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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130 views

Transmembrane Protein Problem

Problem A transmembrane protein has 1000 aa. The 5th aa is found on the external side of the cell membrane. It interacts with the aqueous environment outside the cell. Amino acid 90 is inside the ...
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1answer
2k views

Where do lost membrane proteins go after exocytosis?

Exocytotic vesicles take away membrane proteins and glycocalyx on the cell's plasma membrane surface. When those vesicles are released into the interstitial fluid and wherever else, where do they go? ...
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1answer
26 views

epitope prediction/ mapping

B-CELL EPITOPE PREDICTION Regarding this article: "Such a molecule can be synthesized or, in case of a protein, its gene can be cloned into an expression vector."----- is a particular line in ...
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1answer
750 views

Why doesn't the cell membrane just… break apart?

Forgive me if this is a silly question. I can't understand the basics. Why doesn't the membrane just... break apart? What's keeping the layers in the phopholipid bilayer together? I know that the ...
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2answers
466 views

What is MHC haplotype?

What is MHC haplotype? I did check out the wiki article, but did not understand. (I have not studied biology since last 8 years and now I am going through it because I need it for my research. So if ...
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1answer
403 views

Difference between sequential and conformational epitope

Is the difference only in its structure? Like conformational epitope has 3D structure while sequential has a linear structure?(I have not studied biology since last 8 years and now I am going through ...
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2answers
64 views

Are there known downsides to removing UV mutation hotspots to prevent some skin cancers (Genetic sunblock)?

Khavari et al. recently demonstrated that a significant fraction of one of the major forms of skin cancer (cutaneous squamous cell carcinomas) are associated with a mutated KNSTRN gene (a protein ...
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1answer
112 views

Integration of several environmental signals

I am looking for examples of different functions that are good fit to how signals are computed in order to respond to the environment. Let's make my question more copmrehensible with an example... ...
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1answer
3k views

Rate of cell division in humans

On average, how many cells divide each day in a human being? How long does a cell wait before dividing itself ? I have tried to look on the internet but surprisingly the answer is difficult to ...
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1answer
67 views

SEREX serological analysis of cDNA expression library

What is Serological Analysis of cDNA expression library? I went through this article:http://cancerimmunity.org/serex/introduction/ but could not really make out. Can someone please explain this to me ...
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1answer
34 views

Degenerate Alignment Analysis

Can someone please tell me what is Degenerate alignment analysis? Could not find a good article on the internet that could help me understand what it means? (I have not studied biology since last 8 ...
2
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1answer
70 views

How does core-conductor model correspond to an actual neuron?

Hi guys, looking at your average neuron, it is very difficult for me to imagine how this could be translated into a core-conductor model On the neuron above, where would be the intracellular ...
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1answer
24 views

Microarray probe and target

In a microarray, which one is called a target and which one is the probe? the one that is added later , is that the probe or the one present in the slots of the microarray, that is the probe? (I have ...
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0answers
31 views

TAA- Tumor associated antigen [duplicate]

An approach to find Tumor associated antigens is based on transfection of expression library made from cDNA into cells expressing desired MHC haplotypes. Can someone please explain what this line ...
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2answers
44 views

How is it that ionic diffusion is independent of other ions?

This question arises from the explanation of what the resting potential of a cell membrane is. In the Goldman formula, there is no interaction between different ion types. If diffusion is caused by ...
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1answer
117 views

Are retroviruses cytotoxic?

There are typically hundreds of retroviruses found in healthy human beings. Are retroviruses then cytotoxic? (In other words, are they able to kill or damage other cells).
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2answers
35k views

How many human cells are there in our body, on average?

How many human cells are there in our body, on average? Wikipedia says 1013: Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in ...
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1answer
75 views

How to measure the total number of cells in an average human body?

I have got one assignment to calculate the approximate sum total of all cells in the human body. How to tackle this problem? I know that the current statistics is $10^{13}$ cells. I wanted some hints. ...
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0answers
42 views

What does the term 'epitope mapping' mean? [closed]

Epitope mapping means identifying the binding site of antibodies on the target antigen. This means that the site to be identified is part of the antigen and not antibody, am I right?
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1answer
116 views

What is the functional significance of the difference in cardiolipin/cholesterol ratio in different membranes?

I have read somewhere that the plasma membrane has little cardiolipin but excess cholesterol whereas the inner mitochondrial membrane is rich in cardiolipin and has little cholesterol.I just wanted to ...
3
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1answer
406 views

Mitochondria - are they really separate organisms that once merged into eukaryotic cells?

Theoretically, mitochondria are said to be a separate organism that is concerned with its own life and its own processes. In fact, it even duplicates individually. I know a similar question is here ...
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2answers
41 views

Concentration dependent cellular processes

Are there any famous biological processes that depend strongly on a chemical concentration reaching a particular value, like some sort of switch? E.g. if concentration of chemical x reaches ...
2
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1answer
406 views

How do some plants grow in salt water, while others die?

My question is basically out of curiosity and comes from observing how certain plants (such as mangroves or salt cedar) can grow in seawater. If this gives the plant an advantage, why haven't all ...
8
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1answer
223 views

Can a bacteriophage be used to treat bacterial diseases?

Some bacteriophages reproduce using the lytic cycle which ends with the destruction of the host bacterial cell. I was wondering if theoretically this could be used theraputically to treat bacterial ...
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1answer
118 views

Inductance in cell

In an animal cell, especially neuron and in particular its axon, while there is electrical resistance and capacitance mechanism in the cell, which play essential roles in the cable theory model of ...
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1answer
49 views

Anaphase Microtubule Disassembly

Centromeres move toward the poles as the microtubules that connect them shorten. This shortening is due to the removal of tubulin subunits from the kinetochore ends of the microtubules. I'm confused ...
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1answer
98 views

How does a Na+/H+ antiporter drive osmosis in this “osmotic motor”?

This recent paper in Cell describes a cancer cell using osmotic pressure to move in confined spaces. The cell preferentially inserts Na+/H+ antiporters in the leading membrane. I want someone to ...
2
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4answers
125 views

Why is too much glucose harmful?

I learned the citric acid cycle in biotechnology school and how cells work; about ADP and ATP and how the Cellular respiration (C6H12O6 + 6O2 -> 6CO2+6H2O) works. I am interested in understanding why ...
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2answers
218 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
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2answers
115 views

How can you explain the origin of life out of nonliving matter (abiogenesis)? [closed]

According to biochemist Robert Shapiro, the "primordial soup" theory is as follows: Early Earth had a chemically reducing atmosphere. This atmosphere, exposed to energy in various forms, produced ...
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1answer
89 views

Can NSAIDs impact negatively the healing of tendons?

There are a number of articles regarding NSAIDs having a negative effect on healing conditions like tendonosis and tendinitis. From what I understand the channel through which they reduce inflammation ...
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1answer
63 views

What is the role of lamellar bodies in lung cells?

Lamellar bodies have been found to be secreted in lung cells many of their associated proteins have been identified. What is the current consensus or research on the function that these lamellar ...
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1answer
830 views

RNeasy Mini Kit low 260/230 ratio — can I purify this RNA for further use?

I used Qiagen's RNeasy Mini Kit to isolate RNA from 5*10^5 C28/I2 (immortalized human chondrocytes). However, my yield is low (~25 ng/ul), but my 260/280 ratio is great (~2.3), and my 260/230 ratio is ...
2
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1answer
47 views

Regarding signalling pathways

Do all signalling pathways have something that can inhibit them? If the signal pathway is benefitial and it is inhibited would the inhibitor be caused by a biological problem? Are all inhibitors ...
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1answer
45 views

How long does it take for a cell to synthesize an enzyme?

Where can I find data regarding the times distinct cells take to synthesize distinct enzymes?
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126 views

Database of Multicellular and Unicellular organisms?

I'm trying to annotate a list of organisms taken from NCBI for cellularity (unicellular or multicellular). Does any of you ever found a database with association between an organisms' name or taxa and ...
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4answers
2k 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 ...
2
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1answer
72 views

Can (any) human cells learn?

I'm not talking about single celled organisms, but actual cells in your body. Is there any evidence that they can learn to, say, navigate an environment or avoid an aversive stimulus like an animal ...
3
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1answer
73 views

How much of the jejunum is bypassed during gastric bypass?

There is both long and short limb bypass surgeries. I want to know how much of the jejunum is bypassed with each procedure.
4
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2answers
363 views

What's the difference between naive and memory B cells?

I understand that when naive B cells are exposed to antigens, they become memory B cells, but what is the functional difference between the two? I've looked at the quite a few article on B cells, but ...
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1answer
6k views

Why is ATP the preferred choice for energy carriers?

Why is ATP the most prevalent form of chemical energy storage and utilization in most cells?
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1answer
148 views

What are the lifetimes of cellular components on organelle or molecular level?

I was thinking that even though I know how generally the cell works, I don't really have a feeling of how volatile it is. I want to know what is the lifetime/turnover rate of different constituents of ...
5
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2answers
156 views

Can botulinum toxin be grown or kept from denaturing in an UNWRAPPED 50 pound hay bale?

Botulinum toxin is the neurotoxin protein created when botulism spores grow. The requirements for growth and/or for keeping the toxin from denaturing would seem to be very difficult to create in bale ...
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2answers
69 views

Has an artificial symbiotic relationship ever been created?

Have 2 organisms ever been introduced to create a symbiotic relationship that doesn't occur in their natural environment?
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1answer
75 views

How do penicillin resistant bacteria grow slower in the presence of penicillin?

We put 2 flasks inoculated with Bacillus cereus in 37⁰C: one with 100μg/ml penicillin + 50μg/ml chloramphenicol and the other without penicillin. We found that the OD is higher in the one without the ...
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1answer
526 views

Natural examples of XOR functions at the cellular level

We can often think of cells as a sort of circuit on macromolecules, and can show that they can accurately and robustly implement functions like $\text{MAJ}(x_1,...,x_n)$ (return $1$ if more than half ...
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2answers
8k views

Which human cells have the longest and shortest lifespan?

Which cells in a human have the longest lifespan? Which cell has the shortest lifespan?
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4answers
98 views

Exocytosis of mast cell secretory granules

I've been doing a bit of reading about mast cell degranulation and have become thoroughly lost while trying to understand how the secretory granules are actually secreted. I understand that there are ...
4
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2answers
128 views

A photosynthesizing mouse?

N. Shubin's Your Inner Fish makes the point several times that there is a lot of functional similarity between some seemingly remote gene cousins. If that needed reinforcing we have the spider-goat, ...
2
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1answer
109 views

Why are some scorpion species fluorescent under UV light?

It's known for some scorpion species such as Pandinus imperator, Heterometrus Petersii etc. to be shining under UV light. That makes them easier to capture and collect by humans. Is there any ...