E. coli cells with a mutated z gene of the lac operon cannot grow in a medium containing only lactose as the source of energy because-

1.	They cannot synthesize functional beta-galactosidase
2.	They cannot transport lactose from the medium into the cell
3.	The lac operon is constitutively active in these cells
4.	In the presence of glucose, E. coli cells do not utilize lactose

Which one of the following makes use of RNA as a template to synthesize DNA:

1. DNA dependant RNA polymerase

2. DNA polymerase

3. Reverse transcriptase

4. RNA polymerase

Protein synthesis in an animal cell occurs:
 

Production of a human protein in bacteria by genetic engineering is possible because:

During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle like structure at the point. What is the sequence called -

1. CAAT box

2. GGTT box

3. AAAT box

4. TATA box

A cup has ${10}^5$ bacterial cells. Each bacterial cell divides in 35 minutes. What shall be the number of bacteria after 175 min?

Which of the following exercises control over transcription:
1.  Operator
2.  Regulator
3.  Promoter
4.  Recon

Transduction in bacteria is carried out by:
1.  Bacteriophage
2.  B.G.A.
3.  Mycoplasma
4.  Rickettsiae

Variations in proteins are due to:
1.  Sequence of amino acids
2.  Number of amino acids
3.  R–group
4.  None

Segments of DNA which can move in a genome:
1.  Transposons
2.  Introns
3.  Exons
4.  Cistrons