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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What happens to the precursor protein's signal sequence after it is cleaved?

Where does this signal sequence "go" after it has been cleaved by signal peptidase and what is its next function?
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236 views

Reason for the source of fetal bovine serum

What is the reason that perhaps the most commonly used serum in labs is fetal bovine derived? Is there something about fetal serum that is particularly useful over say serum just harvested ...
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320 views

How do we look inside the cell?

My sister is in 9th grade biology and her teacher avoided answering the question of how we actually study the inside of a cell. I haven't taken biology in a while but I'd like to give her an answer. ...
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132 views

Question about proto-oncogenes and oncogenes?

My textbook says: Growth-promoting genes are called proto-oncogenes. Some can be changed into oncogenes by a point mutation that alters the ability of the proto-oncogene to be switched off. They ...
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222 views

Number of genes required to sustain life

Are there estimates of the minimum number of genes required to sustain life? In what I mean by life here, I don't include viruses.
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83 views

Why does azithromycin not affect human mitochondria?

Drugs like tetracyclines, macrolides and aminoglycosides bind to prokaryotic ribosomes. It is interesting that our body too having mitochondria, which have prokaryotic ribosomes, there is little(?) ...
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Doubt in a multiple choice question involving cell organelles

Find the odd one out and state the category of the rest. Chloroplast Mitochondria Nucleus Grana Now my answers are : 1st possibility : grana Category : presence of DNA in ...
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64 views

Are the ribosomes specific for each organism

If we removed one ribosome from human and we put it inside horse, would the ribosome perform the as it would in humans or it will not work or somewhere inbetween?
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1k views

Can cell exist without Ribosomes? [closed]

Last night I came across a question that goes as follows:- Cells cannot exist without a) cell wall b) cell membrane c) mitochondria d) ribosomes I am getting confused with option B and option D ...
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528 views

How exactly does marijuana damage brain cells?

I've heard that THC can cause permanent damage to brain cells. I've also heard this reffered to anti drug propaganda. Another theory i've read is that temporary effects reduce intelligence but long ...
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Are there verbs for “undergo mitosis” and “undergo meiosis”?

From my experience on SE sites, I believe this is the right site to ask this question under "terminology". I've been trying to find out whether English has one-word verbs for "undergo mitosis" and "...
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68 views

What do proton pump inhibitors do?

I know that sodium azide and 2,4-DNPH inhibit proton pumps. The azide is called an inhibitor and 2,4-DNP is called uncoupler. I want to know what's the difference between the mechanisms of action of ...
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49 views

Why does a cell produce a lot of p53 protein only to later degrade it?

It is known that the half life of p53 is short and so does that play a role in the amount of energy the cell would need to expend to degrade all the p53? By that does the fact that the half life of ...
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174 views

Can general soap kill bacteria?

I have read that general soap can kill bacteria by opening holes in the bacterial membrane. http://questions.sci-toys.com/node/90 However, I found some articles as well saying that it cannot. http:/...
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157 views

Is there a database of cell images?

We're working on an algorithm for processing images of cells, similar to but much more basic than Cell Profiler, and we are looking for a large database of cell images to test our software. Can anyone ...
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48 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 ...
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203 views

Cancer growth and cell division [closed]

I am confused about the prerequisites for cell division and cancer. Which of the following is necessary for the cell cycle to progress? Hormones Growth factor Cyclins Cyclin dependent kinases ...
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93 views

Domains in cell membrane

How is movement of proteins and lipids between different domains of cell membrane prevented? Why is the noncytosolic layer not able to do lateral movements between domains but cytosolic layer is able ...
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22 views

What does “cell type composition” mean?

I am reading an article about detection of differential methylation. They use the term "cell type composition" in the following context: "Researchers need to carefully design studies that associate ...
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202 views

Membrane Permeability to Pyruvate

Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of ...
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232 views

Recommend good conversational books to learn about cell and developmental biology or biochemisty?

I'm an engineer by training and teaching myself the basics of cell and developmental biology. I'm using Scott F. Gilbert's Developmental Biology and Alberts' Essential Cell Biology right now, and they ...
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901 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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72 views

Sodium-Potassium Pump

From my understanding, in the sodium-potassium pump we have Na+ inside the cell and K+ outside the cell, thus forming a so called "salted banana." After reading my textbook I found many statements ...
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58 views

Where can I find a full genealogy of human cell types?

It is said on Wikipedia, that the precursor of blastocyst is a morula, and that the precursor of morula is a zygote. This gives us the part of genealogy tree of cell types. Unfortunately, no full ...
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191 views

How did viruses learn to utilize the workings of a cell?

This is my first post here, so excuse me for its simplicity. Viruses can infiltrate a cell, overtake it and multiply. It has projecting fibers whose ends are shaped as kind of a "key" to a mobile ...
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How do plant cell divide without centrioles?

Most plants do not have centrioles , so What organelle lets them multiply?
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What are the different, high-level programs along which a eukaryotic animal cell can follow?

What are the different, high-level, disjunct (mutually exclusive at one particular point in time) programs or pathways along which a eukaryotic animal cell can follow? Examples of programs would ...
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How long can a unicellular organism live without nutrition? What happens after that? Does it depend on the domain?

Say I have three unicellular organisms: a eukariote, a bacterium and an archaeon. If I cut off nutrition from them at the same time, how long will it take for them to die? What will their death look ...
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64 views

Could a single cell be brought to life?

If a scientist is observing a single cell under a microscope, and then realizes that the cell has died, is it possible to bring that dead cell back to life? For my inquiry, let's assume that the ...
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43 views

What is the purpose of requiring two separate binding systems for the antibody response?

I've read that in most cases, B-cell activation requires helper T-cells. This requires antigen binding by both antibodies and T-cell receptors, using two different antigen-binding proteins, ...
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618 views

Mitosis versus Meiosis I: What's the difference?

At the end of mitosis, one cell has divided into two diploid cells. But at the end of meiosis I, there are two haploid cells. How are the two processes different to produce these two types of cells?
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555 views

How is excretion of metabolic wastes from a cell related to its size?

As with anything that is taking place within a cell, the metabolic waste too must be proportional to the size of the cell. In particular the surface area to volume ratio. But how is the waste ...
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151 views

Can bioluminescence be used for cancer or tumor detection? [closed]

What diagnostic applications, if any, are there in using bioluminescence to detect cancer or tumors (in vivo)?
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180 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 ...
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108 views

Energy metabolism in Cancer cells

The TCA cycle intermediate Isocitrate dehydrogenase commonly undergoes point mutations in cancers. This allows IDH to reduce a-Ketogluterate to 2Hydoxygluterate, causing a reduction in pVHLs ability ...
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104 views

PSI-BLAST website algorithm parameters

http://blast.ncbi.nlm.nih.gov/Blast.cgi In this website, when I want to apply the psi-blast algorithm on a sequence, under the section of algorithm parameters , what does PSI-BLAST threshold mean? ...
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119 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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26 views

Polarized epithelium and localization of ion channels

I'm trying to learn more about polarized epithelial cells of the gut. I am familiar with classic brush border transporters localized to the apical memebrane to facilitate nutrient absorption. I am ...
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147 views

Amino acid profile of GPCRs

You are studying cellular signalling through a newly identified GPCR. Specifically you’re working on a pair of newly identified GPCRs, GPCR-A and GPCR-B. Each binds the same small ligand, but ...
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357 views

Benefits of CLARITY?

What are the benefits of CLARITY over this technique that was published more than a year earlier? Of course the second technique needs a fancier microscope that is likely more expensive and requires ...
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275 views

Why are centrioles aligned at 90 degree with each other?

The centrioles are aligned at 90 degree with each other. What is the function of this?
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328 views

Why did Fair Meiosis evolve?

How and why did Fair Meiosis evolve? I can hardly think that it provided a fitness advantage to the individual carrying the mutation. Why would it? Or did it evolve through lineage selection? Or was ...
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199 views

How do different tissue culture matrices affect background in fluorescent microscopy?

In response to my previous question, I've been reading up a little bit on poly-D-lysine, Collagen I, Collagen IV, laminin, and other tissue culture coatings that promote cell adhesion. I've always ...
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211 views

What molecular processes are involved in pseudopodial extension?

I am curious as to the processes and mechanisms involved in the extension of pseudopodia in amoeba. How does the cell know and control the direction and extent of pseudopodia formation at a molecular ...
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“Acellular” designation for organisms

Why do some biologists refer to single-celled organisms such as Amoeba and Paramecium as acellular (i.e., without cells) rather than unicellular (i.e., one cell)?
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Can a cell start a mitosis if it lacks energy or molecules to complete it?

I'm wondering whether a cell can start a mitosis if it lack molecules or energy to fully complete it. From what I'm reading on wikipedia the cell passes most of its time in the interphase in which the ...
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34 views

Where exactly is 'Colloid' with regards to synthesis of thyroid hormones?

I've researched colloid and it seems to be a substance of microfibres and thin films in which thyroid hormones may be synthesised, but I was wondering where this exactly is... I think it could be in ...