Micro Exam

28 and 14

consumers

Organisms that eat primary producers or other consumers

Decomposers

Organisms that digest the remains of primary producers and consumers

Ecology

Study of interactions of organisms with one another and their environment

Eutrophic

a nutrient-rich environment that supports the excessive growth of algae and other organisms

Hydrothermal vents

undersea geysers that spew out mineral-laden hot water

Hypoxic

an environment very low in dissolved O2

Microbial mat

A type of microbial community characterized by distinct layers of different groups of microbes that together make up a thick, dense, highly organized structure

Nitrogen fixation

conversion of nitrogen gas to ammonia

Oligotrophic

a nutrient-poor environment

Primary producers

organisms that convert CO2 into organic compounds, sustaining other forms of life

Rhizosphere

Zone around plant roots containing organic materials secreted by the roots

Microbes that are able to grow in dilute aqueous solutions are common in nature and often grow in

biofilms

A microbial species can compete with one another by

competitively excluding others or producing compounds that inhibit others

Metagenomics

the cultivation-independent study of microbial communities or their members by analyzing the total microbial genomes in a sample taken directly from the environment

Ocean waters are generally _____ and ____

oligotrophic, aerobic

Oligotrophic lakes may have ______ layers due to ______

anaerobic, thermal stratification

Shallow, turbulent streams are generally ____

aerobic

Soil represents an environment that can change ____ and ____

abruptly, dramatically

Environmental conditions affect the ____ and _____ of the soil microbiome

density, composition

The concentration of microbes in the rhizosphere is generally much ____ than that in the surrounding soil

higher

carbon fixation

process of converting inorganic carbon (CO2) to an organic form

Oligotrophic waters are nutrient ____ while eutrophic waters are nutrient ___

poor, rich

excessive growth of aerobic heterotrophs in water may cause an aquatic environment to become ___

hypoxic

As consumers and decomposers degrade organic materials, CO2 is released during _____ and some ____

respiration, fermentation

steps of the nitrogen cycle:

nitrogen fixation, ammonification, nitrification, denitrification, anammox

nitrogen fixation

process that converts nitrogen gas to ammonia

ammonification

the decomposition process that converts organic nitrogen into ammonia (NH3)

nitrification

the oxidation of ammonium (NH4+) to nitrate (NO3-)

denitrification

the microbial reduction of nitrate to gaseous nitrogen during anaerobic respiration

anammox

anoxic ammonium oxidation

sulfur _____ and sulfur ____ are steps of the sulfur cycle that depend on the activities of prokaryotes

reduction, oxidation

most plants and microorganisms take up _______ and incorporate it into biomass

orthophosphate

Elements recycled by microorgs

Iron, calcium, zinc, manganese, cobalt, and mercury

Photosynthetic organisms convert the energy of light to chemical bond energy in the form of _____ compounds

organic

chemolithoautotrophs harvest energy from reduced ____ chemicals

inorganic

mycorrhiza

symbiotic relationship between certain fungi and the roots of plants

mycorrhizas help plants take up ____ and other substances from soil, in turn the fungal partners gain nutrients for their own growth

phosphorus

Endomycorrhizal fungi

penetrate the root cell wall

Ectomycorrhizal fungi

grow around root cells

Rhizobia

group of gram negative nitrogen fixing bacteria that form symbiotic relationships with legumes (clover, soybeans, etc)

Rhizobia reside as nitrogen fixing ______ in ____ on legume roots

endosymbionts, nodules

nodules

specialized organs on legume roots within which rhizobia fix nitrogen

____ species of rhizobia fix nitrogen in alder

Frankia

a species of cyanobacteria fix nitrogen in specialized sacs in the leaves of the _____ fern

Azolla

in order to eat grass and other plant material, herbivores rely on a community of microbes that inhabit a specialized digestive compartment, usually a ____ or ___

rumen, cecum

first line defenses prevent microbial entry into the body’s tissues, sensor systems detect ____, and effector mechanisms _____ and _____ invaders

invasion, destroy, remove

the skin has two main layers:

the epidermis and dermis

mucous membranes are constantly bathed with ____ and other ____ to help wash microbes from the surfaces

mucus, secretions

lysozymes, peroxidases, lactoferrin, host defense peptides all:

inhibit or kill microorganisms

lysozymes

enzyme that degrades peptidoglycan of the bacterial cell wall

peroxidases

enzymes found in neutrophil granules, saliva, and milk that react with hydrogen peroxide to form antimicrobial compounds

lactoferrin

iron binding protein found in leukocytes, saliva, mucus, milk and other substances
helps defend the body by depriving microorganisms of iron

host defense peptides

defensins and other short amino acid chains that have antimicrobial or other protective properties
aka: antimicrobial peptides

normal microbiota

group of microorganisms that routinely colonize body surfaces and the gut of a given type of host but do not normally cause disease

members of the normal microbiota competitively exclude _____ and stimulate _____

pathogens, host defenses

granulocytes include

neutrophils, eosinophils, basophils, and mast cells

granulocytes

white blood cells characterized by the presence of prominent granules

neutrophils

major type of phagocytic cell in blood, neutrophils quickly move to infected tissues where they destroy invading microbes

eosinophil

type of leukocyte important in ridding the body of parasitic worms
also involved in some allergic reactions

basophils

type of leukocyte involved in inflammation and allergic reactions

mast cells

tissue cells similar in appearance and function to basophils of the blood
involved in inflammation and allergic reactions

monocytes

mononuclear phagocytes of the blood

part of the mononuclear phagocyte system (MPS) of professional phagocytes

macrophages

type of phagocytic cell that resides in tissues and has multiple roles, including scavenging debris, serving an a sentinel cell, and producing pro-inflammatory cytokines

monocytes circulate in _____, macrophages are in _______

blood, tissues

dendritic cells

antigen-presenting cells that play an essential role in the activation of naive T cells

dendritic cells develop from _____ (but some can have other origins)

monocytes

lymphocytes include

B cells, T cells, and innate lymphoid cells (ILCs)

lymphocytes are involved in

adaptive immunity

lymphocyte

group of white blood cells (leukocytes) involved in adaptive immunity

B cells

type of lymphocyte programmed to make antibodies

T cells

type of lymphocyte that matures in the thymus

innate lymphoid cells (ILCs)

group of lymphocytes that lack specificity in their mechanism of antigen recognition
includes natural killer (NK) cells

surface receptors

proteins in the membrane of a cell to which certain signal molecules bind

allow the cell to sense and respond to external signals

Denitrification

Reduces nitrate through a series of steps to nitrogen gas

Nitrogen fixation

Removes N₂ from the air with the primary product of NH₄⁺

Ammonification

Deamination of organic compounds yielding NH₄⁺

Nitrification

The oxidation of NH₄⁺ to NO₂⁻ and NO₃⁻

Which of the following factors can influence the ability of an organism to compete successfully for a habitat?

1. The rate at which the organism multiplies.

2. The ability of the organism to withstand adverse environmental conditions.

3. The ability of the organism to inhibit other microbes by producing antimicrobial compounds.

   
   

layers that would exist in a microbial mat in the correct order from top to bottom layer.

1. A green layer filled with photosynthetic cyanobacteria.

2. A reddish-pink layer consisting of purple sulfur bacteria.

3. A black layer filled with sulfate-reducing obligate anaerobes.

   
   

Microenvironment

Environment immediately surrounding an individual microbe

Ecosystem

Community of organisms and the non-living environment with which they interact

Ecology

Study of the interaction of organisms with each other and their environment

Community

All of the different organisms in a location

Biosphere

All of the ecosystems on Earth

Population

Organisms of the same type in a given environment

Ecological niche

Role of an organism in a particular ecosystem

the ways in which microbes are identified and classified in the laboratory:

16S rRNA sequencing
18S rRNA sequencing
Deducing amino acid sequences in ribosomal proteins

Identify what researchers can learn about a microbial community using metagenomics.

They can identify the genes that are present in a microbial community.
Knowing what genes are present in a community may facilitate identification of microbes.  
They may learn what role a particular microbe has in the environment.

the steps involved in creating an aquatic dead zone in the correct sequence:

1. River water carrying nutrients acquired from urban, agricultural and industrial areas flows into the sea.

2. Algae and cyanobacteria (primary producers) use excess phosphates and nitrates for growth, multiplying rapidly.

3. Heterotrophic microbes metabolize the organic compounds made by primary producers, and consume dissolved O₂.

4. Depletion of dissolved O₂ results in large hypoxic zone, causing animals to flee or die.

TRUE statements regarding microbes in soil.

Dry soils favor the formation of bacterial endospores.
Acidic soil suppresses bacterial growth, allowing fungi to flourish.
Algae and protozoa tend to grow near the soil surface rather than at deeper levels.

soil organism Azospirillum species

fixes nitrogen

soil organism Bacillus species

forms endospores

soil organism Streptomyces species

produces antibiotics

carbon fixation

Process that converts CO₂ to an organic form by living organisms

Ammonification

Decomposition process that converts organic nitrogen into NH₃

Denitrification

Process that reduces NO₃⁻, converting it to gaseous forms such as N₂O and N₂

Sulfur oxidation

Oxidation of H₂S and SO as energy sources

Anammox

Anaerobic oxidation of NH₄⁺ as an energy source

Nitrogen fixation

Reduction of N₂ to form NH₃ for incorporation into cellular material

Methanogenesis

Oxidation of hydrogen gas, using CO₂ as a terminal electron acceptor, and generating CH₄