2
votes
1answer
122 views

Lytic Viruses — Cell lysis?

So in the video my instructor sent on viruses, he said that for lytic viruses, new viruses manufactured by the host cell could get out of the cell in one of two ways. The new viruses would leave by ...
4
votes
2answers
546 views

In biosynthesis of cysteine and methionine, where does the sulfur come from?

Methionine and Cysteine are the two amino acids containing sulfur. According to wikipedia, cysteine is built from methionine. However, the wikipedia also claims that methionine is synthesized from ...
2
votes
1answer
112 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 ...
2
votes
2answers
92 views

Databases for metabolic pathways of human disease

Which databases contain the metabolic pathway of human diseases? I have searched Metacyc and KEGG but didn't find the appropriate metabolic pathway.
0
votes
1answer
155 views

What is the difference between intracardiac and extracardiac reflexes in cardiac regulation?

The primary parameters of heart pumping are strength of contractility (inotropic positive; Frank-Starling relationship) rate of relaxation (lusitropic positive) heart rate (chronotropic positive) ...
1
vote
1answer
319 views

How does a fertilized egg form 23 pairs of chromosomes?

I am always confused about this...so when one cell which has 23 pairs of chromosomes undergoes the two meiotic divisions it produces four cells containing 1 chromatid of every chromosome pair so when ...
4
votes
2answers
43 views

Dyes to bind to double stranded DNA?

Are there any commercially available fluorescent dyes that will bind only to double stranded DNA (not RNA, single stranded DNA etc.) for studying in vitro using confocal microscopy?
2
votes
2answers
410 views

Do recessive alleles really exist?

This question may seem illogical to some, but I seriously have this doubt. I searched google for some proofs but they were extremely complex and I couldn't understand anything. I was just wondering ...
6
votes
1answer
696 views

How much does the distance between a transcription factor binding site and a promoter influence transcription?

Assume we have a synthetic construct with a minimal (inducible) promoter that requires activation for significant transcription to occur. Realistically, how important is the distance between an ...
1
vote
1answer
43 views

Surrogacy Post Fertilization

The wikipedia page on surrogacy highlights two main forms of surrogacy: Traditional Surrogacy and Gestational Surrogacy. Traditional surrogacy inseminates the surrogate mother with sperm, while ...
1
vote
2answers
393 views

X Linked Hardy Weinberg Equilibrium Problem

In a given population under Hardy Weinberg equilibrium, 40.0% of men have hemophilia. What is the probability that a random man and random woman will have a daughter with haemophilia? I think the ...
2
votes
1answer
68 views

Quorum Sensing in Vibrio cholerae

This is a figure summarising the quorum sensing mechanism in Vibrio cholerae. In this video by Bonnie Bassler, she explains how quorum sensing can be targeted to control infections. At 15:09 she ...
2
votes
1answer
2k views

Is urine dirty as soon as it leaves the human body?

Human urine is sterile as long as it is in the human body. But is it dirty after leaving the human body? Could you get sick from it, if you drink it or don't wash your hands, for example?
6
votes
1answer
103 views

Absorption rate of Infrequently eating animals?

Clearly, creatures such as us humans, after vastly increasing the entropy of our food, expel most of the mass that we consume. Some creatures, however, do NOT get the opportunity to eat nearly as ...
23
votes
4answers
11k views

Can humans eat grass?

Can a human eat grass and digest it? Could it be possible to use it as food just like other plants such as wheat or beans?
0
votes
1answer
88 views

Systems Biology of triacylglycerol (TAG) synthesis in Jatropha

I need the genetic regulatory network of TAG synthesis (Kennedy pathway) of Jatropha plant?? Or is there any way to convert metabolic pathway into genetic regulatory network?
1
vote
1answer
219 views

Raising two legs together while lying on bed

Let's do some exercise(duh!) Ok so lie on the bed. Lift your left leg. Put it down. Lift your right leg.Put it down. Easy? Now lift your left leg and without putting it down, lift your right leg. ...
3
votes
2answers
136 views

Are viruses self-propelled?

So obviously, viruses are nonliving. But when my teacher was teaching viruses in the video (we're doing "flip" learning this semester), the way he described it, it seemed like the viruses responded to ...
0
votes
1answer
148 views

what these suffixes mean,-coel,-blast,-cyst? [closed]

in the connective tissue (Bones) we have 3 types osteoblast, osteocoel,osteocyst what are they and why they differ.
4
votes
2answers
218 views

What is the evolutionary purpose of the topology of the human ear?

What is the evolutionary purpose of the topology of human ears? I understand why the ears may have a funnel-like shape but if the various "hills and valleys" do not amplify incoming sound, what ...
0
votes
1answer
52 views

Do's and Don't's of Undergraduate Research? [closed]

I was fortunate enough to get a position as a researcher for the Mayo Clinic's SURF Program this year. My PI's lab focus is on the the immune system's role in CNS axonal and neuronal injury, ...
4
votes
2answers
3k views

No bands show up in gel electrophoresis, not even marker

I haven't seen any gel lanes in neither my PCR samples nor the marker itself when photographing them. This is not my first time performing 1.2% agarose gel electrophoresis. I see gel lanes when I ...
4
votes
2answers
186 views

Evolution in fruits

So, I saw a video on YouTube that says the banana we eat today is not what a banana looked like years ago. Since the banana has been genetically modified over the years, does that qualify as ...
2
votes
1answer
774 views

Why do cells vary in shape and function when they have the same genome and the same organelles?

Why do cells vary in shape and function when they have the same genome and the same organelles. For example: why do all cells have nuclei but red blood cell's don't; why can't the cells of a eye ...
11
votes
1answer
169 views

Beginning of the urogenital system

Are any invertebrate nephridia (proto/meta) homologous with vertebrate kidneys in the sense that embryologically they also begin together with the genital system? When did the embryologic association ...
0
votes
1answer
24 views

S. pyogenes' skin infection diagnostics

S. pyogenes is "flesh-eating" bacteria. It results from life-theatening myonecrosis caused by this organism. S. pyogenes avoids phagocytosis (mediated primarily by capsule, M and M-like proteins, C5a ...
3
votes
3answers
141 views

Why do 6-8% of diphtheria patients do not develop natural immunity after being affected?

I am thinking of why some patients do not have natural immunity after exposure to the A-B toxin of diphthria. I think the A-B exotoxin is the key factor causing this disease and should trigger memory ...
7
votes
4answers
599 views

Looking for a DNA sequence

I am not a biologist. Please pardon me, if my question does not make sense. I am trying to obtain a DNA sequence for pattern analysis in Matlab. I used to generate random sequence ...
3
votes
1answer
269 views

Parasitism and mimicry

I was reading this article which states this: Classical Batesian mimicry, in which an undefended mimic evolves to look like a toxic model, is a parasitic relationship in which the mimic gains ...
1
vote
1answer
54 views

Gene Complementation Question

Hi everyone! Here is a diagram of a genetics complementation problem. My main concern is regarding number 3d. I'm assuming that in this case, it would be complementary interaction and thus ...
2
votes
2answers
132 views

How does the telomere repeat sequence vary in Eukaryotes?

Question: How does the telomeric repeating sequence vary in non-vertebrate Eukaryotes? If you know the repeating sequence of a given species I would appreciate hearing it. Background: Telomerase is ...
3
votes
2answers
169 views

Electronic cigarettes (e-cigs), any health risks?

Background: An electronic cigarette (e-cig or e-cigarette) is a battery-powered device which simulates tobacco smoking patented in 1963 by Herbert A. Gilbert. It generally uses a heating element ...
3
votes
1answer
58 views

How do mosquitoes maintain telomere length?

While the vast majority of eukaryotic organisms maintain their chromosome ends (telomeres) via telomerase, an enzyme system that generates short, tandem repeats on the ends of chromosomes, other ...
9
votes
4answers
688 views

What prevents predator overpopulation?

I've often heard that a population, human or otherwise, will continue to grow as long as there is food available (assuming nothing else is killing them off). It makes sense: if you have food you can ...
2
votes
1answer
194 views

How do TLR1/TLR2 activate the MyD88 dependent pathway

Recently, I've been reading about the MyD88 dependent signalling pathway, with particular reference to its activation in Macrophages and other cells of the immune system on recognition of a pathogen. ...
1
vote
1answer
35 views

How host defends against S. pneumoniae capsule?

The host response involves at least phagocytosis and probably localised acute inflammatory response at least after the colonisation. I am thinking how the host can defend against pneumolysin which ...
6
votes
4answers
490 views

How many transcription factors are there?

In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow (or transcription) of genetic information from DNA to ...
2
votes
1answer
93 views

Plasmid maintenance

I have obtained some plasmids used as integration vectors, this question may apply to all plasmids. I would like to have a somewhat continuos source for these plasmids, let's say that the origin of ...
2
votes
1answer
637 views

How to check if a fastq file has single or paired end reads

I am trying to check if a fastq file has single or paired end reads. How can I achieve this with an error-proof method? I checked wikipedia and MAQ but I want to know if is there a reliable document ...
7
votes
1answer
71 views

Are recessive, deleterious alleles less common on the X chromosome than the autosomes in humans?

As there is a potential for them to be more readily purged in hemizygous males (and in cell lineages in females with the deleterious-allele-bearing chromosome activated), I would expect the frequency ...
4
votes
2answers
95 views

Is there a standard reference for the importance of tumor heterogeneity?

In a recent post, Philip Gerlee highlighted the two biggest contributions of mathematical oncology to cancer research: (1) increasing focus on the progress of cancer as an evolutionary process, and ...
4
votes
1answer
89 views

What is the relation between plasmid concentration and mRNA levels?

Suppose a simple synthetic construct, consisting of a constitutive promoter and a single gene: One of the simplest ways to model GFP transcription is to use an ODE: $\frac{d [GFP_{mRNA}]}{dt} = a - ...
2
votes
0answers
181 views

MTT assay normalization

Since the precise amount of cells in each well of an MTT assay varies, how can I normalize the results by cell number/concentration? How can I take into account the number of cells that have already ...
9
votes
2answers
619 views

Gloves for Cell Culture?

I always wear gloves when I'm doing cell culture. Moreover, I always spray my gloves with ethanol to disinfect, so that I don't contaminate everything. However, I recently heard the argument that ...
1
vote
1answer
27 views

Distribution of genotypes after adverse selection

I am doing some research into Mendelian genetics and came across this phrase called adverse selection. I found a few questions but I am unsure of the calculations. ...
1
vote
1answer
69 views

Genotypic distribution of a population with two characteristics and linkage

I am currently doing some research into distributions and probabilities with Mendellian genetics. I came across this problem that I cannot seem to wrap my head around. Given that the population has ...
0
votes
1answer
90 views

What does this sentence about toxemia and Clostridium tetani mean?

I know that Cl tetani is not invasive and strictly localised. I think toxemia means spread in the blood. I am thinking this sentence The volume of infected tissue is small, and the disease is ...
1
vote
1answer
309 views

What are the pros and cons of eating earth (soil)?

I wonder if there are any benefits to eat earth. What I mean by earth is the topsoil that is sometimes on vegetable (I eat organic vegetables and some of them like spinach are full of topsoil). I ...
1
vote
3answers
87 views

Using PSI-BLAST

I understand that the first BLAST yields almost the same results as blastp. The second time the iterated blast generates different results as it uses different matrix based on our first result. But I ...
4
votes
1answer
224 views

Why is Homo sapiens not categorized as an invasive species?

According to Invasive Species Advisory Committee (ISAC), the definition of the invasive species is “a species that is non-native to the ecosystem under consideration and whose introduction causes or ...

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