Questions tagged [dna-replication]

The biosynthetic process by which copies of a DNA molecule are made.

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1answer
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Does DNA helicase or topoisomerase actually “unwind” DNA?

I am reading through my textbook (Genetics, Brooker 4th edition) and the summary it gives seems imprecise for the functionality of helicase and topoisomerase. The following is an exerpt: ...
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Number of Chromatids in G1

I know that in G1, the number of chromosomes is 23 pairs, so 46. I assumed there were 46 chromatids too. Why is the number of chromatids in G1 actually 0, not 46? Thanks.
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How does the splicing enzyme recognize where to splice the introns?

When the DNA from the nucleus is transcribed to an mRNA, the mRNA is spliced by an enzyme before it goes outside through the nuclear pore. What is the name of this enzyme and how does it recognize ...
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How accurate does the alignment of molecules in DNA have to be?

We have learned that the same information is saved in the DNA in the same place. So when DNA splits and then connects again (during reproduction); how does it maintain the integrity of the information?...
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1answer
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DNA replication - how many times and when does it occur?

I’m currently learning about DNA replication in both prokaryotic and eukaryotic cells. And my lecturer has mentioned that replication is a once in a lifetime activity. And I’m not sure what this is ...
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Why replication collapse but not stall leads to DNA break?

I have been looking into the concept of replication dynamics and was wondering why collapsing but not stalling leads to a DNA break.
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971 views

What is the name of the smallest self-replicating thing?

Some time last year, I found an article on Wikipedia about the smallest something to be able to reproduce. I don't remember exactly what it was, but I am fairly certain that after the initial ...
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DNA Replication

I just wanted to understand the basic steps behind the replication of the lagging strand of DNA: Have helicase unwind it first DNA Primase lays down RNA primers in fragments, called Okazaki fragments ...
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1answer
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How does a thymidine block halt DNA synthesis?

The best I've been able to find is that there's a feedback mechanism, but what is this feedback, and how does the mechanism work? If it's just that the concentration of thymidine is too high, why won'...
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How is the effect of proof-reading on error frequency during DNA replication determined?

An article in Nature Scitable on DNA Replication and the causes of Mutation states that: When an incorrect nucleotide is added to the growing strand, replication is stalled by the fact that the ...
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Is DNA replication a serial or parallel process?

This video entertainingly supplements this 3d animation of DNA strand replication. Does this process happen serially from the beginning to the end of a DNA strand (like having to unzip a six foot long ...
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Can translocation occur within a gene?

I know genes can be translocated between chromosomes but can nucleotide sequences be moved around within an individual gene? Could the following gene: MEN SAW OLD HEN Become: MSA WOL DHE NEN By ...
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4answers
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Is variation a result of Evolution?

We know that the DNA copying mechanism that replicates DNA during cellular division is not 100% accurate and the resultant errors are the source of variation in the members of a population. At the ...
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What errors can occur during DNA replication?

When there is an error in copying DNA (a mutation), what exactly goes wrong? If G goes with C and A goes with T, I don't see how that part can mess up. Is the idea that when the double helix is ...
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1answer
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The Semi-Conservative Model of DNA Replication: Question

My Campbell's Biology textbook contains the following diagram related to the semi-conservative model of DNA replication proposed by Watson and Crick. I have highlighted where my confusion arises in ...
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1answer
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Did the first cell self-replicate or was it multiple first cells? [closed]

We're almost sure by now that the first cell was born in a some kind of underwater vents environment which harvested all the necessary conditions for it to exist. However, did the first cell self-...
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1answer
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After the primer is removed from the leading strand, how does DNA polymerase I add dNTPs without a 3'-OH?

I have a question about replication in prokaryotes. I learned in school that: DNA polymerase needs 3'-OH to add a dNTP. The chromosomes of prokaryotes are usually circular. The primer in the leading ...
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1answer
56 views

At which point does a cell switch its function? [closed]

In a multi cellular organisms there are many cells of different functions. How / when does a cell change its function compared to its parent? Is it done by influence of other cells after its has been ...
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Performing PCR on samples whose DNA concentration is nul

Is it vain to perform a PCR on samples whose DNA concentration was measured as nul by a NanoDrop?
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5answers
326 views

Can your immune system's cells destroy you? (Critical thinking and Fictional sense)

In an imaginary sense, If you alone were replicated into 2 so that there should now be 2 of "you" (meaning you both have the same DNA). Then let's say one of you shrunk to the size of a bacteria, and ...
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1answer
299 views

Does crossover happen between chromosomes from grandparents?

Rephrasing question: does crossover happen after sperm and egg meet each other, but before formed fetus starts to grow? As I understand sperm and egg of human are haploid cells. That means this cells ...
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1answer
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How RNA primer on leading strand is removed during DNA replication and how the gap is filled? [closed]

Please can you explain me how the gap created by the removal of primer on 5'-3' leading strand is filled.
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1answer
621 views

Can Mono-Cell or other organism self-replicate?

I have a question regarding how organism replicate them self to create an other organism, We know that in animal reign, we need a male and female that will generate a new being. what I want to know ...
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1answer
186 views

In the lysogenic cycle, does the provirus split from the cell's main genetic material for replication?

In a diagram of the lysogenic cycle sent by my instructor in a video, it shows the provirus splitting from the cell's main DNA when the dormancy period ends and the viral DNA is "activated". Is this ...
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1answer
288 views

What is the mechanism of labeling a DNA molecule with deuterated water?

I have seen a paper in which deuterated water was used to follow dividing cells. The assumption was that deuterated water will be incorporated into newly synthesized DNA molecules. Is there any direct ...
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DNA replication in $ E.coli $

$ E.coli $ has circular DNA which I guess implies one strand forms the outer circle and the other the inner one. So, is there a way to know if the replicated DNA forms the outer or inner circle? In ...
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How is it possible for phosphate to form two ester bonds in DNA replication?

I understand that in phosphodiester bond formation, two hydroxl groups on the phosphate molecule bind to the 3' and 5' OH groups on two independent pentose sugars. This is a condensation reaction, so ...
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Can DNA be transferred from one person to another [closed]

kissing, handshaking, blood transmission, sexual intercourse etc,through which of these DNA can be transferred to another person ?
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Why a cell contains all DNA when it only needs a few genes?

Is that what they called junk? Why does a simple cell have the DNA code for everything else when it just needs a few codes to function? Wouldn't that be a wasteful?
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DNA synthesis in nucleus

I read somewhere that according to a research, I don't remember what the date was, that our cells stop synthesising DNA around noon and restart it around the sunset. The research told that it was ...
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4answers
649 views

what kind of bonds join the okazaki fragments

During DNA replication, the synthesized okazaki fragments adjacent to each other are joined up directly by DNA ligase-catalyzed phosphodiester bond formation. Can someone point out to me which part of ...
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Replication cohorts in microbial GWAS

Replication in an independent cohort is of course the gold standard in GWAS studies, and many high profile journals will now (quite rightly) not accept finding indicating a phenotype genotype ...
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Is there any technique can quickly expand one set of cell chromosomes?

Assume a cell type is very scarce while isolated out and hard to expand in vitro, and I wanna have more of its chromosomes, is there any technique , in vivo or in vitro or ex vitro, any would count, ...
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Does any specific property decide which DNA strand acts as leading strand template?

Of the two strands of DNA, the one that unwinds in the 3' to 5' direction constitutes the leading strand template, with the other strand of course acting as the lagging strand template. Is there any ...
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Does cancer cells come from same process as evolution? [duplicate]

Here is how I understand it: DNA replication is not 100% perfect and error can happen, this error can be good(evolution) or bad(cancer properties). But its not the only source of cancer cells - DNA ...
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1answer
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Why do you need primers in PCR? [duplicate]

I have read that DNA polymerase requires a primer to bind to the DNA, but I am confused as to why this is the case. When DNA undergoes replication in the cell, there are no primers in the nucleus. Why ...
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1answer
195 views

Stem Cell Replication

Reading from the internet, I've come across quotes that said stem cells have the potential to replicate indefinitely. However, there are other sources that say cells that are specialised will have ...
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765 views

DNA sequence from the middle of a gene

Someone gives you a short DNA sequence that comes from the middle of a gene. 5'- TCTAACTGATTAGC -3' 3'- AGATTGACTAATCG -5' From this sequence, determine the ...
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Don't understand how multiple replication bubbles work

I'm not exactly sure how multiple replication bubbles work, assuming were working with a linear, eukaryotic chromosome. This is a diagram for reference: It appears that the DNA is being synthesized "...
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How are single-stranded binding proteins removed from the lagging strand during DNA replication?

The lagging strand, downstream of the Okazaki fragment, is covered in single-stranded binding proteins (SSBPs) during DNA replication. What is the mechanism which ensures that SSBPs are removed from ...
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Is water released when a phosphodiester bond is made between two nucleotides during DNA replication?

I know that when two sugar molecules (like glucose) connect to each other, H2O is released because of the -OH and -H groups in both of the molecules. I want to know if the same thing happens when two ...
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2answers
443 views

What is open complex in E.coli DNA replication?

The E.coli DnaB helicase is essential for replication initiation from the chromosomal origin of replication ( oriC ) and is present in vivo as a protein complex with six monomers of the DnaC ATPase ...
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The relationship between the shape of the bacterial DNA and the blocking of replication machinery

I was reading a course about tolemers when I arrived to this phrase : [...] The ends of a linear DNA molecule cannot be replicated by the cellular replication machinery (which may be one reason why ...
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Why is there complementary base pairing for DNA?

Why is there complementary base pairing for DNA? Why can't A pair with C given that they can all form hydrogen bond?
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“Prime” structure of DNA Double Helix: Confusion

In this video on DNA replication, the diagram shows the unwound DNA as still being anti-parallel, but the first diagram in this post on Biology SE shows that the individual strands are 5'____5' and 3'...
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Difference between PCR for linear template and a plasmid?

I believe PCR can be conducted both on a linear template and a plasmid, and I was wondering how these procedures differ in what enzymes are used, how the enzymes work on the template, primers used etc....
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DNA replication - 2 new strands or original (parent) and child?

this is my first time here, so go easy on me! I've been trying to find out more about the actual process of DNA replication. Specifically, I am wondering if, when the DNA replicates during cellular ...
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PCR and Semiconservative replication

Why does PCR use heat as opposed to helicase like in semi-conservative replication in order to separate the double DNA strand?