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Glossary
ABA: A plant growth regulator involved in the fruit ripening
process.
Acetyl CoA: Acetyl coenzyme A or acetyl-CoA is an important
molecule in metabolism, used in many biochemical reactions. Its
main function is to convey the carbon atoms within the acetyl
group to the citric acid cycle to be oxidized for energy production.
Actinomycin D: In cell biology, Actinomycin D is shown to have
the ability to inhibit transcription. It does this by binding DNA at
the transcription initiation complex and preventing elongation of
RNA chain by RNA polymerase
Aldehyde: is an organic compound containing a formyl group. This
functional group, with the structure R-CHO, consists of a carbonyl
center (a carbon double bonded to oxygen) bonded to hydrogen
and an R group, which is any generic alkyl or side chain.
Aleurone layer: is a protein found in protein granules of maturing
seeds and tubers. The term also describes one of the two major
cell types of the endosperm, the aleurone layer. The aleurone layer
is the outermost layer of the endosperm, followed by the inner
starchy endosperm.
α-amylase: α-Amylase is an enzyme which has starch and
glycogen, yielding glucose and maltose. It is the major form of
amylase found in humans and other mammals. It is also present
in seeds containing starch as a food reserve, and is secreted by
many fungi
Alleles: An allele is one of two or more forms of a gene or a
genetic locus (generally a group of genes). The form “allel” is also
used, an abbreviation of allelomorph.
Amo-1618: is 2-Isopropyl-4-dimethylamino-5-methylphenyl-1piperidinecarboxylate methyl Chloride.an inhibitors of gibberellin
biosyntheses.
Ancymidol: an inhibitor of gibberellin biosyntheses.
Angiosperms: Derived from the words for “vessel” and “seed”; a
grouping of plants whose seeds are borne in protective structures.
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Antheridia: is a haploid structure or organ producing and
containing male gametes (called antherozoids or sperm).
Auxin: A plant growth regulator that controls cell elongation;
important in many plant growth responses such as phototropism
and geotropism.
Bekanae: from the Japanese for “foolish seedling”, is a disease that
infects the rice plant. It is caused by the fungus Gibberella fujikuroi,
the metabolism of which produces a surplus of gibberellic acid. In
the plant, this acts as a growth hormone, causing hypertrophy.
The afflicted plants, which are visibly etiolated and chlorotic, are
at best infertile with empty panicles, producing no edible grains;
at worst, they are incapable of supporting their own weight, topple
over, and die (hence “foolish seedling disease”).
Biosynthesis: Biosynthesis (also called biogenesis or
“anabolism”) is an enzyme-catalyzed process in cells of living
organisms by which substrates are converted to more complex
products.
Bolting: Bolting is when plants grown in horticulture and
agriculture for their edible leaves (such as cabbage, lettuce,
spinach, and other leafy greens), instead prematurely (before
the crop is harvested) produce a flowering stem (or stems) and
ultimately seeds, in order to reproduce
Cell wall extensibility: Expansive growth of plant cells is
controlled principally by processes that loosen the wall and enable
it to expand irreversibly
Colchicines: is a medication that treats gout. It is a toxic natural
product and secondary metabolite, originally extracted from plants
of the genus Colchicum (autumn crocus, Colchicum autumnale,
also known as “meadow saffron”).
Copalyl pyrophosphate synthase: This enzyme belongs to
the family of isomerases, specifically the class of intramolecular
lyases. The systematic name of this enzyme class is ent-copalyldiphosphate lyase (decyclizing). Other names in common use
include ent-kaurene synthase A, and ent-kaurene synthetase A.
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Cycloheximide: Cycloheximide: is an inhibitor of protein
biosynthesis in eukaryotic organisms, produced by the bacterium
Streptomyces griseus. Cycloheximide exerts its effect by interfering
with the translocation step in protein synthesis (movement of
two tRNA molecules and mRNA in relation to the ribosome) thus
blocking translational elongation.
Cycocel (CCC): (chlormequat chloride) reduces plant height by
inhibiting the production of gibberellins, the primary plant hormones
responsible
Dark-grown protonemata: A protonema (plural: protonemata)
is a thread-like chain of cells that forms the earliest stage (the
haploid phase) of a bryophyte life cycl.
Decarboxylation: Decarboxylation is a chemical reaction that
removes a carboxyl group and releases carbon dioxide (CO2).
Usually, decarboxylation refers to a reaction of carboxylic acids,
removing a carbon atom from a carbon chain. The reverse
process, which is the first chemical step in photosynthesis, is called
carbonatation, the addition of CO2 to a compound. Enzymes that
catalyze decarboxylations are called decarboxylases or, the more
formal term, carboxy-lyase.
DELLA proteins: DELLA proteins are negative regulators of
gibberellin (GA) signaling that act immediately downstream of
the GA receptor.
Dioecious flowers Describes plants in which the male and female
flowers occur on separate plants.
Diterpene: Diterpene, a type of terpene, is an organic compound
composed of four isoprene units and has the molecular formula
C20H32. They derive from geranylgeranyl pyrophosphate. Diterpenes
form the basis for biologically important compounds such as retinol,
retinal, and phytol.
Dynamic equilibrium: A dynamic equilibrium exists once a
reversible reaction ceases to change its ratio of reactants/products,
but substances move between the chemicals at an equal rate,
meaning there is no net change. It is a particular example of a
system in a steady state.
Endosperm: A temporary food storage tissue in seeds, created
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by the fusion of one sperm cell plus the two polar nucleu, and
therefore often triploid.
Ent-gibberellane skeleton
Expansins: Expansin refers to a family of closely related non
enzymatic proteins found in the plant cell wall, with important
roles in plant cell growth, fruit softening, abscission, emergence of
root hairs, pollen tube invasion of the stigma and style, meristem
function, and other developmental processes where cell wall
loosening occurs
Expression: The way a trait shows up in an organism
Gene expression: Gene expression is the process by which
information from a gene is used in the synthesis of a functional
gene product. These products are often proteins, but in non-protein
coding genes such as ribosomal RNA (rRNA), transfer RNA (tRNA)
or small nuclear RNA (snRNA) genes, the product is a functional
RNA.
Genotype: The genotype is the genetic makeup of a cell, an
organism, or an individual (i.e. the specific allele makeup of the
individual) usually with reference to a specific character under
consideration.[
Geranylgeranyl
pyrophosphate:
Geranylgeranyl
pyrophosphate is an intermediate in the HMG-CoA reductase
pathway used by organisms in the biosynthesis of terpenes
and terpenoids In plants it is also the precursor to carotenoids,
gibberellins, tocopherols, and chlorophylls.
Gibberellins: A plant growth regulator that controls the elongation
of internodes
Gymnosperms: Literally, “naked seed”, a grouping of plants that
produces seed that is borne exposed, rather than in a protective
structure.
Hormones: is a chemical released by a cell or a gland in one part
of the body that sends out messages that affect cells in other parts
of the organism. Only a little amount of hormone is required to
alter cell metabolism
Hydroxylation: Hydroxylation is a chemical process that
introduces a hydroxyl group (-OH) into an organic compound.
In biochemistry, hydroxylation reactions are often facilitated by
enzymes called hydroxylases. Hydroxylation is the first step in the
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oxidative degradation of organic compounds in air. It is extremely
important in detoxification since hydroxylation converts lipophilic
compounds into water-soluble (hydrophilic) products that are
more readily excreted. Some drugs (e.g. steroids) are activated or
deactivated by hydroxylation.
Hypocotyls: The hypocotyl (short for “hypocotyledonous
stem”,meaning “below seed leaf”) is the stem of a germinating
seedling, found below the cotyledons (seed leaves) and above the
radicle (root).
Intercalary meristem A meristem located between non-dividing
tissues, such as near the base of a blade of grass.
Lactone ring: In chemistry, a lactone is a cyclic ester] which
can be seen as the condensation product of an alcohol group -OH
and a carboxylic acid group -COOH in the same molecule. It is
characterized by a closed ring consisting of two or more carbon
atoms, and a single endocyclic oxygen coupled with an adjacent
ketone (typical ester type functional group).
Long day plants: Describes plants that initiate flowers when day
length is longer than their critical day length.
M phase of mitosis: Mitosis is the process by which a eukaryotic
cell separates the chromosomes in its cell nucleus into two identical
sets, in two separate nuclei. It is generally followed immediately
by cytokinesis, which divides the nuclei, cytoplasm, organelles and
cell membrane into two cells containing roughly equal shares of
these cellular components.Mitosis and cytokinesis together define
the mitotic (M) phase of the cell cycle—the division of the mother
cell into two daughter cells, genetically identical to each other and
to their parent cell. This accounts for approximately 10% of the cell
cycle.
Microfibrils: A structure made up of several microfibrils wound
together into a “cable;” provide the framework for the plant cell
wall
Membrane vesicles: In cell biology, a vesicle is a small bubble
within a cell, and thus a type of organelle. Enclosed by lipid bilayer,
vesicles can form naturally, for example, during endocytosis (protein
absorption). Alternatively, they may be prepared artificially, when
they are called liposomes. If there is only one phospholipid bilayer,
they are called unilamellar vesicles; otherwise they are called
multilamellar. The membrane enclosing the vesicle is similar to that
of the plasma membrane, and vesicles can fuse with the plasma
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membrane to release their contents outside of the cell. Vesicles
can also fuse with other organelles within the cell
Mevalonic acid pathway: Mevalonic acid (MVA) (derived from
a contraction of dihydroxymethylvalerolactone) is a key organic
compound in biochemistry. The anion of mevalonic acid, the
predominant form in biological media, is known as mevalonate. This
compound is of major pharmaceutical importance. Drugs, such as
the statins, stop the production of mevalonate by inhibiting HMGCoA reductase.
Mitosis Cell division that results in two daughter cells that are
genetically identical to the parent cell.
Mutation A random genetic variation that is passed on to offspring.
Paclobutrazol: Paclobutrazol (PBZ) is a plant growth retardant
and triazole fungicide. It is a known antagonist of the plant hormone
gibberellin. It acts by inhibiting gibberellin biosynthesis, reducing
internodial growth to give stouter stems, increasing root growth,
causing early fruitset and increasing seedset in plants such as
tomato[1] and pepper.[2] PBZ has also been shown to reduce frost
sensitivity in plants.
Phosphon
D:
Phosphon-D
(tributyl-2,
4-dichlorobenzylphosphonium chloride), known as an inhibitor
of gibberellin biosynthesis, enhances photosynthetic electron
transport by up to 200%, with Fe(CN)63-and NADP+ being the
electron acceptors
Phosphoryl choline: Phosphorylcholine: is the hydrophilic
polar head group of some phospholipids, which is composed of
a negatively charged phosphate bonded to a small, positively
charged choline group. Phosphorylcholine is part of plateletactivating factor; the phospholipid phosphatidylcholine as well as
sphingomyelin, the only phospholipid of the membrane that is not
built with a glycerol backbone.
Phosphoryl choline citidyl transferase: This enzyme belongs
to the family of transferases, specifically those transferring
non-standard substituted phosphate groups. The systematic
name of this enzyme class is CDP choline: 1,2-diacylglycerol
cholinephosphotransferase.
Phytochromes: A light-sensitive protein pigment involved in the
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photoperiodic response
Plant pathologists: Plant pathology (also phytopathology) is
the scientific study of plant diseases caused by pathogens (infectious
diseases) and environmental conditions (physiological factors).
Proplastids: Plastids are major organelles found in the cells of
plants and algae. They are the site of manufacture and storage
of important chemical compounds used by the cell. Plastids often
contain pigments used in photosynthesis, and the types of pigments
present can change or determine the cell’s color. They possess
a double-stranded DNA molecule, which is circular, like that of
prokaryotes.
Protease: A protease (also termed peptidase or proteinase)
is any enzyme that conducts proteolysis, that is, begins protein
catabolism by hydrolysis of the peptide bonds that link amino acids
together in the polypeptide chain forming the protein.
Quantitative analysis: in analytical chemistry, the measurements
of quantities of substances produced in reactions rather than simply
noting the nature of the reactions.
Repressors: In molecular genetics, a repressor is a DNA-binding
protein that regulates the expression of one or more genes by
binding to the operator and blocking the attachment of RNA
polymerase to the promoter, thus preventing transcription of the
genes. This blocking of expression is called repression.
Ribosomal RNA: Ribosomal ribonucleic acid (rRNA) is the RNA
component of the ribosome, and is essential for protein synthesis in
all living organisms. It comprises the predominant material within
the ribosome, which is ca. 60% rRNA and 40% protein by weight.
Ribosomes contain two major rRNAs and 50 or more proteins.
Seed dormancy: A dormant seed is one that is unable to germinate
in a specified period of time under a combination of environmental
factors that are normally suitable for the germination of the nondormant seed.Dormancy is a mechanism to prevent germination
during unsuitable ecological conditions, but the probability of
seedling survival is low
Signal transduction: Signal transduction occurs when an
extracellular signalling, molecule activates a cell surface receptor.
In turn, this receptor alters intracellular molecules creating a
response. There are two stages in this process:
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1.A signalling molecule activates a specific receptor protein on
the cell membrane.
2.A second messenger transmits the signal into the cell, eliciting
a physiological response:
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Transcriptional regulator: These transcription factors
position RNA polymerase at the start of a protein-coding
sequence and then release the polymerase to transcribe the
mRNA.
Activators enhance the interaction between RNA polymerase
and a particular promoter, encouraging the expression of
the gene. Activators do this by increasing the attraction of
RNA polymerase for the promoter, through interactions with
subunits of the RNA polymerase or indirectly by changing the
structure of the DNA.
Enhancers are sites on the DNA helix that are bound to by
activators in order to loop the DNA bringing a specific promoter
to the initiation complex.
Ubiquitination: Ubiquitin is a small regulatory protein that has
been found in almost all tissues (ubiquitously) of eukaryotic
organisms. It directs proteins to compartments in the cell, including
the proteasome which destroys and recycles proteins
Xyloglucan endotransglycosylase: In enzymology, a is an
enzyme that catalyzes the chemical reaction in which a beta-(14)
bond in the backbone of a xyloglucan in broken; the xyloglucanyl
segment is then transferred to the O4 of the non-reducing terminal
glucose residue of either xyloglucan or an oligosaccharide thereof.