Questions tagged [dna-replication]

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

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1answer
119 views

Does DNA being circular or linear directly affect the speed of DNA replication?

Let's say we have two DNA molecules of equal length, one belonging to a prokaryote and the other to an eukaryote. It's known that replication of the eukaryotic DNA is faster in this case. One clear ...
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1answer
29 views

Is the leading strand consistent in the same chromosome with multiple replication forks?

If a chromosome has multiple origins or replication, do those origins necessarily pick the same DNA strand as leading and the same one as lagging, or can they be of opposite orientations, sending ...
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Universal clock for humans contained in the telomeric sequences?

I don't know if this would make sense, but imagine that we could only suffer from natural aging (not diseases whatsoever involved). Is there an estimate of what is our natural maximum lifespan that a ...
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1answer
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Why does the structure of RNA change? [closed]

RNA only has one strand, but like DNA, is made up of nucleotides. RNA strands are shorter than DNA strands. RNA sometimes forms a secondary double helix structure, but only intermittently. Why does ...
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1answer
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Can mutation take place in G1 and G2 phases during the cell cycle?

We know that the DNA replicates during the S phase in Interphase. There it might undergo a number of mutations. We also know that the forward half strands are more susceptible to undergoing a mutation ...
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2answers
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Replicate DNA so its visable to the naked eye

So my question has a few sub sections after the main title question. Firstly, is it possible to replicate a pure sample of an individuals DNA to an amount that is visible to the naked eye? If ...
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Eukaryotic DNA polymerase in Leading and Lagging Strand

Different books say a different specifications on which eukaryotic DNA polymerase work in leading strand and which DNA polymerase work in lagging strand. TL,DR: Which one is reality? and if there ...
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How does DNA shape a living organism? [closed]

I'm haven't studied biology so excuse me if I'm getting something wrong. I'm trying to understand how the DNA from a sperm and egg cause the egg too multiply and form a perticular shape (shape of a ...
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How can DNA replication result in hair pin structures?

My professor said that one of the reasons SSB proteins are so important was to prevent the formation of hair pin structures, I can't see how or why DNA would form hairpin structures and there's not ...
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Is there any current knowledge of how DNA polymerase is “motivated” to perform error corrections during transcription?

I was trying to understand the process of how polymerase performs error corrections on DNA. Every paper on this topic mentions what happens during the process, but there's no mention of how it happens....
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3answers
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Why does inbreeding cause genetic defects, but cell division in one's own body does not?

I was watching a DNA transcription video when I realized that cells basically create copies of DNA all the time in our body. There may be a few mutations/errors, but it works out fine. However, when ...
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Why is Homologous Recombination (HR) more frequent at long sequence repeats?

I'm studying plasmids in bacteria (E. coli), and trying to understand the well-cited phenomenon that recombination frequency increases with longer repetitive sequences. I think this also applies to ...
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How exactly does DNA polymerase III detect a mismatched base?

How exactly does DNA polymerase III detect a mismatched base? I know how it removes it, via exonuclease activity, but how does it 'detect' it molecularly in the first place?
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In DNA replication, are there phosphodiester bonds in the primer ? between the RNA nucleotides before being replaced

When hydrogen bonds happen between the RNA nucleotide bases and the DNA bases , do phosphodiester bonds form between the RNA nucleotides in the primer ? No source I read is clear about this, are ...
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What's the transposon difference between chimps and humans?

I was reading that humans and chimps share 98-99% of the same DNA sequence but I also read humans and chimps only share around 20% of the same proteins. Also, 45% of the human genome is transposable ...
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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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In Griffith's experiment, if both S and R strains are added, can the R strain be isolated from the blood of the mice?

In Griffith's experiment on transformation, when both the S strain and the R strain were injected into the blood of the mice, could the R strain be isolated from the blood of the dead mice? I think it'...
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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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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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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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1answer
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How does bonding between non-complementary bases occur?

My teacher told me that when DNA polymerase makes an error (roughly every 10 million nucleotides?) that if, for example, it matches an A with a G that the error remains and is the main cause of point ...
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What are the issues with excessive tandem repeats in replication?

Why is it that tandem repeats like CAGCAGCAG cause primer-template misalignment and diseases like Huntingtons disease? By my understanding, too many such repeats can cause strands to form hairpins and ...
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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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2answers
634 views

Typical DNA replication times

Just out of curiosity (I am completely strange to biology), as I have been unable to find this info on the internet: How long does the whole DNA replication process take? (say, the replication of a ...
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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?
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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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Can a dividing cell that skipped DNA replication become cancerous?

Let's assume that a cell fails to replicate its DNA during the S Phase of the cell cycle. Let's also assume that the appropriate CDKs are inactive (perhaps due to mutation or lack of cyclin proteins ...
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452 views

Chemistry of phosphodiester bond formation by DNA polymerase

As I'm teaching General Biology to my college students, I realized that I don't fully understand how a 3-P nucleotide like ATP is broken down to be incorporated into DNA during replication. How does ...
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1answer
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Are there any particular chemicals that initiate either DNA replication or Transcription ? [closed]

When does the nucleus of a cell "know" when to bind DNA nucleotides ( for Replication ) or RNA nucleotides ( for Transcription ). From what i read, they're both structurally different and free ...
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Can mitochondria become cancerous?

Given that mitochondria have their own DNA and can replicate independently, can they ever become cancerous? For example, could a mutation in their DNA cause them to rapidly replicate, ultimately ...
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1answer
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Error frequency of DNA replication without proof reading activity of DNA polymerase?

Different domains of DNA polymerase contain different activity, like 5'->3' polymerisation and 3'->5' proof reading ...
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2answers
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Molecular animations of, say, protein synthesis, are simplified, but how exactly?

In several animations of biological processes (eg protein synthesis (go to frame 1.20mins), DNA replication, etc), molecules such as amino acids are shown heading straight to the replicating protein ...
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DNA replication precision

This will sound as a super stupid question, but I just read in the Molecular biology of the gene book (7th edition, Watson, Baker, Bell and al.) that one mistake occurs in 10 million nucleotides added ...
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2answers
156 views

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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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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1answer
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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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221 views

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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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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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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In PCR what is the chemical makeup of the primer? DNA or RNA? [closed]

I'm thinking the answer is RNA. Is that right?
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Why does deamination in the lagging strand lead to an increase in the relative number of guanine and thymine to cytosine and adenine?

My question arose from this article on Wikipedia on the GC-skew in bacterial genomes: https://en.wikipedia.org/wiki/GC_skew As far as I understood, the lagging strand (the template strand), during ...
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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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Unsure about definition of “n” and “C” values in mitosis

I am preparing for a Biology exam and I'm reviewing the "n" and "C" notation used in mitosis. My professor said that when the cell replicates its DNA in S phase of mitosis, we get twice the "amount" (...
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1answer
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Why are stem cell therapies more preferred (theoretically) over current measures?

i understand that when stem cells are used to treat injuries using induced pluripotent stem cells (IPS), they can prevent the risk of having any tissue rejection and thus, there isn't a need for use ...
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4answers
751 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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1answer
981 views

What is a DNA clamp exactly?

I used to think that a DNA clamp is a protein. But today I noticed it doesn't appear in this picture. Then I went to it's Wikipedia page, where it was written: A DNA clamp, also known as a sliding ...
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1answer
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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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How is a portion of DNA selected and unwound from nucleosome?

If I understand this correctly during interphase most of the DNA strand is tightly wound around histones in the form of nucleosomes, to conserve space in the nucleus. Yet RNA polymerase in order to ...
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317 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 ...