Questions tagged [dna-replication]
The biosynthetic process by which copies of a DNA molecule are made.
1
vote
0answers
37 views
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 ...
6
votes
1answer
54 views
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 ...
0
votes
0answers
17 views
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 ...
2
votes
1answer
51 views
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 ...
2
votes
2answers
122 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 ...
0
votes
0answers
11 views
Primer design: Calculating free energy for secondary structure
I'm attempting to automate primer design (specifically, primers for RPA, which requires longer primers [~30-35 nc] than PCR), and need to figure out how to calculate the free energy of a primer pair ...
0
votes
1answer
42 views
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?
1
vote
0answers
49 views
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 ?
3
votes
0answers
77 views
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 ...
4
votes
2answers
210 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 ...
-1
votes
1answer
50 views
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 ...
11
votes
1answer
211 views
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 ...
-1
votes
1answer
31 views
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 ...
3
votes
2answers
85 views
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 ...
3
votes
0answers
59 views
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 ...
1
vote
2answers
136 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?
0
votes
1answer
115 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 ...
1
vote
1answer
77 views
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.
2
votes
0answers
175 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 ...
1
vote
0answers
44 views
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 ...
1
vote
1answer
838 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 ...
-3
votes
2answers
2k views
In PCR what is the chemical makeup of the primer? DNA or RNA? [closed]
I'm thinking the answer is RNA. Is that right?
0
votes
1answer
175 views
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 ...
0
votes
1answer
718 views
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 "...
-1
votes
2answers
3k 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" (...
0
votes
1answer
61 views
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 ...
1
vote
4answers
540 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 ...
3
votes
1answer
678 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 ...
1
vote
1answer
183 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 ...
7
votes
3answers
319 views
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 ...
1
vote
1answer
291 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 ...
1
vote
0answers
46 views
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 ...
-1
votes
2answers
2k views
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 ...
3
votes
1answer
50 views
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 ...
3
votes
0answers
141 views
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 ...
4
votes
1answer
339 views
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 ...
0
votes
0answers
523 views
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 ...
2
votes
0answers
32 views
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, ...
9
votes
2answers
1k views
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?
2
votes
0answers
24 views
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 ...
4
votes
1answer
662 views
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 ...
3
votes
1answer
297 views
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 ...
6
votes
1answer
590 views
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 ...
7
votes
1answer
479 views
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 ...
0
votes
2answers
393 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 ...
1
vote
1answer
43 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 ...
0
votes
1answer
39 views
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 ...
1
vote
2answers
67 views
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?
0
votes
1answer
421 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 ...
3
votes
1answer
116 views
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 ...
