1770 : Joseph Priestley - Essential role of air in growth of green plant.
1774 : Joseph Priestley - Discovered O2.
1831 : Robert Brown - Ist discovered and described nucleus.
1838 : Schleiden (German Botanist) - Work on plants.
1839 : Schwann(British Zoologist) - Work on both plants & animals.
1855 : Rudolf Virchow - Omnis cellula-e-cellula (cells arises from
Life originate from pre-existing life : Pasteur (Yeast).
Life originate from non-living (decaying & rotting matter) : Spontaneous
Life originate from pre-existing non-living organic molecules (RNA,
Protein)- Oparin (Russia) & Haldane (England)- Chemical Evolution.
1856 - 1863 : Mendal experiment on garden pea. (7 years)
1860 : Julius von Sachs - Developed hydroponics.
1865 : Mendal published his work.
1866 : Langdon Down - Down’s syndrome.
1869 : Friedrich Meischer - Ist identified DNA and named it nuclein.
1891 : Henking - Discovered X-body.
1891 : Fossil discovered in Java - Homo erectus.
1892 : Ivanowsky - Discovered virus.
1898 : Beijerinek - Contagium vivum fluidum (infectious living fluid).
1898 : Camillo Golgi - Discovered (observed) G.B.
1900 : de Vries, Corre ns and von Tsche rmak inde pende ntly
rediscovered Mendel’s results.
1902 : Chromosome movement during meiosis has been worked out.
1905 : Law of limiting factor (Blackmann).
1928 : Fredrick Griffith - Transforming experiment with Streptococcus
1935 : Stanley - Crystallised viruses.
1937 : Ramde o Misra obtained Ph.D. in Ecology from Lee ds
1938 : Coelocanth fish caught in South Africa.
1945 : Fleming, Chain & Florey - Awarded Nobel prize.
1950 : Watson obtained Ph.D. on a study of the effect of hard X-rays
on bacteriophage multiplication.
1951 : Family planning programme started in India.
1952 : Hershey & Chase-experiment on bacteriophage or Bacterial virus
gives unequivocal proof that DNA is the genetic material.
1953 : Miller experiment - Methane, ammonia, hydrogen & water
1953 : Watson & Crick - Double helical structure of B-DNA &
1953 : Palade : Discovered ribosome.
1954 : Ramachandran - Triple helical model of collagen, published
1954 : Crick complete d Ph.D. on a thesis “X-rays diffraction :
polypeptides and proteins.
1958 : Meselson & Stahl - Work on E.coli proves semiconservative
replication of DNA in prokaryotes.
1958 : Taylor - Work on Vicia faba proves semiconservative replication
of DNA in eukaryotes.
1960 : Katherine Esau - Published “Anatomy of Seed Plants.”
1961 : Melvin Calvin - Nobel Prize.
1962 : Watson, Crick and Wilikins - Nobel Prize.
1963 : Wheat varieties (Sonalika & Kalyan sona) introduced.
1963 : Two enzyme responsible for restricting growth of bacteriophage
in E.coli were isolated.
1966 : Derivative of IR-8 & Taichung native-I introduced.
1969 : Whittaker - Five kingdom classification.
1971 : Govt. of India legalized MTP.
1971 : Diener- Discovered Viroid(free RNA without capsid).
1972 : Singer & Nicolson - Fluid mosaic model.
1972 : Stanley Cohen & Herbert Boyer - Formed Ist recombinant DNA.
1972 : Establishme nt of NCEPC - National Committe e for
Environmental Planning & Coordination.
1974 : Water act.
1980 : Joint forest management, (JFM).
1981 : AIDS was Ist reported.
1981 : Air act.
1983 : Eli Lily (An American company) produces insulin in E.coli by
recombinant DNA technology.
1984 : Establishment of MOEF : Ministry of Environment & Forest.
1986 : Environment Protection Act.
1987 : Montreal protocol. Held in Montreal, Canada.
Disorders of digestive system
The inflammation of the intestinal tract is the most common ailment due
to bacterial or viral infections. The infections are also caused by the
parasites of the intestine like tapeworm, roundworm, threadworm,
hookworm, pin worm, etc.
Jaundice: The liver is affected, skin and eyes turn yellow due to the
deposit of bile pigments.
Vomiting: It is the ejection of stomach contents through the mouth. This
reflex action is controlled by the vomit centre in the medulla. A feeling of
nausea precedes vomiting.
Diarrhoea: The abnormal frequency of bowel movement and increased
liquidity of the faecal discharge is known as diarrhoea. It reduces the
absorption of food.
Constipation: In constipation, the faeces are retained within the colon
as the bowel movements occur irregularly.
Indigestion: In this condition, the food is not properly digested leading to
a feeling of fullness. The causes of indigestion are inadequate enzyme
secretion, anxiety, food poisoning, over eating, and spicy food.
PEM: PEM affects
infants and children to produce Marasmus and Kwashiorkar.
Marasmus is produced by a simultaneous deficiency of proteins and
calories. It is found in infants less than a year in age, if mother’s milk is
replaced too early by other foods which are poor in both proteins and
caloric value. This often happens if the mother has second pregnancy or
childbirth when the older infant is still too young. In Marasmus, protein
deficiency impairs growth and replacement of tissue proteins; extreme
emaciation of the body and thinning of limbs results, the skin becomes
dry, thin and wrinkled. Growth rate and body weight decline considerably.
Even growth and development of brain and mental faculties are impaired.
Kwashiorkar is produced by protein deficiency unaccompanied by calorie
deficiency. It results from the replacement of mother’s milk by a high calorie-
low protein diet in a child more than one year in age. Like marasmus,
kwashiorkor shows wasting of muscles, thinning of limbs, failure of growth
and brain development. But unlike marasmus, some fat is still left under
the skin; moreover, extensive oedema and swelling of body parts are seen
Volumes and capacities of Lungs
Tidal Volume (TV): Volume of air inspired or
expired during a normal respiration. It is
approx. 500 mL., i.e., a healthy man can
inspire or expire approximately 6000 to 8000
mL of air per minute.
Inspiratory Reserve Volume (IRV):
Additional volume of air, a person can inspire
by a forcible inspiration. This averages 2500
mL to 3000 mL.
Expiratory Reserve Volume (ERV):
Additional volume of air, a person can expire
by a forcible expiration. This averages 1000
mL to 1100 mL.
Residual Volume (RV): Volume of air remaining in the lungs even after a
forcible expiration. This averages 1100 mL to 1200 mL.
By adding up a few respiratory volumes described above, one can
derive various pulmonary capacities, which can be used in clinical
Inspiratory Capacity (IC): Total volume of air a person can inspire
after a normal expiration. This includes tidal volume and inspiratory
reserve volume ( TV+IRV).
Expiratory Capacity (EC): Total volume of air a person can expire after
a normal inspiration. This includes tidal volume and expiratory reserve
Functional Residual Capacity (FRC): Volume of air that will remain in
the lungs after a normal expiration. This includes ERV+RV.
Vital Capacity (VC): The maximum volume of air a person can breathe in
after a forced expiration. This includes ERV, TV and IRV or the maximum
volume of air a person can breathe out after a forced inspiration.
Total Lung Capacity (TLC): Total volume of air accommodated in the
lungs at the end of a forced inspiration. This includes RV, ERV, TV and
IRV or vital capacity + residual volume.
Disorders of Cardiovascular system
High Blood Pressure (Hypertension): Hypertension is the term for blood
pressure that is higher than normal (120/80). In this measurement 120
mm Hg (millimetres of mercury pressure) is the systolic, or pumping,
pressure and 80 mm Hg is the diastolic, or resting, pressure. If repeated
checks of blood pressure of an individual is 140/90 (140 over 90) or higher, it shows hypertension. High blood pressure leads to heart diseases
and also affects vital organs like brain and kidney.
Coronary Artery Disease (CAD): Coronary Artery Disease, often referred
to as atherosclerosis, affects the vessels that supply blood to the heart
muscle. It is caused by deposits of calcium, fat, cholesterol and fibrous
tissues, which makes the lumen of arteries narrower.
Angina: It is also called ‘angina pectoris’. A symptom of acute chest pain
appears when no enough oxygen is reaching the heart muscle. Angina
can occur in men and women of any age but it is more common among
the middle-aged and elderly. It occurs due to conditions that affect the
Heart Failure: Heart failure means the state of heart when it is not pumping
blood effectively enough to meet the needs of the body. It is sometimes
called congestive heart failure because congestion of the lungs is one of
the main symptoms of this disease. Heart failure is not the same as cardiac
arrest (when the heart stops beating) or a heart attack (when the heart
muscle is suddenly damaged by an inadequate blood supply).
BLOOD GROUPING SYSTEM
As you know, blood of human beings differ in certain aspects though it
appears to be similar. Various types of grouping of blood has been done.
Two such groupings – the ABO and Rh – are widely used all over the
ABO grouping is based on the presence or absence of two surface antigens
(chemicals that can induce immune response) on the RBCs namely A
and B. Similarly, the plasma of different individuals contain two natural
antibodies (proteins produced in response to antigens). The distribution
of antigens and antibodies in the four groups of blood, A, B, AB and O
. You probably know that during blood transfusion,
any blood cannot be used; the blood of a donor has to be carefully matched
with the blood of a recipient before any blood transfusion to avoid severe
problems of clumping (destruction of RBC).
From the above mentioned table it is evident that group ‘O’ blood can
be donated to persons with any other blood group and hence ‘O’ group
individuals are called ‘universal donors’. Persons with ‘AB’ group can
accept blood from persons with AB as well as the other groups of blood.
Therefore, such persons are called ‘universal recipients’.
Functions of Brain
Sensory processing: The brain receives and processes sensory information from the five senses (sight, hearing, touch, taste, and smell).
Movement control: The brain coordinates and controls voluntary and involuntary movement.
Emotion regulation: The brain regulates emotional responses and experiences.
Learning and memory: The brain is responsible for encoding, storing, and retrieving memories.
Thinking and reasoning: The brain is responsible for complex mental processes such as problem-solving, decision-making, and abstract thinking.
Language processing: The brain processes language and allows for speech and communication.
Homeostasis: The brain regulates various physiological processes, such as hunger, thirst, and temperature control, to maintain a stable internal environment.
(1) Definition: It is well developed electron microscopic network of interconnected cisternae, tubules and vesicles present throughout the cytoplasm, especially in the endoplasm.
(2) Discovery: Garnier (1897) was first to observe the ergastoplasm in a cell. The ER was first noted by Porter, Claude, and Fullman in 1945 as a network. It was named by Porter in 1953.
(1) Definition: Golgi complex is made up of various membranous system e.g. cisternae, vesicles and vacuoles.
(2) These are also called golgi bodies, golgisomes, lipochondrion, dictyosomes, Dalton complex, idiosomes or Baker’s body.
(3) These are also called “traffic police” of the cell.
(4) Discovery: First observed by George (1867) but it’s morphological details were given by Camillo Golgi (1898), in nerve cells of barn fowl and cat .
**Biotechnology important points **
Steps of recombinant DNA technology
(1) Isolating a useful DNA segment from the donor organism.
(2) Splicing it into a suitable vector under conditions to ensure that each vector receives no more than one DNA fragment.
(3) Producing of multiple copies of his recombinant DNA.
(4) Inserting this altered DNA into a recipient organism.
(5) Screening of the transformed cells.
Vector in genetic engineering is usually a DNA segment used as a carrier for transferring selected DNA into living cells. These are as follows:
(1) Plasmid: Plasmid is extra chromosomal, closed circular double stranded molecules of DNA present in most eukaryotes. All plasmid carry replicons pieces of DNA that have the genetic information required to replicate. Plasmid pBR 322 was one of the first widely used cloning vectors, it contain both ampicillin and tetracycline resistance genes.
(2) Phage: It is constructed from the phage l chromosomes and acts as bacteriophage cloning vectors.
(3) Cosmid: The hybrids between plasmid and the phage l chromosome give rise to cosmid vectors.
(4) Beside all these there are artificial chromosomes like
(i) BACs (Bacterial Artificial chromosomes)
(ii) YACs (Yeast Artificial chromosomes)
(iii) MACs (Mammalian Artificial chromosomes) are very efficient vectors for eukaryotic gene transfers.
Application of recombinant DNA technology:
The technique of recombinant DNA can be employed in the following ways.
(1) It can be used to elucidate molecular events in the biological process such as cellular differentiation and ageing. The same can be used for making gene maps with precision.
(2) In biochemical and pharmaceutical industry, by engineering genes, useful chemical compounds can be produced cheaply and efficiently which is shown in table.
Important Points Of Ncert
DISORDERS OF MUSCULAR AND SKELETAL SYSTEM
Myasthenia gravis: Auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle.
Muscular dystrophy: Progressive degeneration of skeletal muscle mostly due to genetic disorder.
Tetany: Rapid spasms (wild contractions) in muscle due to low Ca++ in body fluid.
Arthritis: Inflammation of joints.
Osteoporosis: Age-related disorder characterised by decreased bone mass
and increased chances of fractures. Decreased levels of estrogen is a common cause.
Gout: Inflammation of joints due to accumulation of uric acid crystals.
Important definitions in Biology for NEET 2023
DNA: Deoxyribonucleic acid, a molecule that carries genetic information.
RNA: Ribonucleic acid, a molecule that plays a key role in protein synthesis.
Protein: A macromolecule made up of amino acids that carries out a variety of functions in the cell.
Enzyme: A type of protein that catalyzes chemical reactions in the cell.
Cell membrane: The thin, flexible layer that surrounds all cells and regulates the movement of molecules in and out of the cell.
Mitosis: The process by which a single cell divides into two identical daughter cells.
Meiosis: The process by which cells divide to produce gametes (sperm and eggs), each with half the number of chromosomes as the parent cell.
Gene: A segment of DNA that codes for a specific protein or trait.
Allele: One of two or more alternative forms of a gene.
Mutation: A change in the DNA sequence that can result in altered gene function or the creation of new alleles.
Natural selection: The process by which individuals with advantageous traits are more likely to survive and reproduce, leading to the evolution of populations over time.
Adaptation: A trait or characteristic that increases an organism’s fitness in its environment.
Photosynthesis: The process by which green plants convert sunlight into energy in the form of organic compounds.
Cellular respiration: The process by which cells convert organic compounds into energy in the form of ATP.
Ecosystem: A community of living and non-living things that interact with each other and their environment.
Homeostasis: The ability of organisms to maintain a stable internal environment in the face of changing external conditions.
Evolution: The process by which species change over time as a result of genetic variation and natural selection.
Ecology: The study of the interactions between living organisms and their environment.
Biotechnology: The use of living organisms or their products to develop new products or processes.
Epidemiology: The study of the distribution and determinants of health and disease in populations.
Important definitions of Cell Biology
Chromosome: A structure made of DNA and protein that carries genetic information.
Cytoplasm: The gel-like substance inside a cell that contains organelles and other cell components.
Organelle: A specialized structure within a cell that performs a specific function.
Nucleus: The control center of a cell that contains the cell’s DNA.
Ribosome: The site of protein synthesis in a cell.
Mitochondria: The organelles responsible for producing ATP through cellular respiration.
Chloroplast: The organelles in plant cells responsible for photosynthesis.
Cytoskeleton: The network of protein filaments that give a cell its shape and allow for movement.
Endoplasmic reticulum: A network of membranes in the cytoplasm that is involved in protein and lipid synthesis.
Golgi apparatus: An organelle that modifies, sorts, and packages proteins for secretion or transport.
Lysosome: An organelle that contains enzymes for breaking down and recycling cellular waste.
Vacuole: A membrane-bound organelle that stores materials such as water, nutrients, and waste products.
ATP: Adenosine triphosphate, the molecule that carries energy within cells.
Aerobic respiration: The process of producing ATP in the presence of oxygen.
Anaerobic respiration: The process of producing ATP in the absence of oxygen
Important quick revision points of EVOLUTION
(i) Ancient theories of origin of life: Various theories have been put forward to explain the phenomenon of origin of life. A few of them were only speculations while others were based on scientific grounds. These theories are –
(a) Theory of special creation.
(b) Theory of spontaneous generation or Abiogenesis.
(d) Cosmozoic theory
(e) Theory of sudden creation from inorganic material.
(f) Naturalistic theory
(ii) Oparin’s Modern Theory:
(a) Oparin (1924) proposed that “life could have originated from non-living organic molecules.”
(b) He believed in Biochemical origin of life. Haldane (1929) also stated similar views. Oparin greatly expanded his ideas and presented them as a book “The origin of life” in 1936.
(c) According to this theory, the Earth originated about 4,500 million years ago. When the earth was cooling down, it had a reduced atmosphere. In this primitive atmosphere nitrogen, hydrogen, ammonia, methane, carbon mono-oxide and water were present. Energy was available in the form of electric discharges by lightening and ultraviolet rays. As soon as the earth crust was formed, it was very much folded. Torrential rains poured over the earth for centuries and were deposited in deep places.
(d) Miller’s Experiment: An American scientist (Biologist) Stanley Miller (1953) performed an experiment under support Oparin’s theory of origin of life. He believed that basic compounds which are essential for life can be synthesised in the laboratory by creation in the laboratory, on a small scale, the conditions which must have existed at the time of origin of life on earth.
(e) Miller took a flask and filled it with methane, ammonia and hydrogen in proportion of 2:1:2 respectively at 0°C. This proportion of gases probably existed in the environment at time of origin of life. This flask was connected with a smaller flask, that was filled with water, with the help of glass tubes. In the bigger flask, two electrodes of tungsten were fitted. Then a current of 60,000 volts was passes, through gases containing bigger flask for seven days. At the end of seven days, when the vapours condensed, a red substance was found in the U-tube. When this red substance was analyzed, it was found to contain amino acids, Glycine and nitrogenous bases which are found in the nucleus of a cell.
(f) The entire process of the origin of life, as proposed by Oparin, can be summarised as under –
(i) The Chemical Evolution:
(1) Step 1: Formation of simple molecules
(2) Step 2: Formation of Simple organic compounds
(3) Step 3: Formation of complex organic compounds
(4) Step 4: Formation of nucleic acids and nucleoproteins
(ii) Organic Evolution:
(1) Step 5: Formation of Coacervates
(2) Step 6: Formation of Primitive cell
(3) Step 7: Origin of autotrophism
(4) Step 8: Origin of Eukaryotic cells
Evidences of Organic Evolution
The following are the evidences in favour of Organic Evolution:
(i) Evidences from Classification
(ii) Evidences from Comparative Anatomy
(a) Analogy and Homology (b) Vestigeal organs
(iii) Evidences from Physiology
(iv) Evidences from Serology
(v) Evidences from Embryology
(vi) Evidences from Palaeontology
(vii) Evidences from geographic distribution
(viii) Evidences from Genetics
(i) Evidences from Classification: All the known living animals and plants have been classified into various species, genera, families, order, classes, phyla and kingdoms. The classification of a particular animal is attempted only after its extensive study.
Neural control and coordination important points
In multicellular organisms, following the general principles of body organization, some specialized tissues are used to provide the control and coordination activities.
Nervous system is specialized system that provide control and coordination in animals.
All information, coming from our environment is detected by the specialized tips of some nerve cells, which are usually located in sense organs.
The information, acquired at the end of the dendritic tip of a nerve cell, sets off a chemical reaction that creates an electrical impulse.
This (electrical) impulse, which travels from the dendrite tip to the cell body, and then along the axon to its end of the axon, sets off the release of some chemicals. These chemicals cross the gap, or synapse, and create a similar electrical impulse in a dendrite of the next neuron.
Likewise, the nervous tissue is made up of an organized network of nerve cells or neurons, and is dedicated for carrying information via electrical impulses from one part of the body to another.
If the nerves that detect heat, cold, or any such kind of more sensational element move muscles in a simpler way; so, the process of detecting the signal or the input and responding to it by an output action, is known as reflex action and such connection is known as a reflex arc.
The communication between the central nervous system and the other parts of the body is established by the peripheral nervous system.
Peripheral nervous system consists of cranial nerves, which arise from the brain and spinal nerves.
The brain facilitates us to recognize, think, and take actions accordingly.
The brain is categorized into three major parts or regions, namely the fore-brain, mid-brain, and hind-brain.
Among these three parts (of the brain), fore-brain is the main thinking part of the brain; further, fore-brain are specialized for hearing, smell, sight, etc.
When brain gives command, muscle moves – it happens because muscle cells have special proteins that change both their (muscle’s) shape and arrangement in the cell in response to nervous electrical impulses.
important NCERT Data and Facts
Weight of Brain (adult) & (child): 1300-1400 gm & 350-400 gm
Weight of Heart: 200-300 gm
Brain in weight of humanbody: 2%
Normal Heart Beat: 72 per min
Breathing Rate: 12-16/min
Normal B.P: 120/80 mm/Hg
Blood clotting time: 3-5 min
No. Of RBC: 5-5.5M/ mm³
No. Of WBC: 6000-8000/mm³
No. Of platelets: 1.5-3 lakh/mm³
Amount of hemoglobin: 12-16 gm/100 ml blood
Reproduction in Human Beings✅
Human beings have typical sexual reproduction process where mature male and female mate to produce a new baby.
Male Reproductive System
The male reproductive system produces the germ-cells; further, other part of the reproductive system delivers the produced germ-cells to the site of fertilization.
The formation of sperms or germ-cells takes place in the testes.
The formation of sperm typically requires a lower temperature than the normal body temperature.
The testes secrete hormone, namely testosterone that brings changes in the appearance of boys at the time of their puberty.
The formed sperms are then delivered through the vas deferens, which unites with a tube coming from the urinary bladder.
The urethra, likewise, acts as a common passage for both the sperms and urine.
The sperms are fluids that consist of mainly genetic material; it has a long tail that helps to move towards the female germ-cell.