Organic farming is an alternative agricultural system in which plants/crops are cultivated in natural ways by using biological inputs to maintain soil fertility and ecological balance thereby minimizing pollution and wastage.

1. Aloin - a mixture of glucosides.
2. Its gel used as skin tonic.
3. Cooling effect and moisturizing effect helps in creams, lotions, shampoos, shaving creams, after shave lotions preparation.
4. Used has emollient, antibacterial, antioxidant, antifungal and antiseptic.

Micro organisms are efficient in fixing nitrogen, solubilizing phosphate and decomposing cellulose. They improve soil fertility, plant growth. They are ecofriendly and cost-effective than chemical fertilizers. Example. Azospirillum.

Casuarina, Eucalyptus, Teak, Malai vembu.

There is a gradual decrease in energy transfer at successive tropic levels from producers to higher levels, hence the pyramid of energy is always upright.

The blue green light have short wavelength & penetrates into the water. Green algae is unable to use that component of light. Blue light can penetrate up to 500 ft depth therefore algae are unlikely to survive below that depth.

Taxonomically different species occupying similar habitats (Niches) in different geographical regions are called Ecological equivalents.
E.g: Certain species of epiphytic orchids of Western Ghats of India differ from the epiphytic orchids of South America. But they are epiphytes.

Restriction endonuclease. e.g: Hind II, EcoR I, Pvul, Bam H I, Taq I.

Spirulina can be grown easily on materials like waste water from potato processing plants (containing starch), straw, molasses, animal manure and even sewage, to produce large quantities.

Missense Mutation Non-sense Mutation The mutation where the codon for one amino acid is changed into a codon for another amino acid. The mutations where codon for one amino acid is changed into a termination or stop codon.

(i) Back cross is a cross of F, hybrid with any one of the parental genotypes. 
(ii) They are of two types - Dominant back cross recessive back cross.

(i) Hugo de Vries of Holland
(ii) Carl Correns of Germany
(iii) Erich von Tschermak of Austria

Individuals formed by asexual reproductive methods are morphologically and genetically identical and are called clones.

Sucker - chrysanthemum
Stolon - jasmine

Reproduction is a biological process in which an organism give rise to offsprings. This helps to maintain continuity of its species.

1. It is Andrographis paniculata belongs to Acanthaceae family.
2. It is a potent hepatoprotective to treat liver disorders.
3. Used to make Nilavembu Kudineer to treat malaria and dengue.

Gross Primary Productivity (GPP) is the total amount of food energy or biomass produced in an ecosystem by autotrophs through the process of photosynthesis whereas Net Primary Productivity (NPP) is the proportion of energy which remains after respiration loss in the plant. When we compare GPP with NPP more energy is present in former than in latter.

Aerosols with small particles is reflecting the solar radiation entering the atmosphere. This is known as Albedo effect.
Effects:
1. It reduces the temperature limits, photosynthesis & respiration.
2. The sulphur compounds are responsible for acid rain due to acidification of rain water and destroy the ozone.

The differences between habitat and niche are as follows.

S. No	Habitat	Niche
1	A specific physical space occupied by an organism (species).	A functional space occupied by an organism in the same eco-system
2	Same habitat may be shared by many organisms (species).	A single niche is occupied by a single species.
3	Habitat specificity is exhibited by organism.	Organisms may change their niche with time and season

1. The growing of cells including the culture of single cells or small aggregates of cells in vitro in liquid medium is known as cell suspension culture.
2. The cell suspension is prepared by transferring a portion of callus to the liquid medium and agitated using rotary shaker instrument.
3. The cells are separated from the callus tissue and used for cell suspension culture.

(i) ECORI is from Escherichia ( E ) coli (co), strain RY 13 (R) & first endonuclease (I) to be discovered.
(ii) It contains 2 different antibiotics resistance genes & recognition site for several restriction enzymes.
(iii) This sequence is referred to as a restriction site & is generally -palindromic which means that the sequence in both DNA strands at this site read same in 5' - 3' direction & in-the 3'-5' direction.

(iv) The exact kind of cleavage produced by a restriction enzyme is important in the design of a gene cloning experiment.
(v) Some cleave both strands of DNA through the centre resulting in blunt or flush end.
(vi) These are known as symmetric cuts.
(vii) Some enzymes cut in a way producing protruding & recessed ends known as sticky or cohesive end.
(viii) These are known as staggered or asymmetric cuts.

  Grafting Layering Types Types of grafting Bud/Approach/Tongue
Crown/Wedge Types of layering mound / Air Benefits More useful to get more varieties from a single Plant Can get only one type of offspring Usage More useful in horticultural filed Less useful technique in horticultural field Result Can get highly desirable characters from parent stock to different scion Can get same characteristics from parent to offspring

(i) Three point test cross.
(ii)

If we analyse the loci of two alleles at a time, starting with AB, since AB and ab are parental genotypes, the recombination will be Ab/aB.
The recombinant frequency for these two alleles can be calculated as follows.
\(RF = \frac{Total\ no.\ of \ recombination}{Total\ no.\ of\ progenies}\times100\)
\(\mathrm{RF}=\frac{114+5+4+116}{1200} \times 100 \)
\(\mathrm{RF}=\frac{239}{1200}=19.91 \)
For A and C loci, the recombinants are Ac / aC - RF will be as follows.
\(\mathrm{RF}=\frac{114+134+116+128}{1200} \times 100 \)
\(\mathrm{RF}=\frac{482}{1200}=40.1 \)
For B and C loci, the recombinants are Bc / bC- RF will be as follows.
\(R F=\frac{124+5+4+128}{1200} \times 100 \)
\(R F=\frac{261}{1200}=21.75 \)
All the loci are linked, because all the RF value is less than 50%. In this A - and C loci show highest RF value, they must be farthest apart. Therefore B locis must lie in between them.
The order of genes should be abc. A genetic map can be drawn as follows.
(iii)
 

(i) Incomplete linkage

Rano : 1:2:1

(i) Complete Linkage
(ii)
 
(iii) Observed ratio 1:1