The DNA replication by the action of DNA polymerase takes place in the 3' to 5' direction on the leading strand. The lagging strand which has the opposite orientation or polarity as that of the leading strand requires a more time to get synthesised. The DNA replication of the lagging strand happens in short segments where a RNA primer forms a compliment with a part of the DNA segment on its 3' end. This RNA primer helps initiate the replication of the Okazaki fragments. When the replication on the lagging strand reaches its end, the RNA primer forms a compliment with the last bit of the strand. This small segment gets missed in the end as no more DNA is left to form a RNA primer-DNA compliment. Such shortening of the lagging strand in the replication process is the end-replication problem.
Telomeres are protective ends of the DNA strands. These ends contain a poly-A tail. When the lagging strand replication reaches its end, the RNA primer forms a compliment with the telomere and initiates the replication. This leads to the shortening of the telomere and not the coding segments on the lagging strand of DNA. The telomerase repairs the shortened telomere by re-synthesising it.
Answer:
Remarkably efficient alveolar macrophages crawl freely along the internal and external alveolar surfaces
Explanation:
The alveolar macrophages are present on the internal lumenal surfaces of the alveolar ducts, the alveoli, and the bronchioles.
Alveolar macrophages are phagocytes that uses several surface receptors to release many secretions, to interact with other cells and molecules.
But the alveolar macrophages are intact to the inner surface only and do not crawl freely along the internal and external alveolar surfaces.
Hence, the correct option is " C".
Answer:
The amount of water that evaporates from earth is roughly equal to the amount that falls as precipitation.
Explanation:
In the hydrological cycle, evaporation consists of the conversion of liquid water into water vapor, which reaches the atmosphere. Once the water vapor condenses produces precipitation in the form of rain, snow or hail.
<u>On the earth the amount of water that evaporates is proportional to the water that falls as precipitation</u>. The mass of ocean water is substantially greater than the amount of land, so variations in the proportion of evaporated water and precipitation occur in the hydrological cycle:
- <em>In the oceans, evaporation is greater than the precipitation that occurs.
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- <em>On the continents - firm land - evaporation is less than precipitation.
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This produces a certain grade of compensation in which, globally, the amount of water that evaporates from the earth is roughly equal to the amount that falls as precipitation.
Learn more:
Hydrological cycle brainly.com/question/13189254
The plasma membrane, because it's a selective permeable which means it only allows certain things in like sucrose.
It disrupts homeostasis by putting our body in stress which isn’t good. It fills out alveoli with mucus and our bronchiole is inflamed with music. Besides, it shortens our breathe
