Microbiology 2
Bacteria that can only live with or in the presence of free oxygen
from the air. They require oxygen for respiration.
aerobic bacteria
Bacteria (micro-organisms) that can or must live in the absence of
free oxygen from the air.
anaerobic bacteria
An agent that inhibits growth of micro-organisms but does not kill
those already growing.
antiseptic
Methods used to prevent unwanted micro-organisms entering an
area of an experiment.
asepsis or aseptic
techniques
Free from all pathogens, i.e. organisms that cause disease.
aseptic
Bacteria that are self-nourishing, i.e. capable of making
(synthesising) their own food from inorganic compounds.
autotrophic
bacteria
Microscopic unicellular organisms, prokaryotic in nature. May be
parasites or saprophytes. Some are autotrophic. Many cause disease
or decay and some are used in industry. They are ubiquitous. Are
composed of cell wall, cell membrane, genetic/nuclear material –
DNA (not in a nucleus), plasmids, cytoplasm, flagella and capsule.
bacterium
(bacteria)
A virus that attacks and kills bacterial cells. It is composed of DNA
and protein only.
bacteriophage
A container in which a living thing is used in the production of
something useful, e.g. during fermentation using yeast, yogurt
production using bacteria, etc.
A method of asexual reproduction where a new individual arises
from an outgrowth that may or may not separate to form the
parent, e.g. in yeast. This outgrowth may remain attached to the
parent and form a colony or it may detach from the parent, undergo
further reproduction and form a new colony itself.
bioreactor
budding
Protective mucilage coat surrounding certain bacteria.
capsule
Human disease caused by a virus. Symptoms: red spots or lumps
which eventually turn into scabs, sore throat and tiredness.
chicken pox
Tiny, hair-like cytoplasmic extensions of a cell which beat
rhythmically. In lower animals they are for locomotion; in higher
forms, for propulsion of substances, e.g. mucus from the trachea.
cilia (cilium)
A wall separating the sporangium from the sporangiophore of a
reproducing Rhizopus (bread mould).
columella
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The fourth phase in a growth curve. Numbers decline due to
increased competition for food and space and the build-up of toxic
wastes.
Unhealthy condition in which an organism or part of an organism is
affected by some factor which interferes with normal growth,
development or metabolism of its organs or tissues.
A spore formed within a parent cell, e.g. bacterial spores. Formed in
unfavourable conditions. Cell contents shrink and enclosed by a thick
wall. When suitable conditions return the spore absorbs water, wall
bursts and the spores divide by binary fission.
death phase /
decline phase
disease
endospore
Whip-like process or appendage of a cell, e.g. bacteria. Used for
propulsion.
flagellum (flagella)
An asexual method of reproduction where parts of an organism
break off and are capable of developing into a new organism, e.g.
seaweeds, bacteria, fungi (yeast).
fragmentation
Structures involved in reproduction in fungi (mushrooms) that
produce spores.
fruiting bodies
Plant that has no stamens or pistils (hence no proper flowers or
seeds) and no chlorophyll. Eukaryotic in nature. Feeds on organic
matter. Found in a wide variety of habitats, e.g. salt water, fresh
water, terrestrial, air-borne, e.g. mushrooms, yeasts, toadstools and
moulds (Rhizopus).
fungus (fungi)
Common name for micro-organism. OR something capable of
developing into a new organism, e.g. embryo.
germ
Graph showing population size of micro-organisms over a period of
time. Has five phases: lag phase, log phase, stationary phase,
death/decline phase, and survival phase.
growth curve
Bacteria that cannot make their own food. They may be saprophytic
or parasitic.
heterotrophic
(bacteria)
The capacity of an organism (the host) to withstand the action or
effects of a pathogen or other chemicals or disease.
host resistance
Cause to develop/grow by supplying all the necessary requirements,
e.g. temperature (using an oven), food (as a nutrient medium in the incubate
case of bacteria), etc.
A protein substance produced by cells which have been infected by a
virus. It has the effect of stopping virus growth and protecting
surrounding cells against viral infection. Can be produced by genetic interferon
engineering and is used to treat a variety of conditions (hepatitis B
and C) and some cancers.
Particle or organism large enough to be visible to the naked eye.
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macroscopic
Organism, usually bacterium or virus, not visible to the naked eye.
micro-organism
Collective term for all the hyphal filaments that make up the
vegetative part of a fungus.
mycelium
(mycelia)
Symbiotic relationship between a fungus and plant roots. The
mycelium forms a web over the surface of the roots (exotrophic
mycorrhiza) and their hyphae enter the roots (endotrophic
mycorrhiza).
mycorrhiza
An organism that causes a disease.
pathogen
Shallow round dish with lid into which is placed a nutrient medium
for growing micro-organisms.
petri-dish
An infectious agent made of one or more protein molecules but no
RNA or DNA. They seem to act as catalysts – converting normal
protein into prions, e.g. BSE and CJD.
prion
Component of a virus surrounding one type of nucleic acid.
protein coat
A root-like filament which attaches the mycelium of some fungi to
the substrate. Grows downwards into substrate. It functions like a
root – it supports the fungus and is involved in absorption.
Classification grouping of bacteria called Bacillus. Any bacteria called
Bacillus ~ or B. ~ have this shape; also E. coli, found in the human
colon, is similarly shaped and is responsible for the synthesis of
some B vitamins.
Also: cells in retina of eye stimulated by low light intensity, i.e. dim
light. Responsible for monochromatic vision (can see in black and
white or shades of grey).
rhizoid
rod(s)
Term referring to fungal hypha with cross-walls. Has cells.
septate
A structure in which spores are produced, e.g. in Rhizopus.
sporangium
(sporangia)
The third phase in a growth curve. Birth rate = death rate due to
competition for food, space and the build-up of toxic wastes.
stationary phase
Fungal hyphae which grow horizontally on surface of substrate (e.g.
bread).
stolon
The final phase in a growth curve. Growth settles at a level that the
environment can support or in the case of bacteria, endospores may
be formed due to the adverse conditions.
survival phase
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Noxious biochemical substance (poison of animal or vegetable
origin) formed in the body by a pathogenic organism.
toxin
The infectious part of a virus consisting of the RNA or DNA and the
protein coat.
virion
Unicellular fungus, ovoid or spherical cells found singly or in groups
(e.g. on fruit skins such as apple and grape). Thin cell wall, granular
cytoplasm, nucleus and storage vacuoles. Reproduce by a process
called budding.
yeast
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