| Term |
Definition |
|
| ———————————————————— |
—————————————————————————————————————————– |
|
| Abscisin |
A plant hormone (now known as abscisic acid) that regulates growth, seed dormancy, and leaf or fruit drop. |
|
| Abscission |
The natural separation or shedding of leaves, flowers, fruits, or other plant parts. |
|
| Acanthacarpous |
Bearing spiny or thorny fruits. |
|
| Achlamydeus |
Lacking a floral perianth (sepals and petals absent); naked-flowered. |
|
| Achlorophyllous |
Lacking chlorophyll and therefore unable to perform photosynthesis. |
|
| Achromasia *(also spelled achromasie in some languages)* |
Absence or loss of normal color or staining ability; complete color blindness in medicine. |
|
| Acetaldehyde |
A colorless, volatile organic compound (CH₃CHO) formed during alcohol metabolism and used in chemical synthesis. |
|
| Acetylcholinesterase |
An enzyme that rapidly breaks down the neurotransmitter acetylcholine at nerve synapses. |
|
| Acrocentric |
Describing a chromosome with the centromere located near one end, producing one very short arm and one long arm. |
|
| Acrogynous |
Having the female reproductive organs (archegonia) located at the apex of the stem or branch, especially in bryophytes. |
|
| Actinomorphy |
The condition of having radial symmetry, allowing division into similar halves through multiple planes. |
|
| Actinomycete |
A filamentous, Gram-positive bacterium resembling fungi, many species of which produce antibiotics. |
|
| Actinomycin |
A group of antibiotic compounds that inhibit RNA synthesis; some forms are used as anticancer drugs. |
|
| Actomyosin |
The protein complex formed by actin and myosin that is responsible for muscle contraction. |
|
| Acylation |
The chemical process of introducing an acyl group (RCO–) into a molecule. |
|
| Adelphogamy |
Self-fertilization occurring between flowers or reproductive organs of the same plant. |
|
| Adrenergic |
Relating to or activated by adrenaline (epinephrine) or noradrenaline (norepinephrine), especially in the nervous system. |
|
| Adrenosterone |
A steroid hormone produced by the adrenal cortex, chemically related to corticosteroids and androgens. |
|
| Aerenchyma |
Plant tissue containing large interconnected air spaces that facilitate gas exchange, especially in aquatic plants. |
|
| Aerophyte |
A plant that grows in the air or on exposed surfaces, obtaining moisture primarily from the atmosphere. |
|
| Aeroplankton |
Microscopic organisms, spores, pollen, or other biological particles that drift through the atmosphere. |
|
| Allochthonous |
Originating from another place; in ecology, referring to material or organisms transported into an ecosystem from outside it. |
|