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TLS Online TPP Program

#Question id: 762

Regarding the sugar residues in nucleic acids, which, if any, of the following statements is incorrect?

#Unit 1. Molecules and their Interaction Relevant to Biology

  1. The sugar is always based on a heterocyclic ring that consists of one oxygen atom and four carbon atoms, one of which is connected to a fifth carbon atom, the 5’ carbon atom.

  2. The internal sugar residues in a DNA strand normally have free hydroxyl groups, unlike those in an RNA strand.

  3. Bases are covalently linked to the carbon 1’ atoms of the sugars.

  4. Neighboring sugar residues are linked to each other by a phosphodiester bond that connects the 3’ carbon atom on one sugar to the 5’ carbon atom of its neighbour.

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TLS Online TPP Program

#Question id: 14519

#Unit 13. Methods in Biology

One of the two mutually exclusive events must occur, if the chance of one is 2/3 of the other, then odds in favour of the other are
TLS Online TPP Program

#Question id: 14520

#Unit 13. Methods in Biology

Given =1/3 and 2/3 then P(B) is
TLS Online TPP Program

#Question id: 14521

#Unit 13. Methods in Biology

There are 64 beds in a garden and 3 seeds of a particular type of flower are sown in each bed. The probability of a flower being white is 1/4. The number of beds with 3, 2, 1, and 0 white flowers is respectively
TLS Online TPP Program

#Question id: 14522

#Unit 13. Methods in Biology

A sample space has two events A and B such that probabilities  
TLS Online TPP Program

#Question id: 14523

#Unit 13. Methods in Biology

A man takes a step forward with probability 0.4 and backward with probability 0.6. The probability that at the end of eleven steps he is one step away from the starting point.
TLS Online TPP Program

#Question id: 14685

#Unit 4. Cell Communication and Cell Signaling

In dark-adapted rod cells, a high level of cGMP keeps cGMP-gated nonselective cation channels open, leading to hyperpolarization of the plasma membrane and neurotransmitter release. 
B - Light absorption generates activated rhodopsin, R*, which binds inactive, GDP-bound Gαt protein and mediates the exchange of GDP for GTP . 
C- The free Gαt∙GTP activates PDE by binding to its inhibitory γ subunits and dissociating them from the catalytic α and β subunits . Relieved of their inhibition, the α and β subunits of PDE hydrolyze GMP to cGMP . 
D- The resulting decrease in cytosolic cGMP leads to dissociation of cGMP from the cation channels in the plasma membrane and the closing of those channels . 
E- The membrane then becomes transiently hyperpolarized, and neurotransmitter release is reduced.