) They use O2 for cellular respiration and cannot grow without it. d.) They are poisoned by O2. e.) They will use O2 if it is present, but can obtain energy by fermentation if needed.

They are poisoned by O2. Some obligate anaerobes live exclusively by fermentation; others extract chemical energy by anaerobic respiration, in which substances other than O2 accept electrons at the "downhill" end of electron transport chains.

True or false? Data showing that the Bacteria were the first lineage to diverge from the common ancestor of all living organisms suggest that the Archaea and Eukarya are more closely related to each other than they are to the Bacteria.

True

Organisms that can cause nongonococcal urethritis are classified with _____.

chlamydias Chlamydia trachomatis causes nongonococcal urethritis.

The prokaryotic organisms most likely to be found living in salt ponds are the __________.

extreme halophiles These archaea, which are a type of extremophile, live in salty environments such as the Dead Sea.

The rapid reproduction and large population sizes of many bacterial populations mean that even a small mutation rate can lead to considerable BLANK.

genetic variation

In theory, the two daughter cells are BLANK each other and the parent cell.

genetically identical to

Streptococcus pyogenes is classified with _____.

gram-positive bacteria S. pyogenes attracts the violet Gram stain.

However, mistakes made during DNA replication sometimes result in BLANK, changes to the nucleotide sequence of DNA.

mutations

During binary fission, DNA replication begins at the BLANK and continues all the way around the circular chromosome.

origin of replication

When DNA replication is complete and the bacterium has reached twice its original size, the BLANK grows inward, dividing the parent cell into two daughter cells.

plasma membrane

The chemoheterotroph Proteus vulgaris is a rod-shaped bacterium classified with _____.

proteobacteria Proteus vulgaris is classified with proteobacteria.

Spiral-shaped bacteria are likely to be placed with _____.

spirochetes The name of these organisms provides the answer to the question.

An ecological relationship between organisms of different species that are in direct contact can best be described as __________.

symbiotic

Bioremediation is __________.

the use of organisms to remove pollutants from the environment

What characteristics were used to classify organisms before Woese's tree of life analysis?

Presence of a membrane-bound nucleus Before the tree of life analysis, organisms were classified as prokaryotes if they lacked a membrane-bound nucleus or eukaryotes if they possessed a membrane-bound nucleus.

Which group was not described in Woese's tree of life analysis? Prokarya Bacteria Archaea Eukarya

Prokarya was not one of the groups described in Woese's tree of life analysis.

What is lateral gene transfer?

Physical transfer of a gene from a species in one lineage to a species in another lineage.

How do binary fission and conjugation contribute to the spread of antibiotic resistance in bacteria? *** a.) Serious bacterial infections are treated with: b.) May not kill bacteria with genes for: c.) Kill sensitive bacteria or interfere with: d.) May be acquired from other cells through: e.) May result from: f.) Occurs during: g.) Combines DNA from different cells, resulting in: h.) Contribute(s) to:

a.) Antibiotics b.) Antibiotic Resitence c.) Binary Fission d.) Conjugation e.) Mutations f.) DNA Replication g.) Genetic Recombination h.) Genetic Variation

Binary fission is a form of BLANK because a single individual is the sole parent and passes copies of all its genes to its offspring.

asexual reproduction