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TLS Online TPP Program

#Question id: 2897

The transcription of most protein coding genes in mammals (~70 percent) occurs at a lower rate than at TATA box–containing and initiator-containing promoters and begins at any of several alternative start sites within regions of about 100–1000 bp that have an unusually high frequency of CG sequences. Which one of the following best explains it?

#Unit 2. Cellular Organization

  1. CG-rich sequences are bound by histone octamers more tightly than CG-poor sequences because less energy is required to bend around the histone octamer forming a nucleosome.

  2. During housekeeping gene expression, the enzyme methyltransferase is temporarily silenced by miRNA, thus shutting down global methylation.

  3. As soon as the cytosine is methylated in the promoter region, the enzymes of DNA repair pathways remove the methyl group, thereby ensuring gene expression.

  4. A remarkable feature of the CpG islands is that transcription from these elements is initiated in both directions, even though only transcription of the sense strand yields an mRNA.

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TLS Online TPP Program

#Question id: 5282

#Unit 8. Inheritance Biology

Conjugation allowed between Hfr with genotype A B C D E and F- with genotype a b c d e. At regular intervals, a sample of cells was removed and agitated

vigorously in a kitchen blender to halt all conjugation and DNA transfer. After interrupted conjugation, ex-conjugate were selected on minimal media at regular interval and find different number of ex-conjugate?

abCde   - 10, abCdE    -    30 ,  aBCdE  -     40 , ABCdE  -     20 , ABCDE   -   50

What is gene order of those genes?
TLS Online TPP Program

#Question id: 5283

#Unit 8. Inheritance Biology

A generalized transducing phage is used to transduce an a- b- c- d- e- recipient strain of E. coli with an a+ b+c+d+ e+ donor. The recipient culture is plated on various media with the results shown in the table below What can you conclude about the linkage and order of the genes?
TLS Online TPP Program

#Question id: 5284

#Unit 8. Inheritance Biology

DNA from a strain of Bacillus subtilis with genotype a+b+ c+d+ e+ is used to transform a strain with genotype a - b- c- d-   e-. Pairs of genes are checked for co-transformation and the following results are obtained:

Pair of co-transform genes as follow

D-E,             E-C,                C-B,                  A-D

On the basis of these results, what is the order of the genes on the bacterial chromosome?
TLS Online TPP Program

#Question id: 5285

#Unit 8. Inheritance Biology

A transformation experiment is carried out using donor DNA that is A+B+C+ and a recipient that is A-B- C-. A+ transformants are selected and tested further. Of these, 64% are B+ and none are C+. Also, B+ are selected, and 8% are also C+. What is the gene order
TLS Online TPP Program

#Question id: 5286

#Unit 8. Inheritance Biology

An Hfr strain with genotype A B C D (each gene for amino acid synthesis )and that transfers the A gene very late was mated with recipient strain with genotype a b c d. After mating for several hours, the mixture was diluted and plated on minimal media with four different supplements having various number of colony

Media supplement with amino acid  

                 Colony                                          number

                  A+C                                                 500

                  C+D                                                  50

                     B                                                    10

                     A                                                   250

What is order of gene
TLS Online TPP Program

#Question id: 5287

#Unit 8. Inheritance Biology

Interrupted matting of different Hfr strain with F- E.coli cell resulting generation of following strain  Order of gene is