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

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What's the physical meaning of Svedberg unit?

Sedimentation coefficients, using a centrifuge, are expressed using Svedberg unit (symbol S, sometimes Sv). Wikipedia states that $S = 10^{-13}$ sec but I also saw in a book that actually $S = ...
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6answers
220 views

Sequence analysis software suites

I have used DNAStar laser gene and VectorNTI in the past for cloning, primer design, sequence alignments, etc but no longer have access to these. Are there any comparable replacement suites or what ...
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334 views

Elution of biotinylated RNA

I am using Neutravidin Agarose beads to isolate biotinylated RNA. The thing is, in the manual it says to use 8M Guanidine-HCl, pH 1.5 for elution biotinylated molecules. As far as I know it is a very ...
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2answers
84 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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92 views

What will happen if we expose the brain to an intermittent light?

If a brain is exposed to an intermittent light are specific areas going to fire? If yes, which of them? Is there any experiment about this?
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2answers
88 views

Termination of translation

What dissociates first - the last tRNA, mRNA and release factors or the subunits of ribosomes? I tried searching this from Lehninger but couldn't get a clean answer.
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470 views

Beginning with centrifuge experiment

This is the first time I do a centrifuge experiment with my own centrifuge machine, it's just simple made by a rotor that can rotate the tube at high speed. As I know a centrifuge machine can be using ...
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2answers
179 views

Do the simplest bacteria have ribosomes and helicase?

I find it interesting that all life on earth use DNA. I've seen video on how helicase and ribosomes work together to copy DNA sequences (to RNA) with helicase then recreate them using ribosomes. Does ...
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24 views

Does mung bean nuclease cleave a phosphate group when it's chewing off 5' or 3' ssDNA ends?

I'm looking to create blunt ends from sticky ends with mung bean nuclease for subsequent ligation. Does anyone know full mechanism by which mung bean nuclease will do this? In particular after the ...
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24 views

What are host cellular factors?

With respect to this paper: Global Analysis of Host-Pathogen Interactions that Regulate Early-Stage HIV-1 Replication What does the term "host cellular factors" mean??
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831 views

What are some of the general characteristics of the DH5 alpha strain?

I can not find some useful sources unfortunately. Please tell me about some important characteristics of DH5 alpha. What makes DH5 alpha suitable for the gene cloning?
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26 views

epitope prediction/ mapping

B-CELL EPITOPE PREDICTION Regarding this article: "Such a molecule can be synthesized or, in case of a protein, its gene can be cloned into an expression vector."----- is a particular line in ...
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50 views

Immunodominant Peptide

Can someone please explain me the concept of Immunodominant peptide in simple language?? I did read the wiki article but did not understand it clearly. Please help! (I have not studied biology since ...
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2answers
308 views

Single stranded DNA in gel electrophoresis

From http://www.nfstc.org/pdi/Subject05/pdi_s05_m01_01.htm : ... The separation medium contains a denaturant in order that the electrophoresis is conducted on single-stranded DNA fragments. ...
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1answer
59 views

H O N C alternatives for organic life?

Most organic structures built from hydrogen, oxygen, nitrogen and carbon. They are represent 1-,2-,3-,4- bond relations (chemical valence) which allow to build variety of chain structures. Are there ...
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1answer
89 views

What are the Gateway clonase enzymes?

The Gateway cloning system utilizes what Life Technologies refers to as "Clonase enzyme mix" to catalyze the BP and LR reactions. What is in this enzyme mix? Is there a sequence for them?
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64 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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63 views

Would expression of GroEL and GroES in erythrocytes be a potentially effective therapy for sickle cell disease?

Would expression of GroEL and GroES in erythrocytes be a potentially effective therapeutic strategy for sickle cell disease? Why or why not?
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2answers
2k views

Explanation of the terms “downstream signaling” and “upstream signaling”

In molecular biology, what's the meaning of the terms "downstream signaling" and "upstream signaling"? What's the difference between them?
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113 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 ?
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249 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
61 views

How do cells figure out the big-picture shape?

I'm wondering what makes cells to divide (and stop) in such a way that they make our hands the shape that our hands are...
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1answer
1k 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
41 views

Is the amount of dNTPs rate limiting for very long PCR products?

I'm using the Q5 system and I'm PCRing a product that will have a final length of around 9500 bases. I have noticed that the product is there but very faint. The primer seems to be used up. So my ...
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20 views

What is the protein sequence taken as input in the Path-A prediction system

Considering the Path-A based metabolic pathway prediction (http://nar.oxfordjournals.org/content/34/suppl_2/W714.short). It uses machine learning for pathway prediction. Suppose that the input was a ...
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1answer
36 views

Retrovirus Production

I have been having difficulties with low transduction efficiencies of my retrovirus production. I expand my plasmid of interest (on MiG-GFP plasmid) in DH5α E Coli for ~24 hours, purify with Qiagen ...
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1answer
89 views

Why does gaining a hydrogen in biology considered reducing a molecule? [closed]

I've learnt in chemistry that gaining electrons means reduction, while losing electrons means oxidation. But why is it in Biology textbooks I sometimes come across the term gaining hydrogen??
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2answers
255 views

Why people fear GMOs? Can't we map a plant composition?

My main question is can we map what a fruit is made of? For instance apples are made of 0.0002% of protein X, 0.00001 of protein Y, 0.001% of amino acid Z... etc... If we can, then my next question ...
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28 views

Concentration of degenerate primers should you dilute to?

I'm a little embarrassed to ask but when you have for example four degenerate primers and the end protocol says that the final primer concentration should be 10 µM working stock, should you make the ...
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1answer
44 views

How are lesions in the RNA corrected?

I quite understand why thymine is present in DNA. So we can mark it out where cytosine undergoes a reaction and is converted to uracil. Then we can repair the DNA. But how can we make that out in RNA ...
2
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1answer
29 views

Gene Sequencing and Plasmapper

Is there anything similar to this in Java (especially the circular map sequencing along with hover effect)? For information I would like to convey that I am using Plasmapper and BioJava for achieving ...
2
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1answer
54 views

How do C. elegans manage nutrition?

If there is ample amount of food, do C. elegans worms know when to stop eating or do they store extra energy? Could they put this extra energy to use by moving faster or putting more eggs?
2
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1answer
251 views

Difference between sequential and conformational epitope

Is the difference only in its structure? Like conformational epitope has 3D structure while sequential has a linear structure?(I have not studied biology since last 8 years and now I am going through ...
2
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1answer
29 views

Transcription rate expressed in microarray per hour

This article gives measurement of transcription rate and the unit they're using is microarray per hour. For example, at 27°C the average expression of their genes is 236.1 microarray per hour (page ...
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1answer
273 views

Using RNA-seq to compare gene expression across patients instead of between Control and Experimental conditions

I am working with RNA-seq data from the Cancer Genome Atlas TCGA and I have been reading about how people have compared gene expression levels measured by RNA-seq. Many of the papers I have read talk ...
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35 views

What is the biding site code recognized by the parts of the spliceosome

Another question about another Youtube video. At 0:50, the splicing process begins to remove the non-coding section of the DNA (intron), so the different parts of the spliceosome attach to the borders ...
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2answers
850 views

What is Pan for in pan-caspase?

A simple question (I could not find it on internet): What is Pan for in pan-caspase? Is it any different from the term 'caspase' ?
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2answers
63 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
172 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? ...
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1answer
189 views

Troubleshooting for Agarose Gel Electrophoresis

SI ran my 2% agarose gel on constant voltage (100 V). For a few times it worked at CV but, after a week or so the machine would automatically switch to constant current by itself. And this only ...
2
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1answer
315 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
807 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 ...
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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
203 views

Realtime PCR plate cleaning

Have anyone used realtime PCR, is that the plate for realtime PCR is one-time using or not ? Otherwise how to clean the plate after reaction to prevent wrong result in next time using ?
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1answer
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Why is allolactose the LacI inducer?

For what reason(s) is allolactose, instead of lactose, the "natural" inducer of lac operon repressor?
2
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1answer
222 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
20 views

Why does the inhibition of translation initiation cause the accumulation of 80S ribosomal monosomes?

As I have read in (1), inhibition of translation initiation will increase the number of 80S ribosomes while decreasing the fraction of polysomes due to the polysome-runoff. The net effect is to ...
2
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1answer
64 views

How to isolate host cell RNA (tRNA,mRNA,rRNA) from viral RNA?

A retrovirus with RNA genome infected a host cell. You would like to isolate the host cell’s RNA (rRNA, tRNA, and mRNA) from the virus RNA. What properties can you rely on to determine the three types ...
2
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1answer
25 views

Which is the guideline to choose a molecular target to identify vertebrate hosts from arthropod bloodmeals?

There are some molecular targets to identify vertebrate hosts from arthropod bloodmeals including the Cyt b gene and the COI gene. Which are the standards or characteristics that I have to bear in ...
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40 views

Why is the resting potential of a neuron so close to the equilibrium potential of K⁺?

I know this has something to do with the K+ leak channel. I just don't understand how. I know that 3 Na+ are pumped out for every 2 K+ pumped in. This makes the cell interior net negative. I know ...