(i) Gene therapy:
1. Gene therapy is the treatment of heredity disorders by replacing a faulty gene by a normal healthy functional gene.
(ii) The first clinical gene therapy was given in 1990 by French Anderson to a four year old girl with adenosine deaminase (ADA) deficiency.
(iii) The lymphocytes from the blood of the patient are removed and grown in a nutrient culture medium.
1. A healthy and functional human gene, ADA cDNA encoding this enzyme is introduced into the lymphocytes using a retrovirus.
2. The genetically engineered lymphocytes are subsequently returned to the patient.
3. These cells are not immortal, the patient requires a periodic infusion of such genetically engineered lymphocytes.

S.No.	SOMATIC CELL GENE THERAPY	GERMLINE GENE THERAPY
i.	Therapeutic genes transferred into the somatic cells.	Therapeutic genes transferred into the germ cells.
ii.	Introduction of genes into bone marrow cells, blood cells, skin cells, etc.,	Genes introduced into eggs and sperms.
iii.	Will not be inherited in later generations.	Heritable and passed on to later generations.

1. The foreign DNA that is introduced is called the transgene and the animals that are produced by DNA manipulations are called transgenic animals or the genetically engineered or genetically modified organisms.
2. Transgenic animals are also used for producing products useful for mankind. E.g: Transgenic cow (rosie), which produced human protein enriched milk (2.4 g/L).
3. The milk contained the human alpha lactalbumin and was nutritionally a more balanced product for human babies than natural cow's milk.

(i) Protecting soil quality using organic materials and encouraging biological activity.
(ii) Indirect provision of crop nutrients using soil microorganisms.
(iii) Nitrogen fixation in soils using legumes.
(iv) Weed and pest control based on methods like crop rotation, biological diversity, natural predators, organic manures and suitable chemical, thermal and biological interventions.

Ramapithecus\(\rightarrow \) Austrolopithecus \(\rightarrow \) Homo habilis \(\rightarrow \)  Homo sapiens

(i) Creating awareness and providing medical assistance to build a healthy society.
(ii) Introducing sex education in schools to provide information about adolescence and adolescence related changes.
(iii) Educating couples and those in the marriageable age groups about the available birth control methods and family planning norms. 

Structural gene	Regulatory gene	operator gene
They are concerned with the transcription of mRNA for the synthesis of particular polypeptide	It controls the functioning of operator gene	It determines the functioning of operator gene
They function only when RNA polymerases join	It produces a repressor or apo- repressor for blocking operator gene	It works only when it is not blocked by repressor
They function by forming mRNA for specific polypeptide	It functions through the formation of mRNA of repressor or apo-repressor	It functions through the presence (or) absence of repressor

Semen or seminal fluid is a milky white fluid which contains sperms and the seminal plasma, which is secreted from the seminal vesicles, prostate glands and bulbo urethal glands or Cowper's gland.
The semen comprises of Fructose, ascorbic acid, zinc, cholesterol, protein, calcium, chlorine, blood group antigens, citric acid, DNA, magnesium, Vitamin B12, phosphorous, sodium, potassium, uric acid,lactic acid, nitrogen, and other nutrients for the sperms.

1. In this method of sex determination, the homogametic male possesses two 'X' chromosomes as in certain insects and certain vertebrates like fishes, reptiles and birds producing a single type of gamete.
2. The female sex consists of a single 'Y' chromosome. Thus the females are heterogametic and produce two types of eggs.
3. To avoid confusion with the XX-XO and XX-XY trues of sex determination, the alphabets 'Z' and 'W 'are used here instead of X and Y respectively.
4. Heterogametic females are of two types, ZO-ZZ type and ZW-ZZ type.

Intersexes: 
1. Intersexes refers to the individuals having the characteristics of both female and male sexes and their sexual anatomy does not seem to fit the typical definition of male or female.
Supersexes: 
1. Supersexes ar formed as a result of abnormal combination of sex chromosomes. 
2. Example : Super males in humans human beings have 44+XYY

In the 1950s, experiments conducted by Porter and Edelman revealed the basic structure of the immunoglobulin.
An antibody molecule is Y shaped structure that comprises of four polypeptide chains, two identical light chains (L) of molecular weight 25,000 Da (approximately 214 amino acids) and two identical heavy chains (H) of molecular weight 50,000 Da (approximately 450 amino acids). The polypeptide chains are linked together by di-sulphide (S-S) bonds. One light chain is attached to each heavy chain and two heavy chains are attached to each other to form a Y shaped structure. Hence, an antibody is represented by H₂L₂.
The heavy chains have a flexible hinge region at their approximate middles.
Each chain (L and H) has two terminals. They are C - terminal (Carboxyl) (or) -COOH and amino or N-terminal (or NH₂). Each chain (L and H) has two regions and they have variable (V) region at one end and a much larger constant (C) region at the other end.
Antibodies responding to different antigens have very different (V) regions but their (C) regions are the same in all antibodies.
In each arm of the monomer antibody, the (V) : regions of the heavy and light chains combine to form an antigen - binding site shaped to 'fit' a specific antigenic determinant.
Consequently each antibody monomer has two such antigen - binding regions.
The (C) regions that forms the stem of the antibody class and serve common functions in all antibodies.
The functions of immunoglobulin are agglutination, precipitation, opsonisation neutralization etc.

Oviparous animals lay eggs outside their body. These eggs are exposed to various environmental conditions and may be eaten by predators also. They face lot of risks until the young ones hatche. But the offsprings of viviparous animals are more safe and protected in the maternal womb until they are born.

1. In unicellular organism there is no special structure for reproduction.
2. In binary fission the entire parent body constitute the reproductive unit and disappears when its division into two daughter unicellular cell is completed.
3. These two daughter cells function as two new individuals.
4. There is no remains of parent body cell and parent cannot be said to have died.
5. In fact after binary fission parent continues living as two daughter individual.
Hence, the unicellular organisms which undergo binary fission are called immortal (no natural death).

1. A patient is suffering from ADA deficiency can be caused by using "gene therapy''.
2. Gene therapy is a correction of a genetic defect that has been diagnosed in a child embryo.
3. ADA enzyme is crucial fol the immune system to function.
4. Deletion of the gene for adenosine deaminase results into ADA deficiency.
5. In some children, ADA deficiency can be cured by bone. Marrow transplantation While in others it can be treated by enzyme replacement therapy, in which functional ADA is given to the patient by injection. But the problem with both of these approaches is that they are not completely curative.
6. It may recurrent in nature as in the process of gene therapy, Lymphocytes used are found not to be immortal in nature and the patient requires a periodic infusion of such genetically engineered lymphocytes.
7. For permanent cure, gene isolated from the bone-marrow-cells producing ADA is introduced into cells at early embryonic stages.

1. Hugo de Vries by his experiment suggest that variations is caused due to mutation among the genetic sequence of an individual.
2. Hugo de vries for the first time gave the term saltation which stands for huge mutation in a single step resulting in speciation.
3. Darwin during his voyage in H.M.S. Beagle he found that living organism share similar features existed from million of years.
4. Evolution is a sequential process that leads to betterment of life forms to cope with change in environment and that is passed to successive generation called as natural selection.
5. Mutation is a random process and direction which is not specific.

Adaptive radiation is the process of evolution of different species in a given geographical area starting from a point and literally radiating to other geographical area habitats.
1. Darwins finches were the small black birds which Darwin observed in Galapagos islands.
2. There were many varities of these birds in the same island.
3. Darwin reasoned that after originating from a common ancestral seed eating stock the finches must have radiated to different geographical areas and undergone adaptive changes especially in their breaks enabling some of them to become insectivorous.
4. Living isolation for long new kinds of finches must have evolved which could survive in the new habitats.
5. Australian marsupials (Kangaroos) also show adaptive radiation
6. Marsupials in Australia and placental mammals in north America are two subclasses of mammals they adapted in similar way to a particular food resources, locomotary skill or climate.
7 They were separated from the ori-on ancestor more than 100 million year ago and each lineage continued to evolve independently despite temporal and geographical separation marsupials in Australia and placenta mammals in North America have reduced varieties of species living in similar habitats with similar way of life their overall resemblance in shape, locomotary mode, feeding and foraging are superimposed upon different modes of reproduction.

The major sexually transmitted diseases are
(i) Gonorrhoea
1. Causative agent: Neisseria gonorrhoeae
2. Symptoms: Affects the urethra, rectum and throat and in females the cervix also get affected
3. Pain and pus discharge in the genital tract and burning sensation during urination.
4. Incubation period: 2 to 5 days
(ii) Syphilis
Causative agent : Treponema pallidum
Symptoms:
1. Primary stage: Formation of painless ulcer on the external genitalia.
2. Secondary stage : Skin lesions, rashes, swollen joints and fever and hair loss.
3. Tertiary stage : Appearance of chronic ulcers on nose. Lower legs and palate, loss of movement mental disorder visual impairment, heart problems, gummas (soft non-cancerous growths) etc.
(iii) Hepatitis B
1. Causative agent: Hepatitis B virus (HBV) with DNA.
2. Symptoms: Fatigue, jaundice, fever, rash and stomach pain.
3. Liver cirrhosis and liver failure occur in the later stage.
4. Incubation period: 30-80 days
(iv) AIDS:
1. Causative agent: Human immuno deficiency Virus (HIV) .
2. Symptoms: Enlarged lymph nodes, prolonged fever, prolonged diarrhoea, weight reduction, night sweating.
3. Incubation periods: 2 to 6 weeks even more than 10 years

Human genome project was considered to be a mega project because
1. It had a specific goal to sequence for everybase pair present in the human genome. (Human Genome has 3.1647 billion nucleotide base pairs).
2. It took around 13 years of completion and got accomplished in year 2006.
3. It was a large-scale project, which aimed at developing new technology and generating new information in the field of genomic studies.
4. As a result of it, several news areas and avenues have opened up in the field of genetics, biotechnology and medical sciences.
5. It provided clues regarding the understanding of human biology.

1. The sex determining mechanism of humans is XX-XY type.
2. In humans, out of 23 pairs of chromosomes present, 22 pairs are exactly same in both males and females known as autosomes (body).
3. The 23rd chromosome is the sex chromosome. (i.e) Pair of X-chromosome (XX) is present in females and males having one X and one Y chromosome (XY).
4. During, spermatogenesis, in case of males two types of gametes are produced (x and y).
5. The 50% total sperms produced carry X-chromosomes and the rest 50% carry Y - chromosomes besides autosomes. This condition is called male diagamety.
6. The Y containing sperms and X containing sperms are called androsperms and gynosperms respectively.
7. Female produces only one type of ovum with an X-chromosome. If an ovum fertilizes with a sperm carrying X chromosome the zygote develops into a female (XX) and if an ovum is fertilized with sperm carrying Y-chromosome, zygote thus, formed will be male (YY).

8. Hence, the genetic makeup of sperm, which fertilizes the ovum determines the sex of a child there are 50% chances of having either a male or female in each progeny.
9. Thus, it is by chance phenomenon, so women should not be blamed for giving birth to a girl child

(i) A vaccine is a biological preparation that provides active acquired immunity to a particular disease and resembles a disease-causing microorganism and is often made from weakened or attenuated or killed forms of the microbes, their toxins, or one of its surface proteins.
(ii) Vaccines "teach" our body how to defend itself when viruses or bacteria, invade it.
(iii) Vaccine initiates the immunization process. The vaccines are classified as first, second and third generation vaccines.
First generation vaccine:
(i) First generation vaccine is further subdivided into live attenuated vaccine, killed vaccine and toxoids.
(ii) Live attenuated live vaccines use the weakened (attenuated), aged, less virulent form of the virus
(iii) Eg. Measles, Mumps and Rubella (MMR) vaccine and the Varicella (chickenpox) vaccine, killed (inactivated) vaccines are killed or inactivated by heat and other methods. Eg. Salk's polio vaccine.
(iv) Toxoid vaccines contain a toxin or chemical secreted by the bacteria or virus.
(v) They make us immune to the harmful effects of the infection, instead of to the infection itself.
(vi) Eg. DPT vaccine (Diphtheria, pertussis and Tetanus), (Triple antigen).
Second generation vaccine: contains the pure surface antigen of the Pathogen. :
Eg. Hepatitis-B vaccine 
Third generation vaccine: contains the purest and the highest potency vaccines which are synthetic in generation. The latest revolution in vaccine is DNA vaccine (or) recombinant vaccine

(i) AAU - UUA
(ii) CGA - GCU
(iii) UAU - AUA
(iv) GCA - CGU

tRNA on one hand binds to specific amino acids and on the other hand reads the codon of the amino acid bound to it through its anticodon, it is called as adapter molecule.

Gametogenesis is the process of formation of gametes i.e., Sperms from primary spermatocytes and ova from primary oocyte in testes and ovaries respectively. Meiosis plays the most significant role in the process of gametogenesis.

In testes Sertoli cells secrete inhibin, a hormone which is involved in the negative feedback control of sperm production. (Spermatogenesis).