Why do cells replicate their dna
This is carried out by an enzyme called helicase which breaks the hydrogen bonds holding the complementary bases of DNA together A with T, C with G. The two separated strands will act as templates for making the new strands of DNA. As a result of their different orientations, the two strands are replicated differently: An illustration to show replication of the leading and lagging strands of DNA.
Related Content:. What is a genome? What is DNA? Imagine slicing yourself down the middle and splitting yourself in half, and then using each half of you as a template to recreate the other half. That's the biology behind it, but the bottom line is that DNA is replicated in order to reproduce itself.
Why does DNA replication need to occur? Mar 24, DNA is like the instruction manual for building and operating a cell. Explanation: DNA replication needs to occur because existing cells divide to produce new cells.
Hope this helps! Figure 3: Beginning at the primer sequence, DNA polymerase shown in blue attaches to the original DNA strand and begins assembling a new, complementary strand. Figure 4: Each nucleotide has an affinity for its partner. A pairs with T, and C pairs with G. The color of the rectangle represents the chemical identity of the nitrogenous base.
A grey horizontal cylinder is attached to one end of the rectangle in each nucleotide and represents a sugar molecule. The nucleotides are arranged in two rows and the nitrogenous bases point toward each other.
A set of four nucleotides are in both the upper and lower rows. From left to right, the nucleotides in the top row are adenine green , cytosine orange , thymine red , and guanine blue.
From left to right, the complementary nucleotides in the bottom row are: thymine red , guanine blue , adenine green , and cytosine orange.
Figure 5: A new DNA strand is synthesized. This strand contains nucleotides that are complementary to those in the template sequence. How long does replication take? More on replication. How does DNA polymerase work? What does the molecular structure of a nucleotide look like? What does the lagging strand look like? Watch this video for a summary of DNA replication in eukaryotes. Key Questions What if an error happens during replication? How is DNA stored in the cell before and after replication?
What do the leading and lagging strands look like when they are being replicated? Key Concepts DNA polymerase primer transcription. Topic rooms within Genetics Close. And so DNA is a molecule that can be replicated to make almost perfect copies of itself. Which is all the more amazing considering that there are almost three billion base pairs of DNA to be copied. Replicating all of the DNA in a single human cell takes several hours of just pure copying time.
0コメント