The unequivocal proof that DNA is the genetic material came from the experiments of -

Select the correct statements regarding the menstrual cycle in females:
(A) The first menstruation begins at puberty and is called menopause.
(B) Ovulation occurs mid-cycle (around day 14) when progesterone level is maximum.
(C) In absence of fertilization, corpus luteum degenerates and causes breakdown of endometrium, starting a new cycle.
(D) In humans, menstrual cycle stops around the age of 50 years.
Select the correct answer from the options given below:

Read the following passage carefully and answer the given questions.
Biofertilisers
Biofertilisers are organisms that enrich the nutrient quality of the soil and their main sources are bacteria, fungi and cyanobacteria. You have studied about the nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium. These bacteria can fix atmospheric nitrogen into organic forms. Other bacteria can also fix atmospheric nitrogen while free-living in the soil (examples Azospirillum and Azotobacter). Fungi are also known to form symbiotic associations with plants (mycorrhiza). Many members of the genus Glomus form mycorrhiza. Plants having such associations show other benefits also, such as resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development. Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser. Blue green algae also add organic matter in to the soil and increase its fertility. Currently, in our country, a number of biofertilisers are available commercially in the market and farmers use these regularly in their fields to replenish soil nutrients and to reduce dependence on chemical fertilisers.
Nostoc is an example of :

Which of the following is the most species-rich taxonomic group among animals?

Read the following passage carefully and answer the given questions.
Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). B. thuringiensis forms protein crystals during a particular phase of their growth. Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) which codes for a particular product such as human protein (a-1-antitrypsin) used to treat emphysema. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams per litre). The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk. A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield. A novel strategy was adopted to prevent this infestation which was based on the process of RNA interference (RNAi). This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing). Biopiracy is the term used to refer to the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment. ELISA is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigens (proteins, glycoproteins, etc.) or by detecting the antibodies synthesised against the pathogen.
mRNA silencing through RNA interference (RNAi) refers to the:

Which of the following is/are NOT the step(s) used in separation and isolation of DNA fragments by gel electrophoresis technique:
(A) Staining with ethedium bromide
(B) Exposure to UV Radiation
(C) Cutting DNA fragments into small pieces by using restriction endonuclease
(D) Denaturation of DNA fragments
Choose the correct answer from the options given below :

In flowering plants, double fertilization results in the formation of:

Choose the correct statement for the collision theory of chemical reactions

A resistor R and an inductor L are connected in series to a 24 V, 50 Hz supply. A current of 1 A flows through the circuit. If the current differs in phase from the applied voltage by 60°, the value of impedance in the circuit is

Amniocentesis is used to detect the :

The current through a \(4 / 3 \Omega\) external resistance connected to a parallel combination of two cells with emfs of 2 V and 1 V , internal resistances \(1 \Omega\) and \(2 \Omega\) respectively, is :

\( 10^{18} \) electrons pass from point A to point B in 0.1 s in a conductor. The value of the current is

The relation \(R\) in the set \(\{1,2,3\}\) given by \(R=\{(1,1),(2,2),(3,3),(1,2),(2,3)\}\) is: