biochemistry Hormone classification byNeha yadav

biochemistry Neha yadav.pptx

1. A seminar topic on- Hormones classification Course type: ccc Presented by Neha yadav [ M. Sc .1 st Sem ] Biotechnology Session : 2022 - 23 Course Title : Biochemistry Course code : BTC 103 Directed by Mr . jagnarayan sirdar

2. Content Introduction Characteristics of hormones Classification of hormones Plant hormones Functions of hormones Reference

3. Introduction A hormone is a chemical transmitter . It is released in small amounts from glands , and is transported in the bloodstream to target organs or other cells . Hormones are chemical messengers , transferring information and instructions from one tissue to another and from cell to cell

4. Where are they secreted from? Hormones are secreted from the endocrine glands in the body . The glands are ductless , so hormones are secreted directly into the blood stream .

5. 1 . They are transported to the target cells/ tissue/organ via circulation. 2. They are active in very minute quanti­ties. 3. They are mostly water soluble. 4. They are low in molecular weight. 5. They are destroyed after their actions. 6. They cannot be stored for a longtime; usually they are synthesized and se­creted during the time of requirement. 7. They usually activate target cells by forming hormone receptor complex.

6. classification of hormones Chemical nature 1. Peptide hormones 2. Amino acid derivatives 3. Steroid hormones 1. Group I hormones 2. Group II hormones Mechanism of action

7. Based on chemical nature Amino acid derivative hormones : This category comprises of hormones that are derived from single amino acid Hydrophilic nature That are cannot enter target cells directly ➤For example : norepinephrine , epinephrine , dopamine are derived from the amino acid tyrosine Thyroid hormone

8. Based on chemical nature 2 . Proteins and peptides hormones These hormones are protein in nature The individual hormone could be referred to as peptide , polypeptide or protein in nature , depending on their specific chain length Protein and peptides are large molecules. That are cannot enter target cells directly ➤For example : [ peptides] thyrotropin releasing hormone ( TRH ) is composed of only 3 amino acids ( small peptide ) , [ protein] pituitary gonadotropins possess as many as 180 amino acids ( large peptides ) Insulin , glucagon

9. Based on chemical nature 3. Steroid hormones These hormones are derivatives Of cholesterol or fatty acids [ lipids] Lipophilic nature That are directly enter the target cells For example adrenal cortical hormone Androgen Estrogen Prostaglandins placenta

10. 2. Based on the mechanism of action : • Hormones are classified into two broad groups • Group I and group II based on the location of the receptors to which they bind and signals used to mediate their action

11. Group I and group II hormones Hormones mode of action Lipid Lipid -derived hormones can diffuse across plasma membranes whereas the amino acid - derived and peptide hormones cannot

12. Group I hormone [ lipophilic hormone] These hormones are lipophilic in nature. They are mostly derivatives of cholesterol. These hormones binds to intracellular receptors Example:  Steroid hormones, Estrogen, androgen, glucocorticoids, cholcalciferol, thyroxine  etc form receptor hormone complex ( RHC ) through which their biochemical functions are mediated

13. Based on the mechanism of action 2 . Group II hormones [ hydrophilic] These hormones bind to cell surface ( plasma membrane ) receptors and stimulate the release of certain molecules , namely the second messengers which in turn perform the biochemical functions . Thus , hormones themselves are the first messengers .

14. 2• Secondary messenger is phosphotidylinocitol / calcium Or both ▪︎ eg. Acetylcholine, vasopressin, cholecystokinin, gastrin, gonadotropin releasing hormone, thyrotropin releasing hormone, ▪︎ Insulin, chorynoic somato mamotropin, epidermal growth factors, fibroblast growth factors, GH, prolactin 3• secondary messenger is cyclin [cGMP ] ▪︎ Atrial natriuretic peptide (ANP) On the basis of secondary messengers group II hormones are of 3 types; 1• secondary messenger is cyclin [cAMP ] eg. Adrenocorticotropic hormone, FSH, LH, PTH,ADH, calcitonin, glucagon

15. Plant hormones

16. Functions of hormones • Development and growth • Metabolism of food items • Sexual function and reproductive growth and health • Maintenance of body temperature and thirst • Integrative function; usually balance two system • Maintain consistency of interior of cell

17. Reference 1. https://www.biologydiscussion.com/hormones/hormones-definition-characteristics-and-synthesis-notes/18433 2. https://www.onlinebiologynotes.com/hormones-properties-functions-and-classification/