Tag: biology

The local hormones are known as kinins, which are released to overcome changes in body tissues. Kinins help in vasodilation and increase blood supply to the affected part, causing a mild local pain. Thus, they act as the first aid of the body. The sensation of pain at the time of stinging by a poisonous insect, burning or internal injury is due to kinins. So, they are called, first aid hormones.

Pheromones are the chemicals or compounds which have peculiar odour. These are secreted and released by the organisms with the help of glands present on the skin surface at various locations. These pheromones have odour which help in attracting the other member of the same species. The pheromone initiates a neuronal response and there is change in the physiolodical behaviour of the organism. There are various forms of pheromones like alarm pheromeones, food trail phereomeones and sex phereomones.

The chemical substances that are secreted by cells/tissues or glands are categorised as biological substances. It includes digestive juices, hormones and other secretions. Gastrin, thyroxin and oxytocin are the hormones secreted by stomach, thyroid gland and posterior pituitary respectively. These are biochemical substances. Creatinine is a breakdown product of creatine phosphate and does not fall under the biological category of chemical substances. Thus, the correct answer is D.

Juvenile hormone (JH), produced by the corpora allata, regulates two important processes in insects. The first is development; as an insect develops, the degree juvenility of the next stage is determined by the amount of JH in the blood; the lower the JH, the more adult the next stage. The other function of JH is, in many insects, to regulate the production of eggs in the female's ovaries. Because mating behavior is often synchronized with the ovarian cycle, the mating behaviour and pheromone production to be linked with JH.

Both statements are true so (c) will be the correct answer. All the extra water, excess salts and the nitrogenous wastes such as Urea have to be sent to the excretory system to be thrown out of the body.

• A hormone is derived from Greek"impetus" which 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.
•  Hormones in animals are often transported in the blood.
•  Cells respond to a hormone when they express a specific receptor for that hormone. Hence, Hormones are also known as Impetus. 
 So, the correct answer is 'Impetus'.

Chemically, hormones may be proteins, polypeptide's, amino acid derivatives or steroids. They help the body to cope up with infections, stress. trauma, starvation and extreme temperatures.

• Hormones have diverse chemical structures, mainly of three classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). 
• The glands that secrete hormones comprise the endocrine signalling system. The term hormone is sometimes extended to include chemicals produced by cells that affect the same cell (autocrine or intracrine signalling) or nearby cells (paracrine signalling). Hence, Chemically, hormones are Proteins and Steroids.

• Hormones are derivative of protein, amino acids, and steroids. Hormones are the chemical messenger that provide signals to the cell for performing the particular function. Hormones are used up completely in the metabolism.
• Enzymes are the catalyst, which enhances the biochemical reactions. Enzymes act at the place where they are formed. And enzymes do not get used up in the reaction. Hence, Hormones differ from enzymes in the respect that they are used completely in metabolism.