Problem 13 - Biology

Question

Which of the following does the enzyme primase synthesize? a. DNA primer b. RNA primer c. Okazaki fragments d. phosphodiester linkage

Step-by-Step Solution

Answer

b. RNA primer

Step 1: Identify the function of Primase

Primase is an enzyme that plays a crucial role in DNA replication. It synthesizes a short nucleic acid segment that serves as a starting point for DNA synthesis.

Step 2: Recognize the type of nucleic acid synthesized

Primase synthesizes RNA, not DNA. This means primase creates a short RNA segment.

Step 3: Determine the type of molecule synthesized by Primase

Since Primase synthesizes RNA, the correct term for the segment it produces is an RNA primer.

Step 4: Rule out incorrect options

Okazaki fragments and phosphodiester linkages are not directly synthesized by Primase. Additionally, DNA primers are incorrect since Primase synthesizes RNA primers.

Step 5: Select the correct answer

Based on the information, the option that Primase synthesizes is an RNA primer.

Key Concepts

RNA primer synthesis

Primase is a unique enzyme crucial to the process of DNA replication. It plays the important role of synthesizing RNA primers. These RNA primers are short nucleic acid segments that provide a starting point for the DNA polymerase to begin synthesizing new DNA.
Without the RNA primer generated by primase, DNA polymerase would not be able to add new nucleotides because it can only add onto already existing strands.
This primer is essential because DNA polymerases, the enzymes responsible for synthesizing DNA, cannot start replication on their own.

DNA replication enzymes

Several enzymes work together during the process of DNA replication.
Here are some key players involved:

• **DNA Helicase**: Unwinds the double-stranded DNA
• **Primase**: Synthesizes a short RNA primer
• **DNA Polymerase**: Adds new nucleotides to the growing DNA strand
• **Ligase**: Seals the gaps between Okazaki fragments on the lagging strand

Each enzyme has a specialized function and all are vital for the accurate and efficient replication of DNA.
In particular, primase serves as a foundational step by creating the RNA primer, which allows DNA polymerase to commence DNA synthesis.

Nucleic acid segments

Nucleic acid segments are the building blocks of genetic material. They are formed by sequences of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base.
There are two types of nucleic acids: **DNA** and **RNA**. DNA carries the genetic blueprint of an organism, while RNA is involved in various roles such as coding, decoding, regulation, and expression of genes.
During DNA replication, a short segment of RNA (the RNA primer) is synthesized to provide a starting point for DNA polymerase.
These primers are crucial for initiating the replication process.
Overall, understanding nucleic acid segments helps to grasp the fundamental processes that sustain life.