The study of the molecular processes of the nucleus and cell function.

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617 views

Why is Sanger sequencing inferior for detecting SNPs in cancer cells?

I am familiar with Sanger sequencing, but at the level of an undergraduate. A lecturer of mine tried to describe Sanger sequencing as losing the sequence information in noise when used to detect ...
2
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1answer
110 views

In cancer, why do cells duplicate themselves?

In regards to cancer why do cells replicate themselves? If it's a mutation, what kind of mutation would this be classified as?
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52 views

In genome research, what is the problem in Mapping that may be caused by reads being too short?

In the following scenario: You were given short sequence reads of plant RNA obtained from a next-generation sequencing machine (fragments of 20–30 nucleotides in length). You attempt to map them back ...
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1answer
44 views

Role of isopropanol in plasmid isolation

In plasmid isolation, isopropanol is used to renature only the plasmid macromolecules after we precipitate all macromolecules(DNA, RNA, plasmids) using sodium acetate solution. How does it do that? ...
2
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1answer
114 views

How can Southern blotting be used to establish gene copy number?

I am reading a paper on a certain marine microorganism that can eat alkanes and therefore might be useful for cleaning up oil spills, etc. This sentence struck me as odd (although I am sure that the ...
2
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1answer
147 views

Orientations of codon and anticodon

So 5'-AUG-3' is the start codon on an mRNA transcript Does that mean that the tRNA anticodon is 5'-CAU-3'? Here, I see that the tRNA anticodon for methionine is UAC, and the chart doesn't specify ...
2
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1answer
506 views

Lyonization and X-linked disorders?

Lyonization or X-chromosome inactivation is the conversion of all but one, X-chromosomes in Females into non-coding heterochromatin (i.e. deactivated) leading to the formation of one or more Barr ...
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2answers
155 views

Why did Fair Meiosis evolve?

How and why did Fair Meiosis evolve? I can hardly think that it provided a fitness advantage to the individual carrying the mutation. Why would it? Or did it evolve through lineage selection? Or was ...
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1answer
615 views

Why is allolactose the LacI inducer?

For what reason(s) is allolactose, instead of lactose, the "natural" inducer of lac operon repressor?
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437 views

Optogenetics - How do microbial opsins work?

I'm just introduced to the optogenetics method and am having some trouble grasping the genetics (of the optogenteics) part of things. So we have Retinal and Opsin that form Rhodopsin molecule that ...
2
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1answer
161 views

Can Taq polymerase be used instead of polymerase Vent exo (-)?

Instead of using polymerase Vent exo (-), can I go with the usual Taq polymerase? Do the PCR conditions change (the temperature and master mix concentrations ) in the these two conditions? Do the ...
2
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1answer
24 views

Heterochromatin production limitations

Currently playing with some ideas for a project and needed some guidance. I am wondering, both in Drosophila melanogaster and in general, is the amount of heterochromatin a cell/nucleus can produce ...
2
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1answer
77 views

Biological meaning/interpretation of clustering coefficience

I have been looking for some time to find an answer to the following question. I would be grateful for any help/advice or directions. I work very frequently with large number of proteins and assess ...
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1answer
29 views

Transport of mammalian insulin in vivo

What is the mechanism for transport of insulin in mammalian cells?
2
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1answer
84 views

Transition/Transversion ratio

I'm taking a bioinformatics class and at this point we are just going over basic stuff about molecular biology. Half of the class is doing reading/research on our own, so there isn't much class time ...
2
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2answers
50 views

Molecular simulations without capping n- and c-terminus of polypeptide

When running molecular simulations, what is the consequence of not capping the n- and c-terminus? I have been following gromacs tutorials and haven't come across any that deal with capping the ...
2
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1answer
72 views

Determining sequence of oligoribonucleotide

Oligoribonucleotide X was treated with phosphatase (for removal of 3' and 5' - terminal phosphates), then with RNAase T1, which cleaves all phosphodiester bonds located in a 3' position of ...
2
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2answers
110 views

Image analysis of GFP-tagged protein localization bursts

I'm reading an article (full text here) that analyze the dynamics of localization of a GFP-tagged transcription factor (Crz1) over the time at the single-cell level, by taking movies in a fluorescent ...
2
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1answer
180 views

How to calculate or know by experiment the entropy of enzymes or protein?

How do you calculate or experimentally determine the entropy of enzymes or protein? In particular, I am interested in Boltzmann and conformational entropy, and Gibbs free energy. Any references are ...
2
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1answer
104 views

How does GTP help in the step of codon recognition?

The anticodon of an incoming tRNA base pairs with the complementary mRNA codon in the A site.Hydrolysis of GTP increases the efficiency and accuracy of this step. How does GTP do so ?
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1answer
40 views

Determination of gene direction

I have one sequence that composed of sequences of three genes. I should determine the direction of each gene, but two of these genes are disrupted, and I can't determine the initial codon. Does anyone ...
2
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1answer
86 views

Should I design a primer to detect virus based on NCBI genebank?

When I searched HIV on NCBI gene bank, I found 2 results from 1997: http://www.ncbi.nlm.nih.gov/genome/?term=HIV. HIV can change every day, so I think the sequence from 1997 is not useful. Is it?
2
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1answer
370 views

Manipulation of gene expression using VP16 fusion and engrailed fusion to a transcription factor?

Today, a presenter briefly mentioned that gene expression in sea urchins during development might be manipulated using VP16 and engrailed fusions. On a slide, it said that expression might be ...
2
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1answer
124 views

Histone marks mechanism

I am slightly confused about the mechanisms that makes histone modifications associate with gene expression. That is, H3K36me3 is believed to be present in actively transcribed genes, H3K27me3 in ...
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60 views

Gibson assembly using NeBuilder

I am supposed to construct a plasmid that contains features from two other plasmids. My strategy is to generate three fragments form the two other plasmids. I was encouraged to try Gibson assembly, ...
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87 views

RNA isolation from Drosophila head

I need to isolate RNA from Drosophila head. I basically chop the head off and first homogenize it with a homogenizer (similar to this: ...
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0answers
152 views

Image Processing Suite for bacterial microscopy: Schnitzcells or MicrobeTracker?

I am looking to start doing some work tracking the size and growth of individual bacterial cells in the microscope. In order to analyze the images I need software that can segment the cells, ...
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0answers
39 views

Shortest route for a Nitrogen atom from fossil fuel to a protein in your body?

Millions of years ago fossil fuels originated from plants. A nitrogen atom from fossil fuel is now inside in a protein molecule in your body. What is the shortest path that the nitrogen atom ...
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121 views

Can Pfx polymerase add only one 3' A overhang?

I am trying to clone a PCR product that was amplified using Pfx polymerase into pGemT vector. I had to A-tail the PCR product using Taq polymerase since Pfx only generates blunt end products. My ...
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0answers
150 views

Can I heat Trizol?

I wonder if I can heat Trizol reagent for 30 min 65C. The goal is to disrupt protein-RNA complex while inhibiting nucleases. (I can't use RNasin cause it's inactivated in 65C, and can't use RVC cause ...
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0answers
82 views

Mouse meta-globin mRNA problem

This is an mRNA strand of mouse meta-globin: 5'-ccccagauacggaauucgaau-3' A) Which small RNA (below) is most likely to regulate expression of meta-globin? ...
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44 views

Functioning of EDTA

I know that EDTA chelates metal ions. It weakens bacterial cell wall and inactivates the DNases. What is the reason why it can do so ? I guess it can inactivate DNases by altering the ...
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2answers
95 views

Protein purification methods

Which of the following methods would yield the most purified protein fraction? A. Salt precipitation B. Charge separation C. Affinity purification The first one is the most commonly used, is it ...
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2answers
98 views

Finding a easy and cheap method for dyeing dNTP

I want to measure OD to know the concentration of dNTP. Any idea for dyeing dNTP at cheapest price and easiest way ?
1
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1answer
56 views

A question related to qPCR analysis

Here is the thing. I am using a method, called TU-Tagging, to isolate cell type specific RNA. You can find more about the method here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2783170/ To explain ...
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1answer
66 views

Do “transcription factor binding site” and “operator” mean the same thing?

Can the terms "transcription factor binding site" and "operator" be used interchangeably in all contexts when referring to a DNA sequence, e.g. regardless of a cell type, whether or not the binding ...
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1answer
66 views

Transcribing DNA to mRNA with introns

I have a problem in my bioinformatics class that I thought I was doing right, but someone else is getting a different answer. Here is the problem: Given the following DNA sequence, ...
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3answers
42 views

FRET only works for interactions between 1nm to 20nm.

FRET only works for interactions between 1nm to 20nm. How can you be sure that the interaction that you want to study isn't less than 1 nm/greater than 20nm apart?
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1answer
48 views

Dilution question about RNA

I have a basic and probably silly question. I am isolating RNA with TRIzol. I have performed the basic steps and dissolved the pellet in 50 uL water. I ve measured the concentration and it was 3313 ...
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1answer
110 views

Suggestions for an experiment? [closed]

I would appreciate suggestions for my year-long AP Biology project. Such a project would consists of a standard experiment, to be done over the period of a year, so it would have >to be fairly ...
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2answers
56 views

The role of antibodies interacting with cancer

I'm learning about antibodies. As I understand it, antibodies detect stranger cells/bacterial/viruses by the molecules present in their membranes. In cancer cells, the cancer cell have produce some ...
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1answer
100 views

Preparation of normal DNA polymerase

i don't need Taq polymerase. Just need normal DNA polymerase. So the main idea is preparation polymerase directly from Lactobacillus without using cloned vector. My idea is electrophoresis using ...
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1answer
82 views

What in soy are people allergic to and will these allergens be passed along if an animal that has eaten soy is consumed?

I have two related questions about soy allergies and possible reactions. What is it that are humans who have soy allergies actually allergic to? What is the allergen? If an animal eats soy, are ...
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1answer
53 views

Do you have experience with PacBio?

I prepare a experiment and I found $PacBio SMRT$ as the great way to sequence my PCR products. I find the cost: library preparation 655 dollars + sequencing 435 dollars. It seems very low. Do you have ...
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1answer
48 views

In vitro transcription, contamination problem

I am using a RNA which is in vitro transcripted before I started my project. It turned out it is not prepared properly and has DNA contamination. Instead of perform the in vitro transcription again, ...
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1answer
68 views

DNA ligase mechanism

I am unable to understand what happens to the phosphates from ATP. What are they used for ?Charging 3' end or 5'end ?
1
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1answer
53 views

Photosynthesis: Splitting Water

The splitting of water is an endergonic (non-spontaneous) reaction, and thus would require energy (chemical work to be done) in order to happen. In Photosystem II, an enzyme catalyzes this splitting, ...
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1answer
48 views

Clarification of the procedures to amplify cDNA needed

The typical procedure to obtain cDNA from genomic extracted DNA is the following: RNA is extracted from desired tissue, RNA/DNA hybrid is obtained by virtue of reverse transcriptase RNA dependent DNA ...
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2answers
62 views

How does promoter sequence affect initiation?

I don't know if this might have been highlighted in recent research, but a textbook I have states that "the exact way in which promoter sequence affects [transcription] initiation is unclear" I'm ...
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2answers
287 views

Gel electrophoresis question

Leena is a molecular biology student. She purifies two fragments of DNA, 800 and 300 base pairs long. These were obtained from a plasmid after digesting it with HindIII. Each of these fragments has a ...