TLS Online TPP Program

#Question id: 27257


Because of steric constraints, purines in purine nucleotides are restricted to two stable conformations with respect to deoxyribose, called syn and anti.

            
The two molecules shown in the figures are best described as

#Section 3: Genetics, Cellular and Molecular Biology
  1. A-syn-Adenosine & B-anti-Adenosine

  2. A-syn-Guanine & B-anti- Guanine 

  3. A-anti-Adenosine & B-syn-Adenosine
  4. A-anti-Guanine & B-syn- Guanine 
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TLS Online TPP Program

#Question id: 9592

#Section 2: General Biology

The function of light is to excite a specialized chlorophyll in the reaction centre either by Direct absorption or more frequently, via energy transfer from an antenna pigment, This excitation process can be envisioned as

a.) An electron from the lowest-energy filled orbital of the chlorophyll to the highest-energy unfilled orbital

b.) An electron in the upper orbital is only tightly bound to the chlorophyll and is difficult to fetch the electron nearby molecules

c.)  The electron in the upper orbital is only loosely bound to the chlorophyll and is easily lost if a molecule that can accept the electron is nearby

d.) The promotion of an electron from the highest-energy filled orbital of the chlorophyll to the lowest-energy unfilled orbital

Which combination is CORRECT?

TLS Online TPP Program

#Question id: 9594

#Section 2: General Biology

The first reaction that converts electron energy into chemical energy—What will happened in  the primary photochemical event—

TLS Online TPP Program

#Question id: 9595

#Section 2: General Biology

The process is that the absorbed photon causes an electron rearrangement in the reaction centre chlorophyll, followed by an electron transfer process in which part of the energy in the photon is captured in the form of

TLS Online TPP Program

#Question id: 9597

#Section 2: General Biology

The reaction centre bacteriochlorophyll from purple photosynthetic bacteria was similarly identified as-

TLS Online TPP Program

#Question id: 9598

#Section 2: General Biology

In the oxidized state, reaction centre chlorophylls contain an unpaired electron, Molecules with unpaired electrons can often be detected by a magnetic-resonance technique known as

TLS Online TPP Program

#Question id: 9599

#Section 2: General Biology

The primary donor of PSI, P700, is a dimer of chlorophyll a molecules, in primary donor chlorophyll, additional chlorophylls molecules such as