Explore topic-wise InterviewSolutions in Current Affairs.

It includes the events after the formation of zygote. It is the first cell of new generation events that factors sexually reproducing organisms.

Meiotic division.

'A' Adventitious buds, 

Function - Vegetative propagation

i. Acidobacillus ferroxidens, Acidophillium spp.

ii. Polylactic acid.

iii. Kefir.

iv. Protease.

v. Aspergillus oryzae.

Maize, wheat, rice, bathua, spinach, pulses have biofortified varieties. Maize hybrids have twice the amount of amino acids, fortified wheat variety has high protein content, fortified rice has high quantity of iron. Consumption of such biofortified foods will enrich the nutritive value of our common foods and will vastly improve public health. It may even help overcome several nutrient deficiency disorders latent in our country.

The phenomenon is called parthenogenesis and the cell responsible for it is female gamete, ovum.

Fungi and algae.

The development of zygote depends on the type of life cycle of the organism and the nature of environment.

i. (b) protease

ii. (a) pasteurization

iii. (c) Acetyldehyde

iv. (c) microbial anaerobic

v. (a) Hydrogen

The sludge formed in this process, is used as fertilizer.

Plastic is a non-biodegradable substance. It cannot be degraded back into its original constituents. It remains just like that for many hundreds of years. It causes solid waste pollution in any environment wherever it is thrown indiscriminately. If burnt, it releases very toxic gases. If dumped in landfills it obstructs the other decomposition processes.

If thrown in water bodies, it causes harm to aquatic life. Cattle graze on plastic unknowingly and are killed by it as it clogs inside their alimentary canal. The gutters and rain water drains get clogged due to plastic bags and this causes cities to submerge in water during heavy rains. Nowadays, the fishermen get more than half of plastic if they cast their net in the sea.

People use the plastic bags indiscriminately without any thought towards their environmental impact. There are better alternatives for plastic bags such as cloth bags which can be reused again and again. Therefore, it is absolutely necessary to ban the use of plastic bag.

By presence of cleistogamous flowers.

I. — Protoplasts;

II. — Somatic hybridisation;

III. — Pomato;

IV. — Somatic hybrid

In many algae and fungi, the zygote secretes a thick wall around it self and undergoes a period of rest before germination. It undergoes meiosis and the product of meiosis form haploid individuals.

Eichhornia crassipes /water hyacinth.

Congress grass or carrot grass

Yeast i.e. Saccharomyces cerevisiae is used in the baking industries.

Many microbes are useful to us, such as bacteria which are used for making curds from milk, yeast used to ferment the batter of bread, bacteria used for making other milk products, bacteria and fungi used for making antibiotics. The bacteria are even used for pollution control.

Cheese is made from cow’s milk throughout the world. The steps in the process of cheese manufacture are as follows:

• Chemical and microbiological testing of milk is done.
• Three types of bacteria, viz. Lactobacillus lactis, Lactobacillus cremoris and Streptococcus thermophilus along with some colour is added to the milk.
• It imparts sourness to the milk and it is converted into yoghurt like substance.
• The water from this yoghurt, i.e. whey is not removed to make the yoghurt denser.
• Enzyme, rennet or protease is added to the mixture to make it more denser.
• Later cutting the solid yoghurt into pieces, washing, rubbing, salting, land mixing of essential microbes, pigments and flavours is done in suitable steps.
• The pressed cheese is then cut in to pieces and stored for ripening.

• Yoghurt is one of the milk product produced from milk with the help of lactobacilli (inoculant).
• In the industrial production of yoghurt, the milk is added with condensed milk powder. This increases the protein content of the milk. Then this milk is subjected to fermentation.
• Milk is boiled and then it is cooled till it becomes lukewarm.
• Then the bacterial strains of Streptococcus thermophiles and Lactobacillus delbrueckii are added to this lukewarm milk in 1:1 proportion.
• The Streptococcus bacteria convert the milk into solution containing lactic acid. This makes the proteins to gel out. It makes the yoghurt dense.
• The lactobacilli help in the formation of acetaldehyde like compounds giving a characteristic taste to the yoghurt.
• For commercial reasons, various fruit juices are mixed with yoghurt to impart different flavours forming strawberry yoghurt, banana yoghurt, etc.
• The pasteurization is carried out to increase the shelf life of yoghurt and improve its probiotic properties.

• In cities, the sewage is sent to processing plant and is treated with microbes.
• Microbes that carry out decomposition, are mixed with sewage. Such microbes are able to destroy, pathogens as well as decompose any compounds.
• Some microbes bring about bioremediation of environment, that are used for treating sewage pollution.
• Upon decomposition of the carbon compounds present in sewage, microbes release methane and CO_2.

Bamboo species flower once in its life time generally after 50–100 yrs of vegetative growth. It produces large number of fruits and then dies.

Man made methods of vegetative reproduction are called artificial vegetative propgation. They are mainly as follows :

(i) Cutting : In this method a small piece of any plant organ bearing buds such as stem, (sugarcane, rose, Botrgainuillea etc), root (Tamarind) and leaves (Bougainaillea) are used for propagation. 

(ii) Layering : In this method the roots are artiliciaily method produced on the stem or branches before they are cut and detached from the parent.

(iii) Grafting : In this method, the parts of plants are joined in such a way that they appear and grow as one plant. The supporting part of the plant which is rooted is called stock. The twig or the part of another plant which is joined to it is called scion. Grafting is commonly used in mango, guava, apple, pear, etc.

(iv) Micropropagation : This is a method of propagating the plants by tissue culture technique. This includes culturing of cells, tissue or organs in the laboratory under aseptic conditions resulting in the formation of an undifferentiated mass of cells called callus. Later on a large number of plantlets are produced from this callus.

'A' Offset 

Function  -  Vegetative propagatio

(a) Advantages of micropropagation are:

(i) A large number of palant can be produced in a short duration.

(ii) The plants produced are genetically identical 

(iii) Healthy plants can be obtained from the diseased plants.

(b) Micropropagation is commercially adopted in case of :

(i) Tomato, (ii) Banana (iii) Apple.

(a) Ginger : Rhizome :: Water hyacinth : Offset.

(b) Binary fission : Amoeba :: Multiple fission Plasmodiunt.

(c) Penicillitum: Conidia :: Sponges : Gemmules.

1. Microspore mother cell 16

2. Endosperm cell 24

Amoeba : Unicellular organism which reproduces asexually by binary fission.

i. The above picture shows the lack of management of sewage resulting in waste water being dumped carelessly.

ii. Microbes which can destroy the pathogens of cholera, typhoid, etc. are mixed with sewage. They release methane and CO₂ by decomposition of the carbon compounds present in sewage. Other microbes that decompose chemical compounds are also released. Phenol oxidizing bacteria decompose the xenobiotic chemicals present in sewage.

iii. Hydrocarbonoclastic bacteria like Alcanivorax borkumensis and Pseudomonas are used to clear the oil spillage from ocean water. These bacteria decompose the hydrocarbons. They bring about the reaction of released carbon with oxygen to produced CO₂ and water.

If there are non-biodegradable materials in the garbage, they will not decompose. The plastic, glass, metals etc. will not undergo microbial decomposition, therefore, such items should not be- there in the garbage. The toxic matter, hazardous chemicals and e-waste should also be removed. If such materials are present in the garbage, the microbes will be killed and the entire process of decomposition will be suffered.

When the garbage is compressed, its volume is reduced. The trips of the vans that pick up the garbage can be reduced due to such measures. The land filling sites can also accommodate more garbage if it is compacted.

The sewage generated in our house is carried by the drainage pipes to municipal sewage treatment plants. Here, primary, secondary and tertiary treatment is done on the sewage. The safe water is then released into the ocean.

i. The figure shows modern land fill site where microbial biodegradation process is carried out.

ii. Land-filling sites:

• In the land-filling sites the degradable wastes are transferred. Usually such sites are in urban areas.
• The land-filling sites are away from the residential areas for the hygienic reasons. Here large pits arb dug in open spaces.
• These pits are lined with plastic sheets. Therefore, the leaching of toxic and harmful materials is avoided to reduce the chance of soil pollution due to leachates.
• Compressed waste is put in the pit and is covered with layers of soil, saw dust, leafy waste.
• Specific biochemical substances are added for speedy decomposition.
• Bioreactors which are mixtures of bacteria are mixed at some places.
• Soil microbes and other top layers decompose the waste.
• Soil slurry is used to seal the pits completely.
• After a certain period, best quality compost is formed. Such land filling sites can be reused after removal of compost.

Virus free sugarcane can be developed by tissue culture technique. The meristematlc regions of a  plant are generally free from virus, Healthy and virus free sugarcane plants can by developed by this techmique using meristems as explants.

Procedure : Explants obtained from the meristem apical or young axillary buds or from nodes near the stem apex  are taken and surface sterlized by 0.5% Sodium hypochlorite and  then seeded over the nutrient agar medium enriched with cytokinin under   aseptic conditions. After incubation a  few days under optimal conditions the explants microprogive rise to shoots. these shoots are cut into nodal Jegments of 2-3 cm which are then transferred into a medium containing extra auxin for promoting  root formation. This results in the development of a number of plantlets, which are then hardened and transferred to fields.

Grasses : Runner.

Water hyacinth : Offset.

In orange, the nucellar cells surrounding the embryo sac start dividing, protrude into the embryo sac and develop into a number of embryos of different sizes.

Bamboo species are monocarpic i.e.,they flower and fruit only once during their life span which ranges from 50 to 100 Years.

In orange, nucellar cells surrounding embryosac start dividing, protrude into embryosac and form many embryos.

Bacillus, Yeast and Amoeba.

• By using bio pesticides, soil pollution is minimized. Otherwise by using chemical pesticides and fertilizers there is large scale soil pollution.
• When chemical pesticides are used in agriculture, there is contamination of soil by fluoroacetamide – like chemicals.
• These are harmful to other plants, animals as well as for-human beings. They may cause skin diseases in humans.
• By using bacterial and fungal toxins the pests and pathogens can be destroyed. Such toxins are directly incorporated in the plant materials. E.g. Spinosad is a biopesticide produced as a by-product of fermentation.

Budding : yeast (Saccharomyces)

conidia : penicillium

Internodes of sugarcane can not propagate vegetatively because they do not have buds on them. Buds develop only from the nodes of the stem. Therefore for vegetative reproduction of a plant like sugarcane through stem cutting it should have atleast one nodal region.

Asexual reproduction by zoospores formation takes place in Chlamydomonas. These reproductive units are called as zoospores because they are motile.

There are two sites in the large subunit of the ribosome, for subsequent amino acids to bind to and thus, be close enough to each other for the formation of a peptide bond. The ribosome also acts as a catalyst for the formation of peptide bond 23S rRNA in bacteria is a ribozyme. Amino acids become activated by binding with its tRNA in the presence of aminoacyl tRNA synthetase and ATP.

Penicillium reproduces asexually by spore formation.

Correct answer is C.

The 1^st generation obtained from crossing two parents is called as first filial generation or F₁ generation.

Correct answer is

(B) selfing the heterozygous progeny.

 Correct Option is (D) both (A) and (B)