10
votes
2answers
244 views

Why is venom more common in fish and snakes than other vertebrates?

Reading this question, I wondered why is it that we associate vertebrate venoms so often with snakes and fish, and more rarely with lizards, amphibians, mammals, and birds (apparently never, in ...
1
vote
2answers
51 views

Why will tissue from identical twin be rejected in some cases?

From Medline Plus : Also, transplants from one identical twin to another are almost never rejected. My question : Why can a tissue from an identical twin be rejected ?
0
votes
1answer
38 views

evolution and mutation of microrganisms against medicines?

I presume microorganisms would have very short life span and they would multiply more creating millions of their kind. Is it really a threat to consider when we use anibiotics and other stuff more ...
6
votes
1answer
68 views

How well supported is the hypothesis that aging is mainly caused by the number of mutations in tissues?

I heard the hypothesis, that the (main) reason of aging is the increasing number of mutations in body tissues. The higher the number of mutations is, the older tissue is. Is this true? And how well ...
2
votes
1answer
41 views

Cosmid genomic library, or genomic cosmid library?

Which usage is better for referring to a "cosmid library of genomic DNA fragments"?
1
vote
1answer
154 views

Plastid and mitochondria

I am not biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is difference between plastid, chloroplast and mitochondria? Are there any plant ...
3
votes
1answer
95 views

Activation Of Embryonic Genome

Embryonic gene activation is a process by which the embryo begins to transcribe its newly formed genome.As the embryonic gene activation occurs during early stages the paternal genome may not have any ...
1
vote
1answer
34 views

About a mechanical aid to the heart

I saw a news story a few years ago (I think) about a girl with a poor heart having a device implant that took over only some of the functioning of her heart ( I think they called it a piggy-back ...
1
vote
2answers
335 views

Blast a sequence against multiple databases

I would like to BLASTP a list of protein sequences in fasta format against multiple protein databases. Since I'm only interested in the first hit of each database, it is possible that BLAST result ...
1
vote
1answer
42 views

How do I tell whether a mass spectrum was made with ESI or MALDI?

I was working through a previous exam and came across the following question (with reference to the picture shown below): "What MS ionization method was employed (MALDI or ESI)?" I cannot seem ...
3
votes
2answers
141 views

Do RNA molecules bind each other?

I have a question, maybe a naive one. Let's assume that we isolated some RNA from a tissue. Do RNA molecules can bind each other if they have the complementary sequence? I know that some small RNA ...
14
votes
2answers
2k views

What causes REM atonia to be lost in sleepwalking?

I understand that in normal REM sleep the voluntary muscles are in effect paralysed in order to prevent an individual acting out their dreams. This paper indicates that there are likley to be ...
1
vote
0answers
21 views

Image formation

I have learnt that the brain provides a perception of image due to previous memory and experience. Then how does a blind person attain vision after cornea replacement?
1
vote
2answers
109 views

Modern alternatives of DNA footprinting

Since DNA footprinting is an old method I thought there may be some more recent and effective methods to identify a DNA sequence, do you know any of them?
5
votes
2answers
156 views

Viruses: Adaptation to a new host through repeated host jumps

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly ...
7
votes
2answers
245 views

Can oncogenesis happen without apoptosis pathway being affected?

Has there ever been incidences of one or more cancerous cells having all it's cell-death pathways and apoptosis mechanisms intact and functional?
6
votes
1answer
1k views

Why do Bee stings cause swelling?

Why is it that when a bee stings, a little area around it gets swelled? I think it is some sort of defense mechanism of the body. But how does it help?
0
votes
2answers
86 views

how does DNA and RNA work [closed]

How do the DNA modules tell the cell what to do?
1
vote
1answer
35 views

Standard curve for real time

When performing a standard curve for some new primers to test for fold change, is it necessary to run the standard curve? I mean, in case your experiment has several genotypes for the same ecotype ...
1
vote
2answers
179 views

How do you find pre-miRNAs from mature miRNA Blast output?

So in short, I did a blastn with standalone blast using all known miRNAs against the EST sequences in a genome (word length 7 and e-value 0.01). Now to confirm one of the next steps would be obtain ...
1
vote
1answer
84 views

Can Serous inflammation on pleura pulmonalis cause dry cough and runny nouse?

I am interested in the mechanism between the dry cough and runny nose (serous inflammation) here. I started to think how Acute respiratory viral infection is causing the dry cough. The serous ...
1
vote
1answer
2k views

What is the difference between vegetable and animal fats?

I often hear from many people saying to waiters - "Please, don't put oil to salad". They probably believe the fat from vegetables has the same impact on the weight as an "animal" fat (meat, eggs, ...
6
votes
2answers
287 views

introduction to Chip Seq

I hope this question is suitable for this site. I am concerned about the Chip experiment part so I think it should be okay. I am a Applied Math student starting to get into bioinformatics and so I've ...
4
votes
2answers
156 views

Does increased physical activity increase the rate of cell division?

Ever since learning that the shortening of telomeres is linked to aging I've tried to figure out what causes cells to divide, and if it's possible to slow down the rate of cell division through life ...
4
votes
1answer
253 views

what are the mechanics of sweating?

The causes of sweating aside, i.e. I'm not interested in which and how nerve signals are transmitted to sweat glands. But I would like to read a detailed account on what a sweat gland consists of, ...
7
votes
1answer
436 views

How can highly virulent but uncommon diseases (like ebola) maintain a stable equilibrium?

I'm wondering how can very uncommon diseases remain in a relatively stable equilibrium. For example, if it started to spread, the spread could accelerate and become an epidemic. However, if it doesn't ...
4
votes
1answer
119 views

Topology of closed circular DNA

Why are covalently closed circular plasmid DNAs naturally found in an underwound state ? Is it because this makes it easier for the DNA replication machinery to access and unwind DNA ? Or is it ...
-5
votes
2answers
109 views

Can a person be infected with HIV viruses without contacting them by person-related stuffs? [duplicate]

We know that a person can be infected with HIV viruses when he/she has sexual relationship with those having HIV viruses (and very, very, very rarely, urine/defecation-related transmission) - but I ...
0
votes
2answers
359 views

How to design an experiment with scent triggered memory recall in humans?

I've recently learned that scents can trigger memory recall in humans, and am thinking about setting up an experiment where I would attempt to induce memory recall through exposure to scents. In ...
15
votes
2answers
391 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
0
votes
1answer
87 views

Defining: Evolutionary (quantitative) Genetics and Population Genetics

How do we define the fields that are Evolutionary (quantitative) genetics and population genetics. What set these two fields apart? Can you try to provide definitions? To my intuitive understanding, ...
1
vote
1answer
44 views

conservation of C-peptide sequence in the guinea pig

Where can I compare the C-peptide sequence of guinea pig with human or mouse? I am also interested in finding whether the guinea pig has insulin 1 and 2 to know whether I could use an anti-C-peptide 1 ...
5
votes
2answers
266 views

How Sex Evolved ? and when?

As I know evolution comes bit by bit mutation by mutation How sex evolved which requires a major change in at least two individuals one to become male and one to become female ? When that happened ...
2
votes
1answer
66 views

Most human-like teratoma ever recorded?

I'm curious to learn about the most human teratoma ever recorded. By most human I mean the teratoma which most resembles the form of a human being. I suppose there are several criteria which would ...
4
votes
2answers
347 views

Can animals make their own unsaturated fatty acids?

I know that animals can't make poly-unsaturated fatty acids (PUFA) and so require them from dietary sources. For eg.Omega -3 and Omega 6 fatty acids. My questions : Can animals synthesize other ...
9
votes
1answer
139 views

Why do so many people have group O blood?

Please forgive me in case my question wouldn't make much sense. I was reading about ABO blood groups on Wikipedia, where I learnt that O is a recessive allele, and that it seems the A allele predates ...
1
vote
2answers
378 views

Were early human beings (about 100 - 200 K years ago) far more promiscuous than we are now?

I found that many friends of mine are quite easy in sexual relationship. Ex, I knew a lot of girls went to the night club & met a stranger & brought home to sleep with him even she had never ...
0
votes
1answer
780 views

Identifying internal structure of dissected prawn

Note: Some of the images might be disturbing. I have dissected prawn for the first time. Would like your help in identifying some structures . This is the dissection of the posterior part of the ...
2
votes
1answer
470 views

What is optical density in Lowry's protein estimation method?

I have a few questions: What is an OD value? Why do we use blank solution in Lowry's protein estimation method? If The OD of a protein is 0.01, what does it mean? Thanks in advance.
2
votes
1answer
58 views

About stem cells and Cancer

Do stem cells have an apoptosis mechanism and , if they do could this be used to repair the cell self-destruction pathways in a cancer cell?
3
votes
2answers
307 views

How are two species with similar phenotypes identified as different?

How are two species with similar phenotypes identified as different? Have two different individuals that were thought to be different species ever been determined to be from the same species ( or ...
1
vote
1answer
52 views

Any forms of pneumonia that can be caught?

I am aware of the fact that there are several different types of pneumonia. However, I am wondering if any of these types of pneumonia are contagious from person to person. Is this possible?
2
votes
1answer
111 views

How is a stem-cell induced to assimilate a knock-in DNA construct?

While looking at (daylight) color perception I came across a paper by Jeremy Nathans (et al., Proc. Nat. Acad. Sci., vol. 100 no. 20, 2003, full text here) in which he describes the creation of a ...
3
votes
1answer
24 views

Polarized epithelium and localization of ion channels

I'm trying to learn more about polarized epithelial cells of the gut. I am familiar with classic brush border transporters localized to the apical memebrane to facilitate nutrient absorption. I am ...
3
votes
1answer
96 views

How compatible are mammalian digestive systems?

I'm interested in what kinds of nutrients mammals extract from food and would like to know how similar are the outputs of these systems. For example, if it is possible to successfully replace one ...
3
votes
1answer
94 views

Amino acid profile of GPCRs

You are studying cellular signalling through a newly identified GPCR. Specifically you’re working on a pair of newly identified GPCRs, GPCR-A and GPCR-B. Each binds the same small ligand, but ...
2
votes
1answer
410 views

Why are hybrids infertile?

Let's take a quote from Wikipedia about zebroids. Donkeys are closely related to zebras and both animals belong to the horse family. These zebra donkey hybrids are very rare. In South Africa, they ...
1
vote
2answers
128 views

Which was the last significant event in human evolution? What's next?

At 10.000 BC (12 ka), we became the last of the Homo species on Earth. In evolutionary terms this is a very little time range to something happen, but I'm wondering anyway, in this meantime which are ...
2
votes
1answer
80 views

Saliva test for Toxoplasma gondii?

I am trying to find some reliable gene kit by which you can rapidly test Toxoplasma gondii. I am not sure if it exists. I have an intuition that some tests done during 90s-00s on this species had high ...
0
votes
1answer
18 views

Is nutrient absorption different in Hypersensitive I patients?

I am thinking how the nutrient absorption differs between between patients with allergies (Hypersensitivity I) and those not. The current guideline about number of eggs in diet is one daily ...

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