Bacterial Nuclein Acid Synthesis and Organisation

Question 1

Where is genetic material stored if there is no membrane bound nucleus?

Answer 1

Genetic material is in the form of a nucleoid with additional material on plasmids

Question 2

Briefly explain the process of Transcription

Answer 2

• process by which DNA is copied (transcribed) to mRNA, which carries the information needed for protein synthesis.
  1) pre-messenger RNA is formed, with the involvement of RNA polymerase enzymes
  2) the resultant single strand of RNA is the reverse-complement of the original DNA sequence

Question 3

What is the role of lacZ, lacY and lacA for the lac operon in E. Coli.

Answer 3

lacA - encodes beta galactosidase - required to metabolise lactose

lacY - encodes a permease - required to transpose lactose across the bacterial cell membrane

lacZ - encodes a transacetylase enzyme - detoxification role

all 3 genes are located together in a cluster - the lac operon. coordinated transcription due to a shared promoter, operator and terminator = maximum efficiency.