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 ...
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 ...
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 ...
10
votes
2answers
402 views

Are all mutagens carcinogens?

Not all carcinogens are mutagens. Alcohol and estrogen, for example, does not damage DNA. It's one of the assumptions of the Ames test that mutagenicity implies carcinogenicity, but is this always ...
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
0answers
18 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 ...
4
votes
2answers
126 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?
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 ...
4
votes
1answer
38 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
48 views

(Why) are polar bears more common in Labrador than in southern Greenland?

The Labrador Sea is between Greenland, Labrador, and Qikiqtaaluk: Map source. A Greenlandic source on polar bears states: In Greenland the polar bear lives and breeds in the northernmost parts ...
2
votes
1answer
30 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 ...
1
vote
1answer
48 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
44 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 ...
6
votes
1answer
107 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!
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
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 ...
0
votes
1answer
51 views

What factors affect the likelihood of auditory stimuli causing arousal during sleep?

I've noticed that the sound of water drops makes me wake up from sleep but other more strong sounds don't make me wake up. I can't find anything about this. The only reason I can think of is maybe ...
8
votes
1answer
76 views

How long can Cholera bacteria survive in a dead host?

How long can cholera bacterium survive inside a dead host? Can they remain dormant in such conditions? BACKGROUND On a hill not far from where I live, there was a hospital operating since 16th until ...
3
votes
2answers
96 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
20 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.
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. ...
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
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
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 ...
6
votes
4answers
443 views

What is the viability of Intelligent Design as a supplement to chemical abiogenesis and Darwinian Evolution?

First of all I am not endorsing Intelligent Design (Wikipedia link); I'm asking this because I (someone who does not have a background in biology, organic chemistry, or philosophy) got into a ...
0
votes
1answer
17 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
0answers
109 views

White/Gold vs Blue/Black dress

So I'm sure you've all seen the dress photo where people see the dress as either White and Gold or Blue and Black. It has essentially 'split' the internet because some people see the dress and they ...
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?
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
0answers
14 views

Possible to remove accumulated haze on fluorescence interference filters?

I have a few different fluorescent microscopes, the two that use Mercury lamps are older than 7 years. I notice on those that the thin film filters in the filter cubes (green, red, blue) have ...
2
votes
2answers
36 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 ...
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
17 views

Which data format for mRNA expression matrix is necessary to run pathway analysis with Paradigm?

I am running Paradigm on a matrix of mRNA expression. I read Vaske, Charles J., et al. "Inference of patient-specific pathway activities from multi-dimensional cancer genomics data using ...
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 ...
4
votes
1answer
70 views

Help needed in fish identification

Please help me identify these fish. I looked around but wasn't able to determine its species.
1
vote
1answer
44 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 ...
6
votes
4answers
61 views

Enzymatic error rate

I am aware that each enzyme generate a certain amount of misproducts. This is well documented, for example, for the DNA polymerase. I am interested in enzyme involved in biochemical processes, so for ...
6
votes
2answers
128 views

Reasons why living fossils exist?

A living fossil is a living species (or clade) that appears to be similar to another species otherwise known only from fossils, typically with no close living relatives. A living fossil is ...
5
votes
1answer
67 views

Do people that don't feel pain shiver in the cold?

There are a few diseases that cause an insensitivity to pain. This question asks about the relationship between the cold and pain, which got me thinking: Is shivering a response driven by the ...
2
votes
2answers
25 views

enhancers in cell-type-specific signatures

I was reading an article in nature : Epigenomics: Roadmap for regulation and was confused by the definition or/and interpretation of enhancers. Enhancers are activated through interactions with ...
3
votes
1answer
58 views

Why does cucumber skin kill ants?

I recently read that cucumber skin is an effective repellent for some ants: Set out cucumber peels or slices in the kitchen or at the ants' point of entry. Many ants have a natural aversion to ...
1
vote
0answers
21 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 ...
1
vote
0answers
35 views

How do parrots stabilize their field of view without moving their necks while walking?

Based on my search online, I have found some theories which try to validate the activity of some birds (like pigeons) which involves moving their heads and neck while walking. These theories include - ...
5
votes
2answers
244 views

Effect of steroid hormone on specific cells?

As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why ...
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 ...
7
votes
2answers
64 views

Do other animals have different blood types?

Humans have the ABO and Rhesus blood typing systems. I have two questions about it: Why have we evolved these blood types? Do other animals have different blood types as well?
1
vote
0answers
70 views

Reason for different color perception in left/right eyes?

What could be the reason for a difference in color perception between the two eyes of an adult individual without any known eye conditions? In particular, a difference in the perceived color ...
9
votes
1answer
118 views

How big should the human population be, as predicted by body mass?

I would guess there is a theory in biology which states that the population size for a given species is inversely proportional to the body mass of individuals in that species. In other words, there ...
5
votes
2answers
76 views

The meaning of RNA-seq data

many papers I read mentioned "RNA-seq data". While searching for the meaning of this word, I could not find any layman's definition. As far as I understand, RNA-seq data is the complete RNA ...

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