#Question id: 1520
#Unit 1. Molecules and their Interaction Relevant to Biology
Following statements are regarding to enzymatic processing of benzo(a)pyrene to a more potent mutagen and carcinogen.
A. Liver enzymes, particularly P-450 enzymes, modify benzo(a)pyrene in a series of reactions, producing 7,8-diol-9,10-epoxide, a highly potent mutagenic species that reacts with DNA primarily at the N2 atom of a guanine base.
B. The adduct, (+)-trans-anti-B(a)P-N2-dG, causes polymerase to insert an A rather than a C opposite the modified G base. Next time the DNA is replicated, a T will be inserted opposite the A, and the mutation will be complete.
C. Potent mutagen majorly causes conversion of guanine (G) to thymine (T) bases, a transition mutation.
D. When this potent mutagen applied to cultured bronchial epithelial cells, activated benzo(a)pyrene induces many mutations, including activating mutations at codons 175, 248, and 273 of the p53 gene.
Which of the following statements are correct?
#Question id: 674
#Unit 1. Molecules and their Interaction Relevant to Biology
Proline is not often found in a-helices of proteins because it
#Question id: 73
#Unit 1. Molecules and their Interaction Relevant to Biology
Match the Variation of Reaction Spontaneity (Sign of ΔG) given in Column I with the Signs of ΔH and ΔS given in column II.
|
COLUMN I |
COLUMN II |
|
|
|
|
ΔH |
ΔS |
ΔG = ΔH – TΔS |
|
1. |
− |
+ |
a. The
reaction is both enthalpically and entropically opposed. It is nonspontaneous
(endergonic) at all temperatures. |
|
2. |
− |
− |
b. The
reaction is enthalpically opposed (endothermic) but entropically favored. It
is spontaneous only at temperatures above T = ΔH/ΔS. |
|
3. |
+ |
+ |
c. The
reaction is enthalpically favored but entropically opposed. It is spontaneous
only at temperatures below T = ΔH/ΔS. |
|
4. |
+ |
− |
d. The
reaction is both enthalpically favored (exothermic) and entropically favored.
It is spontaneous (exergonic) at all temperatures. |
#Question id: 68
#Unit 1. Molecules and their Interaction Relevant to Biology
Match the following functional groups given in column I with their respective representatives given in column II.
| COLUMN I | COLUMN II |
| 1. Anhydride | a. RCOOR |
| 2. Ether | b. ROCOCH3 |
| 3. Acetyl | c. ROR |
| 4. Amido | d. RCOOCOR |
| 5. Ester | e. RCONH2 |
#Question id: 7289
#Unit 1. Molecules and their Interaction Relevant to Biology
The following scheme shows the flowering status of a plant species and the photoperiodism. Which of the following conclusions is most appropriate?
#Question id: 15690
#Unit 1. Molecules and their Interaction Relevant to Biology
