Chapter 28: Bacteria and Archaea Flashcards Preview

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Flashcards in Chapter 28: Bacteria and Archaea Deck (34):
1

Discuss the biological impact, abundance and habitat diversity of bacteria and archaea collectively.

Only 5000 species of bacteria and archaea have been named and described, but biologists are virtually certain that millions exist.

2

On a blank sheet of paper draw a large version of Figure 28.1, a phylogenetic tree of the three domains of life. Using information from Table 28.1, add labelled marks to your tree indicating where the following traits evolved: circular chromosome, linear chromosome, membranes with straight fatty acids (MSFA’s), membranes with branched fatty acids (MBFA’s), cell wall with peptidoglycan (CW+P), cell wall without peptidoglycan (CW-P), DNA with histones, nuclear envelope.

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3

Use your textbook or another resource to characterize the size differences between the three domains of life.

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4

Was the common ancestor of all species alive today a eukaryote, a bacterial prokaryote, or an archaeal prokaryote? Explain your reasoning.

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5

Some bacteria cause diseases of multicellular eukaryotes. List the four criteria Koch postulated necessary to establish a causative link between a particular microorganism and a specific disease

  1. The microbe must be present in individuals suffering from the disease and absent from healthy individuals.
  2. The organism must be isolated and grown in a pure culture away from the host organism.
  3. If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear.
  4. The organism should be isolated from the diseased experimental animal, again grown in pure culture, and demonstrated to be the same as the original organism.

6

What are antibiotics and where do we source them?

soil bacteria

Bacillus brevis

7

Relate the niche concept to enrichment cultures used to grow bacteria in laboratories

  • cells are sampled from the environment and grown under specific conditions temperature, lighting, substrate, types of available food, etc.
  • Cells that thrive under the specified conditions will increase in numbers enough to be isolated and studied in detail.

8

Describe how direct sequencing is used to identify bacteria and archaea that have never been isolated or seen.

Direct sequencing is a new technique for documenting the presence of bacteria and archaea that have never been seen because they cannot be grown in pure culture. is based on identifying phylogenetic species

9

Use a table to summarize the morphological diversity of bacteria and archaea.

extensive morphological diversity in terms of size, shape, and motility. Bacteria range in shape from filaments, spheres, rods, and chains to spirals. Bacteria have a range of modes of motility.

10

Explain how Gram staining is used to broadly categorize bacterial species based on their cell wall structure.

2 general types of cell wall exist that can be distinguished by treatment with a dye called the Gram stain.

  1. Gram-positive cells have a cell wall containing an extensive amount of a carbohydrate called peptidoglycan. (which look purple under a microscope) retain Gram stain better than
  2. Gram-negative cells (which look pink).  have a cell wall with two components, a thin layer containing peptidoglycan and an outer phospholipid bilayer.

11

Use a table to summarize the metabolic diversity of bacteria and archaea.

  • all require chemical energy - ATP & carbon compounds
  • Must use one of three sources of energy: light, organic molecules, or inorganic molecules.
  • Autotrophs manufacture their own carbon-containing compounds.
  • Heterotrophs live by consuming them

12

It can be argued that oxygen is toxic to life. What was the oxygen revolution and what is a major advantage for organisms that evolved the capacity to utilize oxygen?

Oxygen is highly electronegative and so is an efficient electron acceptor. Much more energy is released as electrons move through ETCs with oxygen as the ultimate acceptor than is released with other acceptor substances.

13

Explain the significance of certain bacteria and archaea to the ecological cycling of nitrogen.

The nitrite (NO2) that some bacteria produce as a by-product of respiration does not build up in the environment but rather is used as an electron acceptor by other species and converted to molecular nitrate (NO3), which in turn is converted to molecular nitrogen (N2) by yet another suite of bacterial and archaeal species

14

Explain how human dependence on some crop plants that do not form symbiotic associations with nitrogen-fixing bacteria has led to a serious pollution problem in aquatic ecosystems.

The widespread use of ammonia fertilizers is causing serious pollution. When ammonia is added to the soil, much of it is used by bacteria as food, which then release nitrite (NO2–) or nitrate (NO3–). Nitrates cause pollution in aquatic environments. In an aquatic ecosystem, nitrates can decrease the oxygen content, causing anaerobic “dead zones” to develop.

15

Read Canadian Research 28.1 Is There a Universal Tree of Life on pages 563-564. Use a description of lateral gene transfer in bacteria and archaea to argue why prokaryotic genomes are chimeras.

lateral gene transfer between prokaryotic cells is common, up to a third of genomic variation within prokaryotic species may be due to gene transfer and gene loss

chimeras—containing genes obtained from many sources other than their direct ancestors

16

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Firmicutes

Firmicutes

  • Gram positives and most are rod shaped or spherical.
  • metabolically diverse.
  • important components of soil.
  • Some species in this group cause diseases, yet we use some to ferment milk into yogurt.

17

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Spirochaetes

Spirochaeles (spirochetes) are distinguished by their corkscrew shape and unusual flagella.

  • Most spirochetes produce ATP via fermentation. 
  • common in aquatic habitats.
  • Spirochetes cause the diseases syphilis and Lyme disease

18

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Actinobacteria

Actinobacteria

  • Gram positive
  • shape varies from rods to filaments
  • soil-dwelling species are found as chains of cells that form extensive branching filaments called mycelia.
  • Many species heterotrophs.
  • Some species live as decomposers in soil;
  • some live in association with plant roots and fix nitrogen.
  • Tuberculosis and leprosy are caused by members of this group. Species from the genus Streptomyces produce over 500 distinct antibiotics.

19

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Chlamydiae

Chlamydiae

  • spherical and very tiny.
  • endosymbionts—they live as parasites inside animal cells and get almost all of their nutrition from their hosts.
  • cause blindness and urogenital tract infections in humans.

20

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Cyanobacteria

Cyanobacteria were formerly known as “blue-green algae.”

  • They are found as independent cells, chains, or colonies.
  • All perform oxygenic photosynthesis
  • produce oxygen, nitrogen, and organic compounds that feed other organisms in aquatic environments.

21

Today at least sixteen phyla of bacteria are recognized. For each of the six bacterial lineages highlighted in our textbook, list one or two human or ecological impacts. Proteobacteria

Proteobacteria form five major subgroups and are very diverse in morphology and metabolism.

  • Some proteobacteria can form colonies, which can produce a structure called a fruiting body.
  • Pathogenic proteobacteria cause Legionnaire’s disease, cholera, dysentery, and gonorrhea.

22

Explain why the Archaea are misnamed

Domain Archaea is composed of at least three major lineages: the Crenarchaeota, Euryarchaeota, and Korarchaeota. These three groups are highly differentiated at the DNA sequence level, but almost nothing is know about the Korarchaeota .

23

Although future research is likely to reveal multiple phyla of Archaea, our textbook explains there are presently three major phyla recognized. For the two phyla on page 568, list one or two human, or ecological impacts. Crenarchaeota

 Crenarchaeota

  • shaped like filaments, rods, discs, or spheres.
  • metabolically diverse, although some make ATP only through fermentation.
  • They are the only life-forms present in certain extreme environments, such as high-pressure, very hot, cold, or acidic environments.

24

Although future research is likely to reveal multiple phyla of Archaea, our textbook explains there are presently three major phyla recognized. For the two phyla on page 568, list one or two human, or ecological impacts. Euryarchaeota

The Euryarchaeota come in many shapes.

  • They live in every conceivable habitat, including high-salt, high-pH, and low-pH environments.
  • They include the methanogens, which contribute about 2 billion tons of methane to the atmosphere each year.

25

________ use light energy to promote electrons to the top of electron transport chains. ATP is then produced by photophosphorylation.

Phototrophs

26

____________ oxidize organic molecules with high potential energy. ATP may be produced by cellular respiration using sugars as electron donors or by fermentation pathways.

Chemoorganotrophs

27

____________ oxidize inorganic molecules with high potential energy. ATP is produced by cellular respiration with inorganic compounds serving as the electron donor.

Chemolithotrophs

28

________________, a lineage of photosynthetic bacteria, were the first organisms to perform oxygenic (oxygen-producing) photosynthesis.

Cyanobacteria

29

____________ can be shaped like filaments, rods, discs, or spheres.

Crenarchaeota

30

Domain Archaea is composed of at least three major lineages:

the Crenarchaeota, Euryarchaeota, and Korarchaeota.

31

____________ were formerly known as “blue-green algae.” They are found as independent cells, chains, or colonies.

Cyanobacteria

32

__________________ are distinguished by their corkscrew shape and unusual flagella.

Spirochaeles (spirochetes)

33

_____________ are Gram positives and most are rod shaped or spherical.

Firmicutes

34