Questions tagged [cell-biology]

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

Filter by
Sorted by
Tagged with
29
votes
3answers
32k views

Why is saltatory conduction in myelinated axons faster than continuous conduction in unmyelinated axons?

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 ...
13
votes
3answers
2k views

Does a man contain all the genes needed to make a woman?

This question is brought on by a Sci Fi novel I am thinking about writing. The plot device involves a colonist in charge of building a population on a new planet who loses his supply of embryos and so ...
34
votes
3answers
58k 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?
15
votes
1answer
14k views

Can you consider a human as alive, or is it the cells on the body that are alive?

Sorry if this question seems strange, but in the recent time I have been interested in the question of what life is and how you can define life. My question: How long can individual cells live on a ...
22
votes
7answers
8k views

Why would a single celled organism evolve to be multi-celled?

I read a story this week on Richard Lenski who has been 'evolving' E. coli for more than 50,000 generations now. One comment I read was from someone who doesn't accept Evolution who pointed out that ...
7
votes
1answer
1k 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 ...
5
votes
3answers
2k views

which exact mechanism triggers the first cell differentiation after n divisions?

I would like to understand which mechanism triggers the first cell differentiation after n divisions. I read previous articles on SE and Wikipedia articles on cellular differentiation and ...
5
votes
1answer
55k 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 ...
11
votes
1answer
1k views

Why don't the heads of phospholipid bilayers repel hydrophobic molecules?

What I Think I Know: Hydrophilic and hydrophobic things repel each other. Since the cell membrane contains hydrophobic tails, it is difficult for hydrophilic molecules to pass through the cell ...
7
votes
1answer
768 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, ...
22
votes
2answers
9k views

Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
38
votes
1answer
2k views

What is itching?

What exactly at the molecular level is itching? What physiological function does itching serve, if any? I cant remember the reference but a PLCb3 null mice lost the itch phenotype, so presumably it is ...
7
votes
2answers
3k views

Cell life: division for immortality or reproduction with aging

Are the two cells that are derived from one cell, ‘twin sisters’ or a ‘mother and a daughter’? In other words, can a cell really be divided to live an "immortal" life or is cell reproduction the ...
4
votes
1answer
160 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 ...
4
votes
4answers
11k views

Photosynthesis: What Powers the Splitting of Water?

The splitting of water is an endergonic (non-spontaneous) reaction, and thus would require energy (chemical work to be done) in order to happen. In Photosystem II, an enzyme catalyzes this splitting, ...
8
votes
3answers
866 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 ...
6
votes
1answer
425 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.
6
votes
4answers
25k views

Why do cell membranes have a lipid bilayer instead of a monolayer?

Many cells have a cell membrane composed of two layers of lipids. Why is it that they have two layers and not just one? What purpose do this arrangement serve?
44
votes
2answers
4k 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).
31
votes
2answers
9k views

Why do tattoos persist if body cells are regularly renewed?

I am not quite sure if it is true, but I read somewhere that within 7 years all the body's cells are replaced with new ones. I am not quite sure if it is cells or atoms. If it is then why do tattoos ...
10
votes
1answer
11k views

What is the difference between the cellular affix -cyte and -blast?

The affix -blast means an immature cell, and -cyte indicates any cell. So how do we define if a cell is mature (-cyte) or immature (-blast)? How does this apply to odontoblasts and ameloblasts? Why ...
9
votes
1answer
1k 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 ...
24
votes
2answers
59k 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 ...
18
votes
1answer
2k views

The Origin of Mitochondria

For a long time I've just accepted, because it is just what everyone told me, that mitochondria became organelles in the cell when they were "engulfed" by another cell which acted like it's host. This ...
10
votes
1answer
3k views

Why are certain aneuploidies more common?

Certain aneuploidies such as trisomy-21 (Downs syndrome), trisomy-18 (Edward syndrome), Turner syndrome (XO) etc are more common than others. I had a vague thought that it is related to chromosome ...
6
votes
2answers
393 views

Is the covid-19 vaccine-induced copy of the protein spike also damaging cells?

In recent scientific articles, it has been discovered how the spike protein not only is a respiratory disease but also damages blood vessels cells directly, and is connected with higher risk of ...
6
votes
2answers
1k 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 ...
11
votes
1answer
332 views

Can mitochondria become cancerous?

Given that mitochondria have their own DNA and can replicate independently, can they ever become cancerous? For example, could a mutation in their DNA cause them to rapidly replicate, ultimately ...
9
votes
4answers
77k views

How do plant cell divide without centrioles?

Most plants do not have centrioles, so what organelle enables them to multiply?
8
votes
1answer
3k views

X chromosome "weight"?

According to Wikipedia, the X chromosome has approximately 153 million base pairs, while the Y chromosome has only 60 million base pairs. Thus, the difference is roughly 93 million base pairs. My ...
6
votes
1answer
166 views

Macromolecule levels in daughter cells after fission

When a prokaryote undergoes binary fission, how are the non-DNA macromolecules distributed between the two daughter cells? This is motivated by comments on a previous question and a G+ discussion. I ...
6
votes
2answers
155 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 ...
11
votes
3answers
10k 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
1k 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 ...
1
vote
1answer
507 views

Cell biology - Resting membrane potentials

Why do we say there is an overall negative charge on the intracellular side of the plasma membrane at rest, and an overall positive charge on the extracellular side when both potassium and sodium are ...
0
votes
1answer
88 views

Is forced cell growth related to apoptosis?

Could an instance of forced cellular growth cause some cells to have their self-destruct mechanisms to malfunction or 'turn off'thus preventing apoptosis?
15
votes
2answers
4k views

Why is thymine not incorporated into mRNA?

I am aware that in transcription uracil bonds to adenine and not thymine. But what is it that actually prevents thymine from bonding to adenine in transcription, that is not present in replication?
13
votes
3answers
7k views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
13
votes
2answers
8k views

What is the difference between cytosol and cytoplasm?

I've generally seen cytosol defined as the solution inside cells minus the organelles, cytoskeleton, etc and cytoplasm as the cytosol plus the organelles, cytoskeleton, etc. This naturally leads to ...
13
votes
1answer
44k views

Why is DNA double stranded and RNA single stranded? [closed]

Why is DNA present as a double helix structure and RNA as a single helix? What causes the difference between them? What are the practical physiological differences between dsDNA and ssRNA? How are the ...
15
votes
4answers
28k views

Was the mitochondrion or chloroplast first?

I still don't know if the mitochondrion or chloroplast was first? I've looked for it on the internet and in various books but haven't found anything. Does anyone have the answer and a theory which ...
11
votes
3answers
33k 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.
4
votes
4answers
5k 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 ...
4
votes
1answer
107 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 ...
26
votes
5answers
15k 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 ...
14
votes
1answer
1k views

Can an organism exist as a single cell but come together as multi-cellular during certain times?

I am trying to remember a particular segment from a BBC special, about a single celled species. However, at certain times all the individual cells came together to form a structure, not unlike a ...
10
votes
1answer
2k views

What is the difference between organelle membranes?

Cells and organelles are contained in lipid bilayers. I'm particularly interested in eukaryotic organelle bilayers and the biophysicochemical differences between them. Many papers assume a ...
7
votes
1answer
25k views

How do lipid-soluble substances diffuse through the cell membrane?

It’s said that water-soluble substances can diffuse through cell membrane with less ease than lipid-soluble substances because the former encounters impedance in the hydrophobic region of the ...
33
votes
1answer
11k views

How long will a vegetable live for after being harvested?

I understand this might depend on the types of vegetables, but is there an average or studied specifics? Does it die immediately? Is there a way to precisely diagnose death in plants? If so, what are ...
11
votes
1answer
257 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and energy)?...