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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.

More Questions
TLS Online TPP Program

#Question id: 65

#Unit 1. Molecules and their Interaction Relevant to Biology

Identify which of the following pair is enantiomers, diastereomers or meso compounds.
TLS Online TPP Program

#Question id: 783

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the statements below is FALSE?
TLS Online TPP Program

#Question id: 59

#Unit 1. Molecules and their Interaction Relevant to Biology

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?
TLS Online TPP Program

#Question id: 10413

#Unit 1. Molecules and their Interaction Relevant to Biology

Following are certain statements are related to the effect of red and far-red light;
a) under a dense canopy much of the red light is absorbed by plant pigments, resulting in transmittance of mostly far-red light
b) Pr (red) has highest photon flux at 680 nm while Pfr (far-red) has highest photon flux at 730nm
c) Pfr far-red light–absorbing form, which is considered to be the physiologically active form of phytochrome
d) R:FR ratio is strongly affected by the presence of a canopy because chlorophyll absorbs far-red but not red light
Which one of the combinations of above statements is incorrect?
TLS Online TPP Program

#Question id: 10970

#Unit 1. Molecules and their Interaction Relevant to Biology

A mother of blood type A+ who has always been perfectly healthy just delivered her second child. The father is of blood group O−. Knowing that the child is of blood group O− (O, Rh−), what would you expect to find in this child?
TLS Online TPP Program

#Question id: 12183

#Unit 1. Molecules and their Interaction Relevant to Biology

Following statements are regarding to regulation of S phase and mitotic cyclin levels in budding yeast.
A. In late anaphase, the anaphase-promoting complex (APC/C) ubiquitinylates S phase and mitotic cyclins.
B. In late anaphase, the anaphase-promoting complex (APC/C) phosphorylates S phase and mitotic cyclins.
C. During exit from mitosis and G1, Cdh1 is dephosphorylated and active; during S phase and mitosis, Cdh1 is phosphorylated and dissociates from APC/C, and APC/C becomes inactive.
D. During exit from mitosis and G1, Cdh1 is phosphorylated and active; during S phase and mitosis, Cdh1 is dephosphorylated and dissociates from APC/C, and APC/C becomes inactive.
E. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, phosphorylate Cdh1 at the G1–S phase transition.
F. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, ubiquitinylates Cdh1 at the G1–S phase transition.
Which of the following combination is correct?