#Question id: 4127
#Unit 3. Fundamental Processes
Which one of the following statements about ribosomes is true?
#Question id: 4306
#Unit 3. Fundamental Processes
Which of the following molecules helps to "turn off" genes in a cell?
#Question id: 10581
#Unit 10. Ecological Principles
Life-history characteristics associated with K-selected organisms include
#Question id: 9162
#Unit 9. Diversity of Life Forms
If the direction of Earth's rotation reversed, the most predictable effect would be ________.
#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?