biology - vitamins-types, functions, properties

Vitamins-types, functions, properties

1. Vitamins
•The vitamins are natural and essential nutrients, required in small quantities
•major role in growth and development, repair and healing wounds, maintaining healthy
bones and tissues, for the proper functioning of an immune system, and other biological
functions.
•thirteen different types of vitamins and all are required for the metabolic processes.
•Vitamin A, Vitamin B
1,Vitamin B
2 ,Vitamin B
3 ,Vitamin B
5, Vitamin B
6,
Vitamin B
7, Vitamin B
9, Vitamin B
12,Vitamin C , Vitamin D, Vitamin E,
Vitamin K

2. •Types of Vitamins
•Based on the solubility, Vitamins have been classified into two different groups:
1.Fat-Soluble Vitamins.
2.Water-Soluble Vitamins.
•Fat-soluble vitamins
-stored in the fat cells
-as the name suggests, these vitamins require fat in order to be absorbed.
-Vitamin A, D, E and K are fat-soluble vitamins.

3. •Water-soluble vitamins
-not stored in our body as its excess gets excrete through the urine.
-these vitamins need to be replenished constantly.
-Vitamin B and C are water-soluble vitamins.
Properties of vitamins
-Some vitamins are fat-soluble; the others are water-soluble.
-The water-soluble vitamins (B and C) tend to have one or more polar or ionizablegroups
-the fat-soluble vitamins (A, D, E, and K) have predominantly aromatic and aliphatic characters

4. •Functions of vitamins
-to maintain good health
-to prevent deficiency diseases such as Beriberi( weakened muscles, heart, nerves and digestive
system) and rickets (softening of the bones)
-to regulate the repair of body cells
-to combat the ageing process
-to process carbohydrates and release energy in the body

5. Hormones
Hormones are chemicals synthesized and produced by the specialized glands to control and regulate the activity of
certain cells and organs. These specialized glands are known as endocrine glands.
•Types of Hormones
To regulate various functions, different types of hormones are produced in the body.
1.Peptide Hormones
2.Steroid Hormones
•Peptide Hormones
-they are composed ofamino acidsand are soluble in water.
-they are unable to pass through the cell membrane as it contains a phospholipid bilayer that stops any fat-
insoluble molecules from diffusing into the cell.
-Insulin is an important peptide hormone produced by the pancreas.

6. •Steroid Hormones
-they are fat-soluble and are able to pass through a cell membrane.
-Sex hormones are examples of steroid hormones.
•Properties of Hormones
1. Hormones are secreted from their source (an endocrine gland) directly into the blood.
2. They regulate the physiological processes by chemical means. They affect the enzyme systems of the body.
3. They act on target organs or cells usually away from the source.
4. Hormones produced in one species usually show similar influence in other species.
5. They are produced in very small quantities and are biologically very active.
6. Chemically, some hormones are peptides, amines or steroids.
7. Their excess (hypersecretion) or deficiency (hyposecretion), both may lead to serious consequences.
8. Hormones are not stored in the body and are excreted from the body.

7. Functions of Hormones
•Food metabolism
•Growth and development
•Controlling thirst and hunger
•Maintaining body temperature
•Regulating mood and cognitive functions