Terms
1.1 Microorganisms, tiny titans of the earth
Microorganisms life forms too small to be seen by the unaided human eye
Microbial communities Two or more populations of cells that coexist and interact
in a habitat
Culture collection of cells that have been grown in or on a nutrient
medium
Medium Liquid or solid nutrient mixture that contains all of the
nutrients required for microorganisms to grow
Growth The increase in cell number as a result of cell division
Colony Millions of cells grown and divided by a single cell
1.2 Structure and activities of microbial cells
Cytoplasmic membrane Permeability barrier that separates the inside of the cell
from the outside
Cytoplasm Inside of the cell, mixture of macromolecules, small
organic molecules, various inorganic ions and ribosomes
Macromolecules proteins, lipids, nucleic acids, polysaccharides
Ribosomes Structures responsible for protein synthesis, in all cells
Cell wall Lends structural strength to a cell
Prokaryotic Bacteria and archaea, few internal structures, lack a
nucleus and organelles
Eukaryotic Eukarya, plants and animals, algae, protozoa, fungi,
contain organelles
Organelles Membrane-enclosed cytoplasmic structures, include
nucleus (DNA), mitochondria, chloroplasts, specialize cell
with energy
Genome Complement of all genes in a cell
Nucleus In eukaryotic cells, DNA present in several linear molecules
Nucleoid In prokaryotes, mass of chromosomes
Plasmids DNA distinct from that of the chromosome, in prokaryotes
Metabolism Taking up nutrients from the environment and
transforming them into new cell materials and waste
products
Enzymes Proteins that have catalytic activity, required to carry out
reactions that supply the energy and precursors necessary
for the biosynthesis of all cell components
Transcription Information on DNA is copied into RNA
Translation Process whereby the information on an RNA molecule is
used by a ribosomes to synthesize a protein
DNA replication Replication of the genome microbial growth
Motility Allows cells to relocate in response to environmental
conditions
Differentiation Results in the formation of modified cells specialized for
growth, dispersal or survival
Intercellular communication They are ‘aware’ of their neighbors and can respond
Horizontal gene transfer Prokaryotic cells can exchange genes with neighboring
cells, same or different species
Evolution Results when genes in a population of cells change in
sequence and frequency over time descent with
, modification
1.3 Microorganisms and the biosphere
Domains Three major lineages of microbial cell – bacteria, archaea,
and eukarya, 60 genes universally present in all domains
LUCA Last universal common ancestor, common ancestor of all
three domains
Extremophiles Their properties define the physiochemical limits to life,
thrive under extreme conditions
Microbial ecology Ways in which microorganisms affect animals, plants and
the entire global ecosystem
1.4 Impact of microorganisms on human society
Pathogens Cause infectious diseases
Nodules Bacteria convert N2 into NH3 through nitrogen fixation
Ammonia (NH3) Nitrogen source for plant growth, nutrient found in
fertilizer
Rumen Microbial ecosystem in which microbial communities
digest and ferment cellulose (major component of cell
walls)
Gut microbiome Microbial communities present in the animal
gastrointestinal tract
Biofilm Microbes that grow on submerged surfaces
Industrial microbiology Naturally occurring microorganisms are grown on a
massive scale to make large amounts of products at
relatively low cost
Biotechnology Employs genetically engineered microorganisms to
synthesize products of high value (insulin, human proteins)
usually on a small scale
Methanogens Archaea, metabolize anaerobic methane
Bioremediation Microorganisms are used to transform spilled oil, solvents,
pesticides, heavy metals and other toxic pollutants
clean up process
1.5 Light microscopy and the discovery of microorganisms
Antoni van Leeuwenhoek Constructed microscopes (light), first person to see
bacteria
Robert Hooke First book, first description of microorganisms
Magnifitcation The capacity of a microscope to enlarge an image
Resolution Ability to distinguish two adjacent objects as distinct and
separate
Numerical aperture Limit of resolution for a light microscope, light gathering
ability
Contrast Caused by differences between specimens and their
surroundings
1.6 Improving contrast in light microscopy
Staining Commonly used to visualize bacteria with bright-field
microscopy
Gram-stain Important differential straining method, differences in cell
wall structure
Differential stains Stains that render(geven) different kinds of cells different
colors
Gram-positive Purple violet
, Gram-negative Pink, decolorizes by ethanol
Phase-contrast microscopy Based in the principle that cells differ in refractive index
from their surroundings
Dark-field microscope Light does not pass through the specimen, only light that is
scattered when it hits the specimen can reach the lens,
better resolution
Fluorescence microscope Visualizes specimens that fluoresce, filters used cells
glow black in background
DAPI Can be used to visualize cells in their natural habitats (fm)
1.7 Imaging cells in three dimensions
Differential interference contrast A form of light microscopy that employs a polarizer in the
microscopy condenser to produce polarized light
Confocal scanning laser microscopy Computer controller microscope that couples a laser to a
fluorescence microscope several planes of focus in the
specimen (thick specimens)
1.8 Probing cell structure: electron microscopy
Transmission electron microscopy Is used to examine cells and cell structure at very high
magnification and resolution (wavelength of electron much
shorter than light wavelength affects resolution)
Negative staining TEM, intact cells or cell components that can be directly
observed
Scanning electron microscopy The specimen is coated with a thin film of a heavy metal
electron beam scans back and forth across the specimen
Aseptic technique A collection of practices that allow for the preparation and
maintenance of sterile nutrient media and solutions
Sterile Without the presence of living organisms
Pure cultures Contain cells form only a single type of microorganisms
and are of great value for the study of microorganisms
Enrichment culture techniques Allow for the isolation from nature of microbes having
particular metabolic characteristics, facilitate the discovery
of diverse microoganisms
1.9 Pasteur and spontaneous generation
Pasteur Proved that living organisms cannot arise from
spontaneousy nonliving matter , developed a number of
key vaccines for humans and other animals, work on
fermentation
Spontaneous generation Hypothesis that living organisms can originate from
nonliving matter
1.10 Koch, infectious diseases and pure cultures
Koch Postulates A set of criteria for proving that a given microorganism
causes a gives disease
1.13 Woese and the tree of life
rRNA The types of RNA found in the ribosome
Woese Sequence of rRNA molecules and the genes that encode
them could be used to infer evolutionary relationships
between organisms
Phylogenetic tree A diagram that depicts the evolutionary history of all cells
and clearly reveals the three domains
Phylogeny The evolutionary history of organisms
2.1 Cell morphology
1.1 Microorganisms, tiny titans of the earth
Microorganisms life forms too small to be seen by the unaided human eye
Microbial communities Two or more populations of cells that coexist and interact
in a habitat
Culture collection of cells that have been grown in or on a nutrient
medium
Medium Liquid or solid nutrient mixture that contains all of the
nutrients required for microorganisms to grow
Growth The increase in cell number as a result of cell division
Colony Millions of cells grown and divided by a single cell
1.2 Structure and activities of microbial cells
Cytoplasmic membrane Permeability barrier that separates the inside of the cell
from the outside
Cytoplasm Inside of the cell, mixture of macromolecules, small
organic molecules, various inorganic ions and ribosomes
Macromolecules proteins, lipids, nucleic acids, polysaccharides
Ribosomes Structures responsible for protein synthesis, in all cells
Cell wall Lends structural strength to a cell
Prokaryotic Bacteria and archaea, few internal structures, lack a
nucleus and organelles
Eukaryotic Eukarya, plants and animals, algae, protozoa, fungi,
contain organelles
Organelles Membrane-enclosed cytoplasmic structures, include
nucleus (DNA), mitochondria, chloroplasts, specialize cell
with energy
Genome Complement of all genes in a cell
Nucleus In eukaryotic cells, DNA present in several linear molecules
Nucleoid In prokaryotes, mass of chromosomes
Plasmids DNA distinct from that of the chromosome, in prokaryotes
Metabolism Taking up nutrients from the environment and
transforming them into new cell materials and waste
products
Enzymes Proteins that have catalytic activity, required to carry out
reactions that supply the energy and precursors necessary
for the biosynthesis of all cell components
Transcription Information on DNA is copied into RNA
Translation Process whereby the information on an RNA molecule is
used by a ribosomes to synthesize a protein
DNA replication Replication of the genome microbial growth
Motility Allows cells to relocate in response to environmental
conditions
Differentiation Results in the formation of modified cells specialized for
growth, dispersal or survival
Intercellular communication They are ‘aware’ of their neighbors and can respond
Horizontal gene transfer Prokaryotic cells can exchange genes with neighboring
cells, same or different species
Evolution Results when genes in a population of cells change in
sequence and frequency over time descent with
, modification
1.3 Microorganisms and the biosphere
Domains Three major lineages of microbial cell – bacteria, archaea,
and eukarya, 60 genes universally present in all domains
LUCA Last universal common ancestor, common ancestor of all
three domains
Extremophiles Their properties define the physiochemical limits to life,
thrive under extreme conditions
Microbial ecology Ways in which microorganisms affect animals, plants and
the entire global ecosystem
1.4 Impact of microorganisms on human society
Pathogens Cause infectious diseases
Nodules Bacteria convert N2 into NH3 through nitrogen fixation
Ammonia (NH3) Nitrogen source for plant growth, nutrient found in
fertilizer
Rumen Microbial ecosystem in which microbial communities
digest and ferment cellulose (major component of cell
walls)
Gut microbiome Microbial communities present in the animal
gastrointestinal tract
Biofilm Microbes that grow on submerged surfaces
Industrial microbiology Naturally occurring microorganisms are grown on a
massive scale to make large amounts of products at
relatively low cost
Biotechnology Employs genetically engineered microorganisms to
synthesize products of high value (insulin, human proteins)
usually on a small scale
Methanogens Archaea, metabolize anaerobic methane
Bioremediation Microorganisms are used to transform spilled oil, solvents,
pesticides, heavy metals and other toxic pollutants
clean up process
1.5 Light microscopy and the discovery of microorganisms
Antoni van Leeuwenhoek Constructed microscopes (light), first person to see
bacteria
Robert Hooke First book, first description of microorganisms
Magnifitcation The capacity of a microscope to enlarge an image
Resolution Ability to distinguish two adjacent objects as distinct and
separate
Numerical aperture Limit of resolution for a light microscope, light gathering
ability
Contrast Caused by differences between specimens and their
surroundings
1.6 Improving contrast in light microscopy
Staining Commonly used to visualize bacteria with bright-field
microscopy
Gram-stain Important differential straining method, differences in cell
wall structure
Differential stains Stains that render(geven) different kinds of cells different
colors
Gram-positive Purple violet
, Gram-negative Pink, decolorizes by ethanol
Phase-contrast microscopy Based in the principle that cells differ in refractive index
from their surroundings
Dark-field microscope Light does not pass through the specimen, only light that is
scattered when it hits the specimen can reach the lens,
better resolution
Fluorescence microscope Visualizes specimens that fluoresce, filters used cells
glow black in background
DAPI Can be used to visualize cells in their natural habitats (fm)
1.7 Imaging cells in three dimensions
Differential interference contrast A form of light microscopy that employs a polarizer in the
microscopy condenser to produce polarized light
Confocal scanning laser microscopy Computer controller microscope that couples a laser to a
fluorescence microscope several planes of focus in the
specimen (thick specimens)
1.8 Probing cell structure: electron microscopy
Transmission electron microscopy Is used to examine cells and cell structure at very high
magnification and resolution (wavelength of electron much
shorter than light wavelength affects resolution)
Negative staining TEM, intact cells or cell components that can be directly
observed
Scanning electron microscopy The specimen is coated with a thin film of a heavy metal
electron beam scans back and forth across the specimen
Aseptic technique A collection of practices that allow for the preparation and
maintenance of sterile nutrient media and solutions
Sterile Without the presence of living organisms
Pure cultures Contain cells form only a single type of microorganisms
and are of great value for the study of microorganisms
Enrichment culture techniques Allow for the isolation from nature of microbes having
particular metabolic characteristics, facilitate the discovery
of diverse microoganisms
1.9 Pasteur and spontaneous generation
Pasteur Proved that living organisms cannot arise from
spontaneousy nonliving matter , developed a number of
key vaccines for humans and other animals, work on
fermentation
Spontaneous generation Hypothesis that living organisms can originate from
nonliving matter
1.10 Koch, infectious diseases and pure cultures
Koch Postulates A set of criteria for proving that a given microorganism
causes a gives disease
1.13 Woese and the tree of life
rRNA The types of RNA found in the ribosome
Woese Sequence of rRNA molecules and the genes that encode
them could be used to infer evolutionary relationships
between organisms
Phylogenetic tree A diagram that depicts the evolutionary history of all cells
and clearly reveals the three domains
Phylogeny The evolutionary history of organisms
2.1 Cell morphology
