Molecular Basis of Inheritance Test 6

DNA molecules are replicated in both meiosis and mitosis.  DNA unwinds and unzips along its base pair chemical bonds.  Free nucleotides then connect to the exposed base pairs on both strands resulting in the formation of the missing side of each new DNA.

Beadle and Tatum carried out experiment on mutant bread mould that lacked specific enzymes. They demonstrated that gene carry information for making proteins.

A single strand of nucleic acid tagged with a radioactive molecule is calledProbe. Probe is used to know the mechanism of transcription of DNA. Radioactive substance can be easily detected.

Wobbling is a phenomenon where the third base of t-RNA at its 5’ end pair with a non-complementary base of m-RNA.

In figure above, A represent helicase and B represents single strand binding protein. These structures are formed during semiconservative replication of DNA.

There are 64 codons if genetic code is triplet, total 64 codons are formed in which 3 codon are terminator or stop codon. There are 64-3 61 codons and 20 amino acids. More than one codons code for same amino acids, so, genetic code is degenerate.

The DNA segment which serves as ON-OFF switch for transcription is called an operator. Operator attach with template strand to initiate transcription process.

Codon AAA code for amino acid lysine but UUA, AUG and CCC do not code for Valine, cysteine and alanine respectively. So, AAA and lysine pair is correct option out of given options.

During translation initiation in prokaryotes, a GTP molecule is required along with 30S ribosome, m-RNA with formyl-met-t-RNA. GTP provides energy and ribosomes provide site for translation.

UGA, UAG and UAAare called termination or stop codon because they do not code for any amino acid. As soon as any one of them codon is located on m-RNA translation process is stopped.

The mRNA produced by transcription of DNA consists of exons and introns. The removal of introns and joining of exons to obtain mature mRNA is called splicing. It is followed by capping and tailing.

In lac operon the word lac refers to lactose. A polycistronic structural gene is regulated by a common promoter and regulatory genes.

In lac operon concept the sequence of arrangement of structural gene is as lac Z, lac Y and lac A. The z gene codes for beta-galactosidase. The y gene code for permease and a gene encodes a transacytylase.

Figure shown above represent translation process in which protein is produced. Ribosome provide site for protein synthesis and t-RNA brings the amino acids. The ‘x’ is the polypeptide chain produced.

Autoradiogram of VNTR probe gives many band of different size. It differs from individual to individual except monozygotic twins or identical twins.

In human genome project, commonly used host were bacteria and yeast and their vectors are called as Bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC)

Genetic map up of an organism or individual lies in the DNA sequence. If two individual differs, then their DNA sequence should also be different.

Rice genome projects includes finger printing of HindIII and Eco RI and assembling of finger printed BACs into contigs.

Genetic and physical map of genome was generated using information on polymorphism of restriction endonuclease recognition sites and repetitive DNA sequence called microsatellites.

In human genome project, commonly used host were bacteria and yeast and their vectors are called as Bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC)

The double helix describes the appearance of double-stranded DNA, which is composed of two linear strands that run opposite to each other, or anti-parallel, and twist together. Each DNA strand within the double helix is a long, linear molecule made of smaller units called nucleotides that form a chain.

UAA of mRNA do not code for any amino acids so it is a termination codon. If termination codon is present on mRNA, the protein synthesis stops abruptly at that point.

The sensitivity of fingerprinting technique has been increased by use of Polymerase chain reaction (PCR). After that single cell obtained from organism in enough for this technique.

DNA finger printing is highly reliable method of identification of individual involved in crimes. DNA a fingerprinting is a sure method in solving paternity and maternity disputes.DNA fingerprinting cannot be used to cure HIV infection.

The hybridization of probes having radioactive isotopes with various sequence of nitrogen bases with ssVNTR is called Southern blotting.

VNTR of two persons may be similar at certain sites but could be different at other sites because a child inherits 50% of chromosomes from mother and remaining 50% from father. VNTR genes also undergoes different kinds of mutations.