Autopolyploid Organism having more than two sets of homologous
chromosomes; polyploidy in which chromosome sets are all derived from a
single species.
Autoradiography Technique by which large molecules, cell components or body
organs are radioactively labelled and their image recorded on photographic film,
producing an autoradiograph or autoradiogram.
Autoreproduction Ability of a gene, virus, or nucleoprotein molecule to
synthesize several molecules similar to itself from smaller molecules within
the cell.
Autosome Any chromosome other than sex chromosomes. Sex chromosomes,
which differ from autosomes in form, traits, and behavior, are also known as
heterochromosomes or allosomes. Genetic phenomena governed by autosomal
genes are known as autosomal inheritance, which is distinct from sex-linked
inheritance.
Autospore A type of nonflagelIate spore that lacks the genetic potential to produce
flagella
Autotrophic microorganisms Microorganisms that are capable of growing by
synthesizing all of their cellular components through CO 2 reduction; contrasted
with heterotrophic organisms, which require organic compounds made by other
organisms. This distinction is based on carbon assimilation and differs in
definition from lithotrophy, a classification in terms of energy acquisition in
which organic matter serves as an electron donor. Autotrophic microorganisms
are classified into two types according to their means of energy acquisition.
Photoautotrophs, which use light, include Chlorella and most algae, along with
purple and green sulfur bacteria. Chemoautrophs obtain energy by oxidizing an
electron donor through a chemical dark reaction; based on electron donor type,
these include ammonium-oxidizing bacteria (e.g., Nitrosomonas), nitrous
acid-oxidizing bacteria (Nitrobacter), sulfur-oxidizing bacteria, iron-oxidizing
bacteria (Thiobacillus), and hydrogen bacteria (Alcaligenes).
Autotrophy Opposite of heterotrophy. Form of nutrition in which organisms
synthesize the organic compounds they need to survive by absorbing carbon
dioxide, water, and various inorganic salts without requiring organic matter as a
source of nutrients. In photoautotrophs such as green plants, carbon assimilation
is performed through photosynthesis. In chemoautotrophs such as
chemosynthetic bacteria, it occurs through chemosynthesis. Some seaweed
experience strong growth in the presence of organic matter (such as vitamins) as
a nutrient source, while many require such a supply.
Auxiliary cell In the higher red algae, a cell into which the zygote nucleus or one
of its mitotic progeny is deposited and that generates the carposporophyte
generation by mitotic proliferation.
422
Glossary
chromosomes; polyploidy in which chromosome sets are all derived from a
single species.
Autoradiography Technique by which large molecules, cell components or body
organs are radioactively labelled and their image recorded on photographic film,
producing an autoradiograph or autoradiogram.
Autoreproduction Ability of a gene, virus, or nucleoprotein molecule to
synthesize several molecules similar to itself from smaller molecules within
the cell.
Autosome Any chromosome other than sex chromosomes. Sex chromosomes,
which differ from autosomes in form, traits, and behavior, are also known as
heterochromosomes or allosomes. Genetic phenomena governed by autosomal
genes are known as autosomal inheritance, which is distinct from sex-linked
inheritance.
Autospore A type of nonflagelIate spore that lacks the genetic potential to produce
flagella
Autotrophic microorganisms Microorganisms that are capable of growing by
synthesizing all of their cellular components through CO 2 reduction; contrasted
with heterotrophic organisms, which require organic compounds made by other
organisms. This distinction is based on carbon assimilation and differs in
definition from lithotrophy, a classification in terms of energy acquisition in
which organic matter serves as an electron donor. Autotrophic microorganisms
are classified into two types according to their means of energy acquisition.
Photoautotrophs, which use light, include Chlorella and most algae, along with
purple and green sulfur bacteria. Chemoautrophs obtain energy by oxidizing an
electron donor through a chemical dark reaction; based on electron donor type,
these include ammonium-oxidizing bacteria (e.g., Nitrosomonas), nitrous
acid-oxidizing bacteria (Nitrobacter), sulfur-oxidizing bacteria, iron-oxidizing
bacteria (Thiobacillus), and hydrogen bacteria (Alcaligenes).
Autotrophy Opposite of heterotrophy. Form of nutrition in which organisms
synthesize the organic compounds they need to survive by absorbing carbon
dioxide, water, and various inorganic salts without requiring organic matter as a
source of nutrients. In photoautotrophs such as green plants, carbon assimilation
is performed through photosynthesis. In chemoautotrophs such as
chemosynthetic bacteria, it occurs through chemosynthesis. Some seaweed
experience strong growth in the presence of organic matter (such as vitamins) as
a nutrient source, while many require such a supply.
Auxiliary cell In the higher red algae, a cell into which the zygote nucleus or one
of its mitotic progeny is deposited and that generates the carposporophyte
generation by mitotic proliferation.
422
Glossary