Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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1answer
27 views

Photolysis in the Light Reactions of Photosynthesis

I'm a bit confused concerning photolysis. During the light reactions, photons are used to excite the chlorophyll molecules so they are passed to the primary electron acceptor. The electrons initially ...
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1answer
12 views

Trade-offs between phage and yeast displays?

If you wanted to test a peptide you designed, you can do a phage display or a yeast display experiment to assess binding affinity. What are the trade-offs between these two methods? I've heard ...
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2answers
476 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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1answer
50 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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1answer
21 views

Why does opening of the Ca-channels trigger the release of neurotransmitters?

I understand that the opening of the Calcium channels trigger the release of stored neurotransmitter in granules, but what is it about the flow of positive ions that makes the vesicles fuse with the ...
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0answers
19 views

Which of these enzymes is a better target for virtual screening?

I am a MSc student in Applied Biochemistry. For my Masters Thesis, I will be doing some research about finding new potent inhibitors for a specific enzyme of my choice using molecular docking (virtual ...
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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?...
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1answer
53 views

Approximate Cell Doubling Time?

If I know it takes 12 min to occur in mitotic fibroblast cells and I count there are 32 dividing cells in the microscope slide out of a total population of 32034 cells, how do I calculate the ...
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0answers
20 views

Parthenogenesis vs. Fertilization. Is a polar body different from an egg?

In Parthenogenesis that happens by automixis "the replication of an egg by meiosis and the transformation of the haploid egg to a diploid cell occur by fusion with a polar body." =https://www....
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1answer
124 views

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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1answer
17 views

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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1answer
26 views

Is p53 a cyclin dependent kinase? [closed]

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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1answer
39 views

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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26 views

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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2answers
4k views

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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1answer
69 views

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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2answers
142 views

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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3answers
129 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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0answers
47 views

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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0answers
46 views

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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1answer
39 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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1answer
54 views

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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0answers
22 views

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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0answers
52 views

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
999 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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1answer
59 views

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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2answers
2k views

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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1answer
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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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9 views

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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1answer
46 views

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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0answers
17 views

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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0answers
26 views

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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0answers
13 views

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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17 views

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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7answers
5k views

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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3answers
3k views

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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0answers
15 views

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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1answer
26 views

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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1answer
300 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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1answer
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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4answers
92 views

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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1answer
80 views

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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1answer
54 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 ...
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2answers
3k views

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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1answer
61 views

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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1answer
19 views

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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55 views

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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3answers
10k views

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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1answer
97k views

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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1answer
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 ...