Railway Science (Biology – Enzymes and Hormones)

Abscisic acid inhibits growth, inducing seed dormancy, abscission, and stomatal closure during stress. Cytokinin promotes cell division and differentiation in plant tissues. Gibberellin aids in stem elongation, seed germination, and fruit development. Auxin is an essential hormone that controls almost every aspect of plant development.

Auxin: Its primary function is cell elongation and differentiation; It prevents premature fall of leaves, flowers, and fruits. Abscisic acid: This hormone has the opposite effect, acting as an inhibitor of cell division and promoting dormancy and stress responses.

It stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone. ABA plays an important role in seed development, maturation and dormancy.

Salivary amylase is a glucose - polymer cleavage enzyme that is produced by the salivary glands. Saliva contains special enzymes that help digest the starches in food. An enzyme called amylase breaks down starches (complex carbohydrates) into sugars.
ligase enzymes catalyze the joining (ligation) of two molecules by forming a new chemical bond. Lipase enzyme breaks down triglycerides into free fatty acids.

Gibberellins - Plant growth regulators that facilitate cell elongation, help the plants to grow taller. It is produced in greater mass when the plant is exposed to cold temperatures.
Cytokinins - A group of plant growth regulators primarily involved in performing cell division in plant roots, shoot system.
Auxin - A group of naturally occurring and artificially synthesized plant hormones which play an important role in the regulation of plant growth. Insulin - A hormone produced in the pancreas by the islets of Langerhans, which regulates the amount of glucose in the blood.

Growth hormone is a natural hormone, pituitary gland makes and releases that acts on many parts of the body to promote growth in children. Some important Hormones and their function:
Insulin - released by the pancreas which helps in keeping blood sugar levels from getting too high or too low.
Estrogen (female sex hormone) - released by ovaries which is responsible for the reproduction, menstruation and menopause.
Prolactin - released by the pituitary gland after childbirth for lactation. Testosterone (male sex hormone) - plays an important role in the development of male reproductive tissues such as testes and prostate.

It is a plant hormone which helps in stem and root elongation, internodal elongation and helps in floral development. It also stimulates cell elongation in the stem which prevents dwarfness in plants.
Cytokinins are a group of plant growth regulators which are primarily involved in performing cell division in plant roots, shoot systems.
Auxin is the hormone that controls the growth of plants. Ethylene is a natural plant hormone that helps in the ripening of fruits.

Plant hormones (phytohormones) are chemicals produced by plants that regulate their growth, development, reproductive processes, longevity, and even death. Six important phytohormones: Auxins, abscisic acid, cytokinins, ethylene gibberellin, and brassinosteroids.

Auxins - It is found in plants that help in growth, Stem and root cell elongation, embryonic development and flowering transition. Other hormones found in animals:
Insulin - Released by the pancreas which helps keep blood sugar levels from getting too high or too low.
Adrenaline - Secreted by the adrenal gland increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, and enlarging the pupil in the eye.
Thyroxine - Secreted by the thyroid gland which controls the speed of the body's metabolism.

IAA (C₁₀H₉NO₂) - Indole -3-Acetic Acid; Regulates growth and developmental processes such as cell division and elongation, tissue differentiation, apical dominance, and responses to light, gravity, and pathogens. NAA (C₁₂H₁₀O₂) - Naphthalene Acetic Acid; Used for vegetative propagation. IBA (C₁₂H₁₃NO₂) - Indole-3-Butyric Acid; Induces roots in stem cuttings.