5
votes
3answers
140 views

What does it mean for a hormone to be “active”

In my textbook it is stated that the T3 hormone produced at the thyroid gland is 3-5 times more biologically active than T4. How is being active defined and how can this effect be measured?
3
votes
1answer
122 views

Microalgae without cell walls?

Most microalgae have rigid cell walls. Dunaliella Salina is a pretty famous example of an algae with no cell wall, but just a plasma membrane. Are there any other microalgae without a cell wall?. I ...
2
votes
1answer
85 views

What is the insight of Frank Starling law of the heart?

The Frank Starling law appears to be a trivial observation: stroke volume is directly related to the end diastolic volume In everyday language, as more blood fills the heart, the heart pumps more ...
11
votes
1answer
282 views

Why are people unable to develop lasting immunity against Norovirus?

Infection with many viruses will result in decades-long if not lifetime immunity, for example chicken pox. Because of the large number of viruses responsible for the common cold, lifelong immunity to ...
2
votes
0answers
303 views

Can a person's body produce enough electricity to break a wristwatch? [closed]

I know of someone who cannot seem to wear watches without the battery dying or something else about the watch going haywire. this person was told it is because their body is producing too much ...
1
vote
1answer
4k views

How is ATP involved in muscle contraction?

The sliding filament mechanism as explained by my text does not elaborate on how ATP is involved in the cross bridge binding and contraction process. How does muscle contraction utilize ATP? In my ...
0
votes
1answer
325 views

What is a complex?

In my text book it says that "Troponin" is a complex of Troponin C, I and T. In this sense, what is the relation between Troponin complex and C, I, T?
2
votes
1answer
95 views

Retrovirus Production

I have been having difficulties with low transduction efficiencies of my retrovirus production. I expand my plasmid of interest (on MiG-GFP plasmid) in DH5α E Coli for ~24 hours, purify with Qiagen ...
1
vote
2answers
156 views

What's the proton concentration around a DNA helix?

Let's suppose the concentration of a 20-nt DNA strand is $10^{-4}$M and the solution does not contain any salt ions. In a solution with pH 7, $[H^+]=10^{-7}$M, on average each DNA has only 0.001 ...
6
votes
1answer
173 views

Why is there smooth muscle in our bronchioles?

Having muscle tissue in our bronchioles that can constrict seems like a poor choice for tissue. Why would our airway want to ever close up? Wouldn't it be more beneficial for our bronchioles to just ...
3
votes
2answers
268 views

Could an action potential produce few or more neurotransmitters based on the stimulus received?

I reckon that if you would be able to widen the AP width, it would produce more neurotransmitters in that larger time interval. Is that correct? Or does the neuron have a standard amount of ...
3
votes
1answer
127 views

What governs the distribution of blood vessels?

Whenever someone is sick, doctor places 2 fingers on wrist & observes the heart-beat-rate by feeling pulses of a certain artery. To me it seems the distribution of blood vessels are pretty ...
5
votes
1answer
50 views

How can the phenotypic effects of a tumor suppressor mutation be silenced?

I've been reading a little about the "two-hit" hypothesis for tumor suppressor genes here, which mentions that some genes exhibiting haploinsufficiency are exceptions to the hypothesis. I've read ...
8
votes
1answer
232 views

What is this mushroom?

I found a singular mushroom in my back yard, It is jet black, seems to have gills and looks somewhat like a flower do to it's upturned-ness. Sorry for not having spore colors, but I didn't want to ...
3
votes
1answer
93 views

Can yeast in a primary fermentation of wine be used as a source of yeast for new fermentation?

So if I were to pitch bread yeast, and get to primary fermentation, which as I understand it, is the point at which regular cellular respiration can no longer continue due to a lack of oxygen , which ...
0
votes
1answer
147 views

How to tell if a given gene is a tumor suppressor or oncogene?

This is a problem taken from "Concepts of Genetics", Klug et al, 10e. I'm given the following table about the mutations in the BRCA1 gene: $$\begin{array}{c|c|c|c|c} \text{Kindred}&\text{Codon}&...
3
votes
1answer
159 views

Before Evolution was proposed by Charles Darwin, what were the leading secular theories to explain how life developed? [closed]

Outside of evolution, what were the leading scientific schools of thought that Charles Darwin contented with when he published his evolution theory as way of natural selection in 1859?
1
vote
1answer
97 views

Do muscles still hold glycogen reserves if there is no carbohydrate input

Afaik skeletal muscles take glucose from the blood to store it localy as glycogen, to be used in the case of intensive exercise. Does this still happen if the calorie input is exclusively made up ...
0
votes
1answer
124 views

Why should or shouldn't we allow the human body to take its natural course? [closed]

For example, when you are sick but don't feel thirsty, this could be due to baroreceptor reflex that is attempting to readjust salt and water balancing. Why shouldn't a patient be left thirsty and ...
0
votes
1answer
56 views

What causes a small bump in the arterial pressure plot?

In my book there is a plot of the arterial pressure against time. From the plot, during heart contraction, there is greater pressure on the artery and during heart relaxation, there is lower amount ...
3
votes
3answers
595 views

Why are there no trees in Texas?

In Texas, there is lot of grassland and many cotton fields, which need a great deal of water. However, I have not seen any forests or areas with many trees. Why are there no forests or heavily-treed ...
2
votes
1answer
272 views

How to isolate host cell RNA (tRNA,mRNA,rRNA) from viral RNA?

A retrovirus with RNA genome infected a host cell. You would like to isolate the host cell’s RNA (rRNA, tRNA, and mRNA) from the virus RNA. What properties can you rely on to determine the three types ...
15
votes
1answer
1k views

Why do mushrooms grow in rings (sometimes called “Fairy Rings”)?

Mushrooms disperse their spore in all direction. Then why is there a formation of fairy rings? Why do they grow in one shape and not randomly?
1
vote
2answers
141 views

Mosquito physics

What are the environmental limitations of mosquitos I should know of if I want to avoid getting bitten? For example: How fast should I walk in order to be moving too fast for one to bite me? Can a ...
2
votes
0answers
236 views

Why do body parts sometimes get a itching and tingling feeling when falling asleep?

Just before I fall asleep I sometimes experience an itchy and stinging feeling in my body parts. It can be that the nose or neck suddenly start to itch or a tingling stinging feeling in the legs. ...
1
vote
0answers
33 views

Regarding cryonics, why can't you freeze a living body and then thaw it later, fully functional?

Cryonics is very popular in science fiction today, as a method of preserving animals, including humans, for long time storage and thawing the tissue later in the future. What is the difficulties with ...
-1
votes
1answer
168 views

What makes a good phylogenetic tree?

How can one improve a phylogenetic tree? If one was to make the 'golden standard' of phylogenetic trees what features would it have? Would it be highly reliable, well resolved etc? What other features ...
1
vote
1answer
268 views

What does saying a phylogenetic tree is 'well resolved' mean? [closed]

I'm not sure what 'resolution' means in the context of phylogenies.
4
votes
1answer
162 views

Question about epinephrine

In my class we were told that adrenaline (or epinephrine) causes vasoconstriction. My question was I had always thought that people took this via an EpiPen when they were having an allergic reaction. ...
3
votes
0answers
27 views

Is there a cellular mechanism that detects Ribosomal damage?

What kinds of options, if any, do cells (Eukary and Prokary) have for detecting, and repairing damage in Ribosomes (of all types)? I am curious as to what happens when a cell sustains damage of some ...
9
votes
2answers
2k views

Why do people feel pleasure when using roller coasters / centrifuges?

The feeling when using an amusement park unit is usually a pleasure. Why is it not a pain instead? Are there advantages, from an evolutionary point of view, in loving this potentially dangerous ...
5
votes
1answer
113 views

What is this arachnid?

I came across a photo on Wikipedia depicting an Oreocereus celsianus with what looks to me like some kind of harvestman on it. The photo was taken at the San Francisco Botanical Garden. Can anyone ...
2
votes
1answer
43 views

Online resources for entomology?

I'm going to teach a c ollege-level introductory entomology course soon, and I'm looking for free online entomology resources. Does anyone have any recommendations? In particular I'm looking for ...
4
votes
1answer
158 views

Why do people in the scientific community use terminology such as renal, hepatic, cardiac instead of kidney, liver and heart? [closed]

Are there differences between renal, hepatic, cardiac and kidney, liver and heart? Is the "jargon" used more commonly because of tradition, or is there some definitive biological basis to it?
6
votes
1answer
104 views

Software recommendation for protein in electric field modeling? [closed]

I'd appreciate a suggestion for software to compare models of two proteins in an alternating electric field. The more detail, or perhaps direction towards an existing and similar paper, the better. ...
2
votes
1answer
42 views

Workspace preparation and cleanup for DNA work [duplicate]

What steps should be taken in a molecular lab environment to help ensure that DNA samples/stocks are not contaminated, or contaminate other objects in the lab?
2
votes
2answers
89 views

How does a cell create/gain its initial ribosomes for protein synthesis?

I did some quick google searches for how a cellular organism generates or acquires its first ribosomes, but I found nothing. For instance, do the organisms initiating replication form extra Ribosomes ...
1
vote
3answers
85 views

DIY storing family DNAs' samples for future uses (eg medical)

I have a question I could not get an understandable reply from Google and I am no expert in the matter, so my plead to you is if you could give me practical and relatively easy to follow advice. With ...
0
votes
1answer
1k views

What is 'refractile' cell morphology?

I can't find a definition for 'refractile' (not 'refractory', and not explicitly in an optical context). As in: A tumour cell phenotype features increased proliferation, anchorage- and growth ...
2
votes
1answer
635 views

Why didn't a concept like “pointers” in Computer Science evolve in the genome?

I see that the genome contains large regions of repeating sequences called interspersed or dispersed elements. The long dispersed elements (LINES) such as LINE-1, can reach up to 6-8 kb in length. I'...
1
vote
0answers
47 views

Common Metrics of Assessing DNA Sequence Quality

What are commonly accepted metrics for assessing DNA sequence quality (platform-specific answers are fine)? I am relatively new to this topic, and I want to either find or code (in Python or C++) ...
3
votes
2answers
651 views

When glucose production is low, the brain begins using ketoacids as energy… how does that work?

Can someone very generally describe how the brain consumes ketoacids/ketone bodies when blood glucose has been completely depleted?
1
vote
1answer
351 views

What is the so called “hepatic glucose production”

I came across this term in my readings but I do not understand how this works. Can someone direct me to some reference as to what this "hepatic" glucose production is all about?
0
votes
1answer
106 views

Survival with only water but no food [duplicate]

How long can the average, healthy adult human survive with only water?
1
vote
1answer
137 views

Given an EC50 value, how do I reproduce the sigmoidal curve from which this was calculated?

All-trans retinoic acid (atRA) is a potent ligand for a nuclear receptor called retinoic acid receptor alpha (RARa). The concentration of atRA at which RARa is half maximal is 19nM. The dose-response ...
1
vote
2answers
188 views

Can leukopenia in a person with an otherwise normal immune system lead to non-infectious diseases in the long-term?

If a person has developed leukopenia as a side-effect of long-term use of anti-convulsant medications and his/her immune system appears normal otherwise (does not get infections any more often than a ...
1
vote
0answers
21 views

Why is there only adrenoreceptors and no active adrenergic innervation in bronchus and uterus?

Our bronchus and uterus has beta adrenoreceptors, but they have no active sympathetic nervous system innervation in these organs. Was there a sympathetic innervation in trachea and uterus, earlier, ...
1
vote
1answer
54 views

Where to find gene manipulation video (or photos)

I hope Im not asking a dumb question! Where can i find video of gene manipulation in action under microscope? Like extracting a gene from a cell, fixing gene mutations, putting the gene in a vector, ...
4
votes
2answers
43 views

Transformation efficiency

I accidentally spun down the cells after heat shock treatment before adding the media into the tubes while doing transformation? will the transformation work?
3
votes
1answer
78 views

Liver - Regeneration in Cirrhosis

Liver is the most resilient of the human organ (on par with or next to skin). A very interesting experiment on liver regeneration is here. Even if two-thirds of the liver is removed, the remaining ...

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