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Questions tagged [cell-biology]

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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Tumour cell injection into a mice [closed]

I am going to inject mice tumour cells into mice to create them tumours and I am wondering if I need to have special precautions for that, even they are cells from mice tumour I am afraid what can ...
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3answers
1k views

when does osmosis stop

I have a question about osmosis that goes a bit deeper than most basic textbooks so I cannot find the answer.Here's the problem: Imagine an animal cell, say a red blood cell, in a slightly hypotonic ...
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I found something in the water,Who konw what kind of cell in this photo?

I used pipette tips from a glass of mineral water. It's a 500x photo by a cellphone.
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237 views

Passive diffusion of non-polar molecules across plasma membrane

I understand that small, nonpolar molecules that can dissolve in the hydrophobic (nonpolar) part of the plasma membrane are able to cross it and passively diffuse into or out of the cell. But doesn'...
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1answer
662 views

Sickle cell life span

How long do sickle red blood cells "live" before being broken down in phagocytosis? I had trouble doing a normal search as it brings up life span of those inflicted with the disease. Also, I have ...
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12 views

Is it possible to reprogram osteoblasts and osteoclasts to change the angle and shape of the mandible?

Surgery is too expensive. I have just heard of a thing called DNA reprogramming, and there are lots of articles that are reputable and back this scientifically. The idea is that cells/DNA can change ...
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1k views

Can I kill bacteria with distilled water?

Given that bacteria are hypertonic (contain more salts) compared to distilled water, and that they rely on ion concentration differences across the plasma membrane to survive, can I kill a bacterial ...
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1answer
36 views

Can cancer cells transmit from one organism to another?

I know cancer cells are very resilient, so would it be possible for them to survive outside of the original organism for long enough to be absorbed by another? Furthermore, would that type of "...
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56 views

Direction of ATP synthase C ring under different circumstances

In a mitochondrial intermembrane space, the concentration of protons is much greater than in the mitochondrial matrix. In this condition, ATP synthase rotates in a counterclockwise (ccw) manner. In a ...
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115 views

Can sex cells divide?

I understand that most somatic cells divide and go through Mitosis, but I am confused to as what goes through Meiosis. Can sperm cells divide and multiply or is it only cells in the testes (which are ...
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0answers
20 views

How do cells reproduce more slowly in the later stages of the human pregnancy?

I’m a 5th grader learning human reproduction and both my father and teacher told me that in the later stages of pregnancy the cells reproduce more slowly. What are the regulating mechanisms? Is it ...
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127 views

Effects of Free Electrons In a Cell?

I am very new to biology, currently just a student. Recently I learned of the electron transport chain used in cellular respiration. This got me thinking. At the end of the chain, the electrons are ...
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1answer
243 views

How long does it take for cancer to be detectable if it grows from a single cell? [closed]

Assuming cancer has its origins at a single malfunctioning cell, how long would it take for that cell to grow from the point at which it is malfunctioning enough so that it can be detected by the ...
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103 views

Coding potential map, what are the number of possible different starts

Looking at coding potential map, what are the number of possible different starts for the gene identified by the computer algorithm?
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1answer
460 views

Why don't chromosomes double in S-phase?

DNA doubles in S-phase, but chromosomes don't double in S-phase, in spite of the fact that chromosomes are formed by the condensation of DNA. Why is this so?
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145 views

How does phosphorylation take place in prokaryotic cells?

Membranes that are impermeable to hydrogen ions are required for electron phosphorylation. In eukaryotes this happens at mitochondrial membranes. Prokaryotes also make ATP by electron transfer ...
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1answer
73 views

Excess proteins in cells

Damaged proteins are broken down in cells by ubiquitin-proteasome pathway. Do cells experience excess of proteins? If yes, how excess proteins are taken care of?
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281 views

What do you mean by non cellular matrix [closed]

What do you mean by the non cellular matrix in which connective tissues are embedded?
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135 views

Is a microspore diploid?

In gymnosperms the plant body is predominantly sporophytic. It produces microspores or megaspores my textbook says that these undergo reduction division in order to form male gametophytes pollen ...
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Muscle receptors: Juxtaglomerular renin secretion and atrial ANP secretion

I'm searching for the mechanism that allows juxtaglomerular cells to secrete renin or cardiac muscles to secrete ANP due to stretching or lack of stretching. The baroreceptors in the juxtaglomerular ...
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371 views

What is the difference between apomixis, agamospermy and apospory?

Some websites say agamospermy is just a synonym of apomixis but the definition of both terms is different. Others give almost same definition of apospory and agamospermy while also saying that ...
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105 views

How many strains of influenza can occupy a person at one time? [closed]

Could a person's immune system be built eventually to be able to inject all the known strains with in to stay immune?
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2answers
47 views

What directs macromolecules to their cellular locations

For example I know that after transcription a mature mRNA is sent outside of the nucleus through the nuclear pore and then it goes to ribosome. But as for the free floating ribosomes that are out ...
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0answers
18 views

Repeat-Induced Point Mutation in RNA?

this is my first post so please bare with me. For the life of me I cannot find out the specifics on the RIPing mechanism (pertaining to N. crassa) in terms of RNA. I know that this mechanism prefers ...
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1answer
298 views

Do dead cells always contain no nucleus?

If I examine a dead cell, can I be sure that it has not a nucleus? And what about the other organelles?
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1answer
49 views

Catching a cold outside in winter? [duplicate]

We have all heard the typical “Put a jacket on youre going to catch a cold.” Usually stated by an older person typically a grandmother. Excuse the stereotype. Is there any evidence that colder weather ...
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0answers
130 views

Import of H+ ions into the thylakoid space during photosynthesis in plants [closed]

Why are H+ ions pumped into the thylakoid space as the electrons pass through the cytochrome complex from PS2 to PS1 during photosynthesis?
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1answer
72 views

Why is a cellular structure necessary to satisfy the definition of alive? [duplicate]

I was looking at this image and reading through the Wikipedia page for viruses and it says that to satisfy the definition of "being alive" the organism must have a cellular structure, but it seems to ...
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Collagen Type V

Lodish - Molecular Biology of the Cell: "Two quantitatively minor fibrillar collagens, type V and type XI, co-assemble into fibers with type I collagen, thereby regulating the structures and ...
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2answers
324 views

Is DNA a single molecule? [duplicate]

It seems that biology books refer to DNA as 'a' molecule (implying that it is a single continuous uninterrupted strand) ... but in those same books chromosomes are depicted as separate objects ...
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2answers
111 views

How were we able to determine the age of the first cell?

I heard in episode 20 of Youtube channel CrashCourse's biology series that every living organism descended from a single microorganism 3.8 billion years old. I'm astonished by that figure. Even though ...
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1answer
182 views

Negative Oxygen Consumption Rate

Oxygen consumption rate (OCR) is defined as the rate at which cells consume oxygen. I reason that for cells not capable of photosynthesis, OCR is strictly non-negative. That was until I read this ...
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1answer
41 views

Are all/most/any membranes comprised of lipids from the smooth ER?

I'm attending an introductory high school course to cell biology. Based on my understanding, lipids – the building blocks of membranes – are formed in the smooth ER. Are all/most/any membranes ...
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1answer
54 views

Do strictly anaerobic organisms use metabolic reactions requiring oxygen?

When looking through genome annotations of strictly anaerobic organisms I see reactions featuring oxygen. I suspect these are likely an artifact of the annotation process. But I am wondering if it is ...
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0answers
12 views

Solubility of thromboxane A2 agonist U-46619 in H2O

First of all, I'm not sure I can dissolve U-46619 in water so that's also part of the question. If it is soluble in water, how much can I dissolve before saturation? If not, what's the right ...
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3answers
138 views

Biology Intuition and Origin of the “facts” [closed]

I am a graduate physics student but also taking biology classes. I am new to the field of bio. Most of what we do in class seem like memorizations and stating-facts. I am wondering: How can I develop ...
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How can myoglobin be responsible for the red color of meat if it is located in the cytoplasm?

How can myoglobin be responsible for the red color of meat if it is located in the cytoplasm, as the visible part of muscle cells is the membrane (at least as I believe)? Sources: https://en....
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48 views

Do leaves grow larger by adding cells at the centre or at the edge?

I'm writing a paper on wrinkling of plant leaves. For biological and physical background information, I would like to know whether leaves grow by adding cells at the edge, at the center or in a ...
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1answer
2k views

Unsure about definition of “n” and “C” values in mitosis

I am preparing for a Biology exam and I'm reviewing the "n" and "C" notation used in mitosis. My professor said that when the cell replicates its DNA in S phase of mitosis, we get twice the "amount" (...
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1answer
9k views

What organelles are in an onion cell?

I was wondering what organelles are in an onion cell, because, based on the labs we are doing in my biology class, I only saw a nucleus and cell wall. My friends and brother say there are all the ...
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1answer
82 views

Type of plant cell that builds a secondary wall in between two primary walls?

I read that there is this type of pattern in cell wall synthesys. What is the type of cell that does that and in what kind of scenario?
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1answer
511 views

Are centrioles really absent in human neurons?

A booklet (issued by my school) claims, Centrioles, formerly believed to be absent in neurons, have been described in neurons and may be associated with the production and maintenance of neuro(...
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1answer
148 views

Clatherin Mediated endocytosis is pinocytosis or phagocytosis?

This was a question in a test. Clatherin mediated endocytosis is which of the two: pinocytosis or phagocytosis? Precisely what is the difference between the two and CME?
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2answers
90 views

Why are sugars like mannose expressed on the outside of eukaryotic cell membranes?

Bacteria are able to adhere to sugars (e.g. mannose) on the exterior of eukaryotic cells, leading to infection and disease. Why have eukaryotes not evolved so as to dispense with sugars on their cell ...
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1answer
83 views

How to surpass cell death?

Is it possible to surpass/decay cell death. For example to disable the process muscles cells death, by tweaking the transduction pathways: If it's not possible in our age Medicine, what it would ...
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1answer
108 views

Cyanobacteria pools as carbon sinks

According to some scientists, at one point in time in this planet's history cyanobacteria almost drove life to extinction by reducing it to a snowball as they captured vast quantities of carbon and ...
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2answers
139 views

How do membrane proteins find their target locations?

The question might be asked for any kind of "bound" proteins, but I'd like to restrict it to membrane proteins. Assuming membrane proteins (or their main parts) don't (or aren't) build in situ but at ...
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0answers
108 views

Are there special pairs present in the RC of both photosystem I and photosystem II?

I am confused regarding the existence of special pair (primarily regarding PS2). Do both, P680 and P700 have special pair? I have checked various sources online and have come across conflicting ...
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0answers
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What are these lines that connect into cells called?

I just recently watched a very interesting video that showed cell division under a microscope. In the video, you can see cells that have either one, two or more lines connected to them. What are these ...
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2answers
82 views

Meaning of term ‘rapidly labeled RNA’

I encountered the term, “rapidly labeled RNA”, in the article: Rapidly labeled HeLa cell nuclear RNA. I. Identification by zone sedimentation of a heterogeneous fraction separate from ribosomal ...