Biology Test - 44

Protoplasm is the colourless material that is composed of the living part of a cell which includes the cytoplasm, nucleus and other organelles. The virus is a small infectious agent which is made of a protein coat called capsid that surrounds the genetic material. Some of the viruses also contain an envelope that surrounds the capsid. Protoplasm is absent in the virus.

Ovulation is the phase of the menstrual cycle where the ovum gets released from the graffian follicle, this phase is regulated by the activity of different hormones like FSH (follicle-stimulating hormone) and LH (luteinizing hormone). Both LH and FSH attain a peak level in the middle of the menstrual cycle (about the 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle (peak of ovulation) called LH surge induces rupture of graffian follicle and thereby the release of an ovum (ovulation). Thus, Ovulation in mammals is caused by FSH & LH.

In activated sludge system (secondary sewage treatment), the primary effluent is taken to aeration tank. A large number of aerobic heterotrophic microbes grow in aeration tank. They form floes, which digest a lot of organic matter. As the BOD of waste water is reduced sufficiently, it is passed into setting tank where bacterial floes are allowed to undergo sedimentation. The sediment of the settling tank is called activated sludge which is a rich source of aerobic bacteria. It is further processed in anaerobic sludge digester. Biogas commonly called gobar gas is produced by anaerobic breakdown of biomass with the help of methanogenic bacteria. Biogas is made up of methane (50-70%), CO2(30-40%) with traces of nitrogen, hydrogen sulphide and hydrogen. Methanobacterium is an anaerobic methanogenic bacteria which is found in rumen of cattle and helpful in the breakdown of cellulose.

Complete polypeptide is released from thereis correct regarding ribosomes.

Ribosomes are, called as protein factories. Each ribosome has two unequal parts, small and large. The larger subunit of ribosome has a groove for pushing out the newly formed polypeptide and protecting the same from cellular enzymes. The smaller subunit fits over the larger one like a cap but leaves a tunnel for mRNA. The two subunits come together only at the time of protein formation.

The first transgenic plant to be produced is tobacco.Transgenic crops are disease resistant, pest resistant, environmental change-resistant and etc.The world's first genetically modified crop is the tobacco plant, which was produced in 1982; this plant was antibiotic-resistant.Tobacco is widely used as a model plant system in transgenic research for several reasons: its molecular genetics is well understood, its genomic mapping is almost complete, genetic transformation can be readily achieved, tobacco plants survive well in vitro and under greenhouse conditions, and tobacco produces large.

lgA antibodies provide passive immunity to newborn baby.

Passive immunity is also provided through colostrum and breast milk, which contain IgA antibodies that are transferred to the gut of the infant, providing local protection against disease causing bacteria and viruses until the newborn can synthesize its own antibodies.

Chrysophytes are unicellular protists that include diatoms and desmids. the diatoms are covered with silica shells and desmids are covered with cell walls having mucilage layer. chrysophytes do not live in the depths of the seas.

Two butterfly species are competing for same nectar of a flower. To survive and co-exist together they can choose different foraging patterns.

The plant parts which consist of two generations one within the other are pollen grains inside the anther and embryo sac inside the ovule
Pollen grain is haploid inside the diploid anther.
Embryo sac is haploid inside the diploid ovule.

Thiamine deficiency causes decreased energy production because it is a co-enzyme for pyruvate dehydrogenase & alpha ketoglutarate dehydrogenase.

Thiamine is an essential vitamin that plays an important role in cellular production of energy from ingested food and enhances normal neuronal actives. Deficiency of this vitamin leads to a very serious clinical condition known as delirium.