Lesson 7 Flashcards
(30 cards)
What is biological nitrogen fixation?
microbes convert nitrogen into a form that can be used by other organisms
What does Bergy’s Manual categorize bacteria into taxa based on?
Bergy’s Manual categorizes bacteria into taxa based on rRNA sequence
What are some of the identification characteristics used by Bergy’s Manual?
cell wall composition, cellular morphology, oxygen requirements, nutritional properties
Bacteria are essential for ?
Bacteria are essential for life on earth.
Why do we need Nitrogen?
Nitrogen is used by living organisms to produce amino acids, proteins and nucleic acids.
Gaseous Nitrogen (N2) is a gas that exists in the atmosphere as the largest reservoir of Nitrogen.
Organisms cannot use nitrogen in what form?
N2, gaseous nitrogen
Name the two solid forms of nitrogen which plants use.
Ammonia (NH3) and Nitrate Ions (NO3-)
How do animals get their nitrogen?
plants they eat
animals they eat that have eaten plants
Four processes that participate of the cycling of nitrogen.
Nitrogen Fixation, Decay, Nitrification, Denitrification
Nitrogen fixation, decay, and nitrification are parts of the Nitrogen Cycle which do what?
removes nitrogen from the atmosphere, and passes through the ecosystem
What does the denitrification process of the nitrogen cycle do?
replenishes the atmosphere
Azopspirillium: tell me about the organism and what it does.
soil bacteria, with roots of tropical grasses.
fixation by enzyme, nitrogenase.
N2 converts to Ammonia
Rhizobium: tell me about the organism and what it does.
infects roots of leguminous (pea/bean family)
attach to root hair, form root nodules for nitrogen fixation
In what form does decay return nitrogen to the soil?
decomposing animal remains
animal wastes return organic nitrogen to the soil as ammonia
What are decomposers?
bacteria that live in the soil and break down dead decaying organisms, and their wastes
Nitrosomonas
convert ammonia to nitrites
nitrifying bacteria which make nitrogen available to roots of plants
Nitrobacter
convert nitrites to nitrates
nitrfying bacteria which make nitrogen available to roots of plants
What is Nitrification?
process by which ammonia is converted to nitrites, then nitrates
What is Denitrification? What bacteria is involved in denitrification?
reducing nitrates to nitrogen gas, replenishing the atmosphere
use nitrates as an alternative to oxygen, final e- acceptor
Pseudomondas
Azospirillium
soil bacteria, grows w/ roots of tropical grasses
fixation by enzyme Nitrogenase
N2 converts to Ammonia
Rhizobium
infects root of leguminous plant family (pea & bean) through nodules
Rickettsia
rod shaped, gram negative, obligate intracellular parasite
transmitted to humans via insect/tick bite, releases endotoxins, enters host by phagocytosis
responsible for spotted fever disease
Erwina
plant pathogen
Rickettsia is responsible for spotted fever disease, how does it cause this disease?
releases endotoxin, damage permeability of capillaries
