Best Biology notes pdf

Cell and its Types

Cell: Cell is the structural and functional unit of all living organisms. The organisms which are made up of a single cell is called as the Unicellular  while the organisms made up of multiple cell like human being , cow and buffalo are called as the multi-cellular cell. Cell was discovered by the Robert Hooke, an English scientist in 1665.

All cells contain three basic structures:

  • Plasma membrane: It is made up of lipids and proteins and help in the transportation of nutrients form the external environment to inside the cell.
  • Cytoplasm: It is a fluid like substance that contains Cytosol and cell organelles such as mitochondria, chloroplast etc.
  • Nucleus : It is the main parts of the nucleus as it contains the genetic information as DNA present in it. Fluid inside the nucleus is Nucleoplasm.

*Protoplasm is the combined form of the Nucleoplasm and Cytoplasm.

*The Non-living things inside the cell are called as the Deutoplasm.

Cell Theory:

Cell theory is given by M Schleiden a German Botanist and T Schwann a British Zoologist. The main points of the cell theory are.

All living organisms are made up of the cells.

All cells arise from the pre-existing cell (Omnis cellula e cellula).

Virus does not follow the cell theory.


  Detailed of Animal and Plant Cell


Types of cells:

There are primarily two types of cells, i.e. prokaryotic and eukaryotic cells.

 Difference between the two cells


cell 2


chromosomes are the condensed form of the DNA. The cause of this condensation is special types of protein known as histones. When DNA is not condensed, it is called as chromatids. During cell division chromosomes show chromatids held together at a point called Centromere. End points of the chromosomes are known as Telomere. On the basis of position, centromere can be metacentric (present at the centre), sub metacentric (little away from the centre), acrocentric (situated close to the end), and telocentric (terminal centromere).

Types of Chromosomes:

Lampbrush Chromosomes: It was first discovered by the Balbiani , and it resemble the shape of the lamp brush.

Polytene Chromosomes: It was discovered by Balbiani  in salivary gland of  Chionomus larvae.


Chromosomes also contains various genes. Gene acts as a unit  of inheritance in living organisms. It controls the transfer of genetic information from one generation to the next generation.

Cell Division

Cell division is the process by which the parent cell is divided into two or more cells. Cell division is a part of the cell cycle. Cell division is generally of two types:

(1) Mitosis

(2) Meiosis

The major difference between Mitosis and Meiosis

Capture 2


  • chemical compounds found in living organisms.
  • They are the building block of the life and perform important functioning in living organisms.
  • They are compounds of carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus.


Lipids include molecules such as neutral fats, oils, steroids and waxes. They perform the following function:

  • They are hydrophobic in nature.
  • Absorbs shocks.
  • Control the cell activities through hormone actions.
  • Store the concentrated energy.
  • Protection against the desiccation.
  • Steroids is a type of lipids which function both as hormones and structural material.


  • Carbohydrates are hydrates of carbon.
  • Carbohydrates occur both as monomers and polymers.
  • Small carbohydrates are called as sugars, which commonly include Monosaccharides (single sugar) and Disaccharides( bi sugar). Larger carbohydrates are called as polysaccharides.
  • Store the short term energy.
  • It acts as the structural building material.


Proteins are polymers of amino acids; proteins typically make up about half of the total weight of the biomolecules in a cell excluding water. Proteins play a wide variety of role such as:

  • Enzymes: in the form of catalyst.
  • Structural material: in the form of keratin (protein found in hair and nails).
  • Contraction: as actin and myosin fibers that interact in muscle tissues for contraction and relaxation.
  • Signalling : Hormones such as insulin that regulate sugar level in blood

Nucleic Acid

  • Nucleic acids are polymers of nucleotide.
  • Each nucleotide has three main components:
  • A ring shaped molecule which belongs to the class of nitrogenous base.
  • A 5-carbon pentose sugar.
  • One or more phosphate groups.
  • DNA and RNA are two types of nucleic acid.

    Respiratory System

    • The respiratory system is involved in the intake and exchange of oxygen and carbon dioxide between an organism and the environment.
    • The primary organs of the respiratory system are lungs, which carry out this exchange of gases as we breathe.
    • All those organs comes under respiratory system which help in exchange of  gases are – Nasal passage, Pharynx, Larynx or Voice box, Trachea, Bronchi, Bronchioles, Lungs etc.

    Nasal passage :

    • Nasal passage is a channel for air flow through the nose and its inner wall is lined with mucous membrane.
    • Mucous contains innumerable tiny hair like cell that  prevents the particles of sand, bacteria or other small organisms from entering into the body.
    • Mucous makes the air wet entering into the body and equalises it with the temperature of the body.


    • Muscular membranous channel connecting the nasal cavity to the larynx and the oral cavity to the esophagus; it enables breathing, ingestion of food and speech.

    Larynx or Voice box :

    • The part of the respiratory system which connects the pharynx with trachea is called Larynx or voice box and it main function is to produce sound.
    • At the larynx entrance gate there is a thin blade-like door, which is called epiglottis which ensure that the larynx closes during the food intake so that food cannot enter the respiratory system .


    • It enters into the thoracic cavity and divided into two bronchi i.e. right and left.
    • Right bronchi enter into the right lungs after being divided into three branches.
    •  Left bronchi enter into the left lungs after being divided into only two branches.


    • The structure of lung is like sponge and its colour is  red.
    •  There are two lungs in the thoracic cavity i.e. right lung and left lung.
    •  Each lung is surrounded by a membrane which is called pleural membrane.
    • Size of right lung is greater in comparison to left lung.

    The process of respiration can be divided into four parts :

    1. External respiration
    2. Transportation of gases
    3. Internal respiration
    4. Cellular respiration

    1. External respiration: It can be divided into two parts

    (a) Breathing

    (b) Exchange of gases

    Mechanism of Breathing :

    The process of taking air into and expelling it from the lungs is called breathing.

    Inspiration :

    • At this stage, air from the environment enters into the lungs through the nasal passage, due to increases in the dimension of thoracic cavity a low pressure is formed in the lungs and air enters into the lungs from environment. This air continues to enter until the pressure of air inside and outside the body became equal.

    Expiration : In this process air comes out of the lungs.

     Exchange of gases :

    • The exchange of gases takes place inside the lungs. This gaseous exchange takes place on the basis of concentration gradient through normal diffusion.
    • The exchange of oxygen and carbon dioxide gases takes place due to their difference in partial pressures..

    2.Transportation of gases :

    • The process of transportation of oxygen from lungs to the cells and transportation of carbon dioxide from cells to lungs is called transportation of gases.
    • Transportation of gases takes place through blood.

    (i) By mixing with plasma : Carbon dioxide forms carbonic acid after mixing in plasma. Transportation of 7% carbon dioxide takes place in this form.

    (ii) In the form of bicarbonates : 70% part of carbon dioxide in the form of bicarbonates is transported. It mixes with potassium and sodium of blood and forms potassium bicarbonate and sodium bicarbonate.

    3.Internal respiration :

    • Inside the body, gaseous exchange takes place between blood and tissue fluid which is called internal respiration.

    4.Cellular respiration : The process of oxidization of glucose is called cellular respiration.

    Types of Respiration: Respiration is o two types i.e. anaerobic respiration and aerobic respiration.

    1.Anaerobic respiration:

    • When oxidation of food occur in the absence of oxygen ,it is called anaerobic respiration.
    • During this only 2 ATP molecules are produced from one molecule of glucose.
    •  Final product of anaerobic respiration in animal tissue like skeletal muscle cell is lactic acid.
    • Lactic acid causes the pain in muscles  if we do excess exercise



    • 2.Aerobic respiration:
      When oxidation of food takes place in the presence of oxygen , it is called aerobic respiration.

Digestive System

Human beings depend on other organism for food, therefore are called heterotrophic organisms, they need nutrients for various day to day activities. The complete process of nutrition is divided into five stages:

  • Ingestion
  • Digestion
  • Absorption
  • Assimilation
  • Defecation


The process of taking food into the mouth is known as ingestion.


  • There is some food which is not directly absorbable, so the process of conversion of non-absorbable food into the absorbable form is known as digestion.
  • The digestion of food is started from the mouth.
  • In mouth there are Salivary gland which secrets the Saliva in mouth in which two types of enzymes are found, ptyalin and maltase.
  • These enzymes convert the simple sugar and make it digestible.
  • Around 1.5 litre of saliva is secreted in human on an average day, it is acidic in nature (pH 6.8)
  • Through food pipe food reach into the stomach.

Digestion in Stomach:

  • As the food reaches in the stomach gastric glands secretes the gastric juice, this is a light yellow acidic acid.
  • Hydrochloric acid secreted from the Oxyntic cells of the stomach kills all the bacteria coming with food the; and accelerates the reaction of enzymes.
  • Hydrochloric acid makes the food acidic by which ptyalin reaction of the saliva end.
  • Pepsin and Renin are the enzymes in the gastric juice.
  • Pepsin breaks down the protein into peptones.
  • Renin breaks down the Caseinogen into Casein.

Digestion in Duodenum:

  • As the food reaches the duodenum bile juice form the liver combines with it.
  • Main function of the bile juice is to convert the acidic food into alkaline, as it is alkaline in nature.
  • Pancreatic juice form pancreas combines with food and it contains the following enzymes:
  1. Trypsin: It converts the protein and peptone into polypeptides and amino acid.
  2. Amylase: It converts the starch into soluble sugar.
  3. Lipase: It converts the emulsified fats into glycerol and fatty acids.

Small Intestine:

  • Here the process of digestion completed and absorption of digested foods start.
  • In small intestine, intestinal juices secrete and it is alkaline in nature and around 2 liters of intestinal juice secretes per day.
  • Intestinal juice contains the following enzymes:
  1. Erepsin: It converts the remaining protein and peptone into amino acids.
  2. Maltase: It converts the maltose into glucose.
  3. Sucrase: It converts the sucrose into glucose and fructose.
  4. Lactase: It converts the lactose into glucose and galactose.
  5. Lipase: It converts the emulsified fats into glycerol ad fatty acids.


  • The process of reaching the digested food into the blood is called absorption.
  • The absorption of digested foods takes place through small intestine villi.


  • Use of absorbed food in the body is called assimilation.


Undigested food reaches into large intestine where bacterias converts it into faeces which is excreted through anus.

Disorders of digestive system:

Here are some important digestive disorder in human beings.


Expulsion of food from mouth due to irritation in stomach.


Infectious disease resulting in loose frequent bowel.


Yellow colouration of skin and mucous membrane.

Gall stone:

Cholesterol crystallises to from gall stone.


difficulty of defecation due to decreased mobility in large intestine.

Sex Determination:

  • In human beings we determine the sex with the help of the sex chromosome i.e. with the help of X and Y chromosome.
  • In human beings 46 chromosomes are found out of which 44 are found in 22 pairs called autosomes and other two chromosomes are called sex chromosomes.
  • The rest two chromosomes are same in female and are called X- chromosomes (XX).
  • In male the rest two chromosomes are different and are called X and Y chromosomes.
  • During reproduction females produces one type of gametes and containing 22 autosomes and one X chromosomes, while males produces two types of gametes one have 22 + X type chromosomes and other have 22+ Y types of chromosomes.
  • When a male gametes i.e. sperm carrying X chromosomes fertilizes an ova, the zygote develop into female.
  • When a sperm carrying Y chromosomes fertilizes an egg, zygote develops into male.

Some Genetic Disorder occur due to Chromosomes:

Klinefelter Syndrome:

  • When a male have an extra X or Y chromosome in sex chromosomes then the condition will be XXY or XYY instead of XY. The individual became sterile in this condition.
  • In female when an extra X chromosomes is present instead of XY they show normal development but limited fertility, metal retardness is also seen in this type of syndrome.

Turner’s Syndrome:

  • When female has single sex chromosome(X0) their ovaries are rudimentary, lack of secondary sexual character.

Down’s Syndrome:

When an extra chromosomes is  added to 21st autosomal chromosomes this lead to develop Down’s syndrome.

Colour Blindness:

  • This disorder leads to failure to distinguish between red & green colour.
  •  The gene responsible for this disease is situated on a sex chromosomes.

Patau’s Syndrome:

  • This type of syndrome is developed by an addition of autosomal chromosome in 13th chromosome.
  • There is a cut mark in the lip and person is mentally retarded.

Number of Chromosomes in Different Organisms:

Plant Tissue

 Tissue : The group of cells of similar origin, structure and functions is called tissue.

 Types of Plant Tissue :

(A) Meristematic tissue :

Meristematic tissues are those tissues in which the cells remain forever young and divide actively throughout the life of the plant.

Some features of  Meristematic tissues are as follows :

  • It is round, oval or multi-sided.
  •  Its wall is thin and cytoplasm is homogeneous.
  • Cell contains dense cytoplasm and a single large nucleus.
  • There is lack of inter-cellular spaces between the cells.
  • Apical Meristems : These tissues are found in the root and stem apex and the initial growth (specially length) of the plants take place due to these tissue.
  • Lateral Meristems : Due to the division in these tissue growth in the girth of roots and stems takes place. Hence, it increases the width of the root and stem.
  • Intercalary Meristems : They are located at the base of internode. In fact, this is the remains of the Apical Meristems, which is divided by the incoming of permanent tissues in the centre. Plants increase its length by the activity of this. Its importance is for those plants whose apex parts are eaten by vegetarian animals. After being eaten the apex part the plants grow with the help of intercalary meristems only. Like – grass.

(B) Permanent tissue :

Meristematic tissues after cell division and differentiation produce permanent tissue.

Permanent tissues are of following types

Simple tissue:

If permanent tissue is made up of similar types of cells, it is called simple tissue.

Complex tissue :

If permanent tissue is made up of one or more types of cells, it is called Complex tissue.

Complex tissues are of two types

Xylem :

Xylem is a conducting tissues. Its main functions are –

  • Conduction of water and minerals and
  •  To provide mechanical consistency.

Phloem : This is a conducting tissue. Its main function is to conduct foods prepared by the leaves to different parts of the plant.

Plant Hormones:

Following  hormones are found in plants –

Auxins :

Auxins was discovered by Darwin in the year 1880.

This is the hormone which controls the growth of plants.

Its formation takes place in the apex parts of the plants.

Its main functions are –

(i) It prevents the separation of the leaves.

(ii)  It destroys the straws.

(iii) It saves the crops from falling.

Gibberellins :

It was discovered by a Japanese scientist Kurosava in the year 1926.

Its main function are as follows :

  • It turns the dwarf plants into long plants.
  • It helps in creating flowering.
  •  It hep in breaking the dormancy of plant.
  • It motivates the seeds to be sprout.
  • It increases the activity of cambium in the wooden plants.
  •  Large sized fruits and flowers can be produced by its scattering.

Cytokinins :

It was discovered by z in the year 1955 but it was named by Lethem.

Its main function are as follows:

  •  It naturally works in coordination with auxins.
  • It help in cell division and development in the presence of auxins.
  •    It help in breaking the dormancy of seed.
  • It is helpful in making RNA and protein.

Abscisic Acid or ABA :

This hormone was initially discovered by Carnes and Adicote and later on by Waring.

Its main function are as follows:

  • This hormone is against the growth.
  •  It keeps the seeds & bud in dormant condition.
  • It plays main role in separation of leaves.
  •  It delays in flowering of long day plant.

Ethylene :

This is the only hormone which is found in gaseous form.

Its main functions are as follows:

  • It helps in the ripening the fruits.
  •  It increases the number of female flowers.
  • It motivates the separation of leaves, flowers and fruits.

Florigens :

  • It is formed in leaves but helps in blooming of the flowers.
  • It is also called flowering hormones

Traumatic :

  • This is a type of dicarboxylic acid.
  • It is formed in injured cells by which the injury of plants is healed.

    Excretory System

    Excretion : Removal of nitrogenous substances formed during metabolism from the body of human is called excretion. Normally excretion means the release of nitrogenous excretory substances like urea, ammonia, uric acid etc.

    The main excretory organs of human are as follows –

    (i) Kidneys

    • The main excretory organ in human and other mammals is a pair of kidneys. Its weight is 140 grams.
    • There are two parts of it. Outer part is called cortex and the inner part is called medulla.
    • Each kidney is made up of approximately 1,30,00000 kidney ducts which are called nephrons.
    • Nephron is the structural & functional unit of the kidney.
    • There is a cup like structure in the every nephron called Bowman’s capsule.
    • Glomerulus of thin blood vessels are  found in the Bowman’s capsule which is made up of two types of arterioles.

    (i) Afferent arteriole : Which carries the blood to the glomerulus.

    (ii) Efferent arteriole : By which the blood is taken out of the glomerulus.

    • The process of filtration of liquids into the cavity of Bowman’s capsule, is called ultra filtration.
    • The main function of the kidneys is purification of blood plasma i.e. to excrete the unwanted nitrogenous waste substance through urination.
    • The supply of blood to kidneys takes place in large quantity in comparison to other organs.
    • In the kidneys average 125 ml per minute blood is filtrated i.e. 180 litres per day. Out of it 1.45 liters urine is formed daily and the remaining is absorbed back by the cells of nephron and mix into the blood.
    • In the normal urine there is 95% water, 2% salt, 2.7% urea and 0.3% uric acid.
    • The colour of the urine is light yellow due to the presence of urochromes in it. Urochrome is formed by the dissociation of haemoglobin.
    • Urine is acidic. Its pH value is 6.
    • The stone formed in the kidney is made up of calcium oxalate.

    (ii) Skin : Oil gland and sweat glands found in the skin respectively secretes sebum and sweat.

    (ii) Liver : Liver cells play the main role in excretion by converting more and more amino acids and ammonia of blood into urea.

    (iii) Lungs : The lungs excretes two types of gaseous substances carbon dioxide and water vapour. The excretion of some substances like garlic, onion and some spices in which vapour component excreted by the lungs.

Circulatory System

In contrary to open circulatory system where blood flows in open spaces, humans possess closed circulatory system where blood flows through a closed network of blood vessels.

The discovery of blood circulation was done by William Harvey.

There are four parts under it –

(i) Heart

(ii) Arteries

(iii) Veins

(iv) Blood.


  • Heart as the pumping organ works in rhythmic cyclic manner with systole(decrease in volume) and diastole (increased in volume).
  • A heart beat consists of both of these and in humans it lasts for 0.8 second.
  •  It remains safe in the pericardial membrane.
  • Its weight is approximately 300 grams.
  • Heart of the human is made up of four chambers.
  • In the anterior side there is a right atrium and a left atrium.
  • In the posterior side of the heart there is a right ventricle and a left ventricle persist.
  • Between the right atrium and the right ventricle there is a tricuspid valve.
  • Between the left atrium and left ventricle there is a bicuspid valve.
  • Vein is the vessels which carries the blood from the body towards the heart.
  • In the vein there is impure blood i.e. carbon dioxide mixed blood.
  • Pulmonary vein is the exception which always carries pure blood.
  • Pulmonary vein carries the blood from lungs to left atrium. It has pure blood.
  • Artery is the vessel which carries the blood from the heart towards the body.
  • In artery there is pure blood i.e. oxygen mixed blood.
  • But Pulmonary arteries are exception which always carries the impure blood.
  • Pulmonary artery carries the blood from right ventricle to lungs. It contains impure blood.
  • In the right part of the heart, there remains impure blood i.e. carbon dioxide mixed blood and in the left part of the heart there remains pure blood i.e. oxygen mixed blood.
  • The artery carrying blood to the muscles of the heart is called coronary arteries. Any type of hindrance in it causes heart attack.

Course of circulation:

  • Mammals have double circulation.
  • It mean blood have to cross two times from heart before circulating throughout the body.
  • Right atrium receives impure blood from the body which goes into right ventricle. From here the blood went into pulmonary artery which sends it to the lung for purification. After purification it is collected by pulmonary vein which brings it back to heart in left atrium. From atrium it vent into left ventricle. Now this purified blood is went into aorta for different organ of body. This circulation is done is a cardiac cycle.

Cardiac cycle:

  • The cardiac cycle is controlled by two pacemakers in the heart:
  • The sino-atrial node (SA node) located in the top wall of the right atrium
  • The atrio-ventricular node (AV node) located in between the right atrium and ventricle.
  • Both pacemakers are types of nervous tissue.

Blood Pressure:

  • The force that blood exerts against the wall of blood carrying tube is called blood pressure.
  • High in tubes which carry blood to the body parts (systolic pressure).
  • Low in tubes which carry blood to the heart (diastolic pressure).
  • The average blood pressure is 120-80mm Hg.

Wireless Artificial Pace maker:

When SA node becomes defective or damaged the cardiac impulses do not generate.

For this we use wireless pacemaker that regulates the heart by wireless pulses of ultrasound from outside the organ.

It is beneficial over conventional pacemaker as the leads can fail and requiring the additional surgery to replace them.

Cardiovascular Diseases:


It is the hardening of the arteries due to the formation of plaques and calcification in their walls.


Deposition of cholesterol in the walls of arteries due which they become narrow and hinder the blood flow across them.

Heart Attack: It is caused due to sudden decrease in blood  supply to heart which leads to the damage of heart muscles.


Morphology is the branch of biology of that deals with the study and forms of various parts of plants. It includes the external structure of plant such as stem, root, leaves, etc.


  • Primary roots are developed from the radicle of embryo.
  • These roots are further develops into tertiary roots.
  • Roots are always developed in soil.
  • Roots are of two types i.e. Tap root and Adventitious root.

Modification of Tap roots:


Modification of Adventitious Roots:



  • Stem is that portion of plant which grows upwards.
  • It is develop from plumule

Modification of Stem:


Morphology of Leaves:

Its main function is to make food through photosynthesis.

Leaf are made up of leaf base, petiole and lamina.

At the base of leaf small leaf like structure called stipules are present.


Morphology of Flower:

  1. Flower is the reproductive part of the plant.
  2. Flower are generally modified shoot.

Various parts of flower are as follows:


  • It is the male sex organ develops pollen grain.
  • Its unit is stamen.
  • Anther and filament are part of stamen.


  • It is the female reproductive organ.
  • Its unit is carpel.
  • Ovary, Style and Stigma are three different part  of Carpel.


  • The process of reaching of pollen grains to stigma is called pollination.
  • There are two type of pollination i.e. Self- pollination and Cross-pollination.


  • The process of fusion of male nucleus with egg cell is called fertilization.
  • Fertilized egg is called zygote.
  • In angiosperms the fertilization is triple fusion whereas in other category of plants it is double fusion.


  • When fruit are developed without fertilization i.e. in ovary this is called parthenocarpy.
  • These types of fruits are seedless, example- Banana, Papaya, Orange, Grapes, Pine-apple etc.

Fruit and seeds:

  • Fruit is the ripened ovary developed after fertilisation.
  • Seeds are mature ovule developed after fertilisation.

Fruits are divided into three parts:

  • Simple fruits like Banana, Guava etc.
  • Aggregate fruits like strawberry, custard apple etc.
  • Composite fruits like jackfruit and mulberry

Some fruit and their edible parts:


All about Minerals & their Deficiency Diseases

Minerals are specific kinds of nutrients that the body needs in order to function properly. A mineral deficiency occurs when the body doesn’t obtain the required amount of a mineral. Minerals helps in building strong teeth and bones, skin, hair, proper function of nerves, muscle contraction, maintains heart functions, etc.

Some important Minerals necessary for Human Body are:

Sources: Milk, dairy foods, cereals (Ragi), meat, vegetables, fruits (Sitaphals)
Properties: Component of bones and teeth, helps in blood clotting, Muscle contraction, Conduction of nerve impulses etc. Acts as cofactor of Myosin ATPase.
Deficiency: Defective bones and teeth, Tetany and rickets, Loss of muscle coordination

Sources: Milk, dairy foods, Cereals, eggs, fish, meat etc.
Properties: Formation of bones and teeth, Component of nucleic acids, energy molecules and coenzymes
Deficiency: Poor body growth, weak bones and teeth.

Sources: Table salt, vegetables
Properties: Maintains water balance, blood pressure and nervous system.
Deficiency: Improper muscle contraction; nervous depression; loss of Na+ in urine, dehydration

Sources: Vegetables, molasses, banana, date etc
Properties: Osmotic balance; muscle contraction; nerve impulse conduction
Deficiency: Nervous disorder; poor muscle control leading to paralysis

Sources: Green leafy vegetables, soyabean etc
Properties: Cofactor for enzymes e.g. of hexokinase
Deficiency: Heart and vascular irregularities; dilated blood vessels, loss of muscle coordination.

Sources: Common salt
Properties: Main anion of ECF, Acid- base balance
Deficiency: Vomiting and hypochloremic alkalosis

Sources: Liver, eggs, molasses, cereals, pulses, leafy vegetables, apple, guava etc.
Properties: Formation of Hb so help in O2 transport, Component of cytochromes of ETS, Cofactor of catalase enzyme.
Deficiency: Anaemia; skin problems

Sources: Sea foods, leafy vegetables, water, iodized salt etc.
Properties: Normal functioning of thyroid; component of thyroxin so controls BMR
Deficiency: Goiter, Cretinism, Myxoedema

Sources: Beet, cheese
Properties: Cofactor of carbonic anhydrase so helps in CO2 transport, Vitamin A metabolism
Deficiency: Reduced respiration

Sources: Liver, spleen, kidneys, peanuts, beet etc
Properties: Cofactor for enzymes e.g. oxidases and tyrosinase, Component of haemocyanin.
Deficiency: Anaemia

Sources: Water, sea fish, cheese
Properties: Maintains enamel and prevents dental caries.
Deficiency: Dental caries.

  1. Melvin Kelvin was awarded Nobel Prize for his work on Photosynthesis
  2. The largest flower in the world is Refflessia and the smallest one is wolfessia.
  3. Penicillin is obtained from penicillium Notatum.
  4. Reserpine derived from the plant ‘serpentine’ is used to alleviate high blood pressure.
  5. Plants, living in acidic soils, are called oxalophytes.
  6. Photosynthesis is most active in blue and red light in which light energy is converted into chemical energy and 02 is not a limiting process during this process.
  7. The smallest bone, lies stapes is found in the human ear.
  8. Enzymes are basically proteins.
  9. Mitochondria is called the ‘power house of the cell’
  10. Pancreas is both an endocrine and exocrine gland.
  11. Persons of blood group ‘0’ are called ‘Universal Donor’ while that of ‘AB‘ are called ‘Universal Acceptors’.
  12. Seedless fruits are formed by parthenogenesis.
  13. Simple plants that contain no chlorophyll are called fungi.
  14. Spirogyra is commonly known as ‘pond silk’
  15. The longest muscle in the human body is found in thigh.
  16. In a leaf, the opening between two guard cells is stomata.
  17. Gibberellins are responsible for cell elongation.
  18. The chemical name of chlorophyll is magnesium Dihydro prophysin.
  19. Bile is produced in liver and stored in gel bladder.
  20. All arteries, except pulmonary artery carry oxygenated blood.
  21. The main function of W.B. C. is to produce antibodies.
  22. Retina in the eye, acts as a film in the camera.
  23. Human tears contain a mild antibacterial agent, named Lysozyme.
  24. The biggest bone in the human body is femur.
  25. Vitamin B12 is almost never found in plants.
  26. Agrostology is the study of grasses.
  27. Phycology is the study of a algae while the study of fossils is called paleontology
  28. Hydroponics is cultivating plants without using soil.
  29. Palco botany is the study of fossils of botanical specimens.
  30. Pepsin & Lactose enzymes ad on proteins in the digestive system.
  31. The water soluble vitamins are vitamin B and C
  32. A chemical change in DNA molecule is called mutation.
  33. Glycogen acts as a short ­term food reserve in animals.
  34. Estrogen is a female sex hormone.
  35. The enzyme amylase aids in the digestion of starch.
  36. ATP synthesis takes place mitochondria.
  37. 70% of the body weight of a man is water.
  38. The tough transparent membrane that protects the eye ball is called cornea.
  39. Energy is produced in human body by Carbohydrates.
  40. Sugar is the product of the dark reactions of photosynthesis.


  • Organic compound required in small amounts in the die to maintain normal metabolic functions are known as ‘Vitamins’.
  • The term vitamine was changed to vitamin when it was realized that not all vitamins are amines.
  • Many vitamins act as (or) are converted into coenzymes; they neither provide energy nor are incorporated into tissues.
  • These also regulate the Bio-chemical processes in the body.

Vitamins are classified into two groups

  1. Fat soluble vitamins (A, D, E, K). These are rich in liver cells.
  2. Water soluble vitamins (C, B-complex). These are present in much smaller amounts in cells.

Fat soluble vitamins:

Vitamin A:

  • Vitamin A is also known as ‘Retinol‘.
  • Deficiency diseases: Night blindness, redness in eyes (Exophthalmia), degeneration of lachrymal glands.

Vitamin D:

  • Vitamin D is also known as ‘Calciferol’.
  • Deficiency diseases: Rickets in children, Osteomalacia in adults.

Vitamin E:

  • Vitamin E is also known as ‘Tocopherol’.
  • Deficiency diseases: Sterility nutritional nuclear dystrophy, neurosis of heart muscles.

Vitamin K:

  • Vitamin K is also known as ‘Anti hemorrhagic‘.
  • Deficiency diseases: Blood coagulation is prevented, continuous bleeding occurs.

Water soluble vitamins:

Vitamin ‘B Complex’: Vitamin B Complex is a mixture of B1, B2, B3, B5, B6, B7, B9, and B12.

 Vitamin B1:

  • Vitamin B1 is also known as Thiamin.
  • Deficiency diseases: Beri Beri disease which affects the legs.

Vitamin B2:

  • Vitamin B2 is also known as Riboflavin.
  • Deficiency diseases: Dark red tongue, dermatitis, cheilosis occurs at the corners of mouth & lips.

Vitamin B3:

  • Vitamin B3 is also known as Pentothenic acid.
  • Deficiency diseases: Burning sensations of feet.

Vitamin B5:

  • Vitamin B5 is also known as Nicotinic acid/Niacin.
  • Deficiency diseases: Pellagra, dermatitis, diarrhea.

Vitamin B6:

  • Vitamin B6 is also known as Pyridoxine.
  • Deficiency diseases: Dermatitis and convulsions.

Vitamin B7:

  • Vitamin B7 is also known as Biotin (also considered as vitamin H).
  • Deficiency diseases: Dermatitis, blood cholesterol increases, loss of hair and paralysis.

Vitamin B9:

  • Vitamin B9 is also known as Folic acid.
  • Deficiency diseases: Anemia, inflammation of tongue, gastro intestinal disorders.

Vitamin B12:

  • Vitamin B12 is also known as ‘Cynocobal amine’.
  • Deficiency diseases: Pernicious anemia, hyperglycemia.

Vitamin C:

  • Vitamin C is also known as ‘Ascorbic acid’.
  • Deficiency diseases: Scurvy, delay in wound healing.

Human Diseases Caused by Fungi :-

  • Ringworm caused by Microsporum, Trichophyton by direct contact from unbathed cats and dogs or objects handled by infected individuals.
  • Athlete’s foot caused by Trichophyton by Bad foot hygiene where skin remains warm and moist for long period, fungi finds optimal condition, invade dead outer layer of skin.

Human Diseases Caused by Viruses ­

  • Smallpox caused by Variola Virus by direct contact (droplets), indirected by
  • infected articles.
  • Chicken pox caused by Varicella virus by direct contact (droplets) indirected
  • by infected objects.
  • Common cold caused by Rhinovirus by contact.
  • Influenza/Flu caused by Orthomixo­virus by contact (droplets) virus transmitted through discharge from respiratory tracts of persons infected with disease
  • Mumps caused by Mumps virus by direct contact, virus in Saliva and secretion of nose invades salivary glands.
  • Viral encephalitis caused by Encephalitis virus (arbovirus) by some domestic animals reservoir of virus, transmitted by mosquito bite to man.
  • Poliomyelitis caused by Poliovirus by contact, houseflies, fleas, food and water.
  • Rabies (Hydrophobia) caused by Rabies virus (Rhabdovirus) by Bite a mad
  • (rabid) dog
  • Dengue fever or breakbone fever caused by Dengue virus (arbovirus) by Mosquito (Aedes) bite.
  • Acquired Immunodeficiency Syndrome (AIDS) caused by Human T­cell
  • Lenkemia virus (HTLV­IlI) also called LAV (Retrovirus) by blood and sperm among homosexuals, heterosexuals, intravenous drug users, haemophiliacs, promiscuous individuals and prostitutes.

Human Diseases Caused by Bacteria

  • Septic sore throat caused by Streptococcus Sp by Bacteria infect throat and nasal membranes by droplets and direct contact.
  • Diphtheria caused by Irregular rod (Corynebacterium diphtheria) by Bacteria infect respiratory tract by carrier, through contact, droplets and food items.
  • Pneumonia caused by Diplococcus pneumonia by Bacteria transmitted to respiratory tract, including the lungs by droplet infection.
  • Tuberculosis caused by Irregular rod (Mycobacterium tuberculosis) by Bacteria transmitted to lungs, bones and other organs by direct contact droplet infection, food and milk.
  • Plague or Bubonic caused by Short rod (Yersinia pestis) by Rat flea spreads disease from rat to man.
  • Tetanus or Lock­Jaw caused by Clostridium tetani by Bacteria in soil, enter through wound.
  • Typhoid or enteric fever caused by, Salmonella typhi by Flies, food, faces water and carriers.
  • Cholera caused by Vibrio cholerae by Flies food, stools, water and carriers.
  • Bacillary dysentery caused by short rod (Shigella dysenteriae)by Flies, food, faeces, water and carriers.
  • Whooping cough caused by small short rod (Hemophilus pertussis) by Droplets protected during coughing and sneezing.
  • Syphilis caused by Spiral­shaped organism (Treponema pallidam) by direct contact, chiefly sexual intercourse.
  • Leprosy caused by Mycobacterium Leprae by long and close contact with infected persons
  • Botulism caused by Clostridium botulinum by organism produces poison in food.

Human Diseases Caused by Protozoans

  • Amoebic dysentery (Amoebiasis) caused by Entamoeba histolytica by Transmission from man to man through ingestion of cysts in drinking water vegetables and food contaminated with faeces.
  • DiarrheaGiardiasis‘ caused by Giardia intestinalis by Transmission from man to man through ingestion of cysts in drinking water vegetables and food contaminated with faces.
  • Malaria caused by Plasmodium vivax by Transmitted to man by bite of an infected female auophelise mosquito.
  • Sleeping sickness (Trypanosomiasis) caused by Trypanosoma brucei by Transmitted by bite of tse­tse fly

Human Blood

  • Blood is a fluid connective tissue.
  • The quantity of blood in the human’s body is 7% of the total weight.
  • This is a dissolution of base whose pH value is 7.4.
  • There is an average of 5-6 litres of blood in human body.
  • Female contains half litre of blood less in comparison to male.
  • Blood consists of two parts:- (A) Plasma (B) Blood Corpuscles

(A) Plasma

  • This is the liquid part of blood. 60% of the blood is plasma. Its 90% parts is water, 7% protein, 0.9% salt and 0.1% is glucose. Remaining substances are in a very low quantity.
  • Function of plasma – Transportation of digested food, hormones, excretory product etc. from the body takes place through plasma.
  • Serum – When Fibrinogen & Protein is extracted out of plasma, the remaining plasma is called serum.

(B) Blood Corpuscles (40% part of the blood)

This is divided into three parts:

1.Red Blood Corpuscles (RBC)

  • Red Blood Corpuscles (RBC) of a mammal is biconcave
  • There is no nucleus in it. Exception – Camel and Lama.
  • RBC is formed in Bone Marrow( At the embroynic stage its formation takes place in liver.)
  • Its life span is from 20 days to 120 days.
  • Its destruction takes place in liver & spleen. Therefore, liver is called grave of RBC.
  • It contains haemoglobin, in which haeme iron containing compound is found and due to this the colour of blood is red.
  • Globin is a proteinous compound which is extremely capable of combining with oxygen and carbon dioxide.
  • The iron compound found in haemoglobin, is haematin.
  • The main function of RBC is to carry oxygen to all cells of the body and bring back the carbon dioxide.
  • Anaemia disease is caused due to the deficiency of haemoglobin.
  • At the time of sleeping RBC is reduced by 5% and people who are at the height of 4200 metres RBC increases by 30% in them.

2. White Blood Corpuscles (WBC) or Leucocytes

  • In shape and constitution this is similar to Amoeba.
  • Its formation takes place in Bone Marrow, lymph node and sometimes in liver and spleen.
  • Its life span is from 1 to 2 days.
  • Nucleus is present in the White Blood Corpuscles.
  • Its main function is to protect the body from the disease. The ratio of RBC and WBC is 600:1.

3. Blood Platelets or Thrombocytes 

  • It is found only in the blood of human and other mammals.
  • There is no nucleus in it.
  • Its formation takes place in Bone marrow.
  • Its life span is from 3 to 5 days.
  • It dies in the Spleen.
  • Its main function is to help in clotting of blood.

Function of Blood:

  • To control the temperature of the body and to protect the body from diseases.

Clotting of blood.

  • Transportation of oxygen, Carbon dioxide, digested food, conduction of hormones etc.
  • To help in establishing coordination among different parts.

Blood Group of Human

  • Blood group was discovered by Lansteiner in 1900.
  • For this, he was awarded with Nobel Prize in the year 1930.
  • The main reason behind the difference in blood of human is the glyco protein which is found in Red Blood Corpuscles called antigen. Antigen are of two types- Antigen A and Antigen B.
  • On the basis of presence of Antigen or Glyco Protein, there are four group of blood in human:
  • That contains Antigen A – Blood Group A.
  • That contains Antigen B– Blood Group B.
  • That contains both the Antigen A and B – Blood Group AB.
  • That contains neither of the Antigens- Blood Group O.
  • An opposite type of protein, is found in blood plasma. This is called antibody. This is also of two types- Antibody “a” and Antibody “b”.
    Blood Group O is called the Universal Donor because it does not contain any antigen.
    Blood Group AB is called Universal Receptor because it does not contain any antibody

Deoxyribo nucleic Acid (DNA) :

  • DNA stands for Deoxyribo nucleic Acid , it was discovered by Frederic Maischer.
  • DNA is a double stranded molecule made up of elongated chain of sub-units called nucleotides.
  • DNA is mainly found in nucleus and in small amount it is also found in mitochondria an chloroplast.
  • Chemically a nucleotide has three components.

(1) Nitrogenous base

(2) Pentose Sugar

(3) Phosphate group.

  • Nitrogenous  base are of two type i.e.Purine & Pyrimidines. 
  • Purines contain two nitrogen base i.e. Adinine and Guanine.
  • Pyrimidine nitrogen base are Thymine and Cytosine, thus there are four kinds of nucleotide present in DNA i.e. Adinine, Guanine, Thymine, Cytosine.

Structure of DNA:

  • Watson and Crick give the structural model of DN
  • DNA molecule is consists of two polynucleotide strand, forming a double helix structure.
  • Each strand has a backbone of sugar and phosphate, nitrogen base is attached to the sugar.
  • Two strands are joined together by hydrogen bonds between the bases.
  • Adenine pairs with thymine whereas guanine pairs with cytosine.
  • Adenine and thymine are complementary to each other and cytosine is complementary to guanine.

Function of DNA:

  • DNA is genetic material and contains genetic information in coded form.
  • DNA has two main function replication and expression.

2.Ribonucleic Acid (RNA) : 

  • RNA stands for Ribonucleic acid.
  • RNA is single stranded nucleic acid made up of phosphate, ribose sugar and nitrogen base uracil, adinine, guanine and cytosine.
  • It is found in nucleus as well as cytoplasm.
  • Its main function is to synthesis the protein.
  • RNA is of three kind.

    1.Messenger RNA (mRNA): It brings the massage from DNA found in the nucleus to cytoplasm in the coded          form.

     2.Ribosomal RNA (rRNA): Present in ribosome which is the site of protein synthesis.

     3.Transfer RNA (t RNA): It is the carrier of amino acid and transfers it to the ribosome.

Difference between RNA and DNA



  • Virus was discovered by Russian Scientist Iavanosky during the test of Mosaic disease in Tobacco.
  • Virus acts as a link between the living and non-living.
  • Virus is dead but when it comes in contact with the living cell it gets activated.
  • ‘The virus in which RNA  is found as the genetic material are called Retrovirus.
  • Virus is of three types:
  1. Plant Virus: RNA is present as its nucleic acid
  2. Animal Cell: DNA and sometimes RNA is found in it.
  3. Bacteriophage: They kill the bacteria e.g. T-2 phage.


  • Bacteria was discovered by Antony von Lecuwenhoek and its study is known as bacteriology.
  •  Bacteria is of different types on the basis of shape:
  1. Bacillus: This is a rod like or cylindrical.
  2. Round or Cocus: These are round and smallest bacteria.
  3. Comma shape or vibrio
  4. Sprillum: Spring or Screw shaped.
  • Anabaena and Nostoc cyanobacteria fixed the atmospheric nitrogen into soil.

Biology concept

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