Why can't both strands of dna be replicated at the same time?

DNA is a molecule made up of two strands, twisted around each other in a double helix shape. The two strands are complementary which have a 5 prime end and a 3 prime end. To understand this question you must first understand the steps that follow.

DNA Replication:

Step one:

DNA Helicase (unzips) separates the strands.

Step two:

DNA Primase starts the process and makes a small piece of RNA called a primer. This marks the starting point for the DNA.

Step three:

DNA Polymerase binds to the primer and will make the new strand of DNA. DNA Polymerase can only add DNA bases in one direction, from the 5 prime end to the 3 prime end.

The leading strand is made continuously.The lagging strand does not run continuously because it runs in the opposite direction. Each fragment is started with an RNA primer. DNA Polymerase then adds a short row of DNA bases from the 5 prime to 3 prime direction. This results in okazaki fragments because it can only replicate in small chunks. The process is repeated.

Step four:

Once the new DNA is complete the enzyme exonuclease removes all the RNA primers from both strands of DNA.

Step five:

Another DNA Polymerase fills in the gaps that are left behind with DNA.

Step six:

DNA Ligase seals up the fragments in DNA, in both strands to make a continuous double strand.

Final

DNA Replication cannot replicate at the same time due to the leading and lagging strand.

Good luck!

Its striations allow for big movements.

Explanation:

Muscle cells perform important functions in the living organisms. They perform the function of support, movements and controls the body coordination. Three different muscles are skeletal muscle, cardiac muscle and smooth muscle.

Skeletal muscles are attached to bones that involves in the entry and exit side of the body. The skeletal muscles shows striations and has many nuclei that allows the large movements of the body. These striations involves the sarcomere units that allows the body contraction.

Thus, the correct answer is option (2).