4
votes
0answers
120 views

Why are Mammals are unable to produce Essential Fatty Acids?

Why do we have to get them from our diet, and if they aren't taken in our diet we will face disease? Then why we don't have the enzymes which are require for EFA synthesis?
4
votes
0answers
512 views

Do Asian women have more difficult births than Europeans?

I recently heard a claim that Asians in general have more difficult births than Europeans. Is this true? I have found a few studies(1,2) on the effect of ethnicity on birth outcomes but they seem to ...
4
votes
0answers
337 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 ...
4
votes
0answers
84 views

Does DHA increase the effects of clarithromycin?

I've read on this publication that every drug that induces CYP3A can reduce the effectiveness of clarithromycin. Clarithromycin inhibits CYP3A. But it does not say anything about the opposite ...
4
votes
0answers
107 views

Nocioception (pain perception) in subcutaneous tissue

There seem to be no nocioceptors (pain and temperature sensitive nerve endings) in subcutaneous fat. there are nocioceptors and other receptors in veins running through fat, but these can be avoided. ...
4
votes
0answers
122 views

Eye color genetics

I am trying to find a model to link the phenotype eye color to its genotypes. I know that there exists a simple model from Davenport, which explains {brown,blue} eyes. Further, there is an extended ...
4
votes
0answers
129 views

Why do ants dig surface paths?

A few days ago I observed a corridor built and used by ants that went over a path in fields: Why do they build it? It seems it doesn't bring any considerable protection from the surrounding ...
4
votes
0answers
133 views

What is the mechanism by which Melatonin increases dream vividness and intensity in humans?

I'm looking at the wikipedia article on Melatonin and noticed that it mentions vivid dreaming caused by melatonin. I have the "Melatonin and the Biological clock" pamphlet referenced in the article, ...
4
votes
0answers
50 views

Are all Autoreceptors Downregulated by their Respective Endogenous Ligands?

I know that the 5-HT1A and $\alpha$2 adrenoreceptors receptors serve as autoreceptors for serotonin (5-HT) and norepinephrine respectively and are down-regulated by repeat exposure to their respective ...
4
votes
0answers
34 views

Does Doxylamine have any Influence on the Monoaminergic System?

Does doxylamine have any affects on the monoaminergic system? Specifically I am interested in adrenergic or serotonergic activity but additional information on its dopaminergic activity won't hurt ...
4
votes
0answers
83 views

What is the frequency of double-hets between parent and child?

Say both parent and child are genotyped for all SNPs. In this setup we are only looking at variant positions between one parent and child - so neither parent nor child are homozygous reference (no AA/...
4
votes
0answers
39 views

What metabolically happens when an egg fuses with the nucleus of a somatic cell

In stem cell biology, it is recognized that embryonic stem cells are transcriptionally inactive for the first 3 days of development. However, during somatic cell nuclear transfer, the nucleus is ...
4
votes
0answers
127 views

If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?

D1 and D2 both refer to specific types of dopamine receptors. I'm sure it has something to do with the fact that the D1 receptors are in regions different from D2 receptors. I know that adenylate ...
3
votes
0answers
16 views

Names for the degrees for symptoms from drought (or other damage) done to trees

Looking out my window, I see trees suffering from drought. I once knew the name for the degrees visible, but I have forgotten and can't find it on the net. One level was the tree being completely ...
3
votes
0answers
55 views

Why did we evolve to control our breath?

I had this question in my mind and tried to think of why we would evolve to be able to control our breath. I remembered the Aquatic Ape Hypothesis, which makes a lot of sense and would explain it, ...
3
votes
0answers
57 views

In vivo delivery of ssDNA

I am looking for a system with which I can deliver (large quantities of) ssDNA in vivo (say in mice). I do not know whether it is of importance but the 5' end of the ssDNA fragments are assumed to be ...
3
votes
0answers
25 views

What is the effective population size of a simple two deme metapopulation?

I am confused as to how to compute the effective population size $N_e$ of a theoretical structured population. Let's consider here a simple case study. Imagine a 2-deme metapopulation. Each deme is ...
3
votes
0answers
20 views

Phase Transitions of Purified Proteins

Why do solutions of purified protein condense into droplet phases? I'm trying to understand the protein phase transitions. Here is the article http://www.cell.com/cell/fulltext/S0092-8674(12)00634-4#...
3
votes
0answers
26 views

Validity of measurements of respiration in isolated mitochondria

I've recently read a couple of papers on exercise and mitochondria, in which state 4 and state 3 respiration rates and ROS production are assessed in vitro after exercise has been performed (i.e., rat ...
3
votes
0answers
27 views

filtering a BLAST search to only include a certain protein sequence

I am performing a BLAST search and I need to filter the output to a certain family of proteins. Specifically, I need to get matches within the CYP152 family of the Cytochrome P450 proteins. I can ...
3
votes
0answers
37 views

How is a T lymphocyte specific to an antigen but not specific to an epitope?

In my immunology notes, it states that B lymphocytes (and other APCs) capture and present antigens to T lymphocytes that is specific for an antigen, but that the T cells do not necessarily recognise ...
3
votes
0answers
22 views

Effect of ethanol and detergent on cell membranes problem

I am currently writing my biology report for an experiment I did on how ethanol and detergent affect the cell membrane. For my ethanol experiment, all went as expected BUT for my detergent experiment, ...
3
votes
0answers
49 views

What is this wood-infesting insect?

I have these insects in a very old wooden floor. I would like to know whether they are possibly termites, and if not, what they are. They are about 4 mm in length (and I've had difficulty taking a ...
3
votes
0answers
58 views

Are plants really oxygen neutral?

This accepted and most upvoted answer to the question Does grass alone produce enough oxygen for life? claims that plants are oxygen neutral: Plants are oxygen neutral The question wording is a ...
3
votes
0answers
7 views

At which voltage will the conductance decrease due to the narrow pore in a voltage-gated potassium channel?

If you have a voltage-gated potassium channel that do not inactivate, at which voltage would you see decrease in ion conductance related to the narrow path in the pore? With that said I know that in ...
3
votes
0answers
42 views

What happens to the brain during sleep versus unconsciousness?

How does being unconsciousness differ from being asleep and whether it causes breaks in consciousness?
3
votes
0answers
23 views

Breeding Southern Right Whales Genetics

I don't know much about biology. I just like watching David Attenborough videos and this made me curious. I just watched this video about breeding Southern Right Whales, and these two quotes puzzled ...
3
votes
0answers
18 views

Potential homogeneity across cell membrane

During respiration, individual bacteria (and mitocondria) produce a relatively large potential difference (∼100 mV) between the inside and outside, using energy to pump $H^+$ out of the cell to the ...
3
votes
0answers
87 views

How to calculate information content of a DNA sequence

How does one calculate the information content of DNA sequence like ATCGGCT where mutation rate of G's is 10% and the most common mutation product binds with C and A with equal frequency. I know that ...
3
votes
0answers
26 views

Is there a correlation between Animal Intelligence x Playing time?

I'm writing a small text for a blog about playing time and I wish to have more resources about the correlation between Intelligence and Playing time in animals. If not exactly that, maybe some ...
3
votes
0answers
37 views

Is diarrhoea advantageous to the microbe?

Diarrhoea is a common side effect of many feco-orally transmitted bacterial infections. How does diarrhoea help the pathogen? Should it not have a selective evolutionary advantage? Do all symptoms of ...
3
votes
0answers
24 views

Why the name hypopharynx?

Why the tongue (like structure) in cockroach (or other insects) is called hypopharynx? In humans I know it's the lower part of pharynx, not a structure. Isn't this anatomical name misleading? Are ...
3
votes
0answers
22 views

Where do class 2 preservatives end up after digestion?

Do anybody know what happens to class 2 preservatives in general after they are digested - i.e details like weather they are absorbed into blood as simplest elements or excreted out or assimilated to ...
3
votes
0answers
24 views

Runs of homozygosity - degree of inbreeding and disease associations

Been reading recently about methods to determine how inbred a particular person is by measuring their "runs of homozygosity." Loosly, these are defined as regions of the genome (typically >1Mb) where ...
3
votes
0answers
86 views

Behavior of plant guard cells: open or closed stomata

On an exam of mine, I had the following question: The interaction between the guard cells and stomata in a plant leaf can be seen in the diagram below. In which scenario could the guard ...
3
votes
0answers
19 views

Cellular demand for antioxidants

Antioxidants such as ascorbate and glutathione serve to inactivate radicals and counteract spontaneous oxidation reactions, such as unwanted disulfide bonds in proteins. These systems are cycles, ...
3
votes
0answers
48 views

Is $F_{ST}$ a probability and a correlation coefficient?

$F_{ST}$ is one of the most famous and most important statistics of all of evolutionary biology. Yet, many people misunderstand it or misuse the classical results from the literature on $F_{ST}$ (...
3
votes
0answers
24 views

Are there animals that can deliberately manipulate their metabolism, apart from hibernation?

Are there animals that can slow down their metabolism deliberately? I know that hibernation would be one mechanism, and maybe being cold-blooded, but I was wondering if there was maybe an animal that ...
3
votes
0answers
17 views

Controlling the pursuit path of the human eye

The human eye scans images by panning focus along a certain path. Stork et al. (2002) revealed that there is a feedback process involved in moving ocular focus along a path that produces minimum ...
3
votes
0answers
34 views

Minichromosome maintenance protein structure and function

I am having difficulty answering three homework questions which relate directly to Chong et al. (2000). Questions The authors have determined that MtMCM is able to bind both ssDNA and dsDNA (see ...
3
votes
0answers
100 views

Chart of blood pH across different animal species?

How does blood pH vary across species? I can't find an article or chart listing this kind of information. So far I've found bits and pieces like: Human blood pH is nominally 7.4. 7.4 seems to be a ...
3
votes
0answers
36 views

Are all genes transcribed in differentiated cells?

My textbook tells me that it’s specific transcription factors that allow for a different set of genes to be expressed in different cells (differential gene expression). My book gives the example of ...
3
votes
0answers
18 views

Coagulation of blood in small intestine due to trypsin

Trypsin is secreted in the small intestine to convert proteins into dipeptides i.e. to carry out digestion of proteins. However, it is also a coagulating agent which coagulates blood by hydrolysing ...
3
votes
0answers
27 views

What happens to the cell during post-hypothermia?

A friend of mine said that the cell membrane somehow changes after rewarming from hypothermia and that the body does not recognize it's own cells, thus leads the immune system to attack it self. Is ...
3
votes
0answers
17 views

How is the side-polarity of the myosin filament in myofibril maintained?

If myosin molecules are the properly oriented relative to their position in the the myosin filaments, the sarcomere is not functional. But how is the orientation of the myosin molecules determined? ...
3
votes
0answers
27 views

Are there bacteria that respire anaerobically in aerobic conditions?

There are facultative aerobic bacteria that switch to aerobic respiration in an aerobic state, but are there any organisms that would still perform anerobic respiration even when shifted to aerobic ...
3
votes
0answers
41 views

What is the name of the category of viruses that affect only one side of the body?

The Varicella zoster virus causes chickenpox in children and shingles in adults. When the virus attacks as shingles, one of its distinguishing characteristics is that it only affects one side of the ...
3
votes
0answers
32 views

What is an extinction test?

In Stolerman & Olufsen (2001) I read the sentence: After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests. ...
3
votes
0answers
26 views

Do eukaryotes assimilate DNA that is floating in the extracellular membrane?

Prokayotes, which replicate primarily using binary fission, don't get much genetic diversity. For this reason, they take in any genetic material they encounter, in a gambit to help them better adapt ...
3
votes
0answers
42 views

How does glucose delivered intraperitoneal (i.p.) get into the peripheral circulation?

Intraperitoneal delivery of drugs or fluids is something that occurs much more frequently in veterinary medicine than clinical medicine. In veterinary medicine or scientific studies using animals, ...

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