Molecular Basis of Inheritance Test - 19

Conjugation is the process by which one bacterium transfers genetic material to another through direct contact.

1.  Transduction involves the transfer of DNA from one bacterium to another with the use of a bacteriophage. A phage is a virus that infects bacteria.

2.  Transformation is genetic alteration of a cell resulting from the direct uptake, incorporation and expression of exogenous DNA from its surroundings.

Like DNA replication in an organism, PCR requires a DNA polymerase enzyme that makes new strands of DNA, using existing strands as templates. The DNA polymerase typically used in PCR is called Taq polymerase, after the heat-tolerant bacterium from which it was isolated.

1.  Each DNA strand within the double helix is a long, linear molecule made of smaller units called nucleotides that form a chain. 

2.  The two helical strands are connected through interactions between pairs of nucleotides, also called base pairs

Replicon is the unit of DNA that carries a replication origin site and a termination site and is able of self-replication. Cistrons are defined as the unit of function that exhibits cis-trans test. A gene carries several Cistrons.

The smallest unit capable of undergoing recombination is called as recon. A recon consists of one to several mutants, which are the smallest unit of mutation.

In the dsDNA molecule, the distance between base pairs is 3.4 0A.

3.4A × 23 = 78.2

Operon Theory is the concept of gene regulation proposed by François Jacob and Jacques Monod (1961). In the presence of inducer, the repressor is inactivated and dissociates from operator to express the operon.

Thus, the expression of the operon is controlled by a cis-acting operator and by a trans-acting repressor.

The Nucleosome core particle consists of approximately 146 base pairs (bp) of DNA wrapped in 1.67 left-handed super helical turns around a histones octamer, consisting of 2 copies each of the core histones H2A, H2B, H3, and H4.

Chain-termination codon: A set of three adjacent bases in the DNA or their complementary bases in messenger RNA that specifies the end of a polypeptide chain. The three chain-termination codon (in messenger RNA) is UAA, UAG, and UGA.

They are also called termination codon, stop codon, or nonsense codon.

The wild type cells that are capable of utilizing certain nutrients or synthesizing certain compounds and do not require any additional organic nutrients as growth supplements are called prototrophs.

Auxotrophs are the mutant cells that are incapable of utilizing certain nutrients or synthesizing certain compounds and hence they can grow on minimal media plus the specific growth supplement for which they are mutant.