Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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3
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1answer
27 views

Bimodal frequency distribution of size of protein loops

The graph of number of amino acid (AA) residues in a loop Vs the frequency of their occurrence in proteins largely follows a tending-to-zero pattern. However, there appear to be some specific number ...
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1answer
19 views

Selection marker working at low expression levels

I need to express a selection marker on a plasmid in human cells (e.g. HEK293) but because of the technical constraints of my experiments, I know that the expression level of any protein marker will ...
0
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1answer
64 views

Is the lac operon repressed in the presence of both glucose and lactose?

In the presence of both sugars (glucose and lactose) will there be repression of the lac operon completely? I know that more glucose means less cAMP --> less CAP --> less positive regulation, and ...
0
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1answer
32 views

What is the difference between Molecular and Cellular tolerance?

Although I've read that there are three types of tolerance, molecular cellular and behavioural, I cannot seem to find any mechanism of cellular other than desensitization of receptors. If someone can ...
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0answers
30 views

How to animate biological processes for an online video course on high-school biology [closed]

I want to state beforehand, that I was unsure if this was the most appropriate community to post on. Therefore, kindly recommend a more appropriate community, if there is one. I will then either cross-...
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0answers
17 views

Does a low yield of RNA effect the results of subsequent experiments?

I am extracting RNA from brain tissue and I am getting a concentration of 500 ng/µL when measured with a nanodrop. I dilute the pellet in 20 µL of water. When my colleague does the same protocol ...
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0answers
23 views

What happens when we mix diifrent types of restriction enzymes

Let's say we mix different types of restriction enzymes: one that gives a sticky end and one that gives a blunt end and I insert them in a plasmid. Will I get any results at all?
2
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2answers
2k views

Why we need an egg cell donor and a surrogate mother in an organism cloning process?

Could a whole set of artificial organism-cloning process only be operated on the somatic nuclear donor ,which means for example ,can we extract the somatic nuclear from animal "A" and put it into the ...
2
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1answer
28 views

How do enhancers induce transcription?

DNA response elements are DNA sequences that are could be found upstream, downstream of genes that regulate gene expression at the transcriptional level. One type -Enhancers- bind specific ...
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1answer
21 views

what happens to rna length if we have a termination site in additional to the original one

if we have an RNA transcription and we add an additonal temination site in the middle , will i have two RNA molecules or just a short one ?
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1answer
56 views

How to design the primer when you don't have GC?

I have treated my RNA with sodium bisulfite so all my cytosine is converted into thymine. Then I used that RNA for my RT reaction. I have a cDNA template without Cs. Now I am trying to amplify that ...
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0answers
21 views

How does a lymphocyte produce an antibody from an antigen?

I am studying the immune system, and I have a question about the inner workings of antibody production in lymphocytes. As I understand it now, lymphocytes are able to create antibodies based on ...
3
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1answer
62 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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1answer
70 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
23 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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0answers
33 views

Where do methyl groups in the human body come from?

Where do methyl groups in the human body or other mammals come from? Do we synthesize them (where?) Do we get them from our diets (in what? anything beside methionine?) Do our gut microbes produce ...
1
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1answer
44 views

what is the princlple of using DMS (Dimethylsulphate) for structural analysis of rRNA?

I want to check the secondary structure of rRNA (PTC) in a particular position by using DMS footprinting. I have deleted the modified nucleotide (m5c) which is present in the PTC and it helps in the ...
7
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1answer
232 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 ...
32
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3answers
52k views

Why is ATP the preferred choice for energy carriers?

Why is ATP the most prevalent form of chemical energy storage and utilization in most cells?
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0answers
10 views

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)?

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)? The vaping illnesses that have been happening on the news in the United States are being caused by the federal ...
0
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1answer
33 views

Photolysis in the Light Reactions of Photosynthesis [duplicate]

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 ...
0
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1answer
15 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 ...
2
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2answers
498 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 ...
0
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1answer
52 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 ...
0
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1answer
24 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 ...
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?...
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1answer
54 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
23 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
141 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 ...
1
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1answer
19 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
32 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 ...
0
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1answer
40 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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0answers
28 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 ...
7
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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
77 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?
4
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2answers
157 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
144 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
49 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 ...
0
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1answer
42 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??...
2
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1answer
55 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
53 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. ...
2
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3answers
1k 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 ...
1
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1answer
62 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 ...
7
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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?
5
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1answer
83 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 ...
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0answers
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 ...
1
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1answer
58 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
18 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 ...