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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Cell proliferation limit and senescence of embryonic stem cells and fibroblasts

I am trying to understand the importance of proliferation limits and cell senescence. In particular, I would like to compare the proliferation limit of Embryonic Stem cells (ES) and fibroblasts (which ...
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158 views

Which cells are responsible for the extracellular matrix remodeling?

I am studying a case of tendinopathies induced by an alteration of how the extracellular matrix is being remodeled. From my understanding there has to be a careful balance of MMP (metallproteinases) ...
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How extensive is CD47?

CD47 aka the "don't eat me" signal has recently been claimed to be expressed on all tumor cells. This doesn't seem to corroborate with other cell-biology experiments. On what other cells is CD47 ...
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79 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 ...
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314 views

Aerobic vs anaerobic respiration comparison

The following graphs compare glucose decomposition in yeasts (in anaerobic vs aerobic conditions respectively) My question is, why doesn't the first one look like a straight line as the second one ...
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143 views

Can in the case of multiple sclerosis (MS), a too high osmotic pressure in the nerve, lead to a high intracellular concentration of potassium?

Can in the case of multiple sclerosis (MS), a too high osmotic pressure in the nerve, lead to a high intracellular concentration of potassium, and also lead to 'pumping up' of nerve cells, which then ...
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111 views

Creating a cell, not from another cell. Will it be possible?

If some time in the future, we can know exactly what a cell (for example simple prokaryote bacteria) contains, (I mean, exactly which molecules, the shape of them, the density of each, everything), ...
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896 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 ...
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67 views

Why do some internal organs regenerate?

I have been reading about the human liver and zebra fish heart muscle having the ability to regenerate. It seems to me that these organs have very little chance to become damaged or worn out. At the ...
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184 views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
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157 views

Improving transformation efficiencies- induce supercoiling?

From my limited knowledge of science, I know transformation can be one of the hardest step in cloning, and that a large amount of research/trial and error has been done to improve on this step. I've ...
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480 views

Using ion-exchange chromatography to purify DNA from a cell extract - Is DNA more negatively charged then RNA?

When applying this method we have a glass or plastic column of resin which is positively charged. Then we pour cell extract into the column in order to capture the negatively charged particles which ...
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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 ...
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458 views

Are there any multicellular forms of life which exist without consuming other forms of life in some manner?

The title is the question. If additional specificity is needed I will add clarification here. Are there any multicellular forms of life which exist without requiring the consumption (destruction) of ...
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104 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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998 views

Advice on Cell Biology texts by Alberts

I am currently reading "The Chemistry of Life" by Rose. It's a great book (to me as a lay reader at least) and an interesting topic so I am interested in pursuing some of the further reading he ...
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112 views

positive and negative feedback

I want to know more about positive feedback in gene regulation and to know the similarity and differences between positive and negative feedbacks.
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172 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!
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60 views

What is an operon?

What is an operon in a eukaryotic cell, and how does it regulate the expression of genes? I've already read Wikipedia, but it is not enough clear to me. Unfortunately my knowledge in genetics are very ...
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153 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 ...
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137 views

How do detergents get in hydrophobic membrane interior?

According to Molecular And Cellular Biology (Stephen L. Wolfe), Membranes disperse almost instantaneously if exposed to a nonpolar environment or to detergents, which are amphipathic molecules ...
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665 views

Under what circumstances will a human neuron divide?

I read somewhere that a mature neuron loses its ability to divide, except for very specific situations. I was unable to find the description of those situations. What are they? (I'm sorry I'm not ...
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76 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. ...
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109 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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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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106 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, ...
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115 views

What is the smallest oligocelluar organism?

What is the smallest oligocelluar organism? How many cells does it have? EDIT The question is motivated by this comment@Philosophy.SE EDIT as recommended in comments I'm looking for an example of ...
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132 views

Why are transmembrane proteins difficult to crystallise?

I know that in vivo there are a lot fewer transmembranous proteins in general, and that they are produced at a lower rate than their free counterparts. This is mainly because transmembrane proteins ...
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214 views

Are there oligocellular organisms in nature and, if so, what are they like?

I'd think protozoans can be oligocellular, but I haven't found any examples, and I'm curious to know what is the minimum number of cells an organism can have other than a single cell.
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Why does alcohol cause the hemolysis of RBC in a large proportion?

I had today an experiment that we put 95% alcohol to the blood which made it completely transparent so hemolysis must have occurred. I started to think about the reasons. I think that this is because ...
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20 views

Can methylation of a promoter induce gene expression in some rare cases?

Can methylation of a promoter induce gene expression in some rare cases? I've read somewhere that methylation of an intron can induce gene expression (eg. Igf2). How is that even possible? Thank ...
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113 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
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695 views

How does ubiquitin recognize misfolded proteins?

Misfolded proteins are tagged by ubiquitin and then are destroyed by proteasomes. How does ubiquitin know which protein to tag?
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373 views

What plastic eating organisms are there to help with plastic in landfills problem?

I see some popular science articles on the plastic eating bacteria and fungi appearing on the web since 2009. Most of the articles praise discoveries, because such organisms promise to break down ...
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194 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 ...
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813 views

How to convince suspension cells to adhere more tightly?

I'm developing a cell-based assay in 96-well plates that requires adherent cells, as they need to be washed at least twice during the protocol. I'm using in-house strains of HT1080 cells (some ...
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193 views

Reason behind formation of different shapes of cell

I have always wondered how cells are modified to give them a specific shape. On what specific part of a cell does gene regulation act for giving the shape ?
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Simple diffusion of lipid-soluble molecules through phospholipid bilayer — does anything get “stuck” in transit?

It's a pretty elementary concept, and when I first learned of it I don't think I had the foundations to even think of such a question, but I found myself the other day thinking about the amphipathic ...
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106 views

When should endocytosis inhibitors be used in cell binding assays?

I'm beginning to do some cell-binding assays and I would like for my proteins to not be endocytosed by my mammalian cells. Typical suggestions are for the cells to be kept on ice and that the binding ...
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485 views

Lifespan of connective tissue cells

This post is regarding a follow up on my initial post on "Properties and life cycle of chondrocytes and tenocytes". I am elaborating on my question on the lifespan of tenocytes and chondrocytes. ...
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46 views

Chromosome and chromatid numbers during cell cycle phases

A diploid cell in G1 has 6 chromosomes. How many chromosomes and how many chromatids are present in each of the following stages? Here is what I am guessing G1: 6 chromosomes ; 6 chromatids G2: 6 ...
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83 views

Are all functions of a human cell known? [closed]

Please bear with me as I'm intruding into your world from a computer science background. In programming, once you have created a program, you know all functions of that program. Thus, 100% knowledge ...
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140 views

Why mosquito bite is confined to a certain shape?

I think this problem should be asked in a physiology forum rather than biology@ stackex but I'll give it a try. So my question is simple - why a mosquito bite is usually confined to a certain shape ...
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694 views

How does formaldehyde/PBS or methanol fixation of cells affect lysosomal pH?

The question is fairly simple - does formaldehyde or methanol fixation in preparation for immunocytochemistry/immunofluorescent staining affect the pH of the lysosomes? Some background: I'm trying to ...
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100 views

Randomness in living systems

The point of my question is not to talk about events that are uncontrolled by living organisms. My question is about controlled randomness, or I'd like to say adaptive random process. Process that are ...
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160 views

Regarding TIMP and MMP enzymes

Are there substances that can promote TIMP enzyme production, or MMP enzyme production or supression in tendons? Are there medical tests that measure quantities of MMP and TIMP enzymes in tendons?
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553 views

What's the distinction between a tetrad and a synaptonemal complex in meiosis?

What's the distinction between a tetrad and a synaptonemal complex in meiosis? Are they synonyms? I ask because the concepts seem very closely related, but it seems like there may be a subtle ...
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119 views

Does trypsin strip flask coating?

Mammalian cell/tissue cultures sometimes require flasks coated with proteins. My uneducated guess is that these proteins mimic the ECM, perhaps the basal lamina, so finicky contact-dependent cells can ...
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61 views

How to visualize the ECM?

Specifically, I'd like to look at changes in HA (hyaluronic acid) production. Most often you only see people staining the cell surface or removing cells from culture for fixation and then imaging. ...
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102 views

Mechanism of Muscle Growth

According to this video (sorry for the poor reference but it represents my level of understanding in physiology), muscle grow as a consequence of repairing micro-lesions. How are these micro-lesions ...