Read the following passage and answer the questions that follow :
We know that plasmids and bacteriophages are the most commonly used vectors in biotechnology experiments. If we can link an alien piece of DNA to the plasmid DNA, the alien DNA can be multiplied equal to the copy number of the plasmid. Engineered vectors are used these days. Study the diagram of the E. coli cloning vector pBR322 and answer the questions that follow :
(b) (ii) Identify and name two selectable markers shown in the diagram.
The process of copying genetic information from template strand of DNA into RNA is called transcription. It is mediated by RNA polymerase. Transcription takes place in the nucleus of eukaryotic cells. In transcription, only a segment of DNA and only one of the strands is copied into RNA.
(b) (ii) Mention the two additional processes which hnRNA needs to undergo after splicing to become functional.
(c) Name the two restriction sites each in the two genes you have identified as selectable markers.
(b) (i) Identify :
(I) The gene in the cloning vector that controls the copy number of the vector.
(II) The restriction site - C in the "rop" gene.
(a) Why are plasmids and bacteriophages used as cloning vectors ?
(a) Why is the strand of DNA with \( 3^{\prime} \rightarrow 5^{\prime} \) polarity transcribed and not the other strand of \( 5^{\prime} \rightarrow 3^{\prime} \) polarity ?
(b) (i) Why is hnRNA required to undergo splicing ?
Immunity in our body is of two types (i) Innate immunity, and (ii) Acquired immunity. Innate immunity is a non-specific defence mechanism, whereas Acquired immunity is pathogen specific. Acquired immunity is characterised by memory. Antibodies are specific to antigens and there are four types of antibodies produced in our body - IgA, IgE, IgG and IgM. It shows primary response where it encounters the pathogen for the first time and secondary response during the subsequent encounters with the same antigen/pathogen. These immune responses are carried out with the help of two special types of lymphocytes present in the blood.
How is active immunity different from passive immunity ? Write any two differences.
(i) Enlist any four prime goals of the Human Genome Project (HGP).
(ii) List the two methodologies which were involved in the human genome project. Mention how they were used.
(iii) Expand "YAC" and mention what it was used for.
The organ transplants (grafts) are often rejected if not taken from suitable compatible persons. Mention the characteristic of our immune system that is responsible for the rejection.
Name the two types of specialised cells which carry out the primary and secondary responses.
Name any two barriers present in our body that provide innate immunity.
Gene expresses itself in a cell system as a protein/enzyme. How an expression of gene occurs in a cell system, when it needs to occur and how the gene expression is regulated in prokaryotic cell system was studied by the combined efforts of Francois Jacob, a geneticist and Jacques Monod, a biochemist. For their work on lactose metabolism in E. coli and introducing the concept of "lac operon", they were awarded the Nobel Prize in 1965.
It is said that "lac operon" has to be operational at a very low level in the bacterial cell all the time. Justify.
How are the structural genes activated in the lac operon in E. coli ?
Study the graph given below and answer the questions that follow :
(i) Write the status of food and space in the curves a and b.
(ii) In the absence of predators, which one of the two curves would appropriately depict the prey population ?
(iii) 'Time' has been shown on x-axis and there is a parallel dotted line above it. Give the significance of this dotted line.
Why is lac operon said to be a transcriptionally regulated system ?
Why is the regulation of operon called negative regulation ?
Define adaptive radiation. How did Darwin explain adaptive radiation ?
(a) Draw a diagram of human ovum prior to fertilization. Label any four parts.
(b) Explain how polyspermy is avoided during fertilization.
Why and how can bacteria be made 'competent' ?
Mention the sites of action of the hormones 'GnRH' and 'FSH' during spermatogenesis. Write one function of each of these hormones.
(a) Draw a figure of E. coli vector pBR322 and label the following :
(i) Origin of replication
(ii) Ampicillin resistance site
(iii) Tetracyclin resistance site
(iv) "rop"
(b) Mention the significance of origin of replication.
Thorns of Bougainvillea and tendrils of Cucurbita are examples of :
Internal bleeding, muscular pain, blockage of the intestinal passage and anaemia are some of the symptoms caused due to infection by :
Assertion (A) : The interaction between a whale and the small barnacles on its back is considered as commensalism.
Reason (R) : In the above association, neither of the species is benefitted.
