The document presents a seminar on the classification and functions of hormones, focusing on their chemical nature, mechanism of action, and classification into peptides, amino acid derivatives, and steroid hormones. Hormones are defined as chemical messengers released by endocrine glands into the bloodstream to regulate various physiological processes. The presentation includes insights into plant hormones and emphasizes the role of hormones in growth, metabolism, and reproductive health.

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

3. Content
• Introduction
• Characteristics of hormones
• Classification of hormones
• Plant hormones
• Functions of hormones
• Reference

4. 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

5. 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 .

6. 1 .They are transported to the target cells/
tissue/organ via circulation.
2. They are active in very minute quanti­
ties.
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 se­
creted during the time of requirement.
7. They usually activate target cells by forming hormone
receptor complex.

7. 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

8. Based on chemical nature
1. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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 .

15. 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 ]
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

16. Plant hormones

18. 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

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