Satellite DNA is useful tool in:
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Solution
Satellite DNA is useful in forensic science. The polymorphism of minisatellite, microsatellite and minivariant repeats is analysed for DNA finger printing,DNA profiling. It helps in the resolution of crimes, legal disputes etc.
The one aspect which is not a salient feature of genetic code,is its being:
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Solution
Genetic code is non ambiguous. There is no ambiguity for a particular codon. A particular codon will always code for the same amino acid, where ever it is found.
Whose experiments cracked the DNA and discovered unequivocally that a genetic code is a ‘triplet’?
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Solution
Nirenberg and Mathaei (1961) experimentally proved that a single amino acid is determined by a sequence of three nitrogen bases. The sequence of three nitrogen bases determining a single amino acid is called a triplet code. Nirenberg and Mathaei experiments cracked the DNA and discovered unequivocally that a genetic code is a triplet.
Semi-conservative replication of DNA was first demonstrated in:
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Solution
Semiconservative replication of DNA was first demonstrated in Escherichia coli. E. coli is a common type of bacteria that can get into food, like beef and vegetables. The strange thing about these bacteria is that they are not always harmful to you. E. coli normally lives inside your intestines, where it helps your body breakdown and digest the food you eat.
What is not true for genetic code?
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Solution
The genetic code consists of 64 triplets of nucleotides. These triplets are called codons. With three exceptions,each codon encodes for one of the 20 amino acids used in the synthesis of proteins. That produces some redundancy in the code. Most of the amino acids being encoded by more than one codon. The genetic code can be expressed as either RNA codons or DNA codons.
T.O. Diener discovered a:
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Solution
Theodor O. Diener discovered the Potato Spindle Tuber Viroid (“PSTVd”), the first viroid ever identified, in 1971. PSTVd is a small, circular RNA molecule. Dr.Diener discovered that the pathogen causing potato spindle tuber disease is not a virus, as previously believed,but a much smaller, free RNA molecule.
Haploids are more suitable for mutation studies than the diploids. This is because
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Solution
Haploid describes a nucleus cell or organism with a single set of unpaired chromosomes. The haploid number is designated as X. Reproductive cells, formed as a result of meiosis are diploid. Fusion of two such cells restores the normal diploid number. Therefore, haploids are more suitable for mutation studies than the diploids. This is because all mutations, whether dominant or recessive are expressed in haploids.
Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it?
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Solution
Purine is an organic nitrogenous base sparingly soluble in water, that gives rise to a group of biologically important derivatives, notably adenine and guanine,which occur in nucleotides and nucleic acids (DNA and RNA).
Which one of the following pairs of codons is correctly matched with their function or the signal for the particular amino acid?
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Solution
GCU indicates alanine but GUU indicates valine.
Stop codons are UAG, UGA and UAAAUG is the most common start codon which does for methionine.
UUA indicates leucine but UCA indicates serine.
In the DNA molecule
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Solution
In the DNA molecule, there are two strands which run anti-parallel one is 5' - 3' direction and other in 3'-5'direction, the two chains are held together by hydrogen bonds between their bases. Adenine (A), a purine of one chain is exactly opposite thymine (T), a pyramidine of the other chain. Similarly, cytosine (C), a pyrimidine lies opposite guanine (G), a purine. This allows a sort of lock & key arrangement between large sized purine & small sized pyrimidine. It is strengthened by the appearance of hydrogen bonds between the two.