Watson and Crick's DNA Replication

It transcribes the RNA template into a complementary cDNA strand to form a DNA:RNA hybrid and has three enzyme activities: RNA-directed DNA polymerase, RNase H, and DNA-directed DNA polymerase.

The primer is a specific tRNA molecule captured from the host cell that initiates the synthesis of cDNA.

It degrades the RNA chain in DNA:RNA hybrids, allowing the completion of DNA synthesis.

<p>A DNA duplex that directs the remainder of the viral infection process.</p> Signup and view all the answers

<p>RNA-directed DNA polymerase synthesizes DNA from an RNA template, while DNA-directed DNA polymerase replicates the ssDNA remaining after RNase H degradation of the viral genome.</p> Signup and view all the answers

<p>Through a DNA intermediate, using reverse transcriptase to transcribe the RNA template into a complementary cDNA strand.</p> Signup and view all the answers

<p>It provides a free 3' hydroxyl group that serves as the initiation site for DNA synthesis.</p> Signup and view all the answers

<p>RNA-directed DNA polymerase, RNase H, and DNA-directed DNA polymerase.</p> Signup and view all the answers

<p>It replicates the ssDNA remaining after RNase H degradation of the viral genome, yielding a DNA duplex.</p> Signup and view all the answers

<p>Because they use reverse transcriptase to transcribe their RNA genome into DNA.</p> Signup and view all the answers

<p>The DNA:RNA hybrid formed during reverse transcription is a crucial intermediate that allows for the synthesis of a complementary DNA strand from the RNA template.</p> Signup and view all the answers

<p>The RNA-directed DNA polymerase activity of reverse transcriptase allows for the synthesis of a DNA strand from an RNA template, which can lead to genetic recombination and increased protein diversity.</p> Signup and view all the answers

<p>The host cell provides a specific tRNA molecule that serves as a primer for reverse transcriptase, allowing for the initiation of DNA synthesis.</p> Signup and view all the answers

<p>The RNase H activity of reverse transcriptase degrades the RNA chain in the DNA:RNA hybrid, allowing for the formation of a DNA duplex.</p> Signup and view all the answers

<p>The DNA duplex formed during reverse transcription serves as a template for the remainder of the viral infection process.</p> Signup and view all the answers

<p>Reverse transcription allows for the generation of genetic diversity in RNA viruses by introducing errors during the synthesis of DNA from RNA.</p> Signup and view all the answers

<p>The use of a DNA intermediate in the replication of RNA viruses provides a more stable and durable genetic material that can be replicated and transmitted more efficiently.</p> Signup and view all the answers

<p>RNA viruses that use a DNA intermediate, such as retroviruses, replicate their RNA genome through a DNA intermediate, whereas those that do not, replicate their RNA genome directly.</p> Signup and view all the answers

<p>The reverse transcription process is essential for the replication of RNA viruses that use a DNA intermediate, as it allows for the synthesis of DNA from RNA.</p> Signup and view all the answers

<p>The primer for reverse transcriptase, a specific tRNA molecule, contributes to the specificity of DNA synthesis by ensuring that DNA synthesis initiates at a specific site on the RNA template.</p> Signup and view all the answers

<p>The specific tRNA molecule serves as a primer for DNA synthesis, ensuring that DNA synthesis is initiated at a specific site, allowing for accurate and efficient replication of the viral genome.</p> Signup and view all the answers

<p>The RNA-directed DNA polymerase activity of reverse transcriptase transcribes the RNA template into a complementary cDNA strand, forming a DNA:RNA hybrid.</p> Signup and view all the answers

<p>The DNA-directed DNA polymerase activity of reverse transcriptase replicates the ssDNA remaining after RNase H degradation of the viral genome, yielding a DNA duplex.</p> Signup and view all the answers

<p>RNA viruses that replicate their RNA via a DNA intermediate require reverse transcriptase because it can transcribe RNA into DNA, which is necessary for their replication.</p> Signup and view all the answers

<p>The DNA intermediate serves as a stable template for the synthesis of new viral RNA, ensuring accurate and efficient replication of the viral genome.</p> Signup and view all the answers

<p>The RNase H activity of reverse transcriptase degrades the RNA chain in the DNA:RNA hybrid, allowing for the formation of a double-stranded DNA duplex.</p> Signup and view all the answers

<p>The specific base pairing immediately suggests a possible copying mechanism for the genetic material.</p> Signup and view all the answers

<p>Bidirectional replication involves two replication forks, which move in opposite directions, whereas unidirectional replication involves a single replication fork.</p> Signup and view all the answers

<p>They overcome supercoiling, which is necessary for DNA replication to occur.</p> Signup and view all the answers

<p>The leading strand is formed continuously, while the lagging strand is formed from Okazaki fragments.</p> Signup and view all the answers

<p>It describes the process of DNA replication, where the leading strand is formed continuously, and the lagging strand is formed from Okazaki fragments.</p> Signup and view all the answers

<p>One of the two original strands is conserved in each progeny molecule.</p> Signup and view all the answers

<p>Because they lack a 3'-OH group, preventing further chain elongation.</p> Signup and view all the answers

<p>Due to the high error rate of HIV reverse transcriptase, making the virus ever-changing.</p> Signup and view all the answers

<p>To form deoxynucleoside-5'-triphosphate substrate analogs for HIV reverse transcriptase.</p> Signup and view all the answers

<p>They are incorporated in place of dTMP (in the case of AZT) or dCMP (in the case of 3TC).</p> Signup and view all the answers

<p>Their structures allow them to be incorporated into growing DNA chains, blocking further DNA synthesis.</p> Signup and view all the answers

<p>It blocks further chain elongation due to the lack of a 3'-OH group.</p> Signup and view all the answers

<p>Nicks at W and E yield patch recombinant heteroduplexes.</p> Signup and view all the answers

<p>Activator genes can cause mutations in other genes and can move about the genome.</p> Signup and view all the answers

<p>Genetic recombination can generate protein diversity.</p> Signup and view all the answers

<p>The process of replicating the ends of chromosomes is not explicitly stated in the provided text.</p> Signup and view all the answers

<p>The function of DNA polymerases is not explicitly stated in the provided text.</p> Signup and view all the answers

<p>The role of DNA repair mechanisms is not explicitly stated in the provided text.</p> Signup and view all the answers

<p>Genetic recombination</p> Signup and view all the answers

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

<p>Meselson and Weigle's experiment</p> Signup and view all the answers

<p>General recombination</p> Signup and view all the answers

<p>Homologous recombination</p> Signup and view all the answers

<p>Nonhomologous recombination</p> Signup and view all the answers

<p>The semiconservative model ensures that each new DNA molecule contains one old strand and one new strand, allowing for the transmission of genetic information from one generation to the next.</p> Signup and view all the answers

<p>The bidirectional replication mechanism involves two replication forks that move in opposite directions, allowing for the simultaneous unwinding and rewinding of DNA, thus overcoming supercoiling.</p> Signup and view all the answers

<p>Okazaki fragments are short, discontinuously synthesized DNA segments that are formed on the lagging strand during DNA replication.</p> Signup and view all the answers

<p>The specific base pairing (A-T and G-C) allows for the complementarity of DNA strands, enabling the formation of a double helix and the transmission of genetic information.</p> Signup and view all the answers

<p>DNA replication involves the synthesis of new strands that are complementary to the original template strands, ensuring the accuracy of genetic information transmission through the correction of errors by proofreading and editing mechanisms.</p> Signup and view all the answers

<p>The discontinuous synthesis of DNA on the lagging strand results in the formation of Okazaki fragments, which are later joined together to form a continuous strand.</p> Signup and view all the answers

<p>Reverse transcriptase is necessary for the replication of RNA viruses that use a DNA intermediate, as it converts the RNA genome into a DNA molecule that can be integrated into the host cell's genome.</p> Signup and view all the answers

<p>The RNase H activity of reverse transcriptase degrades the RNA template strand in the DNA:RNA hybrid, allowing the formation of a double-stranded DNA molecule.</p> Signup and view all the answers

<p>The specific tRNA molecule serves as a primer for DNA synthesis, allowing the initiation of reverse transcription and the conversion of the RNA genome into a DNA molecule.</p> Signup and view all the answers

<p>The DNA duplex formed during reverse transcription is the template for the remainder of the viral infection process, allowing the integration of the viral genome into the host cell's genome.</p> Signup and view all the answers

<p>The DNA-directed DNA polymerase activity of reverse transcriptase replicates the single-stranded DNA molecule formed during reverse transcription, resulting in a double-stranded DNA molecule that can be integrated into the host cell's genome.</p> Signup and view all the answers

<p>Nicks at N and S yield splice recombinant heteroduplexes.</p> Signup and view all the answers

<p>The RNA-directed DNA polymerase activity of reverse transcriptase transcribes the RNA template into a complementary DNA strand, forming a DNA:RNA hybrid that is essential for the replication of RNA viruses.</p> Signup and view all the answers

<p>Transposons move from place to place in the genome, allowing for recombination of genetic information.</p> Signup and view all the answers

<p>Genetic recombination allows for the rearrangement of genetic information, generating new associations and leading to protein diversity.</p> Signup and view all the answers

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

<p>It showed that activator genes could move about the genome, leading to genetic recombination.</p> Signup and view all the answers

<p>Patch recombinant heteroduplexes</p> Signup and view all the answers

<p>General recombination</p> Signup and view all the answers

<p>Homologous recombination</p> Signup and view all the answers

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

<p>Genetic recombination</p> Signup and view all the answers

<p>Meselson and Weigle's experiment</p> Signup and view all the answers

<p>Nonhomologous recombination</p> Signup and view all the answers

<p>The incorporation of AZT and 3TC into growing DNA chains blocks further chain elongation because they lack a 3'-OH where the next incoming dNTP can be added.</p> Signup and view all the answers

<p>The high error rate of HIV reverse transcriptase makes it difficult to devise an effective vaccine against HIV, as the virus is constantly changing.</p> Signup and view all the answers

<p>Nucleoside analogs like AZT and 3TC work as HIV reverse transcriptase inhibitors by being phosphorylated to form deoxynucleoside-5'-triphosphate substrate analogs, which are then incorporated into growing DNA chains, terminating DNA synthesis.</p> Signup and view all the answers

<p>Phosphorylation is necessary for the conversion of AZT and 3TC into their active forms, which can then be incorporated into growing DNA chains and inhibit HIV replication.</p> Signup and view all the answers

<p>The structure of AZT and 3TC, lacking a 3'-OH group, allows them to be incorporated into growing DNA chains and terminate DNA synthesis, thereby inhibiting HIV replication.</p> Signup and view all the answers

<p>HIV reverse transcriptase inhibitors like AZT and 3TC block the replication of HIV by terminating DNA synthesis, thereby preventing the virus from replicating.</p> Signup and view all the answers