Examples of leading strand in the following topics:
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- Single-strand binding proteins coat the strands of DNA near the replication fork to prevent the single-stranded DNA from winding back into a double helix.
- One strand (the leading strand), complementary to the 3' to 5' parental DNA strand, is synthesized continuously towards the replication fork because the polymerase can add nucleotides in this direction.
- The leading strand can be extended by one primer alone, whereas the lagging strand needs a new primer for each of the short Okazaki fragments.
- The overall direction of the lagging strand will be 3' to 5', while that of the leading strand will be 5' to 3'.
- On the leading strand, DNA is synthesized continuously, whereas on the lagging strand, DNA is synthesized in short stretches called Okazaki fragments.
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- DNA polymerase cannot initiate new strand synthesis; it only adds new nucleotides at the 3' end of an existing strand.
- The "leading strand" is synthesized continuously toward the replication fork as helicase unwinds the template double-stranded DNA.
- Eventually, the leading strand of one replication bubble reaches the lagging strand of another bubble, and the lagging strand will reach the 5' end of the previous Okazaki fragment in the same bubble.
- The enzymes FEN1 and RNase H remove RNA primers at the start of each leading strand and at the start of each Okazaki fragment, leaving gaps of unreplicated template DNA.
- On the leading strand, only a single RNA primer is needed, and DNA is synthesized continuously, whereas on the lagging strand, DNA is synthesized in short stretches, each of which must start with its own RNA primer.
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- Slipped strand mispairing (SSM) is a process that produces mispairing of short repeat sequences during DNA synthesis.
- Slipped strand mispairing (SSM) is a process that produces mispairing of short repeat sequences between the mother and daughter strand during DNA synthesis.
- This RecA-independent mechanism can transpire during either DNA replication or DNA repair and can be on the leading or lagging strand and can result in an increase or decrease in the number of short repeat sequences.
- It can also lead to differences in post-transcriptional stability of mRNA.
- Explain how slipped-strand mispairing can be used as a mechanism to regulate gene expression
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- Coiling these coupled strands then leads to a double helix structure, shown as cross-linked ribbons in part b of the diagram.
- The essence of this suggestion is that, if separated, each strand of the molecule might act as a template on which a new complementary strand might be assembled, leading finally to two identical DNA molecules.
- Indeed, replication does take place in this fashion when cells divide, but the events leading up to the actual synthesis of complementary DNA strands are sufficiently complex that they will not be described in any detail.
- This continuously formed new strand is called the leading strand.
- This new DNA strand is called the lagging strand.
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- Of the viral families with DNA genomes, only two have single-stranded genomes.
- Conversion from single-stranded to double-stranded form is carried out by the host's own DNA polymerase.
- The Microviridae are a family of bacteriophages with a single-stranded DNA genome.
- Conversion of the single-strand form to a double-stranded intermediate, known as the replicative form I
- Cell lysis is mediated by the phiX174-encoded protein E, which inhibits the peptidoglycan synthesis, leading to the eventual bursting of the infected cell.
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- Uncorrected mistakes may sometimes lead to serious consequences, such as cancer.
- Repair mechanisms can correct the mistakes, but in rare cases mistakes are not corrected, leading to mutations; in other cases, repair enzymes are themselves mutated or defective.
- If this remains uncorrected, it may lead to more permanent damage.
- In E. coli, after replication, the nitrogenous base adenine acquires a methyl group; the parental DNA strand will have methyl groups, whereas the newly-synthesized strand lacks them.
- In this interactive, you can "edit" a DNA strand and cause a mutation.
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- PCR is used to amplify a specific region of a DNA strand (the DNA target).
- Two primers that are complementary to the 3' (three prime) ends of each of the sense and anti-sense strand of the DNA target
- At this step the DNA polymerase synthesizes a new DNA strand complementary to the DNA template strand by adding dNTPs that are complementary to the template in 5' to 3' direction, condensing the 5'-phosphate group of the dNTPs with the 3'-hydroxyl group at the end of the nascent (extending) DNA strand.
- Under optimum conditions (i.e., if there are no limitations due to limiting substrates or reagents) at each extension step, the amount of DNA target is doubled, leading to exponential (geometric) amplification of the specific DNA fragment.
- This illustrates a PCR reaction to demonstrate how amplification leads to the exponential growth of a short product flanked by the primers. 1.
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- The two strands of the helix run in opposite directions, so that the 5′ carbon end of one strand faces the 3′ carbon end of its matching strand.
- If the sequence of one strand is AATTGGCC, the complementary strand would have the sequence TTAACCGG.
- During DNA replication, each strand is copied, resulting in a daughter DNA double helix containing one parental DNA strand and a newly synthesized strand.
- Each base from one strand interacts via hydrogen bonding with a base from the opposing strand.
- In a double stranded DNA molecule, the two strands run antiparallel to one another so that one strand runs 5′ to 3′ and the other 3′ to 5′.
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- DNA supercoiling refers to the over- or under-winding of a DNA strand, and is an expression of the strain on that strand.
- DNA supercoiling refers to the over- or under-winding of a DNA strand, and is an expression of the strain on that strand .
- In a "relaxed" double-helical segment of B-DNA, the two strands twist around the helical axis once every 10.4 to 10.5 base pairs of sequence.
- Extra helical twists are positive and lead to positive supercoiling, while subtractive twisting causes negative supercoiling.
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- Double-stranded DNA viruses usually must enter the host nucleus before they are able to replicate.
- The virus may induce the cell to forcefully undergo cell division, which may lead to transformation of the cell and, ultimately, cancer.
- There is only one well-studied example in which a double-stranded DNA virus does not replicate within the nucleus.
- Adenoviruses (members of the family Adenoviridae) are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double stranded DNA genome.
- The replication of poxvirus is unusual for a virus with double-stranded DNA genome (dsDNA) because it occurs in the cytoplasm, although this is typical of other large DNA viruses.