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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104 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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1answer
159 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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1answer
215 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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2answers
40 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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3answers
2k views

DNA is charged negative. Where is all the positive charge in my body?

DNA is charged negative because of its phosphate backbone. Since charges need to be balanced (so that there are no charges building up somewhere), what is the positive charge which neutralizes this ...
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4answers
78 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
146 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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1answer
123 views

Has anyone used Crispr/Cas to induce a knock-in in MEF cells?

Does anyone have experience with the crispr/cas9 platform performed on MEF? Or does anyone recall any relevent articles? Thanks
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1answer
391 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
71 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 ...
2
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1answer
48 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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2answers
100 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
42 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 ...
4
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2answers
89 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 ...
2
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1answer
69 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 ...
2
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1answer
245 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 ...
3
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2answers
62 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?
5
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2answers
144 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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1answer
65 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 ...
4
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2answers
105 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, ...
3
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2answers
73 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 ...
2
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1answer
40 views

Trimming of tRNA precursors

From Molecular Biology of the Cell (4th edition) by Bruce Alberts et al. (Chp 6, Pg 338) : Both bacterial and eucaryotic tRNAs are typically synthesized as larger precursor tRNAs, and these are ...
2
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1answer
84 views

What cells don't have a primary cilium?

It is often stated that most cells in the human body have a primary cilium. Which ones don't? For which cells is it unknown?
5
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1answer
75 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 ...
6
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4answers
84 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 ...
2
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1answer
81 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 ...
2
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1answer
211 views

Why are red blood cells considered to be cells?

Wikipedia states that a cell is the basic structural, functional and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently. It then ...
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0answers
20 views

MAPK signalling pathway initial conditions

I would like to know the initial conditions and locations of the chemical reagents in the MAPK cascasde. I'm going to plug this information into a reaction diffusion simulation. From reading ...
3
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1answer
54 views

How is the growth of benign tumors suppressed?

A benign tumor has an outer layer of cancerous cells beyond which are regular cells (I Think). The Tumor must have some kind of boundary layer like a wall where somehow the cancerous cells can't ...
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0answers
20 views

Why are embryonic germ cells considered stem cells?

In a class that I'm taking we were presented 3 types of stem cells. Adult stem cells which come from bone marrow Embryonic stem cells which come from embryos Embryonic germ cells which come from ...
2
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1answer
63 views

How to study the effect on tau protein isoforms on microtubule based transport?

From what I read, A-beta plaques inhibit microtubule based transport of mitochondria when tau protein is present in the cell. How would I be able to do a test to see if one isoform of tau is more ...
3
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1answer
23 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 ...
3
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1answer
73 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 ...
2
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3answers
106 views

Why doesn't the cytosol dissolve the polar structures?

we know that cytoplasm of cells are filled with water molecules and other hydrophilic molecules so my question is why the water of cytosol doesn't dissolve the ionic part of the lipid bilayer or why ...
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1answer
70 views

Advantage of cup-like shape of blood cells, spores?

Mold spores sometimes have the same shape as platelets in blood. If I were designing a spore it would probably be spherical. Is there any advantage to this cup-like shape? Maybe there is some ...
3
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1answer
47 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.
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2answers
164 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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1answer
113 views

Punnett square and hybrid cross [closed]

A plant breeder crossed two plants, one with red flowers, and the other with white flowers. Red is dominant. Calculate the phenotype and genotype ratios of the F2 generation of this cross. Is this a ...
0
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1answer
24 views

How is bacterial plasma membrane made?

Eukaryotes have ER which manufactures plasma membrane of cells. How is prokaryotic plasma membrane made ? What is the pathway and which enzymes are involved ?
4
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2answers
112 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 ...
4
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1answer
132 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 ...
2
votes
1answer
97 views

Are cell lines potentially dangerous?

More specifically, if a human subject was exposed to, say, a human cancerous cell line (via intravenous injection or through an open wound, for example), is it possible that they would develop any ...
2
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1answer
238 views

How do nutrients get to the cells they need to get to?

I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that ...
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1answer
229 views

What does it mean for a chemical pathway to be conserved?

In many papers the MAPK pathway, (along with many others) is referred to as being conserved: Example: "The mitogen-activated protein kinase (MAPK) cascades are ubiquitous in eukaryotic signal ...
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3answers
2k 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 ...
3
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1answer
53 views

Significance of lipids in biological membranes…?

Membranes are specifically designed by lipids to maintain internal hydrophilic environment in narrow range.There are hydrophobic amino acids among naturally occurring 20 amino acids and as well as ...
1
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1answer
63 views

Missing 4$H_2O$s (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $H_2O$ molecules. Generally, cellular respiration is written thus : $C_6H_{12}O_6 + ...
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1answer
87 views

Plastid and mitochondria

I am not biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is difference between plastid, chloroplast and mitochondria? Are there any plant ...
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1answer
55 views

Bilayer synthesis? [closed]

If we want to design a bilayer from Myristic acid (14 carbon fatty acid). The average bond length between C-C is 1.5 A. What will be average thickness of the membrane? Edited to include the OP ...
1
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1answer
107 views

Consequence of touching Formaldehyde

I accidently touched formaldehyde some days ago. Skin on my hand got dehydrated as if I had placed it in salt solution. I washed it with water and it returned to normal state after 5 minutes. But now ...