Answer:
Because DNA polymerase can synthesize DNA strands in 5' to 3' direction only.
Explanation:
The 5' end of one DNA strand is present opposite to the 3' end of the other strand. But DNA polymerase enzyme can elongate the primers in 5' to 3' direction only. Formation of a phosphodiester bond between the existing nucleotide and the incoming nucleotide requires the free 3'OH. This 3' OH serves in the nucleophilic attack during the formation of the bond.
Therefore, the lagging strand is synthesized discontinuously in the form of short DNA fragments. These are called Okazaki fragments. Primers are formed for short distances which in turn are elongated by DNA polymerase to form the Okazaki fragments. On the other hand, the synthesis of the leading strand occurs continuously in the same direction in which the replication fork moves.
<span>The proteins that are embedded in the cell membrane act as channels to transport substances in and out of the cell.</span>
The answer would be the hardening of the myelin sheath. Multiple sclerosis is a chronic and inflammatory disease affecting the Central Nervous System and can cause a lot of symptoms like sensation changes, visual problems, severe fatigue and muscle weakness.
The correct answers are B & C. Silicon-32 is the parent isotope, which decays into phosphorus-32 (daughter isotope). The silicon-32 amount is halved every 170 years, so we can use this to determine how old the rock is. The amount of phosphorus-32 increases over time, but it is not equal to the amount of silicon-32.
