5
votes
2answers
9k views

Mechanism of Decorticate & Decerebrate Posturing? Also why is only Decorticate Rigidity a misnomer?

I read these two from various books, and got confused. The confusion is - Reticulospinal tracts control gamma motor neurons. Gamma motor neurons control tone of muscle. In decerebrate rigidity, the ...
3
votes
3answers
472 views

Kinetic Vs Potential Energy in Biochemical Contexts

This question is causing great confusion in my head. Which of the following is an example of potential rather than kinetic energy? A) the muscle contractions of a person mowing grass B) water ...
6
votes
5answers
857 views

Relationship Between Evolution and the Increase of Entropy of Earth

I was confronted by this question: Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellar eukaryotic organisms, A) has occurred in accordance with the laws ...
3
votes
1answer
179 views

Which of the two mitochondorial membranes relate to bacteria according to the endosymbiotic theory?

I seached for endosymbiotic theory in Wiki and I found this about endosymbiotic theory: Symbiogenesis, or endosymbiotic theory, is an evolutionary theory which explains the origin of eukaryotic ...
2
votes
1answer
1k views

Making the sense of enzyme Km comparisons

I have encountered comparisons of the Michaelis-menton constant (Km) a few times. Generally speaking if Km of an enzyme is higher, then it's affinity to its substrate is lower. How does this make ...
0
votes
0answers
21 views

Why can I breathe true only One nostril [duplicate]

just so you know, this is not why I breathe OUT only from one nostril. I am literally breathing with only 1 nostril, I can't breathe in any oxygen true my left one. If I like plug the right nostril, I ...
5
votes
1answer
63 views

Repair wrong DNA pair after ending replication?

If there are wrong DNA pair, for example A=G, is there mechanism that could repair such things - after the replication was finished? Or it happens only during replication?
1
vote
2answers
88 views

What happens when the brain is no longer capable of co-ordinating or regulating the heart and breathing rates? [closed]

Does the heart no longer function? Does it go into ventricular fibrillation? What happens?
4
votes
1answer
259 views

Trying to differentiate between the three muscle tissues with small pictures

For an assignment I have to differentiate the three types of muscle tissues in these three pictures . I'm having difficulty seeing the striations and branches etc. because the pictures are so small. ...
4
votes
1answer
301 views

Why is hyper pigmentation the common aftermath of skin lesions and abrasions?

I'm aware that melanocytes produce melanin, giving color to the skin, but why are these cells recruited or overactive when healing skin abrasions, lesions and sores when T-cells and inflammatory ...
9
votes
1answer
350 views

Can people with paralyzed eye muscles see?

As far as I am aware, the saccades of the eye are central to visual perception. If the eye is held still, the human stops seeing, even if light is reaching the retina and the visual pathway is intact. ...
1
vote
1answer
35 views

Why does a tumour's genome change depending on the environment?

According to the book "Primer of The Molecular Biology of Cancer" by Vincent, Theodore and Ateven, the tumour cell is changed depending on its environment. performed genome-wide analysis on three ...
5
votes
1answer
168 views

Can methylation of a promoter induce gene expression in some rare cases?

Can methylation of a promoter induce gene expression in some rare cases? I've read somewhere that methylation of an intron can induce gene expression (eg. Igf2). How is that even possible? Thank ...
9
votes
2answers
4k views

What are the differences between cancer and tumour?

What are the differences between cancer and tumour? I mean is it in the DNA or shape or something else... And how can a benign tumour turn into a malignant tumour? The body has a lot of tumours all ...
2
votes
1answer
216 views

Largest direct ancestor of humans

Going back the genealogical lineage from present humans to the beginning of life, what was the biggest - in terms of body size or mass - animal in this sequence? More generally, what would a time vs. ...
2
votes
0answers
95 views

Does the metabolic rate determine how fast the telomeres shorten?

In many papers one can read that telomeres may play an important role in longevity. According to Calado et al.1 the telomeres of mice are much longer than the telomeres of humans. However, mice have ...
7
votes
1answer
355 views

Is this a grass cell?

I found this picture online claiming it was a grass cell. Clearly it is a cross section image but I was hoping you could tell me if this is actually grass, or something else if anything.
2
votes
1answer
221 views

Does Pseudomonas aeruginosa have any common name at all?

Pseudomonas aeruginosa is the fifth most written about¹ binomial name of all species. I'm having trouble coming to terms with the possibility that such a well researched and studied organism has never ...
1
vote
0answers
18 views

What would happen to a body in an astronaut suit over time if floating free? [duplicate]

I'm not sure if this is best in Biology or Physics, but on Earth we decay to skeletons and then eventually to dust. What would happen in space in a space suit?
1
vote
1answer
27 views

Relation between a compound's toxicity and it's concentration level

I know that ammonia is toxic for the body since it disturbs enzymes of mitochondria. I want to know that why the ammonotelic animals don't get affected by it? I mean that even if there is plenty of ...
3
votes
3answers
422 views

why do some cells in the body prefer necrosis to apoptosis as a means of cell death?

There are many programmed cell death pathways, but some cells show a greater preference for some over the other. I'm wondering as to why if necrosis is an inflammatory response that causes damage to ...
2
votes
0answers
56 views

Cockroaches and magnetic fields

Aloha, I live in Hawaii working with sharks and their sensitivity to magnetism but here we also have large cockroaches. Has anyone worked with cockroaches and magnetism? I wonder if placing high ...
3
votes
1answer
91 views

How long does it take to form a peptide bond?

What is the time taken to form a peptide bond in vivo or in vitro? It isn't mentioned in my course on protein structures. I was just curious to find out if any time scale is known? Given that ...
0
votes
1answer
186 views

Why do humans have eyebrows? [closed]

Why do humans have eyebrows? It seems that it isn't necessary but only humans have them, correct? So what is the use of them for humans? I hear that they protect our eyes. However, isn't that what ...
1
vote
1answer
118 views

Mode of Enzymatic Inhibition via R-Allele

The photo above shows the effects of the R allele of the pea shape gene on the synthesis of an enzyme that converts unbranched starch into branched starch. The r allele of this gene determines an ...
6
votes
1answer
261 views

Why are particular laser-related skin products not recommended for darker skin tones?

This is about products such as: The "Theradome" laser helmet (this claims to stimulate hair growth through lasers) Theradome™, a biomedical engineering company based in the Silicon Valley, is ...
3
votes
0answers
60 views

How Many Generation We can Run a Mycelium of Pleurotus ostreatus/Pearl Oyster?

I am able to grow mycelium successfully on the spent coffee grounds. And mycelium is successfully fruiting once/twice on the same substrate. I am cloning by taking mycelium from the existing one (...
3
votes
1answer
135 views

Identification of unknown bagworm (Singapore)

This bagworm was found in Singapore (near McRitchie Reservoir) some time in June 2012. This is the plant from which the bagworms were obtained: A few examples of the bagworms: The bagworm when ...
1
vote
1answer
41 views

The damage of cancer cells

I read about the molecular biology of cancer, and I have a mess on my head and a lot of questions.. . My primary question is- The damage of the cancer cells is in the dna sequence or in the gene ...
1
vote
0answers
20 views

Question about clusters and populations [closed]

Whats the difference between a cluster and a population?...and do non africans cluster together? Examples European populations or the niger congo cluster.
2
votes
1answer
193 views

Gradualism vs. Punctuationalism

TLDR? Just read the bold bits! I started with Darwin's Origin of Species, and then read Dawkins's first three books The Selfish Gene, The Extended Phenotype, and The Blind watchmaker (I just started ...
1
vote
0answers
54 views

How to measure chemical elements in soil? [closed]

What sort of equipment would one need to ensure that plant soil contains the right concentration of the 13 mineral nutrients necessary for plant growth? As far I understand, it's vital that all the ...
13
votes
2answers
908 views

Species ID: Cape Town mystery insect

This insect bumbled into my bedroom last night - can someone ID it for me? I'm mainly curious because I'd like to know if it poses any danger to my cats (who were very eager to add it to the menu). ...
2
votes
0answers
127 views

Why are riboswitches mostly present in bacteria and not in eukaryotes?

Riboswitches are a rather elegant way to regulate gene expression without any additional machinery. A small ligand binds to the mRNA and directly influences transcription or translation. Most of the ...
1
vote
0answers
48 views

Is there any tree or other plant that produces a new crop in fast cycles? [closed]

Is there any tree or other plant that produces a new crop in fast cycles? By fast I would mean something much more often than once or twice a year, like every month or every few weeks. What is the ...
2
votes
0answers
165 views

Can protein sample be made 2% Triton X-100 free?

The protein I am purifying needed an elution buffer with 2% Triton X-100. I formulated the elution buffer not keeping the CMC in mind. My goal is to make my protein sample triton free to check its ...
0
votes
1answer
76 views

How much mass does a person lose in a day through breathing and perspiration?

Water and carbon are lost through perspiration and breathing. How much mass is lost in this way in a single day for a typical person?
3
votes
0answers
44 views

What has to duplicate before cell enters M phase? [closed]

What has to duplicate before cell enters M phase? DNA histones centrosome mitochondria (any other organelles?) condensins (not sure?) have I forgotten anything? Thank you in advance!
2
votes
1answer
330 views

How can a brainless Cnidarian hunt and defend itself?

Cnidaria, such as jelly fish and sea anemones are radial symmetric en feature a simple body plan. One notable aspect is the lack of a brain. Hence, there is no central guiding structure, no mind or ...
2
votes
1answer
307 views

Does increased cell turnover cause cancerous mutations?

If a certain set of cells or tissue are undergoing a lot of reproduction and repair cycles for some reason, does this inevitably lead to cancerous growths? If the mutation rate exceeds the normal '...
3
votes
0answers
47 views

What are the biological mechanisms of candy causing nausea?

As I sit here after eating too much chocolate, I wonder: What are the biological mechanisms behind eating too much candy candy causing nausea in a healthy individual? Is it a spike in blood sugar, ...
2
votes
3answers
590 views

True or false & fill in the blanks

A ribosome is where amino acids are linked together by peptide bonds. A virus is NOT considered prokaryotic because it does not have a membrane. The nucleotide ATP is one of the most used energy ...
2
votes
1answer
46 views

Is it possible to estimate how much variation in common phenotypes is predicted by genetics?

Phenotypes such as; skin color, eye color, nose shape, lip size, limb proportions, and skull shape. Im trying to find a source for this quote. "If you ask what percentage of your genes is reflected ...
3
votes
2answers
289 views

Assessing probability from a pedigree

This isn't exactly homework but I'd like to treat it as such. I'm asked to find the probability that both (III: 2) and (III: 3) are carriers given that (II: 7) and (III: 1) exhibited the recessive ...
1
vote
1answer
254 views

What is Mendelian Segregation and how is it related to the Hardy-Weinberg equilibrium?

I can't find the exact definition of Mendelian segregation. In addition, I am wondering how it is related to the Hardy-Weinberg equilibrium?
2
votes
0answers
59 views

What species of Cerapoda lived during the Jurassic?

So far, I've found eleven species of Cerapoda that lived during the Jurassic period. Are there any other known species that I've missed? The eleven that I've found out about are: Agilisaurus ...
2
votes
1answer
248 views

How do you convert mtDNA sequences in FASTA to FSTAT format?

I've got control region sequence data from a population of shark and I'm looking to convert this from FASTA to FSTAT in order to calculated the effective population size of females. The software I ...
2
votes
1answer
35 views

Are there any generic (not dependent on symptoms) ways to find parasite infections?

Are there any generic ways to determine if a person is infected with a parasite? With "generic ways" I mean ways that do not rely on symptoms caused by a particular parasite. Also I am mainly ...
0
votes
1answer
113 views

Which of these components has C-H and COOH groups [closed]

A) Amino acids and triglycerides that have a carbon-carbon double bond or B) proteins and fatty acids I think they ...
5
votes
1answer
141 views

How to measure metabolic rates of microscopically small animals?

I want to measure metabolism rates in Tardigrades Metabolic rates will be assessed immediately following their exit from cryptobiosis (an animal dormant state). I know that oxygen levels is the ...

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