DNA polymerase/RNA polymerase

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In summary, DNA polymerase is able to "read" the template strand and insert complementary nucleotides by sensing the geometry of the base pairs formed when a nucleotide binds. Its 3'->5' endonuclease ability also helps to reduce errors during replication.
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How do these enzymes "read" the template strand and "put in" the complementary nucleotide?

Also I've heard that DNA polymerase is less error prone than RNA polymerase. How is this accomplished?
 
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The enzymes let nucleotides diffuse into the active site and bind to the template strand. The enzymes are able to sense when the correct nucleotide has bound to the template by the geometry of the newly formed base pair. Once the enzyme has sensed that the correct nucleotide is bound, it can close its fingers domain, causing the active site to form and catalysis to occur.

DNA polymerase is less error prone in part because it has a 3'->5' endonuclease ability that allows it to remove mistakes (this occurs at the proofreading domain of the DNA polymerase).
 
  • #3


DNA polymerase and RNA polymerase are enzymes responsible for the replication and transcription of genetic material in cells. DNA polymerase is involved in DNA replication, while RNA polymerase is involved in the transcription of DNA into RNA.

Both enzymes have a similar mechanism for "reading" the template strand and "putting in" the complementary nucleotide. They both have a specific active site that can recognize the nucleotide sequence on the template strand. This active site has a specific shape that only allows for the binding of the complementary nucleotide. This ensures that the new strand being synthesized is an exact copy of the template strand.

The process by which these enzymes "read" the template strand and "put in" the complementary nucleotide is called base pairing. In DNA, the bases adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). In RNA, the base uracil (U) replaces thymine (T). The enzyme uses this base pairing mechanism to add the correct nucleotide to the growing strand.

As for the difference in error rates between DNA polymerase and RNA polymerase, it is mainly due to the proofreading ability of DNA polymerase. DNA polymerase has an additional subunit called the 3' to 5' exonuclease which can detect and correct any mismatched bases that may have been added to the growing strand. This proofreading mechanism helps to ensure that the newly synthesized DNA is an exact copy of the original template.

On the other hand, RNA polymerase does not have this proofreading ability, making it more prone to errors. However, the errors in RNA are not as detrimental as they are in DNA, as RNA is a temporary molecule and is constantly being synthesized and degraded in cells. Additionally, RNA molecules undergo further processing before functioning, which can also help to correct any errors.

In conclusion, both DNA polymerase and RNA polymerase have specific mechanisms for reading the template strand and adding the complementary nucleotide. The difference in error rates between the two enzymes is mainly due to the proofreading ability of DNA polymerase.
 

1. What is the function of DNA polymerase?

DNA polymerase is an enzyme that is responsible for the polymerization of new DNA strands during DNA replication. It adds nucleotides to the growing DNA strand in a complementary manner, based on the template strand.

2. How many types of DNA polymerase are there?

There are multiple types of DNA polymerase, each with a specific function. In humans, there are at least 15 different types of DNA polymerase identified, with DNA polymerase alpha, delta, and epsilon being the main enzymes involved in DNA replication.

3. What is the role of RNA polymerase in gene expression?

RNA polymerase is an enzyme that is responsible for transcribing DNA into RNA molecules. It binds to a specific region of the DNA called the promoter and synthesizes a complementary RNA strand using one of the DNA strands as a template. This process is essential for gene expression and protein synthesis.

4. Can DNA polymerase make mistakes?

Yes, DNA polymerase can make mistakes during DNA replication. However, most DNA polymerases have a built-in proofreading function that can correct these mistakes. Additionally, there are other repair mechanisms in the cell that can fix errors in the DNA sequence.

5. Why is RNA polymerase important in the production of proteins?

RNA polymerase is essential in the production of proteins because it is responsible for transcribing the genetic information stored in DNA into RNA molecules. These RNA molecules are then translated into proteins, which are the building blocks of all living organisms. Without RNA polymerase, the genetic code cannot be read and proteins cannot be produced.

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