4
votes
2answers
60 views

Questions on DNA damage

I'm not strong in biology, so bear with me on this: I've been reading that as we age, our DNA is damaged by internal (e.g. errors during replication) and external (e.g. sun damage or radiation) ...
2
votes
1answer
43 views

How did bullying arise evolutionarily?

By bullying, I mean individuals harassing others with name-calling or violence but not for the purpose of gaining resources such as with extortion or theft. The only explanation I've thought of is ...
8
votes
1answer
70 views

What sample sizes are ideal for carrying out Bayesian Skyline Plots?

I am interested in creating Bayesian Skyline Plots to look at demographic changes in certain population groups. However, these populations have very little within population variation. Around 5 ...
3
votes
0answers
26 views

Help with STRING database data

I'm working with data downloaded from STRING database (string-db.org) for protein-protein interactions. My idea is to compare the topology of connections of the same protein on different organisms. ...
5
votes
2answers
31 views

What happens during kefir fermentation process?

I’ve found many sources about the positive effects of kefir for the digestive system. However I haven’t found any information about the fermenting process. What is the exact biology (chemistry?) ...
9
votes
2answers
219 views

What is the explanation for the smaller number of tRNA than codons?

Translation, or decoding, of the four-nucleotide language of DNA and mRNA into the 20–amino acid language of proteins requires tRNAs and enzymes called aminoacyl-tRNA synthetases. To ...
4
votes
1answer
191 views

Why is E.coli used as a model?

Is there a reason for the choice of E.coli as a model for many bacterial systems? Other bacteria such as B.subtilis are also used, but why is E. coli preferred?
1
vote
1answer
21 views

How to correlate the pattern by which CAP activator from E.coli binds to DNA and its mechanism of action?

The catabolite activator protein (CAP) activates the expression of more than 100 genes involved in secondary sugar metabolism in E.coli. Apparently, it always binds in sites that are away from -10 and ...
2
votes
1answer
32 views

What causes the line patterns in the palm of the hand?

The line patterns on the hand are unique to each individual, but what causes these lines and re they advantageous in anyway?
3
votes
2answers
199 views

Is there a specific mechanism for the delivery of pain medication?

For example, when one takes aspirin or ibuprofen does the chemical get dispersed to all pain receptor? My question really is, how does the chemical know where to target in the body? I figure wherever ...
4
votes
1answer
72 views

Is there a DNA analogue to ribozymes? [duplicate]

If not, is it impossible for DNA to have enzymatic activity?
0
votes
1answer
17 views

How long the homologous arms of the “repair” sequence must be to do homologous recombination? [duplicate]

I am trying to figure out the details of the homolougous recombination in order to be able to insert a certain piece of DNA in the host genome after double strand break.. Does anybody know how long ...
3
votes
1answer
94 views

How would you affect bulk DNA gene therapy for a human?

Let's imagine that we understood DNA programming and our genome very well and realized that there were some significant flaws (we die, we need sleep, etc.) And let's imagine that we understand how to ...
6
votes
3answers
44 views

Mechanism by which $lacI^{d}$ is a dominant mutation, impairing the function of normal copies of the Lac Repressor

Jacob-Monod model for the lac Operon was based on experiments using two strands of bacteria which constitutively expressed $\beta$-gal: $I^{c}$(mutation in the gene lacI , which encodes the repressor) ...
0
votes
1answer
46 views

Incubation time of Antarctic Phosphatase in lab [closed]

Antarctic Phosphatase is used to catalyze the removal of 5' phosphate from DNA. If I'm using it in the lab on a sample of 1-5 micrograms of digested DNA, how would I figure out how long to incubate ...
5
votes
1answer
48 views

Is consuming proteins different vs. consuming amino-acids and how?

Yesterday I had a discussion with a friend. He said that consuming proteins and amino-acids is different. He said that those who grow muscles would agree on that. I wanted to argue against that ...
2
votes
0answers
19 views

Atelectesis due to decresed surfactant in lungs

Surfactant is a protein lipid mixture produced by alveolar pneumocytes composed of Dipalmitoyl Phosphatidly Choline lipid,apoproteins and calcium ions. This surface lines the alveolar epithelium ...
7
votes
2answers
50 views

What triggers the migration of robins?

I live in central Massachusetts, and have begun seeing robins, as we generally do in early March. The temperature is well below normal, though, and three feet of snow are covering the still-frozen ...
4
votes
2answers
129 views

What is the IC50 exactly?

I am reading the paper "Activity of the bcr-abl kinase inhibitor PD180970" but I don't understand how IC50 works on table 1. Can you tell with simple words and give me an easy example?
0
votes
0answers
16 views

Why is acid alcohol used as a decorizer in the acid fast stain procedure, as opposed to a neutral alcohol?

Is it to neutralize the negative components of the cell membrane, thus preventing the positively charged dye from adhering to the cell membrane?
9
votes
1answer
81 views

RNA migrating slower than DNA on Formaldehyde Gel?

So I ran into an interesting problem. I'm getting a linear DNA band that is twice as long (4x bases, but as denatured probably only 2x) as an RNA band running at the same size in a formaldehyde gel. ...
1
vote
0answers
18 views

Why do contrasts during CT scans make the body feel warm? [closed]

Why do the contrasts used during CT scans make the body feel hot/warm? I think they use iodine, so why would the bodies response to iodine be a warm sensation? In addition, I think they make one's ...
3
votes
1answer
30 views

Why is knowledge of bacterial pathogenesis important? [closed]

Why is knowledge of pathogenesis increased more and more for common bacterial pathogens? Most of these studies lack a near application in disease control such as vaccines or antibiotics. Examples: ...
2
votes
1answer
43 views

Is it possible to insert DNA without cutting the recognition site with CRISPR/Cas9?

We are looking for a way to insert DNA into a genome, but we would like to do it in a way that the recognition site stay intact to be able to add again DNA at the same location. Do you know if it is ...
5
votes
1answer
72 views

Doubt on genomic code for nucleosome positioning?

I was reading "A genomic code for nucleosome positioning" (by Eran Segal et al). And I am having 2 doubts. The figure(b) in this image from the paper shows the graph of fraction (3-bp moving ...
4
votes
1answer
42 views

DNA sequencing problem

First off, let me start by outlining the problem: Your laboratory has established a technique for examining DNA replication in a cellular extract. To the cellular protein extract, you add ...
5
votes
1answer
99 views

Can human mRNA be translated in vitro by prokaryotes?

As the genetic code is universal, can mRNA from a human cell be correctly translated by a prokaryote in a in vitro translation system?
1
vote
1answer
49 views

How does alternative splicing work?

I am trying to find out what controls what exons are spliced out, and I keep coming across the term cis regulator, but I cannot seem to find a clear explanation of what happens... Thank you in ...
0
votes
1answer
46 views

What are microRNA, siRNA and antisense RNA?

From what I understand, microRNA binds to proteins which can cut certain mRNA strands do that this protein is not synthesised. This seems like gene silencing to me, however I have also come across the ...
1
vote
1answer
17 views

RNA-Polymerase III transcribed genes

I have a list of differentially regulated genes from a high-throughput experiment of the human genome. I would like to find out which of these genes are transcribed by a RNA polymerase III and which ...
3
votes
2answers
101 views

What's a protein pulldown assay?

I'm reading a paper and the authors mention a "protein pulldown" assay. I've never done this before, and googling doesn't bring up much. Could I get a rundown of the basic theory behind it? Also ...
1
vote
1answer
21 views

What are the roles of cadherins in epithelial mesenchymal transitions? [closed]

I know that cadherins control the expression of cancer cells involved in the epithelial-mesenchymal transitions, but I was wondering exactly how the process worked.
2
votes
1answer
32 views

Relationship between leaf structure and Photosynthesis rate

We can see numerous leaf structures in plant kingdom. As the leaves are designed for photosynthesis, their structure must be a factor for any optimization in photosynthesis or chlorophyll ...
3
votes
1answer
65 views

Nomenclature of genes and proteins

With respect to this paper: Identification of Host Proteins Required for HIV Infection Through a Functional Genomic Screen In the abstract, I found names such as Rab6 and Vps35 and TNPO3. So Rab6 ...
1
vote
1answer
20 views

Introducing novel genes to an adult multicellular organism?

Is it possible to introduce a novel gene into the genome of every cell (or at least most cells) of an adult multicellular organism? How would this be done? Thanks, CDB
0
votes
1answer
19 views

What, if any, diseases do larder beetles carry?

I found one of these beetles on my bed as I was attempting to get in. I'm 80% sure my cat carried it in (I found it in the exact same space he had been sitting ten minutes previously). My question is ...
2
votes
1answer
28 views

Can anyone identify this mystery caterpillar?

I found this caterpillar in in El Cerrito, CA and was wondering what kind it is?
1
vote
1answer
34 views

Enzyme\Protein amounts in cancer

I am searching for source, that providing information about enzymes\proteins, in different types of cancers, that their amount in cell is significantly higher - comparing to normal, healthy cell. ...
6
votes
1answer
76 views

Why are there no known photosynthetic archaea?

I'm taking a microbial physiology course and we noted that, while some archaea are phototrophic, there are no known photosynethetic archaea. Are there any physiological characteristics that make ...
2
votes
2answers
38 views

Is it possible to train allergic resistance by exposing yourself to allergens?

My hypothesis is that one can decrease the allergic reactions over time by continuously exposing yourself to slowly increasing doses of allergens. Is there any scientific evidence pointing this right ...
20
votes
2answers
3k views

Do all organisms have to die?

I understand (a little) that there are biological clocks and reason that after a certain amount of time organisms die. I'm wondering if that is something inherent in our DNA or in biology/chemistry in ...
0
votes
0answers
7 views

What is the control level of activation in Paradigm?

I am trying to use Paradigm for pathway analysis on mRNA expression data. In Sample-Specific Cancer Pathway Analysis Using PARADIGM it is written that Each entity can take on one of three ...
2
votes
1answer
30 views

Is Norway spruce (Picea abies (L.) Karst.) isohydric or anisohydric species?

Question from a thesis defense list ask me this. But I can't find the exact answer on the internet or in books. In my thesis, I described isohydric plants, for example maize, lupin, pea, poplar. This ...
6
votes
1answer
110 views

Are gene variants at different loci also called alleles?

I think the title says it. I always read that alleles are gene variants at a given locus, which confuses me. Thanks!
2
votes
1answer
32 views

Monochromator in fluorescence microscopy [closed]

I'd like to ask why are there no fluorescence microscopes that use a monochromator instead of filters? If there are any, then I should change my question as, which ones use it and why are they so ...
1
vote
1answer
46 views

What is the minimum functional biological light sensor? [closed]

As a follow up to this question regarding the evolution of the eye, it was suggested that primitive eyes only needed to evolve a light sensor and could perhaps use the existing biochemical cascade ...
2
votes
0answers
23 views

Is it possible to isolate and analyse intermediates of protein folding?

I would like to know if there is an assay which could allow us to analyse a protein before it has assumed its 3D functional form. While studying structural biology, I only came to know the forces that ...
6
votes
1answer
56 views

Why do some bacteria have most genes on the leading strand of the genome?

Genes in the (+) strand are black and genes in the (-)strand are red. The gene distribution in E. coli genome is somewhat expected: transcribed regions would tend to alternate with non transcribed ...
0
votes
1answer
52 views

Why do insects avoid being on their back?

I have noticed that when insects are placed on their backs, they tend to turn themselves over quickly or else appear to be in distress. Is there a physiologic, anatomic, or adaptive reason why supine ...
1
vote
0answers
31 views

Why do restriction-modification systems work?

Some RM systems (restriction-modification systems) are plasmid-borne and are transferred through bacterial conjugation. As you all know, there are two genes in an RM system, the gene that codes for ...

15 30 50 per page