Known also as "cytology" is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death.
23
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1answer
369 views
What is itching?
What exactly at the molecular level is itching? What physiological function does itching serve, if any? I cant remember the reference but a PLCb3 null mice lost the itch phenotype, so presumably it is ...
21
votes
1answer
258 views
How long will a vegetable live for after being harvested?
I understand this might depend on the types of vegetables, but is there an average or studied specifics? Does it die immediately? Is there a way to precisely diagnose death in plants? If so, what are ...
20
votes
1answer
226 views
How does a cell know its size?
Cells come in all sorts of sizes. How do they regulate their cell size to the point where similar cell types have a fairly mono-disperse size distribution?
Reasked from ...
18
votes
1answer
332 views
Are lymphocyte sizes clustered in two groups?
Tortora writes in Principles of Anatomy and Physiology:
Lymphocytes may be as small as 6–9 μm in diameter or as large as 10–14 μm in diameter.
Those ranges are quite close to each others. Should ...
17
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3answers
134 views
How crowded is the bacterial cell?
I was wondering what is the protein concentration in an E. coli cell. When studying enzyme kinetics and activity in vitro, I would argue that the substrate and enzyme concentrations resemble those in ...
15
votes
5answers
448 views
Online Molecular and Cellular Biology Video Lectures?
I am looking for video lectures to go through to guide my reading in intro molecular and cellular biology. I've had intro bio and I study evolutionary theory, but my molecule- and cell-level knowledge ...
11
votes
3answers
360 views
Why do red blood cells contain haemoglobin and not myoglobin?
So I am reading about muscles and I come across myoglobin. It has a much higher affinity for oxygen than haemoglobin. So why have animals evolved to have haemoglobin in red blood cells, rather than ...
11
votes
1answer
396 views
Is there an advantage to linear chromosomes?
The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
11
votes
1answer
72 views
Does a theory exist for the formation of thylakoid structure?
I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to ...
10
votes
2answers
269 views
Could hydrogen replace oxygen in cellular respiration?
I was wondering what oxygen actually does in the body. I have seen a few answers to other questions that involve the electron chain and I am really not sure what that is. So I was wondering what ...
10
votes
1answer
203 views
Does electricity cause damage on a cellular level?
As I understand it the mechanism of death when a mammal is electrocuted is that the current disrupts the SAN/AVN in the heart causing it to fibrilate or arrest. That's on a macro scale, however. ...
10
votes
1answer
479 views
Is the eukaryotic nucleus composed of a single or double membrane?
I know that it is usually considered a double membrane like those surrounding mitochondria and chloroplasts, but I read a review that stated "according to topological details it is actually a single ...
10
votes
1answer
4k views
How to store vegetables in the refrigerator: In plastic bags or not?
My wife and I are having a debate similar to this one:
I claim that it's better to take the fresh veggies out of the bags and put them in the crisper with humidity control because:
That's what the ...
9
votes
1answer
342 views
Did researchers evolve multicellular yeast or did they just turn on multicellularity?
In this new paper "Experimental evolution of multicellularity" found via Ars Technica the researchers describe having developed multicellularity and apoptosis within 60 days from a unicellular yeast ...
8
votes
3answers
222 views
What triggers meiosis in gonadal cells?
What specific biochemical processes are involved in inducing meiosis rather than mitosis? Why are gonadal cells the only cells in the human body which do undergo meiosis?
8
votes
1answer
198 views
What is a inhibitory tone when talking about neurons?
In this SE answer: Could an "overactive" brain increase the chances of Alzheimer's Disease?
user @nico used the word inhibitory tone What does that ...
8
votes
1answer
167 views
How is the number of mitochondria in a cell regulated?
How does the cell regulate the number of mitochondria in a cell? What happens when there are too many or too few?
8
votes
2answers
495 views
Why can't a human regenerate limbs like some other species?
When a person's arm is amputated, the arm will no longer be able to grow back. However, in salamanders, the arm actually grows back.
In comparison to a human, what is really happening to the cells ...
7
votes
2answers
155 views
Is “exhaustion” of the Hodgkin-Huxley membrane at constant stimulation a real phenomenon?
I was playing around with a simulation of the Hodgkin-Huxley model using their original parameters for the squid giant axon.
By applying a constant stimulation current to the model in resting state, ...
7
votes
1answer
130 views
How Do Large Ocean Viruses Form Their Own Organelles?
Several large viruses (Arslan 2011) form their own organelles within the amoebae they invade.
How do these organelles form?
Reference:
Arslan, D., Legendre, M., Seltzer, V., Abergel, C., Claverie, ...
7
votes
1answer
137 views
Why aren't mitochondria and plastids considered symbiotes of eukaryotic cells?
Mitochondria and plastids have their own DNA, their own membranes, and their reproduction is not tied to the reproductive cycle of the host cell. However, they are considered to be organelles rather ...
7
votes
1answer
39 views
Cell Respiration and Oxidative Phosphorylation
Why and how does the proton travelling through the stalked particle in the inner mitochondrial membrane, cause a conformational change in the ATPase?
7
votes
1answer
136 views
How fast do different organs turn over cells?
It is said that the human body turns over all cells or molecules in 7 year cycles. This is not quite correct, because there are different organs changing at different speeds. My interest is what is ...
7
votes
1answer
135 views
When collecting cell lysates for a Western blot, how do I induce di-sulfide bonds?
I would like to conduct a simple dimerization experiment for some protein I'm collecting from a cultured cells. My thought is, that if I'm running a non-reducing, denaturing PAGE gel, then removing ...
7
votes
1answer
2k views
What is the difference between “dikaryotic” and “heterokaryotic” states in the sexual lifecyles of fungi?
Many fungi undergo a reproductive phase in which more than one genetically distinct nuclei (from 2 separate mating types) is present within the same cytoplasm. In the Ascomycota and Basidiomycota, ...
7
votes
1answer
65 views
How do nuclear receptors locate each other to form a DNA loop?
Nuclear receptors can influence transcription far up- or downstream from their own binding sites by looping DNA (Rubina et al.; J Mol Bio 2004).
I am not sure how exactly the receptors first attach ...
7
votes
1answer
165 views
Do larger multicellular organisms have an increased risk of mutation and thus cancer?
So I was thinking that if each cell has P(X) of becoming cancerous, then the chance of cancer is 1-((1-P(X))^n) where n is the number of cells in the organism.
Since larger organisms have more cells ...
7
votes
2answers
123 views
Does pheomelanin have a useful biological function?
Melanin is a natural pigment that is categorized into two main forms, eumelanin and pheomelanin. It's well documented in the science literature that increased eumelanin levels reduces the risk of ...
6
votes
1answer
163 views
Does DNA contain information beyond protein synthesis?
It's well known that genetic information is stored in DNA. As far as I know, DNA only has information at the protein level. What about higher levels, such as organelles, cells, tissue, organs? Is ...
6
votes
2answers
437 views
What is the main general difference between Mitosis and Meiosis?
I found such a clause:
The general principle is that mitosis creates somatic cells and
meiosis creates germ cells.
However, I cannot agree. Each gametogonium needs to go through mitosis before ...
6
votes
1answer
191 views
Methods of nuclear transfection - nuclear transport
I am reading through the ENCODE papers, which is taking me well out of my comfort zone in terms of modern laboratory techniques. At the risk of asking a question which may well be thoroughly answered ...
6
votes
1answer
72 views
How was the first ribosome theorized to have been made?
Seeing as ribosomes are what help perform the act of translation itself, and the blueprints for they themselves are in nucleotide sequences, how was the first ribosome theorized to have been made? ...
6
votes
2answers
129 views
How do cells “know” what “type” to differentiate into?
I have been reading about Townes and Holtfreter's work in 1955, in which cells are dissociated from a blastocyst in an alkaline solution then mixed together and spontaneously reaggregates based on ...
6
votes
1answer
68 views
How much energy does a cell expend maintaining its contents?
In software engineering, an analogy is sometimes made using biological cells. I would like to know whether it has basis in fact.
People say (Alan Kay was first) that "objects" in software should be ...
6
votes
1answer
103 views
How are synaptic vesicles brought to the synapse?
I'm reading about how synaptobrevin is used to identify synaptic vesicles for tethering near the synaptic cleft. Since neurons have a synapse and dendrites, I'd like to know how exactly the vesicles ...
6
votes
1answer
146 views
How similar are Circulating Tumor Cells and Cancer Stem Cells?
Circulating Tumor Cells (CTCs) are linked with metastasis and their presence can be used to indicate the onset of metastatic cancer. Likewise, the Cancer Stem Cell (CSC) hypothesis suggests that ...
6
votes
1answer
230 views
Does every mitochondrion in a cell contain the same DNA?
I know that mitochondria of eukaryotes have their own DNA, more similar to that of bacteria than to the rest of the cell's DNA. I also know that a cell can have plenty of mitochondria, and I ...
6
votes
3answers
100 views
What gaseous substances do humans emit?
Other than CO2 and Methane what other gases do humans produce or emit?
For example, does skin decomposition, or aerobic respiration emit any special gases that people don't normally realize or know ...
6
votes
2answers
55 views
Macrophage pathogen fixation
Overly simplified, macrophages recognise pathogenic patterns and endocytose anything that matches them.
That also works on bacteria, which are quite often very mobile. What if a bacterium was just ...
6
votes
1answer
126 views
What's a good reference for choosing histological staining chemicals?
It's often difficult to find the appropriate or best stain to use when I want to examine a new type of tissue. I think that's partly because many histological techniques were developed a long time ...
6
votes
1answer
88 views
Macromolecule levels in daughter cells after fission
When a prokaryote undergoes binary fission, how are the non-DNA macromolecules distributed between the two daughter cells? This is motivated by comments on a previous question and a G+ discussion. I ...
6
votes
1answer
382 views
How does water buffer a sudden drop in temperature?
A property of water is that it is slow to heat and cool. According to my biology book, some energy from an increase in temperature would spent breaking hydrogen bonds, so that temperature does not ...
6
votes
1answer
62 views
How are chromatids correctly segregated during mitosis?
In my book this is described as happening by kinetochores depolymerising from their attached microtubule spindle, then being dragged towards the spindle's centrosome by a dynein protein. I can ...
6
votes
1answer
64 views
number of RNA pol II molecules in a given human nucleus?
Does anybody have any estimate on the number of RNA pol II molecules in the nucleus of a given human cell? For example, how many RNA polymerase type II protein complexes would there be on average at a ...
6
votes
0answers
51 views
Pancretic Acinar Cell - ATP, calcium concentration data
I need to find a decent source of data for concentration of ATP and calcium in the pancreatic acinar cell.
So far all I can find is ATP or calcium 'levels' based on fluorescence , which are not ...
5
votes
4answers
1k views
RNA or ribosome, which one moves during translation?
During translation ribosomes decode the genetic information present in the mRNA and protein synthesis takes place. During this process which of those two does move, the ribosome or the mRNA?
5
votes
1answer
59 views
Free-flowing cells and those that are stuck together?
I've been thinking about the development of an embryo from the zygote stage.
How is it that when cytokinesis takes place at that stage, the cells all stick together in a little ball, but later in ...
5
votes
1answer
157 views
Do animal cells have vacuoles?
I overheard a rather heated argument about whether or not animal cells have vacuoles.
One person said that they do, but they're much smaller than vacuoles in plant cells.
The other person said they ...
5
votes
1answer
79 views
Why aren't organelles considered alive?
I'm taking a 3-week Bio I summer course, and my textbook says the cell is the smallest/basic unit of life. I asked my professor why organelles aren't a living unit, and her reply was that they aren't ...
5
votes
1answer
119 views
Can you consider a human as alive, or is it the cells on the body that are alive?
Sorry if this question seems strange, but in the recent time I have been interested in the question of what life is and how you can define life.
My question:
How long can individual cells live on a ...
