Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

262 questions with no upvoted or accepted answers
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9
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0answers
291 views

What is the half-life of dNTPs at 95⁰C?

I'm looking for the half-life of dNTPs, either as a whole or broken into individual bases, at 95 degrees C (or similar). A titration would be great if that exists. I can provide more specifics if need ...
8
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2answers
702 views

How does LCR compare to Assembly PCR

The question pretty much explains itself. How do the two methods compare? I've always used Assembly PCR but the method is prone to mistakes and I'm curious how it compares to Ligase Chain Reaction (...
7
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1answer
226 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 ...
5
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1answer
78 views

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 ...
4
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0answers
34 views

What phosphorylates tau protein & and what causes tau to be phosphorylated?

I want to know what phosphorylates tau protein and its 6 isoforms. I know kinases cause phosphorylation events, and in tau it can be phosphorylated in a healthy neuron in the trans conformation, but ...
4
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0answers
37 views

Can sperm cells penetrate the cell membrane of non-ovum cells?

Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell ...
4
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2answers
107 views

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?...
4
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0answers
2k views

How much salt [NaCl] is too much in DNA precipitation?

In DNA extractions, how much is too much salt in a CTAB extraction buffer? Protocols hover around 2.5 molar; if you go over this (e.g. 25 molar), will you saturate your solution, and precipitate the ...
3
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0answers
37 views

Why are Barr Bodies usually seen along the edge of the nucleus under the light microscope?

We do a typical class exercise of aceto-orsein staining of buccal epithelial cells from female students to visualize Barr bodies under the light microscope. All the illustrations and pictures in the ...
3
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53 views

Is there recent info about the hypothetical ancient two-codon genetic code?

Here is the latest I have found. link This is the basic idea: Evolution does not look ahead and make plans. It would not create a system of mRNA with giant ribosomes to create proteins, until ...
3
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0answers
49 views

Antibody staining

I am staining tissue sections and I did a mistake, I was supposed to have mixed 3 primary antibodies but I stained only with one of them. After the 1h incubation I washed 10 min with PBS and then I ...
3
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0answers
70 views

Proteins folds: relation to splicing and post-translational modification?

Is the secondary structure pattern of protein folds related in any way to alternative splicing and post-translational modification?
3
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0answers
82 views

What's the ratio of saturated to unsaturated fatty acids in human cell membrane?

It's well established that the fluidity of a cell is largely dependent upon the ratio of saturated to unsaturated fatty acids that exist within the membrane, but, what exactly are the values for this ...
3
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0answers
54 views

Why do I see so many kinetochores?

I am analysing RPE-1 cells from humans and I do not understand why I see so many kinetochores by immunofluorescence (more than 100 in many cells). They are in prometaphase.
3
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0answers
72 views

Regulation of the concentration of precursors of DNA and RNA synthesis

What is the specific cellular process for regulating the amount of the four DNA bases (adenine, thymine, cytosine, and guanine) that are present in the cytoplasm of a cell? Basically, how do the cell'...
3
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0answers
91 views

Travelling with tissue samples in RNAlater

I've been in Brazil collecting some samples (ants) and need to travel back to to the UK with - I've got their brains stored in RNAlater, which have been in the freezer at -4C for a bit less than a ...
3
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0answers
169 views

Why does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
3
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0answers
135 views

Artificial reduction of NADP into NADPH by means of an electrical current

I've recently been attempting to artificially drive the formation of NADPH via the NADP reduction mechanism utilized by Ferredoxin-NADP Reductase in the Light-Dependent Reactions of Photosynthesis in ...
3
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0answers
476 views

L-tryptophan in mammalian cell culture

Why must the concentration of L-tryptophan be kept to a relatively low level when culturing mammalian cells? It's an essential amino acid, so I cannot fathom why low concentrations as opposed to ...
3
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0answers
77 views

What Chemical Trigger Causes Ectomycorrhiza To Change From Asexual To Sexual?

I want to know the trigger behind the change of asexual to sexual ectomycorrhiza when symbiosis with a tree root is formed. As ectomycorrhiza attaches itself to a root, it forms a relationship wherein ...
3
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0answers
813 views

Can I leave BL21(DE3) cells in room temperature?

I am preparing competent cells, and I finished inoculating a single colony in SOB. It has been incubating at 37 degrees Celsius for almost 16 hours since, and it's getting very late where I live. I ...
3
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0answers
48 views

Does blood typing still provide a use for ancient tissue analysis?

Modern techniques. In recent years, DNA sequencing has become extremely cheap. This, compounded by the ability to PCR miniscule samples to viable samples for analysis, means that aDNA can be ...
3
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272 views

How does estrogen influence collagen synthesis?

Through what mechanisms does estrogen interact with collagen synthesis? Especially in the context of elevated estrogen levels and genesis of purpura simplex .
3
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0answers
538 views

How to prevent e coli from clumping (for FACS)?

I'm performing FACS on e coli, but the cells are clumping together so each event is multiple cells. I ran a control where I had one flask of e coli expressing GFP, and one flask expressing RFP. Run ...
3
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0answers
258 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, ...
3
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0answers
50 views

Adenosine metabolism

Are adenosine or its catabolites increased in inflamed airways? How can I assess this? I am trying to use inhibitors for adenosine deaminase, xanthine oxidase, and purine nucleoside phosphorylase, but ...
2
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0answers
38 views

Is there other unknown-compound in Blood?

Blood is made of red blood cells, platelets, plasma etc. Let's say, then, there are these $x$ known compounds in blood. But how can one be sure that there is no other compound other than those $x$ ...
2
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0answers
51 views

What regulates cyclic AMP?

After reading a textbook chapter on GPCRs I am still confused by what regulates cAMP. I took in my notes that cAMP is made by adenylyl cyclase and destroyed by cAMP phosphodiesterases (also another ...
2
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0answers
18 views

Using expression vector to express arsenite oxidase genes in E. coli

So I am trying to express a gene cluster that can oxidize arsenite into arsenite autotrophically. The arsenite oxidase gene cluster sequence is linked here: https://www.ncbi.nlm.nih.gov/nuccore/...
2
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1answer
53 views

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 ...
2
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0answers
65 views

Why does M1 RNA together with C5 protein in 100mM Mg(II) fail to cleave tRNA?

Sidney Altman discovered that RNA moeity of RNAse P (M1 RNA) alone is able to perform enzymatic cleavage of ptRNA, which won him the Nobel Prize of Chemistry in 1989. However, when I read the Nobel ...
2
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0answers
77 views

How do molecular biologists determine biochemical pathways?

I'm new to this community, so hopefully this is the right place to ask this question. I know my question is really general, but in all of my biology courses we are merely taught the chemical pathways ...
2
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0answers
57 views

Molecular Docking Enzyme Inhibitor Biosensor?

I had some task to study Molecular Docking relations with Biosensor and I am really new with this discipline (beginner). I am docking C60 with Glucose Oxidase and my question is: what would happen if ...
2
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0answers
37 views

how can I get stronger staining for my lymph node sections

I am using the same protocol and same antibodies that the literature says but still I cannot get good staining for my lymph node sections, I tried to change the fixation method and I am using now ...
2
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0answers
53 views

Sucrose inhibit onion root mitosis? Why?

I am doing an experiment about onion root growing. I had put an onion in different solutions of $C_{11} H_{22} O_1$ in H2O —with the root touching the water—: 0,1M; 0,2M; 0,3M; 0,4M; 0,5M. The ...
2
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0answers
85 views

Would I expect salt precipitate on fibres of DNA in a NaCl water solution?

I just recently conducted an experiment in my biochemistry class where we had to add DNA to distilled water, isotonic saline and 2.5M NaCl. I noticed different physical aspects depending on the ...
2
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0answers
218 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 ...
2
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105 views

Can a phosphodiester bond form between RNA and DNA?

In the initiation of DNA synthesis: the RNA segments are first synthesized by primase and then elongated by DNA polymerase (Wikipedia). What does 'elongated' mean in this context? Is it possible ...
2
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0answers
248 views

Why difference in degree of folding in a cell?

For a cell to maintain constant volume, input should be equal to output of substances. My question is, if the basolateral membrane, by less folding can attain the same rate of transport as of the ...
2
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0answers
42 views

What's the best source characterizing proteolysis cleavage sites in the phagolysosome?

I have found MEROPS and TopFIND via the survey paper Quantitative proteomics and terminomics to elucidate the role of ubiquitination and proteolysis in adaptive immunity. These look like a good start, ...
2
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0answers
35 views

Nucleic acid extractions

Is it fine to leave pulverized plant tissue in CTAB buffer at -80 degrees over night? will the buffer remain effective to generate good quality nucleic acids?
2
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0answers
70 views

Basic molecular biology of nucleic acids book for a mathematician studying DNA and RNA formally?

I am a mathematician studying DNA and RNA language from the perspective of Formal Language Theory. Note that I am aware of these posts: best book for a comprehensive introduction to biology for a ...
2
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0answers
25 views

How does DNA damage increase the activity of p53?

I understand the steps leading up to the halting of the S-cdK checkpoint from there, but I can't find the mechanism by which DNA damage actually increases the activity of p53.
2
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25 views

Does Pre replication complex sit on both strands?

In case of prokaryotes, the ori site have a definite nucleotide sequence. Each ori site have 5 9base-pair consensus sequences and 4 non-consensus sequences. DNAa binds to both types of sequences with ...
2
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0answers
1k views

What is the structure of DNA polymerase III?

According to Snustard and Simmons the structure of DNA polymerase III is the following, where the clamp loader( γ -δ complex ) is present on one side: But according to Lehninger the clamp loader is ...
2
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0answers
64 views

Where am I going wrong in a Reactive Oxygen Species Assay done in N9 cells?

I have followed the modified protocol that was given to me by my senior (who was using for his RAW 264.7 cells - Reference article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308605/ ) for ...
2
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0answers
886 views

What´s the role or function of the homologous arms in a donor template in a knockout/knock edition via Crispr-cas9?

I have to make an exposition in my university about Crispr-cas9 edition and I have some questions about the method. In the knock out/knock in technique is used a plasmid containing the DNA that ...
2
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0answers
80 views

Can telomere length maintenance be an answer to increased life span of human beings?

Telomere shortening may prevent the development of cancer in human aged cells by limiting the number of cell divisions. However, shortening of telomeres impairs immune function and thus might also ...
2
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0answers
76 views

Do users of CRISPR/Cas iterate or parallelize to try multiple guide sequences?

I've read about on-target efficiency and off-target effects in use of CRISPR/Cas9, and about tools that suggest good guide sequences. I am wondering: how many guide sequences do typical CRISPR users ...
2
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0answers
29 views

How do the chemical components of these spices prevent fungal growth?

I am doing an EE on how spices affect fungal growth for the following spices - oregano, garlic, cinnamon, cumin and turmeric. Its been hard to find any sites that say why or how they affect fungal ...