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level: Level 1

Questions and Answers List

level questions: Level 1

Question	Answer
how are DNA fragments charged	Negatively charged
these are short sequences of DNA nucleotides which are synthesized discontinuously and later linked together by an enzyme DNA ligase to create the lagging strand during DNA replication.	okazaki fragments
Which RNAs should be most abundant in animal cell	r-RNA ( 80 percent of the cell ribosomal content)
What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis	The smaller the fragment size, the farther it moves
when does DNA replication in bacteria occurs	Prior to fission
where is rRNA formed ?	nucleolus
what are Ribosomes composed of ?	RNA + Protein
cDNA probes are copied from the messenger RNA molecules with the help of what ?	Reverse transcriptase
out of the three bases of the codon which is the least important?	The third base of the codon is the least specific and hence least important.
Which antibiotic inhibits interaction between tRNA and mRNA during bacterial protein synthesis?	Neomycin
Amino acid sequence, in protein synthesis is decided by the sequence of which RNA	mRNA
One gene-one enzyme hypothesis was postulated by	Beadle and Tatum
One turn of the helix in a B-form DNA is approximately	3.4 nm
During protein synthesis in an organism, at one point the process comes to a halt. which codons could bring it to a halt	UAG, UGA, UAA
Thymine is also known as a pyrimidine nucleobase. what is the other name?	5-Methyl uracil
The association of histone H1 with a nucleosome indicates	that DNA will be packed normally in the cells
what is read in a contiguous fashion in mRNA	A codon
Removal of introns and joining the exons in a defined order in a transcription unit is called	Splicing
Semiconservative replication of DNA was first demonstrated in	Escherichia coli
Whose experiments cracked the DNAand discovered unequivocally that the genetic code is "triplet"?	Nirenberg and Mathaei
The one aspect which is not a salient feature of genetic code, is its being	Ambiguous
what cell/organism does not follow the central dogma of molecular biology?	HIV
Which enzymes will be produced in a cell in which there is a nonsense mutation in the lac-y gene ?	B-galactosidase
functioning unit of DNA containing a cluster of genes under the control of a single promoter	operons
Several ribosomes attached to a single mRNA form?	Polysome
what are the binding site of t-RNA with m-RNA and amino acids ?	m-RNA-anticodon loop and amino acid-CCA end
what does allolactose acts as ?	inducer
one gene one enzyme relationship was first established in which organism?	neurospora crassa
a gene containing multiple exons and at least one intron is termed as	split gene
a plasmid and was one of the first widely used E. coli cloning vectors. Created in 1977 in the laboratory of Herbert Boyer	pBR322
gene which is responsible for the synthesis of a polypeptide chain is	structural gene
it is the example of repressible gene ( ON plus co-repressor gives OFF)	tryptophan operon
the end product of a metabolic pathway may bind a repressor to make the latter active enough to bind to the operator. the end product is called?	co reppresor
DNA is not present in which cell organelle ?	ribosomes
the cutting of DNA at specific points became possible with the discovery of	restriction enzyme
rRNA is sythesized in	nucleus
commonly used vectors for human genone sequencing are	BAC and YAC
analysis of chromosomal DNA using southern hybridisation technique does not use	PCR
what is a functioning unit of DNA containing a cluster of genes under the control of a single promoter.	operon
in plants and animal cells chromatids are made up of	DNA,RNA HISTONE AND NON HISTONE
codon with dual functions is	AUG
the most unstable RNA is	heterogenous nuclear RNA
hargobind khora contributed to genetic engineering by synthesing	artificial gene
The experiment demonstrated that DNA replicated semi-conservatively, meaning that each strand in a DNA molecule serves as a template for synthesis of a new, complementary strand. who did this expeeriment?	Meselson and Stahl
the DNA fragments separated on an agarose gel can be visualized after staing with	aniline blue
the final proof for dna as the genetic material came from the experiments of	heshey and chase