#Question id: 1583
#Unit 4. Cell Communication and Cell Signaling
These cells are involved in cell-mediated immunity and destroy virally infected cells:
#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: 5671
#Unit 5. Developmental Biology
Match the following mechanism of polyspermy (Column I) with events (Column II).
|
Column I |
Column II |
|
A. Fast block to polyspermy |
i. chemicals from the fusing sperm cytoplasm alter the sodium ion (Na+) channels on the membrane |
|
B. Slow block to polyspermy |
ii. enzyme cortical granule serine protease, cleaves the protein posts that connect the vitelline envelope |
|
iii the concentration of free Ca2+ in the egg cytoplasm increases |
|
|
iv. an electric change in the egg cell membrane |
|
|
v. the concentration of free Na+ in the egg cytoplasm increases |
Which of the following is correct?
#Question id: 5628
#Unit 5. Developmental Biology
In sea urchins, the acrosome reaction is initiated by-
#Question id: 12890
#General Aptitude