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

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

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

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

A sequence of how many nucleotides in messenger RNA make a codon for an amino acid:

1. Four

2. One

3. Two

4. Three

DNA fingerprinting refers to:

During transcription, if the nucleotide sequence of the DNA strand that is being coded is ATACG, then the nucleotide sequence in the mRNA would be:

1. TCTGG

2. UAUGC

3. UATGC

4. TATGC

Number of base pairs in human chromosomes are:

1. $3<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^9$

2. $3<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^7$

3. $6<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^8$

4. $6<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^7$

The following ratio is generally constant for a given species:

Initiation codon in eukaryotes is:
1.  UGA
2.  CCA
3.  AGA
4.  AUG