1
vote
0answers
64 views

To define the total Resistance of Systemic Blood Circulation

Some systems are in parallel. For instance, the resistance of lungs $R_{\text{lungs}}$. Assume here for simplicity that these parallel systems can be handled linearly. We also consider only Total ...
1
vote
1answer
41 views

Sitting much, thrombosis and hypoxia

I am thinking the more reasons why sitting much lead to thrombosis i.e. clotting of blood in blood vessels and then hypoxia in the deep tissues eventually. What are the physiological mechanisms for ...
2
votes
1answer
94 views

Why does the arch of aorta coils?

My study materials use the word vesselcompression chamber of aorta to emphasize aorta's elastic property. The arch of the aorta only coils, not its straight part. I think the reason why the arch ...
2
votes
2answers
45 views

RNA secondary structure comparison

Do you know any program which can compare two and more different RNA secondary structures? I need find some (dis)similarities between lots of predicted secondary structures. And create maybe common ...
1
vote
0answers
20 views

Is a neurostimulation implant for the soft-palate component of obstructive sleep apnea plausible?

There are currently ongoing clinical trials for neurostimulation implants designed to keep the tongue from blocking the airway in obstructive sleep apnea. The nerves for this are in the neck and ...
1
vote
1answer
463 views

Amber eye color in Neolithic Africa

Given what we know of the genetics of eye color and their historical distribution, is it possible or at least plausible for a person born in the Horn of Africa during the early Neolithic (ca. 9000 ...
7
votes
1answer
90 views

is it possible to completely reconstruct a family tree by DNA comparison alone?

Having DNA samples of all or almost all members of a population of, say, a few hundred or thousand individuals, is it possible to draw the entire family tree of those individuals? (Let's not assume ...
1
vote
1answer
78 views

Voltage-gated Potassium channels in the action potential of cardiomyocyte?

There is one type of potassium voltage-gated channels open in Phase 1 too. Some call them early repolarization channels. I am not convinced that the channels are different in different phases: 0, 2, ...
0
votes
1answer
46 views

Why is Aorta sometimes called Compression chamber?

I find this statement that Aorta is called Compression Chamber in my study materials. Aorta can it keeps blood flowing it can accumulate potential energy for bumping and compression However, why ...
2
votes
2answers
188 views

Do humans have a “dominant” neurotransmitter system/sensitivity within their brain?

I've recently heard a podcast, in which Dr. Helen Fisher suggests that there are "4 broad personality types", and each one is associated with a particular neurotransmitter: The corresponding ...
5
votes
0answers
302 views

Which of the cell types commonly found in mammals has the greatest number of mitochondria?

This is basically a fun question, inspired by this answer on scifi.se. So, which cell type will have the greatest number of mitochondria? Obviously, I am talking about wild type, healthy individuals ...
2
votes
3answers
259 views

What do you see if you look at your own retina with the same eye? (optical feedback)

When you record a video while pointing the viewfinder towards the screen showing a live preview you create optical feedback: video example. An anoalogous effect occurs when you turn your microphone ...
0
votes
1answer
107 views

Regional circulation and Cardiac output? [closed]

I am reading my study materials and think what is the systemic POV here Regional circulation Blood flow within the tissue/organs based on the functional demands of the tissue. E.g. The ...
4
votes
3answers
528 views

How many (taxonomic) families are there?

Approximately, how many families have been identified? I've often often come across figures for the total number of species on Earth. Recently, I found myself wondering about the encompassing ranks ...
0
votes
1answer
15 views

How does Mupirocin affect in staphylococcal infection?

I found this sentence confusing Transitor carriers of staphylococcal infections 70% because of mupirocin i/n. Mupirocin is drug which affects some way. I am not ...
1
vote
1answer
35 views

Staphylococcus AG structure?

I found this statement in my study materials in the section of Staphylococcus The AG structure: protein AG (species specific); polysaccharide AG (serotype specific). I know what is ...
0
votes
0answers
67 views

Identification of a mysterious lifeform, what is this? [duplicate]

For the third time in a row, I found a mysterious life-form inside my house. I live in the Netherlands in the Eindhoven region, in a city called Oss near a forest area. Before I set it free outside, I ...
1
vote
1answer
260 views

Birds and Dinosaurs

This came up in an argument with some friends. I know that birds are direct descendants of dinosaurs, shown pretty clearly through the fossil record. However, is it proper to say that birds are ...
0
votes
1answer
34 views

Characteristics of radius of blood vessel

Which properties do determine the radius of blood vessel? I have these thoughts distension, elasticity, contractility and cross-sectional area of the walls. Is there any other properties?
2
votes
1answer
333 views

Elution of biotinylated RNA

I am using Neutravidin Agarose beads to isolate biotinylated RNA. The thing is, in the manual it says to use 8M Guanidine-HCl, pH 1.5 for elution biotinylated molecules. As far as I know it is a very ...
3
votes
1answer
590 views

Death by exsanguination not painful?

Several places on the internet seem to purport that animal sacrifice is painless because exsanguination causes no pain. That sounds unscientific to me and an attempt to appease culture than than using ...
1
vote
1answer
25 views

To understand synthesis of e-NOS and n-NOS with respect to Ca and calmodulin

I found this sentence in my notes interesting E-NOS and n-NOS are Ca-calmodulin dependent ferments. They are synthesized in small concentration as a response to physiological signals which ...
6
votes
1answer
222 views

What percentage of the (additive or not) genetic variance is explained by the 'n'- most important loci?

Standard models in population genetics look up at the evolution of few loci which impact fitness. The variance in fitness is determined by the genetic variance and the environmental variance (and the ...
0
votes
2answers
55 views

To understand Second messenger signalling in I/c and E/c

I found this picture in my study materials. I think it is too schematic and ignores the big pictures. I think the thing connected to the hormone is receptor. The second messanger is then connected ...
1
vote
0answers
90 views

Osmosis - occurring in both ways? [closed]

So I did a prac to identify the osmotic potential of potato tuber cells. There were 5 test tubes with different concentrations of sucrose (0M,0.25M,0.5M,0.75M,1M); a small slice of potato was placed ...
1
vote
0answers
62 views

How many blood types are there? [duplicate]

In total how many blood types are there? And why do people normally know only 8 of them? (A+, B+ , AB+ and O+ and Rh- counterparts)
3
votes
2answers
240 views

Correlation between muscle size and absolute strength

Is there a linear connection between muscle size and the power it can produce? If not, why? And what is the true correlation if any, can it be described with an appropriate function? What other ...
0
votes
1answer
157 views

Can you approximate Cardiac Output by Ohm's law?

I found this sentence from my notes which I cannot understand PR < CO, CO $\uparrow$, PR > CO $\downarrow$ where ...
0
votes
2answers
349 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 ...
1
vote
1answer
97 views

Gene distance and Recombination Frequency: Mechanism

Why is the recombination frequency higher if the genes are farther apart?
3
votes
1answer
83 views

Is a single x-ray photon capable of doing enough damage to the DNA of a cell to kill that cell? [closed]

Ionizing radiation is damaging to DNA, but is there such a thing as a safe dose below which no DNA damage could occur? I'm not asking about a minimum safe dose overall, just whether or not there's an ...
1
vote
1answer
82 views

In vitro transcription, contamination problem

I am using a RNA which is in vitro transcripted before I started my project. It turned out it is not prepared properly and has DNA contamination. Instead of perform the in vitro transcription again, ...
3
votes
1answer
84 views

Why do hummingbirds build nests with live ferns instead of dead materials?

Hummingbirds prefer to build their nests with spore-bearing ferns, and mosses. This is helpful for the reproduction of the ferns, which are then better able to spread their seeds. But how is this ...
1
vote
1answer
93 views

Calculating photosynthetic efficiency

While calculating photosynthetic efficiency, do we take into account the Gross Primary Production or the Net Primary Production ?
4
votes
0answers
138 views

How do duplicate brain regions (ex: left/right amygdaloid body) operate together?

I frequently hear talk about parts of the brain like "Amygdala" or "Hypothalamus", so I looked them up in an app called "essential anatomy". What I see is that there's mirror symmetry, and most of ...
1
vote
1answer
116 views

Is end-systolic volume (ESV) the same as residual volume?

I am reading this site and my study materials. The end-systolic volume (ESV), 50-60 ml, is the volume of blood found in ventricles after systole and contraction of ventricles. I think ESV is the same ...
3
votes
3answers
88 views

Can 'hardware' thermalization explain memory decay?

Often we are able to memorize very precise bits of information (exact addresses, birthdays of inlaws, number of dirty socks under the bed), but over time our recollection tends to become fuzzy. We no ...
6
votes
2answers
130 views

What type of force holds my body rigid & doesn't make it collapse?

My query is that as atoms & its molecules have inter & intra molecular forces,like that only what type of force keeps the cells bonded to each other & prevent it from collapsing ever ...
3
votes
2answers
181 views

Can diploidy evolve in absence of sexual reproduction?

Theoretical question Can diploidy (or polyploidy) evolve from a haploid lineage in the absence of sexual reproduction ? For what theoretical reason? How can such evolution take place? Empirical ...
-1
votes
1answer
80 views

Can nature create codes and specified complexity? [closed]

Is there an example of nature creating codes or specified complexity? It is said by Creationists that codes can only come from minds, and since DNA has a code, it was created by a mind. Is this true? ...
0
votes
1answer
49 views

An over-simplified model of cell division and its relation to stem cells

I am a mathematician, and I decided to try to model cell division with math and see what conclusions came out of it. I had some questions concerning stem cells that came up in the model. In an ...
1
vote
1answer
57 views

RNA integrity and RNA fragmentation

After RNA isolation and before following experiments, I know that RNA quality so called RNA integrity is so important. So why there is a RNA fragmentation kit? Do we need RNA intact or fragmented? ...
1
vote
1answer
65 views

Dilution question about RNA

I have a basic and probably silly question. I am isolating RNA with TRIzol. I have performed the basic steps and dissolved the pellet in 50 uL water. I ve measured the concentration and it was 3313 ...
0
votes
2answers
402 views

Can you answer Ray Comfort's question on Biological Evolution? [closed]

https://www.youtube.com/watch?v=U0u3-2CGOMQ There's this video on Youtube about biological Evolution that has gone viral. I'll paste it above for your convenience. To cut to the chase, Ray Comfort ...
0
votes
1answer
54 views

Normal position of Electrical axis only in the III lead?

I found this sentence in my notes which is not exact enough: Electrical axes Excitatory processes have definite direction and magnitude and could therefore be represented as vectors. At ...
6
votes
2answers
499 views

Why aren't we ambidextrous?

It seems so simple that if my brain can tell my right hand to do something, then it should be able to tell equally well to the left ? This seems like a pretty major evolutionary advantage. Why haven't ...
0
votes
1answer
81 views

How does a smoker's pleasure work?

I smoke. For some reason, I've always had this idea that the pleasure of smoking works more or less like this: from the lungs, the nicotine reaches the blood, with which it travels to the brain, and ...
1
vote
1answer
73 views

Physiology of skin and leather: why do salt borders occur?

I discussed a leather store about the white border aka salt border on leather shoes. They said that it is due to inner features of leather and you could try to add some fat/cream to push it back ...
-1
votes
1answer
70 views

Can a certain part of human dna can be replaced with other animals dna?

Human DNA consists of adenine, thymine, guanine and cytosine. Can thymine of other animal can be placed with humans thymine?
0
votes
1answer
68 views

Difficulty in developing certain vaccines

I have a college level background in Biology, say at the level of Campbell. I am very curious to know why it's extremely difficult to develop vaccines for certain diseases. Two cases which I am really ...

15 30 50 per page