Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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1answer
25 views

Size constraints on CRISPR guide RNA

I had a quick questions on the size limitations of a CRISPR guide. More specifically on the shorter end. Can I make a guide that is say 7-10bp and still have an active complex? I transfect using an ...
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3answers
295 views

How can I set micropipette volume with decimal separators, for example 109.5 in p200?

And how can I set: 150.1 in p200 871.3 in p1000 840.5 in p1000?
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1answer
2k views

Can bacteria, viruses, and cancer cells be destroyed by resonance?

Radiotherapy has been used to treat cancer. Can the resonances by coordinated electromagnetic waves (and/or other forms of waves), of various frequencies, amplitudes and pulse rates, directed from ...
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1answer
46 views

Improving DNA quality and yield from stool samples

I prepared genomic DNA from pig stools but the concentration was very low — about 3~4 ng/µl, when I measured it using nanodrop. The A260/A280 and ...
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1answer
61 views

Why pellet and resuspend E. coli for plasmid prep

For maxipreps, cant you just add all the stuff that would be in P1 (RNase A, EDTA) then just add P2? Because if we pellet cells then resuspend theres got to be a reason, right? Is it slats and other ...
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1answer
28 views

Could deutrium oxide be used to make organic compounds with Deutrium instead of hydrogen? [closed]

I am wondering for prokaryotes if Deutrium Oxide could be made into Deutrium Glucose or other biological compounds with Deutrium.
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3answers
12k views

Do we consume dna, proteins of other organisms?

When we eat raw meat, e.g. chicken or fish, we are actually consuming the DNA, proteins etc. which are present in their cells. Wouldn't this affect our cell functions as this DNA might enter our ...
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1answer
36 views

How to identify whether something is in linkage disequilibrium?

If the following loci indicated the presence of an SNP in flu strains, is Locus 2 and Locus 3, which are located 10 bp apart in linkage disequilibrium? "When alleles and molecular markers are ...
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0answers
14 views

Why are higher doses of atropine required to produce central effects?

Reason given in my book is restricted entry into the brain..is it something to do with the chemisty?
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2answers
732 views

How will changing the concentration of a Tris buffer affect amylase enzyme activity?

For instance if you increase the amount of Tris but pH still does not change then will the enzyme activity still proceed normally? If it does change the pH will it change enzyme structure and why?
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1answer
64 views

Gene vs Protein homology

I am trying to find homologs for some proteins and I am wondering if it is better to find it by comparing the proteins or the coding genes or either is fine.
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1answer
32 views

Why do we use different micropipette tips for different volumes? [closed]

Isn’t it easier to use a 1000 µl micropipette tip for all volumes? I don’t understand why there are different tips for smaller volumes. Does it affect the accuracy of the pipette for very small (<...
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1answer
78 views

Melting point of animal fat and plant fat

I notice in daily life that animal fat typically has a higher melting point than plant fat does. I wonder the reason why this happens. What exactly contributes to this difference? Is it because of the ...
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1answer
87 views

Why are there inverted repeats in response elements?

The following picture shows an inverted repeat sequence in a response element. Response element sequences for glucocorticoids, estrogen, and thyroid hormone show that they all contain inverse repeats. ...
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1answer
50 views

When muscles contract is the process similar to how non-newtonian fluids react?

I'm trying to understand how muscles contraction/tension works but getting loss in on the cellular level. From my understanding, when muscle tissue need to contract, the cells are flooded with calcium?...
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1answer
95 views

Is there a reliable source for storage and stability of reducing agents like DTT?

Reading the literature on DTT, one is confronted with a confusing mass of papers; some claim that a 1M solution in water is stable, other papers say it is not. I use the reaction with DTNB to show ...
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0answers
22 views

How to take precise/low number of cells from cell lysate? [closed]

I would like to know that how can we take low or precise number of cells from a cell lysate? (without using any protein quantification assay). Let say, If I have a cell line having cell density 5x10^...
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1answer
31 views

Does *E. coli Dh5 Alpha* strain has the ability to degrade polyethylene?

Does E. coli Dh5 Alpha strain has the ability to degrade polyethylene? What are the bacteria that can be used as a control in the research of polyethylene degradation?
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1answer
110 views

Antigen molecular mimicry

Let us consider a situation in which the body is attacked by a microbe, and the microbe is captured by the immune system for recognition of surface antigens. The surface antigen recognized mimics one ...
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0answers
62 views

What M9 stands for

Can anyone tell me what M9 stands for in M9 medium? I have tried googling but I still cannot find it.
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3answers
203 views

Retrieve all predicted cds from NCBI

Please apologies if this has been answered somewhere else, but I couldn't find an answer to this problem. I would like to retrieve all the predicted coding sequences on the NCBI ftp for a given ...
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1answer
42 views

Is studying chemical and physical properties of chemical substances that make up organisms really a task of molecular biology?

I have read in a high school textbook that (translated into English by myself): "Branch of science that concerns itself with studying chemical and physical properties of substances that make up ...
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0answers
28 views

Can we spike with a different enzyme to a SYBR Green Master Mix?

I followed the standard SYBR Green Protocol for doing a qPCR. For which I used 10 uL of 1X SYBR Green Master Mix Forward Primer and Reverse Primer (each at a final conc. = 8.5 uM) Template (unknown ...
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1answer
133 views

Barr body. How does it work? [duplicate]

Barr's body is a spiral X chromosome. If I'm not mistaken, one random chromosome (a healthy woman) is inactivated in each cell. Which X chromosome is inactivated in a given cell is random. I've heard ...
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3answers
211 views

Knockout and knockdown of gene

Out of curiosity, I got this question whether knocking out (deletion) of a gene on one side and knocking down (RNAi) of the same gene on the other side will affect the cell in a similar manner or not. ...
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4answers
8k views

What is the longest-lasting protein in a human body?

Protein life times are, on average, not particularly long, on a human life timescale. I was wondering, how old is the oldest protein in a human body? Just to clarify, I mean in terms of seconds/...
10
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1answer
337 views

Why don't the heads of phospholipid bilayers repel hydrophobic molecules?

What I Think I Know: Hydrophilic and hydrophobic things repel each other. Since the cell membrane contains hydrophobic tails, it is difficult for hydrophilic molecules to pass through the cell ...
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2answers
238 views

Are redundant codons used in translation?

I am learning about redundancy in genetics and I came across this statement in my textbook: more than one codon for an amino acid means that some codons are redundant - the process of protein ...
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2answers
380 views

How do I calulcate the amount of concentrated stock solution to add to get the correct dilution?

For example, how much loading buffer (6X) do I need for my PCR reaction with a volume of 25 μl? What is the general way to calculate it?
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3answers
784 views

Why did scientists think humans had 100,000 genes (before the Human Genome Project)?

One of the major results of the Human Genome Project (HGP) was that humans have far fewer separate genes than previously thought. From a 2004 article about the HGP: Francis S. Collins, director of ...
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2answers
64 views

Name of dsRNA (or dsDNA) where all strands are identical

What is the name of dsRNA (or DNA) where all component strands are identical (i.e. where the complex consists of multiple copies of the same ssRNA)? Example: 2 identical ssRNAs forming a dsRNA ...
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2answers
390 views

Are codons that map to the same amino acids interchangeable?

From wikipedia, in the section on the RNA codon table, I see a mapping between codons and amino acids. There, Valine is related to GUU, GUA, GUG, GUC. Does it mean in the same context that these ...
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2answers
344 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 ...
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1answer
60 views

What would “N” and “V” stand for in DNA barcoding?

I'm currently looking protocol for PAT-seq, and when it talks about the barcoding that's utilized, the documentation mentions there being an "N" and "NN" in the sequence, as well as a "V". For example:...
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3answers
94 views

Biological validation of computationally determined gene-gene interaction

How can a computationally determined three-way gene interaction be biologically validated? What kind of assays or tests must be performed using cell/tissue-based and/or mouse models to prove that the ...
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1answer
181 views

What is trans-complementation?

Is trans-complementation a complementation of transgenes? The crystal structure reveals a trans-complementation mechanism whereby an incomplete immunoglobulin-like domain assimilates an isoform-...
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1answer
210 views

How did genome duplication in jawed vertebrates allow gene specialization?

I am currently reading from Chapter 15 in Principles of Life, 2nd Edition: Many gene duplications affect only one or a few genes at a time, but in some cases entire genomes may be duplicated. When ...
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0answers
29 views

How does Ran GDP get from the cytoplasm back to the nucleus following nuclear import and export?

I understand that in Ran-dependent nuclear import Ran GTP binds importin in the nucleus, and after diffusing through the nuclear pore complex Ran GTP is hydrolyzed to Ran GDP and releases importin. ...
4
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1answer
507 views

Enzyme Inhibition in relation to Aspirin

I see that aspirin (in part) works by inhibiting cycloxygenase isoenzymes and that this inhibiting is irreversible. I've had a few classes mentioning this topic in passing, but never with depth. I ...
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2answers
4k views

Is tyrosine hydrophobic or hydrophilic?

I’ve seen tyrosine classified as a hydrophobic amino acid due to its aromatic ring in some textbooks and as hydrophilic due to its hydroxyl group in other textbooks. How does tyrosine actually ...
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1answer
169 views

Hydrophobic interactions in the helix-turn-helix

This slide states that the second helix works to stablize the configuration of the two helixes via hydrophobic interactions. What exactly is this hydrophobic interaction? In other words, what ...
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3answers
95 views

You need DNA to make RNA, and RNA to make DNA, so they had to come into existence at the same time?

A statement I recently read: 'Evolution is debunked and gives no basis for morality. Natural Selection throws away info, it does not add. You need DNA to make RNA, and RNA to make DNA, so they had to ...
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1answer
79 views

Protein electrophoresis

Three proteins A, B and C of equal molecular weight are being investigated in a study. They contain six, four and four cysteine residues respectively. Only Proteins A and B were treated with β-...
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3answers
21k views

Why does replication require primers while transcription does not?

In transcription, there is no need for any primer. I guess the basic mechanism of DNA polymerase & RNA polymerase is the same. So why does replication have the need for a primer?
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1answer
241 views

What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I ...
4
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1answer
10k views

Manual Primer Design for a gene on the reverse strand

My question might sound very naive and stupid but I am hopeless now. I read so many websites and pages but could not figure out this PCR primer design thing completely. Some genes are on the reverse ...
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2answers
854 views

What makes/breaks the hydrogen bonds between DNA and RNA during transcription?

So I know that RNA polymerase catalyzes the phosphodiester bonds that hold the sugar backbones of a growing mRNA molecule together during transcription. However, I'm less sure about the hydrogen bonds ...
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0answers
36 views

Does every protein encoding gene necessarily have a transcription factor?

For instance, transcription factor gene A is responsible for activating gene B that encodes protein 1. However, it is possible for genes like gene B to encode proteins without having transcription ...
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2answers
6k views

How does translational coupling work in prokaryotes?

Today I heard about a phenomenon called "translational coupling", where the translation of one protein influences the translation of another protein. The messenger RNA levels don't seem influenced. ...
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1answer
83 views

Does the deletion of Chromosome 20 cause immunity against prion disease?

I was reading recently about prion disease and it caught my attention that a normal prion protein is coded n chromosome 20, therefore, in order for an infectious prion protein to attack, there must be ...