1.Many polyploids are more vigorous and more adaptable than diploids.
2. Many ornamental plants are autotetraploids and have larger flowers and longer flowering duration than diploids.
3. Autopolyploids usually have higher in fresh weight due to more water content.
4. Aneuploids are useful to determine the phenotypic effects of loss or gain of different chromosomes.
5. Many angiosperms are allopolyploids and they play a role in the evolution of plants.

(a) 'psy' gene is obtained from Daffodil plant (Narcissus pseudonarcissus).
(i) 'crt-l ' gene is from Erwinia uredovora bacterium.
(ii) 'lyc' gene is from wild-type rice endosperm.
(b) Golden rice can control Xerophthalmia.

Sharbati Sonora is a mutant variety of wheat, which is developed from Mexican variety (Sonora 64) by irradiating of gamma rays.

Polyethylene Glycol (PEG) and Dextran Sulphate.

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.

(i) A type of structural chromosomal abbrevation.
Reverse tandem duplication
(ii) The duplicated segment is located immediately after the normal segment but the gene sequence order will be reversed.

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) Genome editing or gene editing is a group of technologies that has the ability to change an organism's DNA.
(ii) These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed.
(iii) A recent one is known as CRISPR-Cas9 which is short form of Clustered Regularly Interspaced Short Palindromic Repeats and CRlSPR-associated Protein 9.
(iv) The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate and more efficient than other existing genome editing methods.

Linkage Crossing Over 1. The genes present on chromosome stay close together It leads to separation of linked genes 2. lt involves same chromosome of homologous chromosome It involves exchange of segments between non-sister chromatids of homologous chromosome 3. lt reduces new gene combinations It increases variability by forming new gene combinations. Lead to formation of new organism

Multiple alleles of a series always occupy the same locus in the homologous chromosome. Therefore, no crossing over occurs within the alleles of a series.
(i) Multiple alleles are always responsible for the same character.
(ii) The wild type alleles of a series exhibit dominant character whereas mutant type will influence dominance or an intermediate phenotypic effect.
(iii) Proterminal synapsis: Pairing starts from the telomeres
(iv) Random synapsis: Pairing may start from anywhere.

GM Food - Benefits:
1. High yield without pest.
2. 70% reduction of pesticide usage.
3. Reduce soil pollution problem.
4. Conserve microbial population in soil.
Risks - believed to:
1. Affect liver, kidney function and cancer.
2. Hormonal imbalance and physical disorder.
3. Anaphylactic shock (sudden hypersensitive reaction) and allergies.
4. Adverse effect in immune system because of bacterial protein.
5. Loss of viability of seeds show in terminator seed technology of GM crops.

Properties of Vectors:
1. Vectors are able to replicate autonomously to produce multiple copies of them along with their DNA insert in the host cell.
2. It should be small in size and of low molecular weight, less than 10 Kb (kilo base pair) in size so that entry/transfer into host cell is easy.
3. Vector must contain an origin of replication so that it can independently replicate within the host.
4. It should contain a suitable marker such as antibiotic resistance, to permit its detection in transformed host cell.
5. Vector should have unique target sites for integration with DNA insert and should have the ability to integrate with DNA insert it carries into the genome of the host cell. Most of the commonly used cloning vectors have more than one restriction site. These are Multiple Cloning Site (MCS) or polylinker. Presence of MCS facilitates the use of restriction enzyme of choice.

(i) pBR 322 plasmid is a reconstructed plasmid and most widely used as cloning vector;
(ii) It contains 4361 base pairs. In pBR, p denotes plasmid, Band R respectively the names of scientist Boliver and Rodriguez who developed this plasmid.
(iii) The number 322 is the number of plasmid developed from their laboratory.
(iv) It contains amp^R and tet^R two different antibiotic resistance genes and recognition sites for several restriction enzymes.
(v) ori and antibiotic resistance genes. Rop codes for the proteins involved in the replication of the plasmid.

(i) Sutton and Boveri independently proposed the chromosome theory of inheritance.
(ii) Somatic cells of organisms are derived from the zygote by repeated mitotic division. These consist of two identical sets of chromosomes. One set is received from female parent and the other from male parent which constitute the homologous pair.
(iii) Chromosomes retain their structural uniqueness and individuality throughout the life cycle of an organism.
(iv) Each chromosome carries specific determiners or Mendelian factors which are now termed as genes.
(v) The behaviour of chromosomes during the gamete formation provides evidence to the fact that genes are located on chromosomes.

Direct or Vector less Gene Transfer
In the direct gene transfer methods, the foreign gene of interest is delivered into the host plant without the help of a vector, The following are some of the common methods of direct gene transfer in plants.
(i) Chemical mediated gene transfer: Certain chemicals like polyethylene glycol (PEG) and dextran sulphate induce DNA uptake into plant protoplasts.
(ii) Microinjection: The DNA is directly injected into the nucleus using fine tipped glass needle or micro pipette to transform plant cells. The protoplasts are immobilized on a solid support (agarose on a microscopic slide) or held with a holding pipette under section.
(iii) Electroporation Methods of Gene Transfer: A pulse of high voltage is applied to protoplasts, cells or tissues which makes transient pores in the plasma membrane through which uptake of foreign DNA occurs.

(iv) Liposome mediated method of Gene transfer: Liposomes the artificial phospholipid vesicles are useful in gene transfer. The gene or DNA is transferred from liposome into vacuole of plant cells. It is carried out by encapsulating DNA into the vacuole. This technique is advantageous because the liposome protects the introduced DNA from being damaged by the acidic pH and protease enzymes present in the vacuole. Liposome and tonoplast of  vacuole fusion resulted in gene transfer. This process is called lipofection.

(v) Biolistics: The foreign DNA is coated onto the surface of minute gold or tungsten particles (1-3 \(\mu\)m) and bombarded onto the target tissue or cells using a particle gun (also called as gene gun/ micro projectile gun/shotgun) Then the bombarded cells or tissues are cultured on selected medium to regenerate plants from the transformed cells.

Applications of Biotechnology
1. Biotechnology is one of the most important applied interdisciplinary sciences of the 21st century. It is the trusted area that enables us to find the beneficial way of life.
2. Biotechnology has wide applications in various sectors like agriculture, medicine, environment and commercial industries.
3. This science has an invaluable outcome like transgenic varieties of plants e.g. transgenic cotton (Bt-cotton), rice, tomato, tobacco, cauliflower, potato and banana.
4. The development of transgenics as pesticide resistant, stress resistant and disease resistant varieties of agricultural crops is the immense outcome of biotechnology.
5. The synthesis of human insulin and blood protein in E.coli and utilized for insulin deficiency disorder in human is a breakthrough in biotech industries in medicine.
6. The synthesis of vaccines, enzymes, antibiotics, dairy products and beverages are the products of biotech industries.
7. Biochip based biological computer is one of the successes of biotechnology.
8. Genetic engineering involves genetic manipulation, tissue culture involves aseptic cultivation of totipotent plant cell into plant clones under controlled atmospheric conditions.
9. Single cell protein from Spirulina is utilized in food industries.
10. Production of secondary metabolites, biofertilizers, biopesticides and enzymes.
11. Biomass energy, biofuel, bioremediation and phytoremediation for environmental biotechnology.

The diagrammatic representation of position of genes and related distances between the adjacent genes is called gene mapping. 
Uses 
(i) Used to determine gene order.
(i) Identify the locus of a gene.
(i) Calculate the distance between genes.
(i) Useful in predicting results of dihybrid and trihybrid crosses.
(i) Allows the geneticists to understand the overall genetic complexity of particular organism.

Crossing over is a process that includes four stages.
1. Synapsis
(i) Pairing between two homologous chromosomes is initiated during sub stage zygotene stage of prophase I of meiosis I
(ii) Homologous chromosomes are aligned side by side resulting in the formation of bivalents. It also occurs in zygotene sub-stage of prophase I of meiosis I tetrads.This pairing phenomenon is called synapsis.
 2.Tetrad Formation
(i) Each homologous chromosome of a bivalent begin to form two identical sister chromatids.
(ii) They remain held together by a centromere at this stage each bivalent has four chromatids. This stage is called tetrad stage.
3. Cross Over
After tetrad formation, crossing over occurs in pachytene stage.
The non-sister chromatids of homologous pair make a contact at one or more points. These points of contact are called Chiasmata.
At chiasma, X-shaped structures are formed, where breaking and rejoining of two chromatids occur. This results in reciprocal exchange of equal and corresponding segments between them synapsis and chiasma formation are facilitated by protein filaments called synaptonemal complex.
4. Terminalisation
After crossing over, chiasma starts to move towards the terminal end of chromatids known as terminalisation. As a result, complete separation of homologous chromosomes occurs.