Replication (3) Flashcards
1
Q
What is replication?
A
Replication can be defined as the process of making a new DNA molecule from an existing DNA molecule that is identical to the original molecule. This takes place in the nucleus during the interphase (in between cell divisions) in the cycle of a cell.
2
Q
Why is replication necessary?
A
The DNA needs to produce another molecule exactly the same as itself to ensure that the genetic code is passed on to each new daughter cell formed during cell division.
3
Q
How does replication take place? (7)
A
- The process is catalyzed by the enzyme DNA polymerase.
- The double helix unwinds.
- The weak hydrogen bonds holding the base pairs together break, allowing the two strands to part. Like a zip unzipping.
- Each single chain of bases is exposed.
- Free nucleotides in the nucleoplasm become attached to their matching, exposed base partners. Make sure you know what the matching pairs are.
- The fact that A will only bond with T and C only with G, makes sure that the sequence of the bases in the daughter DNA is exactly the same as in the parent DNA. One DNA double helix, therefore, becomes two identical double helices.
- The two daughter DNA molecules each twist to form a double helix which then winds itself around the histones (proteins), forming a chromosome. The whole procedure only takes a couple of seconds.
