Which of these can catalyze exonuclease activity in the 3 prime to 5 prime direction?
Bacteriophage T4 DNA polymerase Bacteriophage (phage) T4 encodes a DNA polymerase that catalyzes DNA synthesis in a 5′ to 3′ direction. The phage polymerase also has an exonuclease activity that acts in a 3′ to 5′ direction, and this activity is employed in the proofreading and editing of newly inserted bases.
Which way does DNA polymerase read?
Each strand in the double helix acts as a template for synthesis of a new, complementary strand. New DNA is made by enzymes called DNA polymerases, which require a template and a primer (starter) and synthesize DNA in the 5′ to 3′ direction.
Why do Okazaki fragments occur?
Okazaki fragments form because the lagging strand that is being formed have to be formed in segments of 100–200 nucleotides. This is done DNA polymerase making small RNA primers along the lagging strand which are produced much more slowly than the process of DNA synthesis on the leading strand.
What direction is the leading strand?
The first one is called the leading strand. This is the parent strand of DNA which runs in the 3′ to 5′ direction toward the fork, and it’s able to be replicated continuously by DNA polymerase.
How many Okazaki fragments are there?
Despite the much larger DNA content of eukaryotic compared with prokaryotic cells, Okazaki fragments are ∼1200 nt long in bacteria but only about 200 nt long in eukaryotes (Ogawa and Okazaki 1980). This means that to prepare for every human cell division, >10 million fragments must be made and joined.
How are Okazaki fragments welded together?
How are they welded together? Okazaki fragments are short segments of DNA synthesized away from the replication fork on a template strand during DNA replication. Many such segments are joined together by the enzyme DNA ligase to make up the lagging strand of newly synthesized DNA.
What are Okazaki fragments quizlet?
Okazaki fragments are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections.
Why is replication called semi conservative?
As the DNA double helix is unwound by helicase, replication occurs separately on each template strand in antiparallel directions. This process is known as semi-conservative replication because two copies of the original DNA molecule are produced. Each copy contains one original strand and one newly-synthesized strand.
Which of the following protein is required for connecting Okazaki fragments?
Which of the following protein is required for connecting Okazaki fragments? Explanation: After initiation, the chain elongation and joining of Okazaki fragments take place by DNA gyrase, DNA ligase, DNA polymerase. 8.
What is the major difference between DNA polymerase 1 and 3?
The main difference between DNA polymerase 1 and 3 is that DNA polymerase 1 is involved in the removal of primers from the fragments and replacing the gap by relevant nucleotides whereas DNA polymerase 3 is mainly involved in the synthesis of the leading and lagging strands.