Lipids

The lipids are a heterogeneous group of compounds related to fatty acids. They are not soluble in water but soluble in organic solvents i.g, alcohol, ether and benzene. Lipids include fats, oils, waxes, cholesterol and related compounds.

Characteristics: 

1: As hydrophobic compounds, they are components of cellular membranes.

2: Because of higher proportion of C-H bond and very small portion of oxygen, lipids store double amount of energy compared to the same amount of any carbohydrate.

3: Some lipids provide insulation against atmospheric heat and cold and also act as water proof material.

waxes in the exoskeleton of insects and cutin an additional protective layer on the cutical of epidermis of some plant organs e.g, leaves, fruits, seeds etc. 

Classification: 

1: Acylglycerols:

It is composed of glycerol and fatty acid. The most widely spread acylglycerol is triacylglycerol which is also called triglycerides or neutral lipids. Chemically acylglycerol can be defined as the easters of fatty scids and alcohol.

Ester: 

 It is a compound produced as a result of a chemical reaction of an alcohol with an acid and a water molecule is released.

OH is released from alcohol and H from an acid. H and OH combine and form a water molecule.

Fatty acids: 

Fatty acid are one of the most important component of triglycerides which show following properties.

         1: Fatty acids contain even numbers (4-30) of carbon atoms in straight chain attached with hydrogen and having an acidic group COOH (carboxylic group).

        2: They may contain no double bonds (saturated fatty acids) or contains up to 6 double bonds (unsaturated fatty acids).

       3: In animals the fatty acids are straight chains, while in plants these may be branched or ringed.

       4: The solubility of fatty acids to organic solvents and their melting points increase with increasing the number of carbon atoms in chain. Palmitic acid (C16) is much more soluble in organic solvent then butyric acid (C4). The melting point of palmitic acid is 63.1 degree as against -8 degree for butyric acid.

Fats:

1: Fats containing unsaturated fatty acids are usually liquid at room temperature are said to be oils and fats containing saturated fatty acids are solid. Animals fats are solid at room temperature, whereas most of the plant fats are liquid.

2: Fats and oils are lighter than water and have a specific gravity of about 0.8. They are not crystalline but some can be crystalline under specific condition.   

2: Waxes:  

1: Waxes are widespread as protective coatings on fruits and leaves. Some insects also secrets wax like bees.

2: Chemically waxes are mixture of long chains alkanes " with odd number of carbon ranging from C25 to C35"  and alcohols, ketones and esters of long chain fatty acids.

3: Waxes protect plants from water loss.

4: Waxes protect plants from abrasive damage.

5: They also provide water barrier for insects, birds and animals.  

3: Phospholipids:  
1: Phospholipids are derivatives of  Phosphatidic acid. which are composed of glycerol, fatty acids and phosphoric acids.
2: Nitrogenous bases such as choline, ethanilamine and serine are important components of  phospholipids.
3: They are widespread in bacteria, animals and plant cells and frequently associated with membrane. 
4: Phosphatidylcholine is one of the most common phospholipids. 

4:Terpenoids:
Terpenoids are very large and important group of compounds which are made up of simple repeating units, isoprenoid units. This unit by condensation in different ways gives rise to compounds such as rubber, carotenoids, steroids, terpenes etc.

Carbohydrates

The literally means of carbohydrate is hydrated carbon. It is made of carbon, hydrogen and oxygen. The ratio of hydrogen and oxygen is same as in water. Chemically carbohydrate can be defined as the polyhydroxy aldehyde or ketones, complex substance which on hydrolysis yield polyhydoxy aldehyde or ketone subunits. It general formula is Cn(H2O)n where n is whole number from 3 to many.

Hydrolysis:   

           "The break down of large molecules into small by utilizing water molecules".

Occurrence and Source of carbohydrate:

They are found in all organisms and almost all parts of cells. It occur abundantly in organisms. Green plants are main source of carbohydrate. It is first product of photosynthesis. Other compounds of plants are produced from carbohydrate by different chemical reactions.

Functions:

1: Carbohydrates play both structural and functional roles.
2: Simple carbohydrates like glucose, are the main source of energy in cells.
3:Some carbohydrate like cellulose, are the main component of cell walls in plants and micro-organisms.
4: Carbohydrate in cells combine with protein and lipids  to form glycoprotien and  glycolipid  respectively. They have structural role in extracellular matrix of animals and bacteria cell wall. Both these conjugate molecules are components of cell membrane. 

Classification of Carbohydrate:  

Carbohydrate also called saccharides means sugar and are classified into three groups.

1: Monosaccharide

2: Oligosaccharide

3: Polysaccharide 

Monosaccharide:

1: These are sweet in test.

2: These are simple sugar.

3: They are easily soluble in water, and cannot be hydrolyzed into simple sugar. 

4: Chemically they are either polyhydroxy aldehyde or ketone. All carbon atoms in a monosaccharide except one, have a hydroxyl group. The remaining carbon atom is either apart of an aldeyde group or a keto group. The sugar with aldehyde group is called aldo-sugar and with the keton group is called keto-sugar.

4: Classification of Monosaccharides: In nature Monosaccharides with 3 to 7 carbon atoms are found. They are called trioses (3C),tetroses (4C), pentoses (5C), hexoses (6C), heptoses (7C). They have general formula (CH2O).

5: Glysaccharide and Dihydroxyacetone, both trioses (C3H6O3) are intermediates in respiration and photosynthesis. Tetroses are rare in nature occur in some bacteria. Pentoses and hexoses are most common. From the biological point of view the most important hexsose is glucose. It is an aldo sugar.

6:Most of the mono saccharides form a ring structure when in solution. eg, ribose  form five cornered structure called ribofuranose and glucose form sis sided structure called gtycopyranose.
7:in free state glucose is present in all fruits but being abudntant in grapes, dates and figs. Our blood cotains 0.08% glucose. in combine form it found in many disaccharides and polysaccharides. Glucose naturally produced in green plants which take carbon dioxide from air and water from the soil to synthesize glucose. Energy consumed in this process which is provided by sunlight. This process is called photosynthesis.
  

Oligosaccharide:

1: These are comparativly less sweet in test.

2: They are less soluble in water.

3: On hydrolysis oligosaccharides yield from tow to ten monosaccharides. The ones yielding two monosaccharides are known as disaccharides. Those yielding three monosaccharides are known as trisaccharides and so on. The covalent bond between two monosaccharides is called Glycosidic bond C-O.
4: Phsiologically important disaccharides are maltose, sucrose and lactose. Most familiar
 disaccharides is sucrose (cane sugar) which on hydrolysis yields glucose and fructose, both of which are reducing sugar. Its formula is

C12H22O11.

Polysaccharide: 

 1: These are the most complex and most abundant carbohydrate in nature.
2: They are test less and usually branched.
3: They are formed by several mono saccharide units linked by glycosidic bonds.
4: They are sparingly soluble n water.
5: They have high molecular weight. i.g, strach,glycogen, cellulose, dextrins, agar, pectin and chitin etc.

Strach:

 1: It is found in fruits, grains, seeds and tubers.

2: It is main source of carbohydrates for animals.

3: On hydrolysis it yields glucose molecule.

4: Give blue color with Iodine .

Types:

There are two types of strach.

Amylose: Have unbranched chains of glucose. It is soluble in hot water.  

Amylopectin:  Have branched chains and are in soluble in hot or cold water.

Glycogen: 

1: It is also called animal strach.
2: It is the chief form of carbohydrate stored in animals body.
3: It is abundantly found in liver and muscles through in all animals cells.
4: It is insoluble in water, and gives red color with iodine 
5: On hydrolysis it also yields glucose molecule.

Cellulose:  

1: It is most abundant carbohydrate in nature. 
2: Cotton is the pure form of cellulose. 
3: It is the main component of cell wall of plants. 
4: It is highly insoluble in water.  
5: On hydrolysis it also yields glucose molecule. 
6: It is not digested in human digestive track. In herbivores it is digested because of micro-organisms in their digestive track. These micro-organisms secrete an enzyme called cellulase for digestion. Cellulose give no color with iodine.

 

Water

Importance Of water in living Organisms:-

Water is very important in life. It is the medium of life.It is most abundant inorganic compound in living organisms. Its percentage different from 65 to 89 in different organisms. Human tissues contain water about 20% water in bone cells and 85 % in brain cells. 

Properties of water:-  

1:Solvent:  

For polar substances water is excellent solvent because of its polarity. When we dissolve ionic substances in water, dissociate into positive and negative ions. When we dissolve non-ionic substance into water it dispersed in water, because they having charged groups in their molecules. In solution ions and molecules move randomly and are in more favorable form to react with other molecules and ions. It is due to solvent property of water. That almost all reaction in cells take place in aqueous media. In cells chemical reactions are speed up by enzymes which need water for its proper function. Non polar molecules are insoluble in water such as fates, due to this characteristic it help to maintain membrane which make compartment in cell.

 2: Heat of vaporization:
 It can be defined as "calories absorbed per gram of water vaporized".  Due to presence of hydrogen bonding water needs lots of energy to change its form from liquid to gas. The heat of vaporization of water is 574 Kcal/kg, which play a very important role maintain the heat produced by oxidation. It provide cooling effect to plants when water transpired, to animals when water respired.  
3: Diffusion:  It can be define as " the movement of  molecules from higher concentration to the area of lower concentration.  Water diffuses not only itself but also causes the diffusion of ions and molecules of other substances dissolved in it. Diffusion cause equal distribution of molecules. 
4: Organize non-polar molecules:
 Non- polar molecules such as oil do not form hydrogen bonds with water. it means non-polar molecules move away from the water molecules so they can be refer as "hydrophobic" which mean water fearing. The non-polar molecules form bond with each other in a water solution and become organized. 5: Protection: 
Water is a very effective lubricant that gives protection against damage result from friction i.g.tears protect surface of eyes from the rubbing of eyelids. Water is fluid cushion around organs that helps to protect them from damage.  
6:Ionization of water: 
Water is slightly ionizing compound since it ionize to the extent of about one in 550million molecules. The water molecules ionize to form H ion and hydro Oxley ion. This reaction is reversible but equilibrium is maintained.

7: Capacity of heat:  The specific heat capacity can be defined as "the number of calories required to rise the temperature of 1g of water by 1 degree", The specific heat capacity of water is 1.0. It has a great ability of absorbing heat with minimum change in its own temperature. This due to hydrogen bonding in water molecule. It require lots of energy to break hydrogen bond. Due to this property water work as temperature stabilizer for living organisms. And also protect them against sudden changes in environment temperature.

Carbon

Carbon is basic element of organic compounds. carbon have central position in the skeleton of life because of its unique characteristics.

Properties of carbon:

Tetravalent:   

                         It is tetravalent element. It react with other elements by forming covalent band (sharing of electrons). Carbon atom combine with four atoms of other elements by  symmetrically arrangement, in the result give stable configuration. because of this propety of tetravalency, carbon atoms synthesis complicated cellular structures.   

 Stable chain and rings: 

                      Carbon atoms combine to form stable rings, branched and unbranched molecules. This property of carbon is very responsible for the vast verity of inorganic molecules. The base of organic molecule is C-C bond.

Source of energy:

                  In cellular activities C-H band is the potential source of energy i.g, cellulose, protein, fats etc.

Peptide bond: 

                      C-N bond in amino acid linkage to form peptide bond and form protein.

Give stability to complex molecules:

                   C-O bond in glycosidic linkages provide stability to complex carbohydrate.

 

Biological Molecules

Biochemistry: 

                                 It is a branch of biology, which is consist of chemical components and chemical processes in living things. it is very important for understanding anatomy and physiology, because all of the structure of living organisms are result of biochemical reactions i.g, photosynthesis, digestion, respiration, muscle contractions can all be explained by biochemical terms.

Organic compound:

                                                   Any molecule containing carbon and hydrogen.Most important organic compounds in living organisms are carbohydrate, protein,  lipids and nucleic acid.

Inorganic compounds:

                            They do not contain carbon and hydrogen together in a molecule i.g   carbon di oxide, water etc.

Metabolisms:

                  Sum of all reaction taking place within the cell.

Type of metabolic reactions:

1: Anabolic reaction: 

                          Those reaction in which simpler substance combine to form complex substance.in this reaction energy is required.

2: Catabolic reaction:

                          Those reaction in which complex substance break down into simpler ones. in this reaction energy is released.

Coordination of catabolic and anabolic reactions

Explanation: 

                 In living cells anabolic and catabolic reaction go side by side. simpler molecule combine to form complex molecule and complex molecule broken down into simpler one. In other words anabolic and catabolic reactions are coordinated.The inter conversion of carbohydrates, protein and lipids contentiously occur in living cells.

Branches Of Biology

Biology is a very wide field of study and having very large amount of information.For our easily understanding and studying biology, it is divided into many branches. But mainly it is divided into two branches.

Main Branches: 

Zoology:
                       It is a branch of biology, in which we study about animals.

Botany:
                   It is a branch of biology, in which we study about plants.

Other Branches:

Morphology: 

                          In which we study about the structure of  living things.  

Anatomy:

                        In which we study about the internal structure of living things.

Histology:

                       It is a microscopic study tissue.

 Physiology:                

                In which we study about the function of different parts of animals and plants.

Cell Biology/ Cytology:

               In which we study about the function and structure of the cells.  Palaeontology: 

                    In which we study about the fossils and its relationship with evolution of life on earth. 

Palaeobotany:

             In which we study about the plant fossil.

Palaeozoology:                                                                                                In which we study about the animal fossils. 

Microbiology:                                                                                                  In which we study about the microorganisms i.e. microscopic Algae and Fungi, Bacteria, Protozoa, and Viruses.

Freshwater Biology:

              In which we study about the organisms living in freshwater i.e. lakes, revers etc. 

Marine Biology:

              In which we study about the life of organisms living in seas and oceans. Parasitology:

              In which we study about the parasites.  

Human Biology:  

                   In which we study about the of man.  

Social Biology: 

            In which we study about the communal life and social behavior of human being.

Biotechnology:

            In which we study about the use of living organisms, process in manufacturing and service industries. 

Genetics:

            In which we study about the hereditary characters transmitted from parents to offspring. 

Taxonomy: 

                 It deals with naming and classification of living organisms into groups and sub-groups.Closely related organisms are placed in the same group.

 Embryology: 

            In which we study about the development of an  organism  from a zygote( Fertilized egg).

Zoo-geography:  

             In which we study about the distribution of organisms in nature.

 Molecular Biology:

             In which we study about the structure of organisms, cells and their organelles at molecular levels. 

Environment Biology/ Ecology:

             In which we study about the organisms and its relation to their environment (included inorganic and organic environment).

Biology

Introduction: 

Biology is a study of living things. like physics, chemistry it is also branch of science. in bio the biologists study about living things as well as non-living things which affect the living thing in any way. the literal meaning og biology is "study of life". 

Property Of Living Organisms:

Living organisms have following properties:

1:They are complex things and highly organized.

2:They are composed of one or many cells.

3:They contain genetic program of their characteristic.

4:They acquire and use energy.

5:They grow in size.

6:They carry out and control numerous chemical reactions e.g Respiration and photosynthesis.

7:They can maintain a fairly constant internal environment e.g Homeostasis.

8:They can produce offspring similar to themselves e.g Reproduction.

9:They can respond to changes in their environment e.g Neurons.

Any thing containing all these properties,
simultaneously can be declared as living thing.