Biology: CUET Mock Test - 7 - Class 12 MCQ

Raising crops for the production of ethanol is known as energy cropping. Fermentation is carried out with the help of Yeast. After fermentation, alcohol is separated through distillation.

Wood most suitable for fuel should be highly combustible. It should be hard and it should have a high calorific value. It should burn with good flame and sufficient heat.

Hydrocarbons were first isolated from plant latex by Melvin Calvin. Utilising petroleum plants for energy cropping was also suggest by Melvin Calvin.

The first petroplant discovered was Euphorbia lathyrus by Calvin. 100 tonnes of the dry weight of this petroplant can yield 80 tonnes of crude oil and 200 tonnes of fermentable sugars.

Biogas formation yields manure for two crops in one acre and 2m³ of fuel gas having 9000 kcal of energy with useful one being 2700 kcal and at 30% burning efficiency.

Good fuel or firewood include the woods of Acacia, Albizzia, Dalbergia, Adina, Terminalia, Casuarina, Quercus, etc. Bad fire or fuelwood include the woods of Pinus, Mangifera, Bombax, Michelia, etc.

Radioactive wastes are not organic wastes. Organic wastes include animal wastes, human wastes, agricultural wastes, crop residues, forest residues, aquatic weeds, etc.

 Wood used as a source of energy is called fuelwood. It is a renewable source of energy which can be harvested even by unskilled labours.

Producer gas is obtained through the process of combustion. It is used as an industrial fuel, in running certain engines including irrigation sets and manufacture of ammonia.

The various energy crops include Sugarcane, Sugar beet, Potato, Tapioca and Maize. Energy crops can be used to produce alcohol and other energy fuels.

Social forestry is the raising and exploitation of small forests on common village lands, roadsides, railway embankments and other vacant lands by groups of people for obtaining their requirements of firewood, fodder and minor timber at very low cost.

Bioenergy is the energy obtainable from biological sources i.e. living organisms, their wastes and residues. This includes animal energy and biofuels.

The full form of AIDS is Acquired Immune Deficiency Syndrome. This means deficiency of the immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease.

The transmission of AIDS takes place by Parenteral Route (though blood contact involving unscreened transfusion of blood, poorly sterilised surgical instruments, etc.), Sexual Route and Transplacental Route-Infection from infected mothers to foetus.

The given figure represents the structure of HIV. HIV consists of a core RNA with reverse transcriptase surrounded by a protein coat. The protein coat around the core consists of a protein called P-24. Outside this protein, the coat is a layer composed of another protein called P17.

After getting into the body of the person, the virus enters into macrophages where the RNA genome of the virus replicate to form viral DNA with the help of enzyme Reverse Transcriptase.

When the virus attacks the immune system of the body, it gets into the macrophages where the RNA genome of the virus replicates to form the viral DNA. This viral DNA gets incorporated into the host cell’s DNA and directs the infected cells to produce virus particles. The macrophages continue to produce virus and in this way acts like HIV factory.

In India, AIDS infection was detected in 1986. In India, HIV positivity had reached high proportions in an area adjoining the golden triangle (Laos, Thailand and Myanmar) due to intravenous drug addictions.

AIDS was first reported in the USA amongst homosexuals in 1981 and in last years or so, it has spread all over the world killing more than 25 million people.

The outermost envelope consists of a phospholipid bilayer studded with glycoproteins (GP120 and GP41). The major cell infected by HIV is the Helper T-lymphocytes that bears the CD4 receptors site. The attachment pf virus to CD4 receptor site is by the help of GP120 on the protein coat of the virus.

HIV is a retrovirus having a rounded outline. The core has two single strands of genomic RNA, enzyme reverse transcriptase, protein P-15 associated with genomic RNA, inner covering of P-24 and outer of P-17.

Due to the decrease in the number of T-lymphocytes, the person starts suffering from infections that could have been otherwise overcome such as those due to bacteria, viruses, fungi and even parasites.

In India, the National AIDS Control Organisation (NACO) and other non-governmental Organisations are doing a lot to educate people about AIDS. WHO has started a number of programmes to prevent the spreading of HIV infection.

AIDS is characterised by a reduction in the number of CD4 or helper T₄-lymphocytes because of infection of the Human Immunodeficiency Virus. It is also called a slim disease.

The full form of CMI is Cell-Mediated Immunity. The immune system comprises of T- lymphocytes that defend the body against pathogens, cancers and foreign structures like tissue transplants.

T-lymphocytes are called as Competent lymphocytes. The cells develop antigen specificity through the previous contact. T-lymphocytes respond to specific antigen by forming a clone of cells.

T-cells of our immune system gets differentiated into Killer or cytotoxic cells, Helper cells, Suppressor cells and Memory cells. Killer, Helper and Suppressor T-cells are also called as Effector cells.

B-cells produce antibodies in response to the instruction received from Helper T-cells. Along with this, Helper T-cells also attract macrophages to the site of infection.

Killer T-cells are responsible for producing pores in the plasma membrane of the antigens. The interaction of Killer T-cells with antigens will produce perforins to kill the infected cells.

Helper T-cells can be distinguished from Killer T-cells by the presence of CD-4 receptor. CD-8 receptors are present in both Killer T-cells and Suppressor T-cells.