Mastering DNA Replication

The three important functions of DNA polymerase are: (1) Polymerase activity of adding Deoxyribonucleoside triphosphate (dNTPs) in a 5' to 3' direction while synthesizing a new DNA strand, (2) 3' to 5' exonuclease activity that removes the mismatched base, preventing DNA damage due to replication errors, and (3) 5' to 3' exonuclease activity that removes damaged or mismatched DNA segments in the double-stranded DNA.

The enzymes involved in elongation during replication, besides polymers, are DNA polymerase one, DNA polymerase three, single strand binding protein, topoisomerase of DNAbilase, and DNAbilase.

<p>3' to 5' exonuclease</p> Signup and view all the answers

<p>The DNAA protein binds to the origin of replication and forms a replication bubble, which initiates the replication process in prokaryotes.</p> Signup and view all the answers

<p>The sliding clamp or bitering structures loop around the DNA and increase processivity by keeping the polymerase enzyme attached to the template DNA, allowing for longer stretches of replication without dissociation.</p> Signup and view all the answers

<p>The three parts of DNA Polymerase I are polymerase, 3' to 5' exonuclease, and 5' to 3' exonuclease. The polymerase is responsible for adding nucleotides, while the exonucleases are responsible for removing nucleotides from the ends of DNA strands.</p> Signup and view all the answers

<p>The process of phosphodiester bond formation during DNA replication involves the formation of a covalent bond between the hydroxyl and phosphate groups, creating a phosphodiester bond.</p> Signup and view all the answers

<p>Beta clamp</p> Signup and view all the answers

<p>It removes nucleotides from the three prime end of the growing chain and removes incorrect or mismatched bases</p> Signup and view all the answers

<p>The single-strand binding protein stabilizes the exposed single-stranded DNA by stretching it out and keeping it in position.</p> Signup and view all the answers

<p>The alpha subunit performs the 5' to 3' DNA polymerase activity, the epsilon subunit performs 3' to 5' proofreading activity, and the theta subunit acts as a stabilizer of epsilon.</p> Signup and view all the answers

<p>The two types of exonuclease activities of DNA polymerase are the three prime exonuclease activity and the five prime exonuclease activity. The three prime exonuclease activity removes nucleotides from the three prime end of the growing chain and removes incorrect or mismatched bases, while the five prime exonuclease activity acts as an editor and removes about ten to twelve nucleotides at a time from the five prime end of double standard DNA. The five prime exonuclease activity also clears the path for the advancing polymerase by removing distorted segments.</p> Signup and view all the answers

<p>EnergirAs</p> Signup and view all the answers

<p>Epsilon subunit</p> Signup and view all the answers

<p>Polymerase three</p> Signup and view all the answers

<p>5' to 3'</p> Signup and view all the answers

<p>DNA polymerase one is loosely bound and not processed enough, which makes it unsuitable for the tightly controlled replication process.</p> Signup and view all the answers

<p>The primesome protein assembly is composed of HELIKs, Primase, and five other subunits. Its function is to add ribonucleotides during DNA replication, but not to add or seal entities.</p> Signup and view all the answers

<p>DNA helicase binds to the DNA helix and gradually opens it up by breaking the hydrogen bonds. It also breaks hydrogen bonds and opens up DNA at the replication fork.</p> Signup and view all the answers

<p>DNA polymerase 1 removes RNA primers and fills gaps with entities.</p> Signup and view all the answers

<p>DNA polymerase is a large polypeptide made up of 928 amino acids and has a finger-like structure with a thumb. Its function is to hold the template DNA and add Deoxyribonucleoside triphosphates (DNTPs) in the 5' to 3' direction during DNA synthesis.</p> Signup and view all the answers

<p>The replication fork will stop and the DNA polymerase falls off.</p> Signup and view all the answers

<p>DNA ligase</p> Signup and view all the answers

<p>Five prime to three prime direction</p> Signup and view all the answers

<p>To stop the replication clock in one orientation</p> Signup and view all the answers

<p>The radioactive pulses were used to expose the DNA fragments and track the progress of replication.</p> Signup and view all the answers

<p>DNA polymerase synthesizes nucleotides in a five prime to three prime direction by forming a phosphodiester bond between the three prime hydroxy and the one possible group, following the ATTC rule and in an anti-parallel direction to the template structure.</p> Signup and view all the answers

<p>DNA helicase binds to the DNA helix and breaks the hydrogen bonds, gradually opening it up to initiate the replication process.</p> Signup and view all the answers

<p>The presence of small DNA fragments in the gradient</p> Signup and view all the answers

<p>2' to 4' exonuclease activity</p> Signup and view all the answers

<p>DNA helicase binds to the DNA helix and breaks the hydrogen bonds to gradually open it up. This allows other proteins and enzymes to access the DNA strands for replication.</p> Signup and view all the answers

<p>DNA replication occurs simultaneously on both strands, with both daughter strands polymerized in the 5' to 3' direction. The leading strand is synthesized in one continuous molecule while the lagging strand is synthesized in small fragments that are joined later on.</p> Signup and view all the answers

<p>To load the beta clamp</p> Signup and view all the answers

<p>The circular chromosome in bacterial DNA indicates that the DNA has a double parent strand and two daughter strands, which are essential for the replication process.</p> Signup and view all the answers

<p>RNA primers are synthesized to provide a starting point for DNA polymerase to add DNTPs and extend the DNA strands. They provide a three prime hydroxy group, which is necessary for DNA polymerase to work.</p> Signup and view all the answers

<p>RNA primers synthesize a small strand of RNA, which acts as a primer for DNA polymerase to add DNTPs and extend the strands. They provide a primer with a three prime hydroxy group, which is needed by DNA polymerase.</p> Signup and view all the answers

<p>RNA primers synthesize a small strand of RNA, which acts as a primer for DNA polymerase to add DNTPs and extend the strands. The three prime hydroxy group of the RNA primer is used by DNA polymerase to add new nucleotides.</p> Signup and view all the answers

<p>The termination of replication happens with the help of two proteins, one of which is the test protein.</p> Signup and view all the answers

<p>Self-study is required to determine how these chemicals are impacting the DNA polymerase, DNA HIDs, or single-strand binding proteins.</p> Signup and view all the answers

<p>Arthur Conbur discovered DNA polymerase in E. coli through an experiment involving extraction and purification. He added DNA polymerase to the extract and found that DNA strands were formed when treated with oxidants.</p> Signup and view all the answers

<p>The essential components required for in vitro DNA synthesis are primer, template DNA, DNTPs, and polymerase. The primer is significant because it provides a starting point for the polymerase to initiate DNA synthesis.</p> Signup and view all the answers

<p>To provide a free three prime hydroxide group to build upon</p> Signup and view all the answers

<p>RNA fragments supply the oligonucleotide primer with a free three prime hydroxide group to build upon during DNA synthesis.</p> Signup and view all the answers

<p>To remove the mismatched base, preventing DNA damage due to replication errors</p> Signup and view all the answers

<p>The polymerase activity of DNA polymerase is crucial for DNA replication health because it adds new nucleotides in a specific sequence to form a complementary strand to the original DNA template, which is essential for the accurate replication of genetic information.</p> Signup and view all the answers

<p>Hans Clemens</p> Signup and view all the answers

<p>The small exocuclease fragment of DNA Polymerase I was discovered by Hans Clemens. It has been used in molecular biology labs before the discovery of Taq polymerase.</p> Signup and view all the answers

<p>It can add twenty nucleotides per second before falling off the DNA</p> Signup and view all the answers

<p>DNA polymerase I can only add twenty nucleotides per second before falling off the DNA. If it was the replicative enzyme in E. Coli, the bacteria would take five point three days to divide.</p> Signup and view all the answers

<p>UV radiation exposure</p> Signup and view all the answers

<p>Researchers identified a mutant e. Coli lacking polymerase one activity through UV radiation exposure, which caused a mutation in the gene that codes for the polymerase one enzyme.</p> Signup and view all the answers

<p>DNA polymerase 1</p> Signup and view all the answers

<p>DNA polymerase 2 has 3' to 5' exonuclease activity, while DNA polymerase 3 has 5' to 3' exonuclease activity.</p> Signup and view all the answers

<p>The tau protein dimerizes and opens up the DNA helix to help with replication.</p> Signup and view all the answers

<p>Polymerase III</p> Signup and view all the answers

<p>Polymerase III is the chief DNA replicating enzyme of E. coli.</p> Signup and view all the answers

<p>More heavy bands and less short bands are produced</p> Signup and view all the answers

<p>The DNA strands were separated using either alkaline solution or sucrose density centrifugation.</p> Signup and view all the answers

<p>It is used by DNA ligase to seal the gap at the end of replication</p> Signup and view all the answers

<p>DNA ligase seals the gap between 5' phosphate and 3' hydroxyl group using ATP.</p> Signup and view all the answers

<p>Okazaki fragments</p> Signup and view all the answers

<p>Okazaki fragments are short DNA fragments that are produced on the lagging strand during DNA replication. They differ from the leading strand in that they are made in the opposite direction.</p> Signup and view all the answers

<p>Second task protein</p> Signup and view all the answers

<p>Both clockwise and anti-clockwise</p> Signup and view all the answers

<p>The task protein is responsible for stopping replication in one orientation but not in the opposite orientation.</p> Signup and view all the answers

<p>The role of 3' to 5' exonuclease activity of DNA polymerase is to remove any incorrectly paired nucleotides or mismatched bases that may have been incorporated during DNA replication. This activity helps to prevent DNA damage due to replication errors and maintains the accuracy of DNA replication.</p> Signup and view all the answers

<p>The fork will stop and the DNA polymerase falls off</p> Signup and view all the answers

<p>In small fragments that are joined later on</p> Signup and view all the answers

<p>It adds Deoxyribonucleoside triphosphate (dNTPs) in a 5' to 3' direction while synthesizing a new DNA strand</p> Signup and view all the answers

<p>Replication terminates at a 350 base pair region with seven charged sequences that can stop replication. Casp proteins help to move the replication fork in different directions.</p> Signup and view all the answers

<p>DNA polymerase can only act in the 5' to 3' direction, which explains how both daughter strands are synthesized in the same direction despite having opposite template strands.</p> Signup and view all the answers

<p>The three important features of DNA polymerase are five prime to three prime polymerase activity, exonuclease activity, and a proofreading function.</p> Signup and view all the answers

<p>DNA replication occurs in two strands- the leading strand and the lagging strand- in the 5' to 3' direction. The leading strand is replicated continuously, while the lagging strand is replicated discontinuously in small fragments known as Okazaki fragments.</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Five prime to three prime polymerase activity, endonuclease activity, and a proofreading function</p> Signup and view all the answers

<p>Prokaryotic bacteria have a single replication origin, while eukaryotes have multiple origins due to their large DNA size. Additionally, the replication process in both involves DNA polymerase and DNA helicase proteins, but eukaryotic replication also involves other enzymes like DNA polymerase one, DNA polymerase three, single strand binding protein, topoisomerase of DNAbilase, and DNAbilase.</p> Signup and view all the answers

<p>Small DNA fragments indicate that they were either synthesized by DNA polymerase during replication or formed by breaking materials from bigger fragments.</p> Signup and view all the answers

<p>PCR is a precursor to DNA replication and is used to amplify specific DNA sequences, while DNA replication is the process of copying an entire DNA molecule. DNA polymerase 1 is the enzyme responsible for DNA replication.</p> Signup and view all the answers

<p>Nalodexic acid</p> Signup and view all the answers

<p>Bacteria use NAD as a cofactor, whereas T4 ligase is used in a molecular biology lab</p> Signup and view all the answers

<p>DNA replication was discovered in the 1950s, but the enzymes responsible for synthesizing DNA were not yet known.</p> Signup and view all the answers

<p>The replication process begins with the formation of the replication bubble. This involves the DNA helicase breaking the hydrogen bonds and opening up the DNA strands. The replication bubble then opens up to form replication forks, which allow the DNA to be replicated in two strands- the leading strand and the lagging strand- in the 5' to 3' direction.</p> Signup and view all the answers

<p>Ligase is essential in cloning experiments and DNA synthesis because it seals the gaps left after DNA polymerase 1 fills in the gaps, allowing for the creation of a complete strand of DNA.</p> Signup and view all the answers

<p>It is not processed enough</p> Signup and view all the answers

<p>A small primer of ten to twelve nucleotides is required to begin the synthesis, which is synthesized by RNA primes. After elongation, the primer is removed and replaced with DNA nucleotides. This process forms part of the initiation and elongation.</p> Signup and view all the answers

<p>DNA polymerases one and two are not involved in bacterial replication, but DNA polymerase three is essential for survival because it is a multi-subunit complex and a hollow enzyme that is required for replication.</p> Signup and view all the answers

<p>DNA polymerase I is not a replicative enzyme. It is considered too abundant because it is present in large amounts in E. Coli cells, but it cannot effectively replicate DNA on its own.</p> Signup and view all the answers

<p>The replication fork is blocked by the second task protein due to reverse orientation facing beta sheets.</p> Signup and view all the answers

<p>To hold the DNA</p> Signup and view all the answers

<p>E) Coli would take 5.3 days to divide</p> Signup and view all the answers

<p>7</p> Signup and view all the answers

<p>The sliding clamp holds the DNA during replication, and DNA polymerase 2 has five subunits that act as a clamp motor.</p> Signup and view all the answers

<p>The exonuclease activity of DNA Polymerase I allows for the removal of incorrect nucleotides that may have been added during DNA replication. This helps to ensure that the final DNA sequence is accurate and free from errors.</p> Signup and view all the answers

<p>Replication occurs in the 5' to 3' direction. In the leading strand, DNA polymerase adds nucleotides continuously in the same direction as the replication fork. In the lagging strand, DNA polymerase adds nucleotides in the opposite direction to the replication fork, resulting in the formation of Okazaki fragments that are later joined by DNA ligase.</p> Signup and view all the answers

<p>Single-stranded binding proteins</p> Signup and view all the answers

<p>It can both remove and add nucleotides</p> Signup and view all the answers

<p>Prokaryotic bacteria have a single replication origin while eukaryotes have multiple origins due to their large DNA size.</p> Signup and view all the answers

<p>Single-stranded binding proteins keep the DNA strand open, allowing polymerases to add nucleotides in the 5' to 3' direction.</p> Signup and view all the answers