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Questions tagged [dna-replication]

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

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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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How do reoviruses manage to get nuceic acids inside their core given they stay in the host cell to replicate ?

To avoid host cell shut off and apoptosis, reoviruses produce capped mRNA internally within a core particle and the only viral genome released in the cytoplasm of the infected cells is ssRNA. Where ...
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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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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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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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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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Hi, im trying make a work about Hayflick limit, and I have a question about the DNA replication. [duplicate]

What I do not understand is why in almost the whole literature it is written that the telomere shortening will only be on the lagging chain, although the leading chain at the beginning with the end ...
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Why can nucleotides be only added in the 5' to 3' direction? [duplicate]

In semi-conservative replication, why is it that DNA polymerase joins nucleotides in a specific direction?
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1answer
61 views

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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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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How to make a large 30 KB plasmid from scratch?

Whats the process to make a comparably large DNA sequence from scratch. That is to say, how does one go from a text file with 35 thousand bases to a plasmid ready to transfection a cell? ...
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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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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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1answer
536 views

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 DNA replication involve RNA primers and not DNA primers?

It is a known fact that RNA primers are required in DNA replication(in vivo). Won't DNA primers serve the purpose better, considering they are more stable and would the make the replication process ...
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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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1answer
2k views

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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Viral genetic potential

A question goes: The DNA of the adenovirus carries genes. Suggest what these genes code for. It's clear that they code for several specific protein components in the virus like the capsomeres, ...
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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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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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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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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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1answer
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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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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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What is the Biological Mechanism by Which a Red Heifer's Skin is Colored Red?

Obviously from this picture Picture of a Red Angus Heifer it is possible for there to be a red cow. So what is the biological mechanism that makes such a cow red? And why are regular cows only ...
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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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Are bacterial RNA polymerases distributed evenly throughout the cell or localized?

Bacterial cells aren't internally compartmentalized with membranes (like eukaryotes). This naturally leads to an image of a homogeneous interior, but bacterial cytoplasm isn't homogeneous. Case in ...
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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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Do telomeres appear at just one end of the chromosome?

I have just studied DNA Replication for my Biology Class and I have this question that leaves me stuck, though I have tried to figure it out myself. During telomere replication, I am aware Telomerase ...
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When does the kinetochore form?

According to Wikipedia, the outer plate... is assembled in the surface of the chromosomes when the nuclear envelope breaks down. However is makes not mention of when the inner portion of the ...
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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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When does histone synthesis occur in relation to DNA replication?

Do histones have to be synthesized before DNA is replicated to allow the DNA to coil around histones?
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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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1answer
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Reason behind formation of positive supercoils during DNA replication/ transcription

When a twist is unwound without cutting the DNA strands or is removed by cutting the strand(s) and resealing, negative supercoils are introduced in the DNA. From Cell and Molecular Biology -Karp But ...
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What is the purpose of two cell divisions in meiosis?

At the moment, my thoughts are that the two cell divisions are necessary for recombination to occur, although I am not sure. I cannot really see why technically, the chromosome from each parent cannot ...
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How do point mutations arise from mistakes in DNA replication?

Hi! I'm trying to make sense of this illustration (from the textbook Biological Science by Scott Freeman). The general question is: How do point mutations arise from mistakes in DNA replication? If ...
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1answer
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DNA & mRNA During Transcription

Just a simple, quick question: how are the mRNA and the template strand of the DNA structured during transcription? I've seen models and videos of them when they're both flat/straight (is that just ...
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Clarification on the parts of plasmids

So I'm basically asking about the role of several DNA elements, specifically within plasmids here (at least for simplicity). In particular, the origin of replication (ori), the ribosome binding site (...
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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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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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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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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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367 views

dNTP concentration for reverse transcription from RNA to cDNA

Does it affect the results if I use the half of dNTP amount in a reaction that it says in my protocol? I usually use 4 microlitres per reaction and this time I did a mistake and I used 2. The final ...
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1answer
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Do mitochondria contain the genes to specify themselves?

My book says : "Mitochondria contain their own genetic material so when a cell divides, the mitochondria replicate themselves under the control of the nucleus." The book means that the mitochondria ...