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.

A DNA duplex that directs the remainder of the viral infection process.

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.

Through a DNA intermediate, using reverse transcriptase to transcribe the RNA template into a complementary cDNA strand.

It provides a free 3' hydroxyl group that serves as the initiation site for DNA synthesis.

RNA-directed DNA polymerase, RNase H, and DNA-directed DNA polymerase.

It replicates the ssDNA remaining after RNase H degradation of the viral genome, yielding a DNA duplex.

Because they use reverse transcriptase to transcribe their RNA genome into DNA.

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.

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.

The host cell provides a specific tRNA molecule that serves as a primer for reverse transcriptase, allowing for the initiation of DNA synthesis.

The RNase H activity of reverse transcriptase degrades the RNA chain in the DNA:RNA hybrid, allowing for the formation of a DNA duplex.

The DNA duplex formed during reverse transcription serves as a template for the remainder of the viral infection process.

Reverse transcription allows for the generation of genetic diversity in RNA viruses by introducing errors during the synthesis of DNA from RNA.

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.

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.

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.

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.

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.

The RNA-directed DNA polymerase activity of reverse transcriptase transcribes the RNA template into a complementary cDNA strand, forming a DNA:RNA hybrid.

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.

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.

The DNA intermediate serves as a stable template for the synthesis of new viral RNA, ensuring accurate and efficient replication of the viral genome.

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.

The specific base pairing immediately suggests a possible copying mechanism for the genetic material.

Bidirectional replication involves two replication forks, which move in opposite directions, whereas unidirectional replication involves a single replication fork.

They overcome supercoiling, which is necessary for DNA replication to occur.

The leading strand is formed continuously, while the lagging strand is formed from Okazaki fragments.

It describes the process of DNA replication, where the leading strand is formed continuously, and the lagging strand is formed from Okazaki fragments.

One of the two original strands is conserved in each progeny molecule.

Because they lack a 3'-OH group, preventing further chain elongation.

Due to the high error rate of HIV reverse transcriptase, making the virus ever-changing.

To form deoxynucleoside-5'-triphosphate substrate analogs for HIV reverse transcriptase.

They are incorporated in place of dTMP (in the case of AZT) or dCMP (in the case of 3TC).

Their structures allow them to be incorporated into growing DNA chains, blocking further DNA synthesis.

It blocks further chain elongation due to the lack of a 3'-OH group.

Nicks at W and E yield patch recombinant heteroduplexes.

Activator genes can cause mutations in other genes and can move about the genome.

Genetic recombination can generate protein diversity.

The process of replicating the ends of chromosomes is not explicitly stated in the provided text.

The function of DNA polymerases is not explicitly stated in the provided text.

The role of DNA repair mechanisms is not explicitly stated in the provided text.

Genetic recombination

Transposition

Meselson and Weigle's experiment

General recombination

Homologous recombination

Nonhomologous recombination

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.

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.

Okazaki fragments are short, discontinuously synthesized DNA segments that are formed on the lagging strand during DNA replication.

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.

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.

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.

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.

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.

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.

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.

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.

Nicks at N and S yield splice recombinant heteroduplexes.

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.

Transposons move from place to place in the genome, allowing for recombination of genetic information.

Genetic recombination allows for the rearrangement of genetic information, generating new associations and leading to protein diversity.

Recombination

It showed that activator genes could move about the genome, leading to genetic recombination.

Patch recombinant heteroduplexes

General recombination

Homologous recombination

Transposition

Genetic recombination

Meselson and Weigle's experiment

Nonhomologous recombination

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.

The high error rate of HIV reverse transcriptase makes it difficult to devise an effective vaccine against HIV, as the virus is constantly changing.

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.

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.

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.

HIV reverse transcriptase inhibitors like AZT and 3TC block the replication of HIV by terminating DNA synthesis, thereby preventing the virus from replicating.