The study of cells: their physiological properties, structure, environmental interaction, division, life cycle, and death, as well as the organelles they contain. Also known as cytology.

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3answers
8k views

What is the distinction between chemokines, cytokines, interferons and interleukins?

They all seem to describe molecules of similar function and many people seem to use them interchangeably. Also please include any other similar molecules if I've forgotten any in the list above.
6
votes
2answers
50 views

Why do epithelial cells arrest in response to serum?

Primary epithelial cells, for example human mammary epithelium, fail to proliferate (arrest) in serum-containing medium. Therefore, a common growth medium for epithelium contains pituitary extract ...
2
votes
1answer
37 views

Why is there a compound highlighted in red in a KEGG Module search?

Considering the following module: http://www.kegg.jp/kegg-bin/show_module?M00115+C00003 why is the compound C00003 marked in red?
0
votes
1answer
30 views

Presence of reaction module in bacteria but not in Eukaryotas (human)

From the statistics page, I found that the Module-M00008 is present only in bacteria and not Eukaryotes. Why so? I noticed that all the compounds necessary or the reaction are present in human body ...
2
votes
1answer
34 views

Who compared developmental biology to crystallography?

I need to find out the name of a nineteenth century biologist who compared developmental biology to crystallography. His idea was that crystals are formed from 'cells' (defined molecular units) that ...
2
votes
1answer
48 views

What happens to IP3 molecules after release from IP3 receptors?

IP3 molecules bind to IP3 receptors and open up the calcium channels on the endoplasmic reticulum. I am wondering what happens to IP3 molecules after they have been released from the IP3 receptor? Do ...
2
votes
1answer
143 views

Are there histones present in the cytoplasm?

In this paper the authors depleted core histone heterodimers H3-H4 at 90 % from the cytoplasm of Xenopus oocytes. They state that their concentration is in the order of 6 uM. My question is, are ...
1
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2answers
72 views

Referencing the homologous chromosomes

There exist a co-ordinate system from chromosomes like "12p11.3". In this system, first integer range from 1 to 23 i.e it takes homologous chromosomes as a pair. If we want to distinguish among ...
1
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1answer
91 views

Choosing the best assay for my experiment? [closed]

Which of the following assays can be used to determine whether cell death specifically due to apoptosis has occurred in a given cell sample? Choose all that apply. WST-1 Assay Caspase Colorimetric ...
12
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3answers
2k views

What is happening when we get a tan?

Almost everyone nowadays wants that nice summer tan, but what exactly is going on beneath the skin? I've heard a few different theories about tanning - such as a tan is nothing but the pigmentation in ...
2
votes
1answer
181 views

Why do some people burn and others tan?

Connected to What is happening when we get a tan? - Why do some people burn while other people tan? Very pale people tend to just burn while other people tan very nicely, what causes this difference? ...
6
votes
1answer
2k 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 ...
1
vote
0answers
23 views

Genetic tests on S. cerevisiae to determine mutation locus on genes

I am studying the metabolism of galactose in the budding yeast Saccharomyces cerevisiae. After a random mutagenesis screen, several mutant strains were isolated that grow well in glucose but are ...
2
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1answer
57 views

T7 Tagging in Synthetic Biology

What is a T7 tag and can if be used to purify synthesized proteins? Is it charge based like a His tag?
4
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1answer
698 views

What happens to the red blood cell in CaCl₂ solution?

Here's the problem: One red blood cell is placed in a hypertonic solution of NaCl, another is placed in a solution of CaCl2 equimolar with the NaCl solution. What would you expect to happen and why? ...
5
votes
1answer
41 views

How are the physiological properties of mitochondria measured?

this is my first question on BiologySE. I am a Physics and Mathematics student currently doing a project on cell growth simulation. I am doing literature survey and I have a question about cellular ...
0
votes
0answers
62 views

Cell Line With DNMT3a Mutation

I am looking for a cell line (preferably hematopoietic) that has an inactivating DNMT3a mutation. I have checked the Cancer Cell Line Encyclopedia but of all the hematopoietic cell lines I know I ...
1
vote
2answers
260 views

Can you Transfer Cancer Between People via Saliva or other Bodily Fluids?

This may sound like a strange question. But could a Cancerous cell be transferred from one person to another from Oral contact e.g. Through Saliva, or other exchange of bodily fluids? I know that ...
5
votes
3answers
206 views

How can a ligand be an integral membrane protein?

My background is in mathematics, and not biology, so please bear with me. I am currently working on a project involving the effects of Epidermal growth factor treatment (EGF) on cell migration. I am ...
1
vote
3answers
199 views

Trypsin and cell culture

I am doing an experiment where I have treat the cells with a drug and calculate their counts. I would like to know if is bad to trypsinize the cells in consecutive days i.e. twice within 48 hours. How ...
5
votes
1answer
462 views

Time spent in phases of cell cycle

I am looking for references to papers containing the time intervals spent in different phases of the cell cycle (ej., G0, G1, S, G2, M for eukaryotes) for different cells. In particular, I am ...
1
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1answer
40 views

Mitochondrial inner membrane

I know that the cristae of the inner membrane can be tubular or vesicular but I would like to know what are the functions of each .
3
votes
0answers
103 views

Can I leave BL21(DE3) cells in room temperature?

I am preparing competent cells, and I finished inoculating a single colony in SOB. It has been incubating at 37 degrees Celsius for almost 16 hours since, and it's getting very late where I live. I ...
4
votes
2answers
253 views

Breakdown of energy expenditure at the level of a single cell

The metabolic rate measures how much energy an organism expends over a unit of time. Its breakdown for the human body in terms of its functions is well documented : so much for the heart, for the ...
3
votes
1answer
59 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
2
votes
4answers
278 views

Do I need to serially dilute E. coli cultures for optical density measures?

I am expected to track cell growth by measuring the incubating culture's cell concentration every 30 minutes or so. So my questions are: Why do I need to do serial dilution (assuming that I do)? Why ...
5
votes
2answers
151 views

Are fish roe unicellular?

Are roe (fish eggs, caviar, etc.) single cells? I have tried looking this up on google (sadly, to no avail), and I am guessing they might be multicellular (like bird eggs) or consist of one cell plus ...
4
votes
1answer
43 views

Proline Iminopeptidase v Proline Aminopeptidase

We're an undergraduate independent research team and we are having trouble purchasing commercial proline iminopeptidase as it is unavailable on Sigma Aldrich and very expensive on other websites. We ...
1
vote
1answer
85 views

Why is the gene regulation in eukaryotic cells needs multiple level of control than in prokaryotic cells?

That "eukaryotic cells are more complex" and "compartmentalized" are used to justify the need of more level of control of gene expression. I get the basic idea but can't convince myself why complexity ...
2
votes
2answers
264 views

A question on glycolysis

In the first step of glycolysis, the glucose ring is phosphorylated. Phosphorylation is the process of adding a phosphate group to a molecule derived from ATP. As a result, at this point in ...
1
vote
2answers
29 views

T7 Tagging Next to Met

Will a T7 tag still work if it is placed next to a start codon? Meaning, will it still work with a Met attached to it in the amino acid sequence? Thank you!
2
votes
2answers
197 views

What are multicell spheroids?

I'm from a maths background and I'm doing some research on mathematical models of cancer. I've come across alot of literature mentioning "multicell spheroids" in the context of avascular tumours. I ...
-2
votes
1answer
159 views

What is the difference between electrons and energy? [closed]

I'm studying microbiology right now and I have come across something confusing to me. I thought electrons provided energy to the cell by being incorporated into reducing powers and eventually driving ...
3
votes
1answer
276 views

How did the endoplasmic reticulum come to be?

Organelles are sub-cellular compartments in cells. However prokaryotes don't use organelles to organise their intracellular space. Evolutionarily, there is evidence that mitochondria and ...
2
votes
1answer
242 views

Why are hard boiled eggs so homogeneous?

A eukaryotic animal cell is a complicated piece of biological machinery. Some major structures inside of the cell (see the image below) include: the nucleus, mitochondria, Golgi vesicles, and various ...
7
votes
2answers
3k views

Multi-nucleated cells: advantages and examples?

This question arises because I saw that monocytes and leukocytes are commonly called 'mononuclear cells' in the scientific literature. The implication of course being that other immune sub-types are ...
9
votes
2answers
169 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 ...
1
vote
1answer
39 views

How many NOD like receptors in Human?

This is pretty specific question maybe. Anybody have an estimate? For Toll Like Receptors there are something like 10... http://www.jbc.org/content/276/4/2551.long I'm only finding NOD1 and NOD2 => ...
4
votes
1answer
47 views

Why MHC class I antigen presentation exist in normal cells?

The book "Kuby Immunology" states that normal infected cells might present antigenic peptides on their surface via MHC class I, but these can't activate naive CD8 cells. Only infected professional ...
4
votes
1answer
63 views

Are stem cell lines cryogenically preserved or commercially available like HeLa cells are?

There are HeLa cells, which were taken from sick cancer patient and now is growing worldwide in different laboratories for experiments. HeLa cells can be kept because they are immortal and so they are ...
1
vote
0answers
34 views

What is a “NuMA protein”?

I just got out of a lecture on mitosis and this part was incredibly confusing. After searching my textbook it doesn't cover it that well either. The professor mentioned a NUMA protein that is ...
5
votes
1answer
177 views

During the process of correcting mutations via gene therapy, is the defective gene removed?

Just recently started learning about gene therapy, many websites explain that the corrected DNA can be added to the genome using a vector and all that. I just don't understand what happens to the ...
8
votes
1answer
142 views

What specific membrane adaptations do cells have for saline-rich environs?

Are the cells of marine animals and flora equipped with special ion exchange pumps to mitigate the effects of a saline-rich environment? Or have the cell's membranes adapted through structural ...
0
votes
1answer
131 views

GPCRs: Gi and Gs

GPCR = G-protein coupled receptor Gi = G inhibitory alpha subunit Gs = G stimulatory alpha subunit Are there structural differences between Gi and Gs subunits (secondary structure)? Or is it just ...
4
votes
2answers
1k views

Are there human cells, apart from red blood cells and platelets, without a nucleus?

I know that blood platelets and erythrocytes do not have a nucleus. Are there more cells in the human body without a nucleus, such as pancreas, cartilage, or lung cells?
3
votes
0answers
27 views

Why do flagella form a bundle only when they rotate counterclockwise during chemotaxis?

During Chemotaxis in bacteria with flagella, the flagellar rotation dictates how the cell moves. If the flagella rotate counterclockwise, then they form a bundle at one end of the cell (---O) and ...
5
votes
1answer
60 views

Do non-enzyme catalysed reaction pathways exist?

Can their be a kind of chemical reaction pathway in a cell, that is catalyzed or regulated but NOT necessarily by enzymes? I could not find anything on Google. I have almost no background in biology, ...
3
votes
0answers
50 views

How many cells are there in the apical meristematic tissue?

How many cells are there in the apical meristematic tissue? Looking at this picture... , I would tend to think that there are few hundreds cells in the meristem tissue. But I guess this is a ...
3
votes
1answer
98 views

Microalgae without cell walls?

Most microalgae have rigid cell walls. Dunaliella Salina is a pretty famous example of an algae with no cell wall, but just a plasma membrane. Are there any other microalgae without a cell wall?. I ...