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TLS Online TPP Program

#Question id: 124

What is the role of cholesterol in animal cell membranes?

#Unit 1. Molecules and their Interaction Relevant to Biology

  1. Blocks the association of the fatty acyl chains of phospholipids at high temperature.

  2. Aids in the transport of small hydrophobic molecules across the membrane.

  3. Is a receptor site for hormones on the surface of membranes.

  4. Broadens the temperature range of optimum membrane fluidity.

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TLS Online TPP Program

#Question id: 18956

#Unit 13. Methods in Biology

It is possible to calculate the number of clones that must be present in a gene library to give a probability of obtaining a particular DNA sequence. This formula is:
 
where N is the number of recombinants, P is the probability and f is the fraction of the genome in one insert. Thus for the E. coli DNA chromosome of 5 × 10 6 bp andan insert size of 20 kb ( f = 0.004), the number of clones needed ( N ) would be 1 × 10 3 ,with a probability of P will be
TLS Online TPP Program

#Question id: 4294

#Unit 3. Fundamental Processes

Not surprisingly, in several instances, the two binding sites for the regulatory ribosomal protein are related to each another. In the case of the S8 ribosomal protein, the two binding sites share substantial similarities. The sequence of the binding site in the mRNA reveals a clear mechanism by which S8 inhibits translation. Which of the following are INCORRECT regarding this mechanism?

A. Free rRNA content in cytoplasm activates ribosomal protein biogenesis

B. RNA-binding proteins regulate their expression by binding to their own mRNAs, including some aminoacyl-tRNA synthetases

C. In case of “NO FREE rRNA” ribosomal protein transcript is efficiently translated by autoregulation process

D. In case of “NO FREE rRNA” ribosomal protein transcript undergoes to autorepression
TLS Online TPP Program

#Question id: 11433

#Unit 1. Molecules and their Interaction Relevant to Biology

An amino acid contains no ionizable group in its side chain (R). It is titrated from pH 0 to 14. Which of the following ionizable state is not observed during the entire titration in the pH range 0 - 14?
TLS Online TPP Program

#Question id: 18656

#Unit 13. Methods in Biology

Which of the following is true about SDS-PAGE?
TLS Online TPP Program

#Question id: 1987

#Unit 4. Cell Communication and Cell Signaling

A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to