3
votes
1answer
163 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 ...
7
votes
3answers
25k views

Does Human Female Meiosis II occur after fertilization with sperm?

I am reading the answer and I am getting confused by the sentence: At the end of meiosis I females have two daughter cells and meiosis II only occurs if and when fertilization occurs by a sperm ...
1
vote
1answer
128 views

What's the meaning of 'plasma' in 'plasma membrane'?

I wonder why is it called plasma membrane - what's the biological meaning of the word 'plasma'?
2
votes
2answers
1k views

Calcium levels and nerve hyperexcitation

Why does lower blood calcium levels (or lower calcium levels in ECF) cause nervous hyperexcitaton? Why does it cause over stimulation of nerves and muscles and spasmic contractions of muscles? This is ...
0
votes
0answers
20 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 ...
3
votes
3answers
291 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 ...
5
votes
3answers
395 views

If someone were to die on the moon, would their body decay?

I heard that the footprints of Neil Armstrong are still there, so I was wondering if someone were to die there, would they remain preserved, too? If not how long would it take for them to decay?
1
vote
2answers
64 views
4
votes
1answer
199 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. ...
1
vote
1answer
109 views

What specific sensory nerves act as receptors for “pins and needles” (neuropathy)?

According to this excellent answer, the difference between "pain" and "pins and needles" (neuropathy) is that different receptors (sensory nerves) trigger in reaction to different stimuli. Different ...
1
vote
1answer
58 views

How and where do nerves share pathways to the brain?

I am interested in understanding how pain receptors send signals to the somatosensory cortex (the part of the brain that registers various nerve signals such as pain, presure, temperatures, etc). ...
1
vote
1answer
34 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 ...
2
votes
0answers
77 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 ...
1
vote
2answers
48 views

Why are nausea and dizziness such common side effects from medication?

Why are nausea and dizziness such common side effects from medication? If you go through your medicine cabinet and look at side effects, those might just be on every single bottle. Is there some ...
1
vote
1answer
75 views

Why is sarcoma more prevalent and common in right heart?

Ewing's sarcoma or Ewing sarcoma is a malignant small, round, blue cell tumor. It is a rare disease in which cancer cells are found in the bone or in soft tissue. It is more common in right heart than ...
2
votes
2answers
1k views

Why aren't animals diverse in phenotype? [duplicate]

I am not comparing a cat with leopard. I am just saying that we humans are all one type of creature and we are diverse (I am not saying we are class of mammals and phylum of etc and kingdom etc, ...
5
votes
1answer
284 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. Thanks!
1
vote
1answer
85 views

Which came first in hominid evolution: language or bipedalism? [closed]

I suspect both language-use and upright-posture have anatomical consequences. So does the fossil record show which came first? NOTE: To the folks who marked this question "homework": This is ...
10
votes
1answer
3k views

On the genetics behind caste marriages

I am in India where it is typically a custom to marry within one's caste. Basically the caste system originated with roots in people's professions - Each of priests, carpenters, troupers, etc had a ...
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?
2
votes
0answers
45 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 ...
1
vote
1answer
94 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 ...
0
votes
1answer
159 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 ...
6
votes
1answer
252 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 ...
1
vote
1answer
371 views

How to determine if this blood disorder is recessive or dominant?

This question is from "Concepts of Genetics," Klug & Cummings, 10e. "Thalassemia is an inherited anemic disorder in humans. Affected individuals exhibit either a minor anemia or a major anemia. ...
1
vote
1answer
38 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 ...
10
votes
2answers
817 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
1answer
44 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 ...
2
votes
1answer
109 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 ...
4
votes
1answer
72 views

Statistics on energy consumption breakdown per biological functions across organisms?

Are there any statistics available on how much energy organisms use for each biological functions (i.e. something similar to the line of "Bacteria spend X% of energy on information processing, Y% for ...
2
votes
1answer
152 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
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.
6
votes
0answers
479 views

Evolutionary reasons why you cannot tickle yourself but masturbate

There are obviously good reasons that explain why you cannot tickle yourself (see e.g. here). This got me thinking why it is possible to masturbate... Wouldn't it make more sense to not being able to ...
2
votes
1answer
204 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
100 views

Plant tissue culture [closed]

Tissue culture means that cells are propagated and multiplied under controlled conditions. Suppose the following situations: a) A seed being is embedded in an Agar medium and germinated under ...
5
votes
2answers
421 views

Why do skin and nail go blue in cyanosis?

I have learned that Cyanosis presents with blue skin and nails. What is the reason for the blue coloration of the skin and nails? Why wont the skin and nails turn another color in the visible spectrum ...
0
votes
1answer
64 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?
1
vote
0answers
46 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 ...
2
votes
0answers
87 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
42 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
122 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 ...
2
votes
3answers
437 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 ...
7
votes
1answer
254 views

What is the limit of time resolution in fMRI?

I was reading about a few studies on estimating functional connectivity between brain areas using fMRI signals. However, as far as I know that fMRI has a very poor time resolution, roughly in the ...
5
votes
1answer
103 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 ...
3
votes
0answers
38 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
0answers
58 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 ...
3
votes
2answers
214 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 ...
3
votes
0answers
42 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, ...
8
votes
1answer
159 views

Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene A, with alleles ...
-3
votes
1answer
71 views

Could we engineer humans to behave like insects? [closed]

First off, though complex, I'm assuming insects are at an earlier evolutionary stage than humans. That being said, could humans be genetically engineered to behave like insects? I'm not talking about ...

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