How do lactic acid bacteria (LAB) initiate setting of milk into curd?

(a) Describe aminoacylation of tRNA.

(b) Explain the process that takes place in the ribosomes when mRNA makes its entry into it in a prokaryote.

(c) Due to transcription error, ATG codon of DNA is transcribed into UAG in mRNA which translates a non-functional polypeptide chain in the ribosome. Justify the statement.

OR

Explain how does lac operon in E.coli operates:

(a) in the absence of an inducer.

(b) in the presence of an inducer.

(a) State what is an ecological succession.

(b) Write one similarity and one difference between hydrarch and

xerarch sucessions.

(c) Explain the mechanism of co-evolution as seen in orchid Ophrys and bee.

OR

(a) List any two ways the biodiversity loss affects any region.

(b) Explain any two causes of biodiversity loss, with the help of suitable examples.

Write the scientific name of the tropical sugar cane variety of South India. Why was the need felt to cross it with the sugar cane variety of North India?

State the fate of trophoblast of a human blastocyst at the time of implantation and that of the inner cell mass immediately after implantation.