Railway Science (Biology – Enzymes and Hormones)

Enzymes - It regulates the speed of chemical reactions carried out in the cells of the living organism. Catalyst denotes a substance that has the ability to increase the rate of a chemical reaction, and is not changed or destroyed by the chemical reaction that it accelerates.
Hormones are chemicals that coordinate different functions in body by carrying messages through your blood to our organs, skin, muscles and other tissues.

Saliva is a mixture of water, electrolytes, inorganic ions, mucus and enzyme (salivary amylase). Salivary amylase (Ptyalin) is a glucose-polymer cleavage enzyme that is produced by the salivary glands.
It comprises a small portion of the total amylase excreted, which is mostly made by the pancreas. Amylases digest starch into smaller molecules, ultimately yielding maltose, which in turn is cleaved into two glucose molecules by maltase.

Prolactin is a hormone that is produced by the pituitary gland in mammals. It is responsible for the production of milk in females and the development of the mammary glands.
Plant Hormones: Ethylene - Responsible for the ripening of fruits and the dropping of leaves.
Abscisic acid - Responsible for the closing of stomata and the inhibition of growth. Gibberellins - Responsible for the growth of stems and leaves.

Auxin regulates growth, particularly by stimulating cell elongation in stems and prevents premature fall of leaves, flowers, fruits. Cytokinin influences growth and the stimulation of cell division. Gibberellins are the plant growth regulators.

Estrogen is a hormone that is produced by the ovaries. It helps to control the growth and development of the female reproductive system. The endometrium thickens during the menstrual cycle to prepare for a possible pregnancy. If a pregnancy does not occur, the endometrium sheds and the menstrual cycle begins again.

Thymus secretes the peptide hormones called thymosins which regulate the production of lymphocytes to protect the body from allergies and infections. The pituitary gland (master gland) is located at the base of the brain and attached to the hypothalamus by a stalk.
The hormones produced by hypothalamus are of two types, the releasing hormones (which stimulate secretion of pituitary hormones) and the inhibiting hormones (which inhibit secretions of pituitary hormones).
The pineal gland (biological clock) is located on the dorsal side of the forebrain. It secretes a hormone called melatonin (Sleep regulator).

Melanin - It is produced within the skin in cells called melanocytes and it is the main determinant of the skin color of darker-skinned humans. Carotenes are orange, yellow and red pigments found largely in fruit, vegetables and dark green leafy vegetables. Keratin is the type of protein that makes up your hair, skin, and nails. Keratin can also be found in our internal organs and glands.

Glucagon - It is produced by the alpha cells, found in the islets of Langerhans, in the pancreas, from where it is released into the bloodstream.
Insulin - A hormone made by the pancreas that allows our body to use sugar from carbohydrates.
Vasopressin - It plays essential roles in the control of the body's osmotic balance, blood pressure regulation, sodium homeostasis and kidney functioning.

Bacteria (as they are single-celled organisms without specialized cells or organs for hormonal regulation). Hormones are our body's chemical messengers. They travel in our bloodstream to tissues or organs.
They work slowly, over time, and affect many different processes, including Growth and development. Important Hormones: Testosterone, Insulin, Cortisol, Growth hormone, Melatonin, Thyroid hormones, Progesterone, Follicle-stimulating hormone.

Thyroxine hormone - Secreted into the bloodstream by the thyroid gland. Primary function - Stimulate the metabolism of carbohydrates, protein and fats in the cells to produce energy.
It also plays a role in digestion, brain development, and control of muscles. Thyroid stimulating hormone (TSH) - Regulates the production of thyroid hormones, thyroxine (T4) and triiodothyronine (T3).
Parathyroid hormone (PTH) - Secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.
Triiodothyronine (T3) - It affects almost every physiological process in the body, including growth and development, metabolism, body temperature and heart rate.