Bio - Chapter 27, Bacteria and Archaea

Why is salt a good preservative to use for foods such as pork and fish?

Prokaryotic cells living in the food will shrink from their cell walls, impacting their ability to reproduce.

Gram-negative bacteria have __________ peptidoglycan than gram-positive cells, and their cell walls are __________ complex structurally

less...more

A gram-negative cell wall consists of __________.

a thin layer of peptidoglycan surrounded by an outer membrane containing lipopolysaccharides

Bacteria that __________ tend to have abundant internal membranes.

are photosynthetic

Bacterial flagella have a very complex structure composed of 42 distinct proteins. What is the most likely explanation for the evolution of these complex structures?

exaptation

The bacteria that cause tetanus can be killed only by prolonged heating at temperatures considerably above boiling. This suggests that these bacteria...

produce endospores

Plasmids:

Replicate independently of the main chromosome, can be involved in transfer of genetic material between prokaryotic cells, are transferred from one bacterium to another by conjugation, often contain antibiotic resistance genes.

How is it possible that as many as 9 million mutations can arise each day in the population of E. coli inhabiting one human?

A large population size and a rapid reproduction rate combine to produce many mutations without a particularly high mutation rate.

In the absence of meiosis and sexual reproduction, what general process allows genetic recombination among prokaryotes?

horizontal gene transfer

horizontal gene transfer

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms.

Which of the following statements about transformation is true?

It can be facilitated by cell-surface proteins that recognize compatible DNA.

An F+ bacterial cell...

acts as a donor during conjugation

Conjugation

A temporary union of two organisms for the purpose of DNA transfer.

Which of the following is/are true about R plasmids?

They can be transferred from one bacterium to another via conjugation, and they can carry several resistance genes.

Organisms that use light for their energy source and CO2 for their carbon source are called...

photoautotrophs

In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth, consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the organisms would be most likely to survive?

chemoheterotrophic bacteria

The Desulfovibrio bacterium breaks down organic matter (which it must have) and uses sulfate (not oxygen) as an electron acceptor. As a result, it produces hydrogen sulfide (H2S), accounting for the "rotten egg" smell of swamp muck. Oxygen is a deadly poison to Desulfovibrio. We would call Desulfovibrio a(n)

obligate anaerobic chemoheterotroph

Substances required by typical nitrogen-fixing cyanobacteria?

carbon dioxide, nitrogen, water, light, and some minerals

What is the role of heterocysts in a cyanobacterial filament?

They carry out only nitrogen fixation.

Biofilms are an example of...

metabolic cooperation among prokaryotic species

Portions of the genomes of certain prokaryotic species are very similar to portions of the genomes of distantly related prokaryotes. The process that most likely accounts for this genetic similarity is

horizontal gene transfer

Which subgroup of proteobacteria contains many species that are closely associated with eukaryotic hosts in mutualistic or parasitic relationships?

alpha

Which subgroup of proteobacteria contains many species that are predators of other bacteria?

delta

Which group of bacteria is unusual in that they lack peptidoglycan in their cell walls?

chlamydias

Which of the following is a difference between bacteria and archaea?

They have different chemicals in their cell membranes and cell walls.

Cyanobacteria

They are the only prokaryotes that perform plantlike, oxygenic photosynthesis, nitrogen-fixing cyanobacteria are the most self-sufficient of all organisms, some are single cells, whereas others live in filamentous colonies, some species may carry on nitrogen fixation.

Prokaryotes found inhabiting the Great Salt Lake would be...

Extreme halophiles (salt-loving prokaryotes)

Which of the following groups of prokaryotes is classified as a member of the domain Archaea?

Methanogens

Which clade of archaea includes most of the extreme thermophiles?

Crenarchaeota

Prokaryotes are completely indispensable to which chemical cycle?

Nitrogen

A type of ecological relationship called __________ involves one organism living at the expense of another organism.

Parasitism

Which example below is a correct statement about Bacteroides thetaiotaomicron, a bacterium that lives in the human intestines?

The bacteria have a mutualistic relationship with the human body.

Ticks that live on deer and field mice are responsible for spreading the bacterium __________, which causes __________.

Borrelia burgdorferi ... Lyme disease

Which statement is true regarding cholera?

Its symptoms are caused by an exotoxin that stimulates intestinal cells to release chloride ions into the gut

Scientists hypothesize that the O157:H7 strain of E. coli is so different from the K-12 strain because of

horizontal gene transfer over many years, most likely through the action of bacteriophages

Which statement about prokaryotes is true?

Prokaryotes are widely used for bioremediation.