Be more specific please on this question
Answer:
A,B and E
Explanation:
- I+: I refers to the lac repressor, the + indicates that the repressor is functional
- P+: P refers to the promoter region and the + indicates that the promoter is functional
- Oc: O refers to the operator region, but the Oc indicates that the operator is constitutive ie. that it is always on/ can't be turned off.
- Z-: Z refers to the LacZ gene which produces β-galactosidase. Z- indicates that this gene is non-functional
- Y+: Y refers to the LacY gene which produces the permease protein. Y+ indicates that this gene is functional
So based on the breakdown above:
- C is not true because the lac operon is an inducible system. The operator needs to be able to be repressed. In this case the operator is constitutive (always on) which is not the correct form.
- D is not true because Z-, no β-galactosidase is produced.
Only A, B and E apply.
"Viruses straddle the definition of life. They lie somewhere between supra molecular complexes and very simple biological entities. Viruses contain some of the structures and exhibit some of the activities that are common to organic life, but they are missing many of the others. In general, viruses are entirely composed of a single strand of genetic information encased within a protein capsule. Viruses lack most of the internal structure and machinery which characterize 'life', including the biosynthetic machinery that is necessary for reproduction. In order for a virus to replicate it must infect a suitable host cell".
From The Bacteriophage T4 Virus
