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(d) introducing bone marrow cells producing ADA into embryo at an early stage of development.

The various steps involved in the production of transgenic organisms are : 

1. Identification and separation of desired gene. 

2. Selection of a vector (generally a virus) or direct transmission. 

3. Combining the desired gene with the vector. 

4. Introduction of transferred vector into cells, tissues, embryo or mature individual. 

5. Demonstration of integration and expression of  foreign gene in transgenic tissue or animals. Transgenic animals such as mice, rat, rabbit, pig, cow, goat, sheep and fish have been produced.

Dolly was the first mammal (Sheep) clone developed by Ian Wilmut and Campbell in 1997. Dolly, the transgenic clone was developed by the nuclear transfer technique and the phenomenon of totipotency. Totipotency refers to the potential of a cell to develop different cells, tissues, organs and finally an organism.

The mammary gland udder cells (somatic cells) from a donor sheep (ewe) were isolated and subjected to starvation for 5 days. The udder cells could not undergo normal growth cycle, entered a dormant stage and became totipotent. An ovum (egg cell) was taken from another sheep (ewe) and its nucleus was removed to form an enucleated ovum. The dormant mammary gland cell/udder cell and the enucleated ovum were fused. The outer membrane of the mammary cell was ruptured allowing the ovum to envelope the nucleus.

The fused cell was implanted into another ewe which served as a surrogate mother. Five months later dolly was bom. Dolly was the first animal to be cloned from a differentiated somatic cell taken from an adult animal without the process of fertilization.

Gene augmentation therapy which involves insertion of DNA into the genome to replace the missing gene product and Gene inhibition therapy which involves insertion of the anti sense gene which inhibits the expression of the dominant gene.

1. Transgenesis is a powerful tool to study gene expression and developmental processes in higher organisms. 

2. Transgenesis helps in the improvement of genetic characters in animals.Transgenic animals serve as good models for understanding human diseases which help in the investigation of new treatments for diseases.Transgenic models exist for many human diseases such as cancer, Alzheimer’s, cystic fibrosis, rheumatoid arthritis and sickle cell anemia. 

3. Transgenic animals are used to produce proteins which are important for medical and pharmaceutical applications. 

4. Transgenic mice are used for testing the safety of vaccines. 

5. Transgenic animals are used for testing toxicity in animals that carry genes which make them sensitive to toxic substances than non-transgenic animals exposed to toxic substances and their effects are studied. 

6. Transgenesis is important for improving the quality and quantity of milk, meat, eggs and wool production in addition to testing drug resistance.

(d) Cloning by nuclear transfer

Somatic cell therapy involves the insertion of a fully functional and expressible gene into a target somatic cell to correct a genetic disease permanently whereas Germ line gene therapy involves the introduction of DNA into germ cells which is passed on to the successive generations. Gene therapy involves isolation of a specific gene and making its copies and inserting them into target cells ’to make the desired proteins.

During gene therapy the lymphocytes from the blood of the patient are removed and grown in a nutrient culture medium. A healthy and functional human gene, ADA cDNA encoding this enzyme is introduced into the lymphocytes using a retrovirus. The genetically engineered lymphocytes are subsequently returned to the patient. Since these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes. The disease could be cured permanently if the gene for ADA isolated from bone marrow cells are introduced into the cells of the early embryonic stages.

(b) ii, iii and iv

(c) Both statements 1 and 2 are true.

Correct Answer is: (d) SCID

Transgenesis is the process of introduction of foreign DNA (exogenous DNA) into the genome of the other organism to create and maintain stable heritable characters.

1. SCID (Severe Combined Immuno Deficiency) disease was the first disease treated by using gene therapy. 

2. There are two strategies involved in gene therapy namely Gene augmentation therapy, which involves insertion of DNA into the genome to replace the missing gene product and Gene inhibition therapy, which involves insertion of the anti sense gene which inhibits the expression of the dominant gene.

1. For each cycle of PCR two primers are required. 

2. Primers are the small fragments of single stranded DNA or RNA which serves as template for initiating DNA polymerization. 

3. DNA polymerase is an enzyme that synthesize DNA molecules by pairing the Deoxyribo Nucleotides leading to formation of new strands.

4. DNA polymerase used in PCR is Taq polymerase which is isolated from a thermophilic bacteria called Thermus aquatics. Taq polymerase will remain active ever at very high temperature (80°C) and hence used in PCR amplification technique.

(c) Kary Mullis

(a) R explains A.

The first clinical gene therapy was done for SCID. Severe Combined Immuno Deficiency disease is caused by ADA deficiency. It was done by French Anderson in 1990.

The Polymerase Chain Reaction (PCR) is an invitro amplification technique used for synthesising multiple identical copies (billions) of DNA of interest. The technique was developed by Kary Mullis in the year 1983.

Xylem and phloem are called complex tissues because they contain more than one type of cells, which perform vital functions in plants.

1. PCR – Polymerase Chain Reaction. 

2. Denaturation, Renaturation or Primer annealing and Primer extension are the three steps in PCR technique.

1. Polymerase Chain Reaction (PCR) technique. 

2. Enzyme Linked Immuno Sorbent Assay (ELISA)

The PCR technique can also be used for amplifications of RNA in which case it is referred to as reverse transcription PCR (RTPCR). In this process the RNA molecules (mRNA) must be converted to complementary DNA by the enzyme reverse transcriptase. The cDNA then serves as the template for PCR.

PCR and ELISA

Microspore mother cells 25 x 4=100 pollen grains and from megaspore mother cells 25 ovules respectively.

 100 pollen grains, 25 ovules.

(a) Digital automated identification system

Primary growth produces growth in length and development of lateral appendages. Secondary growth is the formation of secondary tissues from lateral meristems. It increases the diameter of the stem. Secondary tissues are formed by two types of lateral meristems, fascicular cambium and cork cambium. 

Fascicular cambium: The vascular bundles have intrafascicular cambium between xylem and phloem. Interfascicular cambium is formed from parenchyma cells between vascular bundles. Fascicular and interfascicular cambium join to form a complete ring of vascular cambium. The cells of cambium ring divide diagonally to form secondary phloem outside and secondary xylem towards the inner side. The amount of secondary xylem produced is always greater than that of secondary phloem. Due to formation of greater amount of secondary xylem, the cambium ring moves towards the periphery and the primary xylem and phloem which were near together are separated far apart. 

Cork cambium: The outermost layer of cortex becomes meristematic and is called cork cambium. Sometimes hypodermis also become meristematic and forms cork cambium. The cells of cork cambium divide by periclinal division towards outer side to form cork. The cork has rectangular cells which become dead at maturity. These are highly thick walled due to the presence of a chemical called suberin. Thus cork is also called suberised tissue. The cork is impervious to water and thus outer layers like hypodermis and epidermis become dead. 

The cells of the cork Cambium also divide towards their inner side by periclinal divisions to form secondary cortex. It has loosely packed parenchymatous cells which are thick walled. The phellem, phellogen and phelloderm are collectively called periderm. All dead cells outer to cork cambium form bark. It includes dead cells cork, hypodermis and epidermis.

The new taxonomical tools which are based on electron microscopic images to study the molecular structure of cell organelles are neo-taxonomical tools.

ALIS : Automated Leafhopper Identification System. 

DAISY : Digital Automated Identification System. 

ABIS : Automatic Bee Identification System. 

SPIDA : Species Identified Automatically (spiders, wasp, bee wing characters). 

Draw wing : Honey bee wing identification.

The unique nomenclature for each organisms is necessary as it is uniform in all countries and in all languages. A scientific name refers to only one organism.

Herbarium and Botanical garden may be used as tools for the plant taxonomy. Museum, Taxonomical keys and Zoological parks are classical tools for animal studies. Field visits, survey, identification, classification, preservation and documentation are the important components of taxonomical tools.

(b) Charles Darwin

The unit of classification containing concrete biological entities is taxon.

The scientific name should be italicized in printed form and the generic name and specific name should be underlined separately if it is handwritten.

• The first alphabet of the generic name should be of uppercase.
• The specific name (species) should be in lower case letters.
• The name or abbreviated name of the scientist who first published the scientific name may be written after the specific (species) name along with the year of publication, e.g. Felis Leo Linn., 1958.
• If the specific (species) name is framed after any person’s name, the name of the species shall end with i, ii or ae. e.g. Ground – dwelling lizard Cyrtodactylus varadgirii

The system of naming the organism with two names, generic name and specific (species) name is known as binomial system of nomenclature, e.g. Pavo cristatus – Indian pea fowl.

(c) two words for the name of a species

(d) Linnaeus

(c) genus & species

(d) Theophrastus

(b) Carolus Linnaeus

(a) Candolle

Linnaeus considered a few characters of organisms for classifying them. Later many characters were considered for classifying organisms. Morphological, anatomical and embryological characters were considered.

The classification of organisms based on evolutionary and genetic relationship among them is known as phylogenetic classification.

The evaluation of resemblances and differences of organisms through statistical methods followed by computer analysis to establish the numerical degree of relationship among them is known as numerical taxonomy.

• Non-living things can also increase in mass by accumulation of material on surface. 

• Many organisms do not reproduce (e.g., mules, sterile worker bees). 

The three major disorders of consciousness are coma vegetative state, and minimally conscious state. In coma, which typically is present for the first one to two weeks after brain injury, patients are not awake or aware, meaning that they do not open their eyes, have only reflex responses and are unaware of those around them.

If a coma lasts more than two or three weeks, it evolves into the vegetative state. In this state, unlike coma, wakefulness is present, which means that patients' eyes open either spontaneously or in response to stimulus. However, as in coma, awareness is not present. If the vegetative state persists for more than three to six months, the term persistent vegetative state is applied.

(c) identification

Reproduction cannot be used as an all inclusive defining characteristic of living organisms as there are few organisms that cannot reproduce like mules, worker bees, infertile man or woman etc.

Inclusive means ‘all other things included’.

Exclusive means ‘not with other things’

Correct Answer is: (d) Calyptrogen

(b) Evolutionary and Phylogenetic

(d) Piliferous layer is made up of parenchyma cells without intracellular space.