Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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analysis of post transplantation lineage tags

I'm having some trouble understanding some bits of a study, mostly about the Sleeping Beauty system and TARIS model, from this paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408613/ I ...
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Can any one explain me the structural difference between proteins and peptides? [closed]

I have read in books that proteins and peptides are fundamental components of cells which carryout important biological functions.Can any one explain me the structural difference between proteins and ...
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Is p53 a cyclin dependent kinase?

I've been reading some research papers about p53 and associated tumour suppressor proteins, such as p21. I see them referred to and associated with cyclin-dependent kinases. Is p53,p63 et cetera part ...
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Can Cas13 be used with multiple crRNAs in the same reaction?

CRISPR-Cas13 equipped with crRNA (complementary to transcripts of interest) can be designed to target ssRNA transcripts in cells. Upon successful crRNA and ssRNA binding, a fluorescent domain on ...
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Autodock4 -soft docking

AutoDock4 is a software tool for the analysis of protein-ligand interaction. How could I turn on/off the smooth potential in AutoDock4? I need to do two docking. The first one is soft docking with ...
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Prokaryotes Genome

What function of repetitive sequences of Prokaryote? I see a gap (intergenic region) between 2 coding strand. But just only a single origin region in Prokaryotes. How it can transcription coding ...
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Why do most organisms have negative supercoiled DNA?

It has been observed that in nature most organisms have negative supercoiled DNA and that few organisms have positive supercoiled DNA. Some of the organisms that have the positive supercoiled DNA live ...
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Lab technique to distinguish between single stranded and double stranded DNA?

What lab techniques exist to differentiate between single-strand and double-stranded DNA?
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Can different proteins be produced during translation of a single mRNA in eukaryotes?

Is there a translational mechanism that eukaryotes can use to produce different proteins from a single transcribed mRNA?
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118 views

How Incomplete dominance can be explained at molecular level?

What is exactly happening at the molecular level when two genes constitute incomplete dominance? Whether the protein formed from each of the genes constitute a new protein having a different function ...
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Can two proteins activate/inhibit the same gene at the same time?

Suppose there are two proteins inhibiting a particular gene. Its not necessary that both will inhibit the gene at the same time instance right? So if one protein has already inhibited that gene before ...
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Can enzymes be modeled using classical mechanics?

When enzymes interact with substrates (i.e. a small ADP molecule and the much larger ATP synthase), does quantum mechanics play a significant role? Or can the interactions be relatively accurately be ...
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36 views

What would be the effect of excess taq polymerase on the PCR?

I just had one question regarding the possible effect of putting to much Taq polymerase in my PCR tube? Instead of 5µl I put 50µl (10x more). Do you think it will have a bad effect on the reaction??...
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Where does the number 67 in the nuclear protein/antigen Ki-67 come from? Why not 66 or 68?

I have read in in the original paper that in the year 1983 a research group in Kiel, Germany (that's where the Ki- in the name comes from) developed monoclonal mouse antibodies against Hodgkin ...
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Are human cells tetraploid during cell division?

If human cells are diploid, and DNA replicates before cell division, does it mean that our cells are tetrapolid for a short period of time (DNA replication - cell division). Photos of chromosomes are ...
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Fluorescence assays to identify protein concentration without adding a large peptide sequence?

I'm trying to find a way of tagging a protein with something visually quantifiable to track protein concentration through potential purification steps and screen for the most efficient such steps. ...
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3answers
995 views

How does high-fidelity of DNA replication depend on the formation of hydrogen bonds?

Replication has an error rate of less than 1 in 100 million. DNA polymerase forms H-bond with the H-bond acceptor atoms in the minor groove. <-- enhance fidelity here? Binding of the triphosphate ...
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Ligation without purifying insert

I am planning to insert a 45 bp sequence in a vector. After restricting my insert to create compatible sticky ends, I am finding no way to clean it up. Is there any way for cleaning this fragment ...
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What stops messenger RNA from binding to itself?

Since mRNA is single-stranded, and (mostly) floats freely within the cytosol, what stops it from folding onto itself (like DNA) and preventing transcription?
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A little help understanding DNA supercoiling

I am studying molecular biology from Lewin's Genes XII and got confused in the supercoiling topic. Since then I read from several other sources and so far understood the following. However, I can't ...
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Methods: Homologous recombination and retroviral infection

I'm looking for a textbook that explains these methodologies: Use of homologous recombination to insert a gen-cassette into another organism's gen. Use of retroviral transduction to deliver genes ...
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During DNA foot-printing, what is the purpose of radioactively labeling only one end of the DNA fragment?

I read that during DNA foot-printing analysis, DNA is radioactively labeled on one end before being cleaved by DNase 1. I understand that it is labeled so in order to locate the fragment on a gel, but ...
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How to map A single N1-methyladenosine (m1A) by primer extension?

I want to map a single N1-methyladenosine (m1A) modification by primer extension. I have silenced a gene which is responsible for guiding modification of m1A then I confirmed the silencing. My next ...
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Relevance of old atomic theory in understanding biology?

I have seen the explanation of many biological reactions using the high school atomic theory (I don't remember the name but it involves using lewis dot structure). So is it the case that the effect of ...
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How do I prepare a Basal medium for autotrophic mutant creation

Minimal medium (MM) was prepared by adding 2.0 g sodium nitrate (NaNO3) to 1 L of basal medium (BM) fol- lowing Correll et al. (1987). Chlorate resistant sectors (CRSs) were generated on two media i.e....
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Nutrition and experimental biology

We know that food in the stomach is present in the form of chyme treated with pepsin and hydrochloric acid, if we take food crush it with saliva and then treat it with Pepsin and HCl (in the lab),and ...
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Online Molecular and Cellular Biology Video Lectures?

I am looking for video lectures to go through to guide my reading in intro molecular and cellular biology. I've had intro bio and I study evolutionary theory, but my molecule- and cell-level knowledge ...
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Book Recommendations: GRE Subject Test In Biochemistry, Cell And Molecular Biology

There are probably a lot of really good answers that may vary significantly in terms of content. I'm looking for a set of books that I can read in preparation for the GRE Subject Test In Biochemistry,...
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what is minimal promoter and what is basal promoter?

what is minimal and basal promoter and what are their elements and what is the difference between the two?I'm confused. searched a lot, but didn't found any satisfactory answer. please help
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Which one is better to use for water stress experiment GWAS or RNASeq?

This is my first time in this area of research. I am working on 95 varieties of bambara groundnut. I have done the agromorphological characterization of these varieties as well as the genetic ...
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297 views

Why is the Tm defined as the temperature at which 50% of dsDNA has changed into ssDNA?

In molecular biology, Tm is defined as the temperature at which 50% of dsDNA is converted to its single stranded form. Intuitively it would seem that the melting temperature should have been defined ...
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36 views

What causes the elongation of Genome down the evolutionary time line [closed]

Theory of natural evolution says that complex life forms arose from simpler ones e.g. starting from Eubacteria to modern day multicellular eukaryotes. {If we try to reduce these changes happening at ...
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Why do mutations not take place in mRNA of higher eukaryotes?

Is it because it is too short-lived to be mutated? Both DNA and RNA are nucleic acids so how is mRNA protected? RNA viruses undergo mutations to evolve so I guess it is not immune to mutations
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Viral RNA to DNA

I have a question concerning reverse transcriptase. Why is it that when the viral rna is converted to viral dna( as in the case for hiv), the virus develops resistance to medicine? Under what ...
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Design rules for DNA linkers

I want to use double stranded DNA linkers to physically bind two "things" together, by grafting ssDNA on each one of them and using DNA hybridization as the locking mechanism. I do not expect the ...
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Why do specifically bananas go brown quicker in the fridge?

Perhaps the title should be: Why don't all fruits containing phenol residues go brown quickly when left in the fridge? Bananas go brown over time because of the oxidation of phenol residues. ...
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What are the uses of Helical Wheel Projections in Structural Biology?

I have seen helical wheel projections used to illustrate amphipathic helices in proteins. Are there any other uses for these models?
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What is an acceptable qPCR efficiency when adjust using the Pfaffl equation?

I have efficiencies of 76% and 85%. THis is clearly below what is normally acceptable. But the pfaffl equation corrects this, doesnt it? However is it acceptable to publish this data?
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Which are more beneficial: lyophilized or hydrolized collagen peptides?

Looking at two different manufacturing methods for collagen peptides: hydrolyzed vs lyophilized (freeze dried), I read that hydrolyzed results in a hydrophobic biolayer molecule collagen peptide. Re:...
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How does the body switch between aerobic and anaerobic respiration?

Lets take the case of a person doing heavy exercise. Aerobic respiration is taking place, but oxygen is about to be finished up. Glycolysis occurs, Krebs cycle finishes. Now NADH and FADH2 enter ...
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Why do we add salt when precipitating DNA?

All the DNA extraction protocols I have seen involve adding salts to the extraction buffer. What is the purpose of the salts? What happens if they aren't included?
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127 views

Why is it thought that protein folding is determined solely by amino acid sequence?

It seems that it is a generally accepted idea that protein folding is completely determined by the sequence of amino acids, but why do people believe that? Is it simply that no example of a protein ...
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222 views

Does depolymerisation take place at the minus end of microtubule?

Wikipedia says that Dynamic instability refers to the coexistence of assembly and disassembly at the 'ends' of a microtubule. but Karp's Cell Biology, 7th edition says Dynamic instability is ...
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Software to model and analyse protein–ligand interactions

I am currently trying to model a certain protein (Golgi Mannosidase II) and compare the induced fit of the inhibitor swainsonine. I would like to be able to analyse the distances between bonding ...
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92 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.
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E. coli & aspartate

I am familiar with the linkage between aspartate/ligand binding, receptor methylation, and flagellar behavior re. style of locamotion, but I do not know what the bacterium does with the aspartate it ...
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652 views

When did CRISPR/Cas9 evolve and what is the likelihood that a superior system for live cell genome editing has already evolved on earth since then?

I've read that CRISPR/Cas9 is currently being implemented and tested for its ability to edit genomes in live cells, and that it is supplanting other genome editing tools in labs, such as TALENs and ...
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456 views

number of chromatids seen in karyotype

The karyotype is performed on a cell whose cycle has been stopped in metaphase or pro metaphase, using colchicine or by other means. In the textbooks I read that during the S phase each of the 46 ...
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47 views

Insertion Confirmation Cloning Strategy

So I am in a bit of a time constraint. Essentially, I inserted a DNA fragment via molecular cloning which contains a unique RE site. I need to confirm whether my colony has or does not have the ...
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How can you band wheat chromosomes using Giemsa dye?

I am working with wheat chromosomes and trying to stain the chromosomes. However, during staining with Giemsa dye chromosomes appear totally dark. I'm not sure why this might be. Anyone have any ideas?...