(a) Why must a cell made 'compelent' in biotechnology experiments ? How does calcium ion help in doing so ?
(b) State the role of 'biolistic gun' in biotechnology experiments.

(a) Why must a cell made 'competent' in biotechnology experiments ? How does calcium ion help in doing so ? (b) State the role of 'biolistic gun' in biotechnology experiments.

why is making cells competent essential for biotechnology experiments? List any two ways by which this can be achieved.

(a) Why should a bacterium be made 'competent? (b) Explain the role of 'microinjection' and 'gene gun' in biotechnology .

The break-down of glucose in a cell occurs in any of the following pathways : Three experiments (A, B, C) have been set up. In each experiment, a flask contains the organism in growth medium, glucose and a brown dye that changes its colour to yellow when the pH decreases. The mouth of the flask is attached to a test tube containing lime water (Calcium hydroxide , as shown in the figure) . In C, but not in A and B , air is removed from the flask before beginning the experiment. After a period of growth, the following observation were made : A : Lime water turns milky , the dye colour remains the same B : The dye colour changes , lime water does not turn milky C : Lime water turns milky , the dye colour remains the same (a) Question : Identify which of the reactions is the pathways depicted above is taking place in each experiment . Give reasons for your answer . (b) Question : Identify which of the reactions in the pathways depicted above is expected to occur in Red Blood Cells (RBCs)

Explain the following : (a) How does the middle ear help in hearing ? (b) Why does vitamin A deficiency produce night-blindness ? (c ) What is the role of lacrimal gland ? (d) How does the iris adjust the size of the pupil ?

State the working principle of potentiometer. With the help of the circuit diagram, explain how a potentiometer is used to compare the emf's of two primay cells. Obtain the required expression used for comparing the emfs. Write two possible causes for one sided deflection in a potentiometer experiment.