Chapter 27: Bacteria and Archaea(3) Flashcards
What are the diverse nutritional and metabolic adaptations that have evolved in Prokaryotes?
- Phototrophs obtain energy from light
– Chemotrophs obtain energy from chemicals
– Autotrophs use CO2 as a carbon source
– Heterotrophs require an organic nutrient to make organic compounds e.g. glucose
Explain prokaryotic metabolism concerning O2.
– Obligate aerobes require O2 for cellular respiration
– Obligate anaerobes are poisoned by O2 and use fermentation or anaerobic respiration
– Facultative anaerobes can survive with or without O2
Nitrogen is essential for the production of _____ and _______.
Nitrogen is essential for the production of amino acids and nucleic acids
How do some prokaryotes metabolize nitrogen?
In nitrogen fixation, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3).
Explain the metabolic cooperation involved in cyanobacterium Anabaena.
In the cyanobacterium Anabaena,
– photosynthetic cells
– specialized nitrogen-fixing cells called heterocysts exchange metabolic products
What are the major groups of bacteria?
- Proteobacteria
- Chlamydias
- Spirochetes
- Cyanobacteria
- Gram-positive bacteria
(PiCS Come on instGRAM)
Metabolic cooperation between different prokaryotic species often occurs in surface-coating colonies known as
_________.
Metabolic cooperation between different prokaryotic species often occurs in surface-coating colonies known as biofilms
Explain the traits of proteobacteria and its sub-groups.
Proteobacteria
* These gram-negative bacteria include
– photoautotrophs,
– chemoautotrophs, and
– heterotrophs
- Can be aerobic or anaerobic
SUB-GROUPS:-
Alpha
Beta
Gamma
Delta
Epsilon
What are the characteristics of alpha-proteobacteria?
Alpha-Proteobacteria
* Many species of alpha-proteobacteria are closely associated with eukaryotic hosts
- It is hypothesized that mitochondria evolved from aerobic alpha-proteobacteria through endosymbiosis.
(A symbiotic relationship where one organism lives inside the other is known as endosymbiosis)
Give two examples of alpha-proteobacteria.
- Rhizobium, which forms root nodules in legumes and fixes atmospheric N2
– Agrobacterium, which produces tumors in plants and is used in genetic engineering
What are the characteristics of beta-proteobacteria?
- Soil bacteria that play an important role in nitrogen recycling by oxidizing ammonia to nitrate
- ex: Nitrosomonas
What are the characteristics of gamma-proteobacteria?
- This subgroup’s auto-trophic members include sulfur bacteria which obtain energy by oxidizing H2S, producing sulphur as a waste product
- Heterotrophic members of the group also include pathogens such as Legionella, Salmonella, and Vibrio cholerae
What are the characteristics of chlamydias?
- These are parasites that live within animal cells
- Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission
What are the characteristics of spirochetes?
- These bacteria are helical heterotrophs
- Some are parasites, including
– Treponema pallidum, which causes syphilis, and
– Borrelia burgdorferi, which causes Lyme disease
What are the characteristics of cyanobacteria?
- These are photoautotrophs that generate O2
- Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis
What are the types of gram-positive bacteria?
Gram-positive bacteria include
– Actinomycetes, which decompose soil
– Bacillus anthracis, the cause of anthrax
– Clostridium botulinum, the cause of botulism
What are the smallest known cells (gram-positive bacteria)?
Mycoplasmas
What are the archaea that live in extreme places called and what are the types?
Some archaea live in extreme environments and are called extremophiles
- Extreme halophiles live in highly
saline environments - Extreme thermophiles thrive in
very hot environments
What are methanogens?
Methanogens live in swamps and marshes and produce methane as a waste product
– Methanogens are strict anaerobes and are poisoned by O2
What are the crucial roles played by prokaryotes in the biosphere?
- Prokaryotes play a major role in the recycling of chemical elements between living and nonliving components of ecosystems.
- Chemoheterotrophic prokaryotes function as decomposers, breaking down dead organisms and waste products
What is the impact of bacteria on soil nutrient availability?
- Prokaryotes can sometimes increase the availability of nitrogen, phosphorus, and potassium for plant growth
- In other instances, they can “immobilize” or decrease the availability of key plant nutrients
