Cell is a basic structural and functional unit of life.
Robert Hooke in 1665 coined the word 'cell'.
Anton von Leeuwenhoek first saw and described a live cell.
Robert Brown later had discovered the nucleus.
Cell theory was proposed by Schleiden and Schwann in 1855 to explain the concept of the cellular nature of living organism.
Prokcaryotic Cells
Prokaryotic cells are morphologically most primitive.
Prokaryotic cells are devoid of membrane bound organelles like plastids, mitochondria and advanced (9+2) flagella.
Prokaryotic cells are represented by bacteria, cyanobacteria (blue green algae) mycoplasma and PPLO (pleuropneumonia like organisms).
Eukaryotic Cells:
A eukaryotic cell consists of the following components:
Cell Wall
The cell wall is a non-living, semi-rigid, external protective covering of the cell.
Cell wall is entirely lacking in animals.
It is made up of cellulose secreted by the cell itself.
Cell Mebrane
The cell membrane is a living, thin, elastic and semi- permeable membranous covering of plant and animal cells.
Fluid mosaic model of plasma membrane
J. Singer and G. Nicolson in 1972 proposed the most accepted model of membrane structure. The plasma membrane is a lipid-bilayer with proteins embedded in it.
Lipids are amphipathic, i.e., they are structurally asymmetric with polar hydrophilic and non-polar hydrophobic group.
One of the most important function of plasma membrane is the transport of the molecules across it.
Endoplasmic Reticulum (ER)
There are two types of endoplasmic reticulum i.e.,
Smooth or agranular ER - They do not have attached ribosomes on their surface.
Rough or granular ER - They bear ribosomes on their surface, for protein synthesis.
Golgi apparatus
Golgi apparatus or Golgi complex is a stack of flattened, membrane bounded, parallely arranged organelles that occur in the association of endoplasmic reticulum in the cytoplasmic matrix.
The Golgi apparatus principally performs the function of packaging materials to be delivered either to the intra-cellular targets or secreted outside the cell.
Lysosomes
Lysosomes are popularly called "suicide bags".
Vacuoles
In plant cells, the vacuoles can occupy up to 90 percent of the volume of the cell. The vacuole is bound by a single membrane called tonoplast. They are responsible for maintenance of turgour pressure.
Mitochondria
Mitochondria are also called as powerhouse of cells.
Plastids
Plastids are found in plants and few protists Euglena.
Ribosomes
Ribosomes are smallest cell organelles. They are protein synthesising factories. There are two types of ribosomes viz., Prokaryotic or 70S ribosomes - Eukaryotic or 80S ribosomes
Nucleus
Nucleus is centrally located, spherical and largest more...
Diffusion is a random movement of individual molecules from a region of higher concentration to a region of lower concentration. Diffusion rates are affected by concentration gradient, membrane permeability, temperature and pressure.
The substance that have a hydrophilic moiety, find it difficult to pass through membrane. The movement of such molecules are facilitate, for which proteins provide site at which such molecule cross membrane. This is called as facilitated diffusion.
Active transport uses energy to pump molecules against a concentration gradient.
Plants-Water Relations
Water Potential: The potential energy of water is referred to as water potential. It is measured in term of pressure.
\[{{\psi }_{w}}={{\psi }_{s}}+{{\psi }_{p}}\]
Osmosis: It is the diffusion of water through a semi-permeable membrane. It depends on two factors
(i) Concentration of dissolved solutes in a solution
(ii) Pressure difference.
Plasmolysis: If a turgid cell is placed in a solution that has more solutes, it exerts a higher osmotic pressure and water will move out.
Isotonic solution: When concentration of outer solution (in which cell is placed) is equal to concentration of cell sap.
Hypotonic solution: When concentration of outer solution is lower than concentration of cell sap.
Hypertonic solution: When concentration of outer solution is higher than concentration of cell sap.
Imbibition: It is a type of diffusion by which movement of water takes place along a diffusion gradient. Factors influencing the rate of imbibition are nature of imbibant, surface area of imbibant, temperature, concentration of solutes, pH of imbibant.
Cohesion Theory:
Proposed by Henry Dixon 1914.
Evaporation of water from the leaf to atmosphere decreases the water potential of the epidermal cells.
Transpiration
Loss of water in the form of water vapour from plant through the small pores (stomata) present on leaves is called transpiration.
The Pressure Flow or Mass Flow Hypothesis
It was put forward by Munch (1930). According to this hypothesis, organic substances move from the region of high osmotic pressure to the region of low osmotic pressure in a mass flow due to the development of a gradient of turgor pressure.
Hydroponics: The system of growing plants in soilless culture (also called solution culture or tank farming) is known as hydroponics.
Role of Essential Elements (Macro and Micro) and their Deficiency Symptoms
S. No.
Name of element
In which form they are absorbed
Functions
Deficieny symptims
1.
Nitrogen
\[NO_{2}^{-}\],\[NO_{3}^{-}\]or\[NH_{4}^{+}\]
Major constituent of proteins, nucleic acids, vitamins and minerals.
Chlorosis (yellowing of older leaves
2.
Phosphorous
\[{{H}_{2}}PO_{4}^{2-}\]or\[HPO_{4}^{2-}\]
Constituent, of cell membrane, nucleic acids, more...
The food that we consume must be broken down into simpler absorbable forms so that they can be easily absorbed and transported to various parts of our body through blood. This task is accomplished by the digestive system.
Study of heredity and variation is called genetics.
Term genetics was given by - Bateson.
Father of genetics - Gregor Johann Mendel.
Father of experimental genetics - Thomas Hunt Morgan.
Father of human genetics - Archibald Garrod.
Some Terms in Genetics
Gene: It is segment of DNA. It is basic unit of heredity
Back cross: It is cross which is performed between hybrid and one of its parents.
Test cross: Test cross is crossing of offspring with unknown dominant phenotype with the individual homozygous recessive for the trait.
Monohybrid cross: It is a cross between two organisms of a species which is made to study the inheritance of a single pair of alleles or factors of a character.
Monohybrid ratio: Monohybrid ratio is usually 3:1 (phenotypic ratio) or 1: 2:1 (genotype ratio) in which 25% of the individuals carry the recessive trait, 25% pure dominant and 50% have hybrid dominant trait.
Dihybrid cross: It is a cross between two organisms of a species which is made to study the inheritance of two pairs of factors or alleles of two genes.
Dihybrid ratio: Dihybrid ratio is 9: 3: 3: 1 (phenotypic ratio) where 9/16 first recessive and second dominant and 1/16 carry both the recessive traits.
Mendel conducted cross hybridization experiments on Garden Pea plant (Pisum sativum). The first was the Principle of segregation, which claimed that each trait was specified by paired hereditary determinants (alleles of genes) that separate from each other during gamete formation. This law is also called Law of purity of gametes or Law of splitting of hybrids.
Gregor Mendel was the first individual to apply a modem scientific approach to the study of heredity. Mendel proposed two basic principles of trasmission genetics.
Mendel's second basic conclusion was the Principle of independent assortment, which stated that the segregation of one pair of genes-controlling a given trait - was not influenced by the segregation of other gene pairs. The chormosome theory provided a physical basis for the principle of independent assortment. Genes located on different chromosomes move to gametes independently of each other during meiosis.
Human Blood Groups and Multiple Allele
The system of blood groups in humans was discovered by Karl Landsteiner in 1900s.
There are four phenotypes of Blood namely A, B, AB and O produced by three different alleles.\[{{I}^{A}}\],\[{{I}^{B}}\]and i of a gene.
The allele\[{{I}^{A}}\] and \[{{I}^{B}}\] are equally dominant and do not interfere with expression of each other hence the allele \[{{I}^{A}}{{I}^{B}}\] are said to be co-dominant because both are expressed in the phenotype AB.
Linkage is the phenomenon of certain genes staying together during inheritance through generations without any change or separation due to their being present on the same chromosomes.
Linkage in the genes can be identified by test cross.
The rearrangements of linked genes due to crossing over is known as recombination. Recombination also occurs more...
The strategies for enhancement in food production aim at
- increasing the amount of food obtained from animals.
- increasing the yield of agricultural crops.
Animal Husbandry
Animal husbandry deals with the care, breeding & management of domesticated animals that are useful to humans.
Poultry Farming
Poultry is a rearing of domesticated fowls (chickens), ducks, geese, turkeys, guinea fowls and pigeons.
Poultry birds exclusively grown for meat are called broilers, layers are for egg production, and cockerel for young male fowls and rooster are mature male fowls.
Fisheries
Pisciculture is the rearing, breeding and catching of fishes.
Aquaculture is rearing and management of useful aquatic plants and animals like fishes, oysters, mussels and prawns, etc.
Bee keeping or Apiculture
Apiculture is rearing and breeding of honeybees for the production of honey.
The commonest species of honeybee is Apis indica.
Animal Breeding
Animal breeding is the production of new breeds of domesticated animals with improved traits.
- Inbreeding: Mating between the closely related animals of same breed.
- Out-breeding: Mating between the animals which are not closely related.
- Out-crossing: Mating between the animals of the same breed which do not have a common ancestor.
- Cross-breeding: Mating between the superior animals of different breeds of the same species.
MOET (Multiple Ovulation Embryo Transfer) technique is a programme which improves the chances of successful production of hybrids.
Plant Breeding
Plant breeding refers to the modification and improvement of genetic material of plants resulting in the development of crops which are more beneficial to human beings.
Crop
Variety
Resistance to diseases
1.
Wheat
Himgiri
Hill bunt & leaf and stripe rust
2.
Cauliflower
Pusa snowball K-l Pusa shubra
Blight black rot Black rot and curl
3.
Brassica
Pusa Swarnim (Karan rai)
White rust
4.
Cowpea
Pusa Komal
Bacterial blight
5.
Chilli
Pusa Sadabahar
Chilly mosaic vims, Tobacco mosaic virus and leaf curl.
Table: Crop varieties bred by hybridization and selection for disease resistance to fungi, bacterial and viral disease.
Examples of insect pest resistance crops bred by hybridization are
(i) Pusa Gaurav variety of Brassica is resistant to aphids.
(ii) Pusa Sawani and Pusa A-4 varieties of Okra (Bhindi) are resistant to shoot and more...
Health is a state of complete physical, social and mental well-being and not merely the absence of disease or infirmity.
Disease is any condition which interferes with the normal structure and function of the body that is manifested by a characteristics sets of symptoms and sign.
Bacteriol Diseases
Typhoid: Typhoid is caused by Salmonella typhi. Typhoid spreads through food, milk and water contaminated with intestinal discharges either directly or through flies and personal hygiene. Typhoid is diagonsed with widal test.
Pneumonia: It is caused by Streptococcus pneumonia or Haemophilus influenza. It infects alveoli of lungs and spread by coughs, sneezes, by sharing drinking glasses and eating utensils with an infected person and contact with used tissue or handkerchiefs.
Viral Diseases
Rhinoviruses causes one of the most infectious disease called common cold. Rhinovirus is spread from one person to another by hand to hand contact or from one person sneezing close by another person.
Protozoan Diseases
Malaria: It is caused by Plasmodium species & spread through female Anopheles mosquito. Primary host are female mosquito of genus Anopheles and humans acts as intermediate host.
Malaria result in anaemia, toxaemia and splenomegaly (enlarged spleen).
Plasmodium enters the human body as sporozoites (infectious form) through the bite of infected female Anopheles mosquito. Plasmodium sporozoites enters the bloodstream and travel to liver where they divide repeatedly & other attack the red blood cells resulting in their rupture.
Amoebic Dysentery or Amoebiasis
It is caused by Entamoeba histolytica. It is a protozoan parasite in the large intestine of human.
Helminthic Diseases
Filariasis
Filariasis is caused by Wuchereria bancrofti.
Fungal Diseases
Fungi cause’s diseases and these are known as mycosis.
Microsporum, Trichophyton and Epidermo-phyton are responsible for ringworms, which is characterized by appearance of dry scaly lesions of the skin, nails and scalps.
Sexually Transmitted Diseases
Sexually transmitted diseases (STDs) are a group of communicable diseases that are transmitted mainly by sexual contact. STDs are caused by a wide range of bacterial, viral, protozoal and fungal agents.
STDs
Pathogen
Syphilis
Treponema pallidum (bacterium)
Gonorrhoea
Neisseria gonorrhoeae (bacterium)
Vaginitis
Candida albicans (fungus)
AIDS
Human immunodeficiency virus (virus)
Diabetes mellitus
It is caused by the deficiency of insulin hormone and is characterized by excessive concentration of sugar in the blood and urine. Diabetes insipidus, on the other hand, is characterized by excessive urination, urine being sugar- free and is caused by the deficiency of more...
The idea about ecology was first started by Reiter.
The term ecology was given and defined by Haeckel as Ecology is the study of the interactions between the organism and their environment.
Population: The collection of individuals of a given species is called population.
Community: The interacting groups of populations of various species constitute a community.
Ecosystem: A biological community and the physical environment associated with its constitute ecosystem.
Biome: A major ecological community or complex of communities that extends over a large geographical area.
Species is a group of organisms that resembles each other more than they resemble to any other organism, and that can breed among themselves and produces fertile offspring.
Habitat: It is a specific place or locality where an organism lives.
Ecotone: It is the marginal vegetation present in between two well established habitat.
Environment: It is the sum total of physical and biotic conditions influencing the behaviour of the organism.
Atmosphere: The multilayered gaseous envelope. It is divided into 5 distinct layers troposphere, stratosphere, mesosphere, ionosphere & exosphere.
Water Resource: It is the major component of the hydrosphere and covers about 374th of the earth's surface.
Out of this 97% is sea water which cannot be used directly. Only 3% is fresh water.
Out of 3% about 77% is stored in ice caps, about 22.5% is ground water. Only about 0.5% is present in river & lakes which is available for direct use.
Aquatic animals which can tolerate only a narrow range of salinity are called stenohaline.
Aquatic organisms having wide range of salt tolerance are called euryhaline.
Soil: Soil is a mixture of inorganic mineral particles derived from weathering of rock and organic matter consisting of humus.
On the basis of the size of particles, soil is of following types:
(i) Clay-upto.062mm (ii) Silt-.002to.02mm
(iii) Fine sand - .02 to .2 mm (iv) Coarse sand - .2 to 2 mm
(v) Fine gravel - 2 to 5 mm (vi) Coarse gravel - 5 and more
Population: It is the total number of individual of a particular species inhabiting a particular area at a particular time.
Demography: Study of population.
Population Characteristics
(1) Population density: It is number of individuals per unit area of environment.
(2) Natality: This is addition of individuals in a population due to birth.
(3) Mortality: It is the rate of death of individuals in a given population.
(4) Population Dispersion
(i) Emigration - One way outward movement.
(ii) Immigration - One way inward movement.
(iii) Migration: It is a cyclical movement with respect to and weather that during life history of an animal at definite intervals, and always includes a return trip from where it began. more...
