The immediate adverse effects of drugs and alcohol abuse are manifested in the form of reckless behaviour, vandalism and violence. Excessive doses of drugs may lead to coma and death due to respiratory failure, heart failure or cerebral hemorrhage. A combination of drugs or their intake along with alcohol generally results in overdosing and even deaths. The most common warning signs of drug and alcohol abuse among youth include drop in academic performance, unexplained absence from school/college, lack of interest in personal hygiene, withdrawal, isolation, depression, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family and friends, loss of interest in hobbies, change in sleeping and eating habits, fluctuations in weight, appetite, etc.

The various means of prevention and control of drug addiction are:

(i) Avoid undue peer pressure: Every child has his/her own choice and personality, which should be respected and nurtured. A child should not be pushed unduly to perform beyond his/her threshold limits; be it studies, sports or other activities.

(ii) Education and counselling: Educating and counselling him/her to face problems and stresses, and to accept disappointments and failures as a part of life. It would also be worthwhile to channelise the child's energy into healthy pursuits like sports, reading, music, yoga and other extracurricular activities.

(iii) Seeking help from parents and peers: Help from parent and peers should be sought immediately so that they can guide appropriately. Help may even be sought from close and trusted friends. Besides getting proper advise to sort out their problems, this would help young to vent their feelings of anxiety and guilt. 

Sexually transmitted diseases are infections that are passed from one person to another though sexual contact. 

Primary symptoms of AIDS:

(i) Fever, cough, body weak.

(ii) Decrease of body wait, stomach pain.

Prevention of AIDS:

(i) Use of condoms every time you have sex.

(ii) Don't share needles with anyone.

The genetic code is the set of rules used by living cells to translate information encoded within genetic material into proteins.

 Alfred Hershey and Martha Chase in 1952 worked with viruses that infect bacteria called bacteriophages.

The bacteriophage attaches to the bacteria and its genetic material then enters the bacterial cell. The bacterial cell treats the viral genetic material as if it was its own and subsequently manufactures more virus particles. They worked to discover whether it was protein or DNA from the viruses that entered the bacteria. 

They grew some viruses on a medium that contained radioactive phosphorous and some others on medium that contained radioactive sulphur. Viruses grown in the presence of radioactive phosphorous contained radioactive DNA but not radioactive protein because DNA contains phosphorus but protein does not. Similarly, viruses grown on radioactive sulphur contained radioactive protein but not radioactive DNA because DNA does not contain sulphur. 

Radioactive phages were allowed to infect to E. coli bacteria. Then as the infection proceeded, the viral coats were removed from the bacteria by agitating them in a blender. The virus particles were separated from the bacteria by spinning them in a centrifuge. 

Bacteria which was infected with viruses that had radioactive DNA were radioactive, indicating that DNA was the material that passed from the virus to the bacteria. Bacteria that were infected with viruses that had radioactive proteins were not radioactive. This indicates that proteins didn’t enter the bacteria from the viruses. DNA is therefore the genetic material that is passed from virus to bacteria.

 Multivoltine species is a species that has two or more broods of offspring per year.

Scientific name of two silk worms: 

(i) 'Bomyn mori'.

(ii) Antheraea assama.

Host plants: 

(i) som, saibalu, Digkaloti, Mejangkori.

In an ecosystem generally sun is the only source of energy. The autotrophs like plants etc. fix the sun radiant energy, to make food from simple inorganic materials and convert it into chemical energy. All organisms are dependent for their food on plants directly or indirectly. So animals i.e. herbivores feed on plants and these herbivores are eaten by the carnivores form a food chain. 

The energy trapped by the producer hence is passed on to the primary consumer and then to the secondary consumer. Ultimately this energy goes to the decomposers. The food chain or web formed is due to this interdependency of organisms. There are mainly two basic types of food chains Grazing Food Chain.

(i) Grazing Food Chain (GFC): This type of food chain starts at the producer level and completes at the decomposer level. This type of food chains have so many levels like- producer, herbivore, carnivore and at last the decomposers. Here in each level 90 percent of the total energy is consumed. For example: Grass – Deer- Tiger.

(ii) Detritus Food Chain (DFC): It begins with dead organic matter. It is made up of decomposers which are heterotrophic like fungi and bacteria. They meet their energy requirements by degrading detritus, with the help of some digestive enzymes secreted by them, into simple inorganic materials which are subsequently absorbed by them. 

 There are three major types of RNAs: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). All three RNAs are needed to synthesis a protein in a cell. The mRNA provides the template, tRNA brings aminoacids and reads the genetic code and rRNAs play structural and catalytic role during translation.

Human Genome project was an international scientific research project with the goal of determining the sequence of nucleotide base pairs that make up human DNA.