___ In normal cells there are three stop codons and these are recognized by tRNA
ID: 91385 • Letter: #
Question
___ In normal cells there are three stop codons and these are recognized by tRNAs with specific anticodons. ___ You observe a very large pairing loop in meiosis. It is most likely to be from a translocation ___ After sequencing the wild type genomic clone for the AAA gene you find a 32 base pair inserting in the middle of the gene that is missing in the wild type cDNA clone of this gene. The 32bp are due to an insertion mutation. ___ The probability of isolating a gene from a genomic library is highly dependent on the cell type from which the library was originally constructed ___ The probability of isolating a gene from a cDNA library is not dependent on the cell type from which the library was originally constructed ___ Two individuals have identical amino acid sequences for their histone proteins. There is no possibility that an RFLP exists between these two individuals in the DNA sequence encoding the histone gene. ___ cDNA libraries possess 5' and 3' untranslated regions (UTR) ___ A polymorphic single base site is called a SNP ___ Most active genes reside in euchromatin ___ Histones, non-histone proteins and DNA together form chromatin in the eukaryotic nucleusExplanation / Answer
Answer:
1. False
Explanation:
No tRNAs in the cell have anticodons that complement any of the three possible stop codons.
When a ribosome reaches the codon UAG, UAA, or UGA on an mRNA strand then protein synthesis is terminated. A protein known as a release factor binds to the ribosome and adds a water molecule to the end of the amino acid chain. This reaction hydrolyzes the polypeptide chain from the tRNA, allowing the protein to exit the ribosome. Without the stop codon, protein synthesis would simply stop without releasing the completed protein.
2. False
Explanation:
Very large deletions tend to be lethal. This is likely due to genomic imbalance or the unmasking of recessive lethal genes. Therefore, the observed very large pairing loop is more likely to be from a heterozygous inversion.
3. False
Explanation:
Genomic clones are simply DNA derived directly from a genome. Genomic DNA would incorporate some sequences such as introns or regulatory sequences that would not be found in cDNAs. A cDNA library simply contains sequences that are complementary to mRNAs which lacks the introns.
4. False
Explanation:
The goal of creating genomic libraries is to fragment the entire genome of an organism into a series of overlapping fragments and incorporate them all into suitable vectors. The library (or clone bank) may be stored as transformed bacteria (in the case of plasmid vectors) or infected bacteria or bacteriophages (in the case of lambda vectors).
The genomic clones does not depend upon the cell type as all the cells of an organism contain the same genes although the expression patterns may be different.
(Since there are more than 1 question, the first four questions have been answered according to the rules of Chegg)
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