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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21 views

What percent of cells are lysed when I make my smoothie?

This is an entirely irreverent question, but it does concern biology. I'm a physicist by training so I like to be able to estimate order of magnitude. I made a smoothie the other day with milk, ...
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2answers
280 views

Growth factors vs. mitogens

According to Campbell Biology, A growth factor is a protein released by certain cells that stimulates other cells to divide. and according to Wikipedia, A mitogen is a chemical substance ...
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2answers
172 views

Density of cells in human tissues?

Where can I find values, or estimates, of the density of cells in human tissues? Maybe an overall estimate, or distinct values for distinct tissues? Or maybe not human, but mammal tissues (which ...
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1answer
748 views

Difference between protein channels, protein carriers and protein pumps?

I'm revising for my biology exam and I don't fully comprehend the difference between protein channels, carriers and pumps. I know that: Protein channels do not require ATP (passive transport) The ...
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2answers
292 views

How many centrioles/basal bodies are there in multi-ciliated cells throughout the cell cycle?

I thought there were only two centrioles per cell, that convert to the basal body at some point during the cell cycle. I also thought there's one basal body per cilium, so I'm not clear on where the ...
3
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1answer
146 views

HOw are AMP's “recharged” to become ATP's in a cell?

I understand that after the translation stage of ribosomal protein synthesis, tRNA molecules are floating in the cytoplasm without attached amino acids until they find the correct aminoacyl tRNA ...
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1answer
89 views

Which step in endocytosis requires ATP?

Everybody seems to agree that endocytosis is an energy-using process, and as such requires ATP hydrolysis. However, which particular step requires it? More precisely, which 'molecular machine' ...
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1answer
60 views

How difficult is it to make a shRNA/miRNA/siRNA to silence/knockdown NaV1.7 voltage gated sodium channels in humans?

There have been various research projects that experimented with shRNA/miRNA/siRNA to specifically silence/knockdown NaV1.7 voltage gated sodium channels in small animals like rats & guinea pigs. (...
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12 views

Do you know of any scratch assay video databases?

It would be of great help for a statistical work we have been asked to carry out at our University. Thank you very much in advance.
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1answer
54 views

Do snRNAs exit the nucleus or not?

In Molecular Biology of The Cell (Alberts, et al., 2015), it lists the various RNAs that are trafficked through the Nuclear Pore Complex (NPC) into the cytoplasm. The list includes snRNAs, but I ...
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2answers
269 views

At any given moment, how much energy is stored in the human body as ATP?

At any given moment, approximately how much energy is stored in the human body as ATP in the ADP-P-bond? This of course depends on what type of cell it is and the activity of the individual in ...
3
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1answer
68 views

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 ...
3
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1answer
41 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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2answers
48 views

At which end does polymerization of microtubules occur?

My book says that polymerization and depolumerization of microtubules occurs on the + end however, I've found a note that says that depolymerization occurs on the - end. I need help please :) thank ...
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1answer
51 views

Is HSV-vector-mediated miRNA expression in dorsal root ganglia stable?

My question is on the following article: "Reduction of voltage gated sodium channel protein in DRG by vector mediated miRNA reduces pain in rats with painful diabetic neuropathy" My question is, do ...
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0answers
28 views

Effects of pH vs membrane potential within a cell? [closed]

How are these two concepts related? Does changing each result in the same effects? As in: what kind of reactions/processes would be affected if we changed the pH within a cell? Would the results ...
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2answers
88 views

In cell division, are daughter cells identical?

I understand that after a cell replicates, there will be two daughter cells instead of one. But wouldn't one of them be the old cell that created the second one? The old cell having gone through G0, ...
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1answer
35 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
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1answer
187 views

Do human somatic cells have 46 chromosomes all the time?

As far as I know, a human somatic cell has the cell cycle: Interphase and Replication (mitosis). In interphase the cell has 2 growth phases (G1 + G2) and a synthesis one (S phase being in between G1 ...
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0answers
18 views

How sorbitol treatment selects ring stage of plasmodium falciparum

I would like to know the basic chemistry behind ring stage selection by sorbitol. Sorbitol is used for Synchronising the plasmodium culture in ring stage. How the chemical retains or selects ring ...
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1answer
54 views

Are nucleotides at the ends of DNA stripped on aging?

I had the following understanding (now after reading a popular science article seeming wrong understanding): DNA in (regular) cells (in human and some other organisms) are protected by telomers. ...
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1answer
48 views

cell specialisation and their location

When we create new cells, how come they are of the 'right' type at the 'right' place? For example, when I make a new cell on my lips, it's obviously not the same as a new one in my kidneys. Is the ...
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1answer
56 views

Common genes and enzymes involved in pathogen entry into host

Many microbes like Salmonella, E.coli, Legionella pneumophila etc. enter host cells via cystoskeleton remodeling of the host cell. Do all microbes follow the same path or there are any other ways for ...
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2answers
2k views

Book Recommendations: GRE Subject Test In Biochemistry, Cell And Molecular Biology

There are probably a lot of really good answers that may vary significantly in terms of content. I'm looking for a set of books that I can read in preparation for the GRE Subject Test In Biochemistry,...
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293 views

Contact Inhibition of Cell Division: Signaling Pathway

The following article refers to contact inhibition of cell division in epithelial cells, specifically MDCK cells: Collective and single cell behavior in epithelial contact inhibition. In their review ...
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0answers
17 views

Ions in different cell compartments

I would like to understand the distribution of metal ion concentrations (such as Mg2+) in the different cell compartments. I tried very hard but still couldn't find such information. Could anyone help?...
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2answers
75 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
63 views

Which steps occur in each phase of Meiosis and Mitosis [closed]

MITOSIS In mitosis am I correct in saying that the spindles attach to the centromeres at the end of prophase/prometaphase? (I read this in an answer to another question) MEIOSIS Does the ...
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1answer
50 views

Why only mitochondria and plastids?

Why are there only two unique semi-independent organelles? Why are there no others, symbiogenesis seems like it should be a relatively common thing. So do most organelles just lose all their DNA? Or ...
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2answers
7k views

Why is saltatory conduction faster than continuous conduction?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
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1answer
36 views

How chameleons change color? [closed]

Well, I was watching a video about chameleons and I saw that their cells can change color. Can someone explain me how is this possible?
4
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1answer
90 views

How much of the jejunum is bypassed during gastric bypass?

There is both long and short limb gastric bypass surgeries (along with several other variations on intestinal bypass procedures). How much of the jejunum is bypassed with a long-limb and short-limb ...
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2answers
202 views

Why is succinate dehydrogenase attached to the inner mitochondrial membrane?

Succinate dehydrogenase is attached to the inner mitochondrial membrane. All the other enzymes of the Krebs cycle are located within the matrix of mitochondria, though. In biological systems, there ...
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1answer
89 views

What determines whether the maternal or paternal allele is expressed?

I am taking cell biology and have this question: During the process of gene expression, it is possible to express either the maternal allele or the paternal allele. When and how is the determination ...
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1answer
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 ...
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1answer
63 views

What are allogametes? please explain [closed]

Allo means different or unrelated I guess.Please clear me the meaning with some examples.
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0answers
24 views

Degenerate primer designing software

Can any one provide online free degenerate primer designing software. I have tried couple of them like CODEHOP is one where BLOCK formatting step finding difficulty, can anyone help me out....
5
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1answer
78 views

Are surface area or volume conserved during cell division?

I am a student of physics of mathematics with very little knowledge of biology. Nevertheless, I am very keen on biophysics and I'm trying to learn the biological concepts that I need on the way. I'm ...
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1answer
140 views

Cancer in myogenic heart cells? [duplicate]

Why cancer does not occur in myogenic heart cells? Is there any special ability in heart cells to resist cancer ?
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2answers
2k views

Can brain cells move?

I was discussing this with my brother. I'm pretty sure I read somewhere that they can move. Thanks EDIT: By movement I mean long distance migration (preferably within the brain only).
2
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1answer
72 views

Reseach on feeling pain of other people

I'm more of a tech than bio kind of guy, but I have read and learned a lot alongside of my girlfriend's education. Which is very interesting!! Currently I want to investigate : people claiming to ...
4
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1answer
771 views

What kinds of cells does human saliva contain?

I have heard that our saliva contains cells. What cell types can be found in human saliva?
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1answer
86 views

Why do eggs lack an endoplasmic reticulum?

Trueman's Elementary Biology book I found says that the endoplasmic reticulum is absent in eggs, but no reason is given. Why is it absent?
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5answers
4k views

Why are there no known animals with an odd number of legs?

In my 6th grade science book it is said that there are no three legged animals, and that no animal with an odd number of limbs exists. I checked Wikipedia and could confirm this: There are no ...
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1answer
45 views

What does uniprot consider “unambiguous” evidence for the subcellular domain of a protein?

Uniprot has annotation for subcellular location of protein domains. This topological domain information of proteins is under the TOPO_DOM flag. In most cases the ...
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1answer
44 views

Lysosome function [closed]

Does any cell have lysosomes in it? Or maybe there are other organelles that do the same function. I read about it a lot and I can't find a good answer.
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0answers
35 views

How do cell repair mechanism ratios change as they age?

I have seen that embryonic stem cells are shown to use homologous repair for double strand breaks rather then non-homologous end joining (NHEJ). [1] I am wondering if something also happens to a cell'...
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1answer
115 views

What were the first neural systems like?

I'm curious about the origin of the neural network. I'm thinking perhaps once life evolved beyond the single cell organism, it needed a simple neural network to coordinate those cells, and cell ...
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1answer
53 views

Which organs need to have fluid compartments in order to develop properly?

I am a student, slightly struggling with the new concept of fluid compartments. I know that there are two main types of fluid compartment, extra and intracellular fluid. I also read that most organs ...