A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomena.

Veena observes that during winter setting of milk into curd takes more time while during summer, the same process happens faster. She asks about this difference in time taken to her elder sister. She also asks her sister about why certain reactions occur rapidly while others occur slowly. Her sister explains her about the various factors that affect the rate of chemical reactions. Based on the above scenario, answer the following questions. Why do you think setting of curd occur at different rates during different seasons?

Draw all the possible structural formulae having molecular formula C_(6)H_(14) . Give names to all the isomers. Which difficulties were faced by you while naming? As the time progressed, the carbon compounds became very large in number and their common names caused confusion. A need was felt to have a logical system acceptable to all for naming the carbon compounds.

Aminoacids, as the name suggests, have both an amino group and a carboxyl group in their structure. In addition, all naturally occurring aminoacids (those which are found in proteins) are called L aminoacids. From this, can you guess from which compound can the simplest aminoacid be made?

Answer the following Read the paragraph and answer the questions given below it. Food poisoning can occur due to contamination of food by various bacteria and fungi.Clostridia are bacteria responsible for spoilage of cooked food. There are around 100 species of this bacteria viz. Clostridium tetani, Clostridium botulinum, etc. that are present either free living in soil or the alimentary canal of humans and other animals. The bacteria are rod- shaped and produce pottle-shaped endospores in adverse environmental conditions. These microbes cannot withstand normal oxygen levels in air and grow under anaerobic conditions. Do you know about any rod-shaped, anaerobic micro-organism that is useful to humans?