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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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Do all bacterial cells have a double membrane?

I’m reading that gram positive and negative bacteria have an inner plasma membrane surrounding the cytoplasm, then a periplasmic space, then an outer membrane. How does this compare to my general ...
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What are these balls in meshopyll cells? [Plant biology]

Anybody knows what are these small balls? The picture was collected with a confocal fluorescence microscope. These balls have a green epifluorescence and they are in mesophyll cells of rice leaves.
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Isolation of Intact Granules from Mast Cells

How to isolate intact granules from mast cells without using sucrose and percoll?
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How did genome replication first synchronise with cell division?

It is obvious that cell division in living organisms is now synchronised almost perfectly with DNA replication and, furthermore, the line of division has to intersect exactly the space between the two ...
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45 views

What is meant by “a codon codes for an amino acid”? [closed]

What is meant by "a codon codes for an amino acid"? Does it mean in order to build that amino acid you must combine those three nucleotides? Does it mean anything more than provides the instructions ...
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Why did protocell division coincide exactly with RNA replication?

I know that, in the RNA world, it has been suggested that the first protocell formed by a hollow liposome structure encapsulating an RNA molecule. However, from then on it becomes confusing: I've ...
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61 views

What is the meaning of “Rb is in the active state”?

I am reading about cyclins, cdks and Rb (Retinoblastoma) and some of the terminology is not clear to me. I understand that when CDK phosphorylates Rb, it disconnects from E2F, and E2F can act as a ...
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34 views

how can I get stronger staining for my lymph node sections

I am using the same protocol and same antibodies that the literature says but still I cannot get good staining for my lymph node sections, I tried to change the fixation method and I am using now ...
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30 views

Does cellular/organism death happen to enable evolution? [duplicate]

On the topic of whether we could conceivably understand death and extend human lifespans significantly - I'm wondering if any smart folks can point me to where my thinking regarding death may be wonky....
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Hepatocytes polyploidy

Why are some hepatocytes polyploid?
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Seeing essential vacuole-oils with microscope

Background As an experiment of chemistry we will distille organic volatile compounds with water vapor distillation. The vegetal (clove) is on the image below. Question As this compounds are stored ...
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60 views

Difference between morphogens and evocators in development?

I am specifically interested in this within the context of 1950's developmental biology (I presume the meaning and scope of usage of the terms has changed since then), as I am reading Alan Turing's ...
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Distinction between primary and secondary tumor

How can a primary tumor be distinguished from a secondary tumor? I tried finding it on the internet but it only said that they are found by means of immunohistology but I couldn't understand how....
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What's the difference between autolysis and apoptosis?

https://en.wikipedia.org/wiki/Autolysis_(biology) https://en.wikipedia.org/wiki/Apoptosis Both terms describe a very similar thing: cell self-desctruction. I've seen both terms applied to the ...
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29 views

Why inhbition of RTK will not help in a case of mutant EGF?

I was given the following as an example for a quiz question but i don't understand the answer. Any help will be most welcome: Question: Iressa is a Tyrosine Kinase Inhibitor. As a young oncologe, ...
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36 views

How does secondary cell wall in a plant cell develop?

"Secondary cell wall gradually develops through the compilation of different chemical substances secreted from Protoplasm on the middle lamella" --------- Is this correct? Actually this sentence is ...
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1answer
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Why don't cells double gene expression after S-Phase?

In the cell cycle (G1-S-G2-M), all of the DNA is replicated during the S or Synthesis stage. The cell may then spend some considerable time in the G2 phase before splitting in the M phase. Since there ...
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1answer
38 views

Harvest honey without damaging brood cells [closed]

I want to make a homemade beehive, I want to know how to differentiate honey cells and brood cells, therefore, I'd like to know how can I organize the beehive so bees will create honey and brood cells ...
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26 views

How to perform TUNEL Assay for yeast?

Currently, I am working on yeast strain CEN PK and I want to carry out TUNEL Assay to detect the amount of damage upon treatment with some damaging agent. We have a kit in the name of TUNEL Assay Kit -...
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How are the two mating types, a and α, for S. cerevisiae pronounced?

In reading about S. cerevisiae there are two mating types, one being the Latin letter a and the other being the Greek letter α. ...
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Antibody staining

I am staining tissue sections and I did a mistake, I was supposed to have mixed 3 primary antibodies but I stained only with one of them. After the 1h incubation I washed 10 min with PBS and then I ...
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1answer
138 views

Comparison between transmission Electron Microscope (TEM) to Scanning Electron Microscope (SEM)

Can someone state the advantages of transmission Electron Microscope (TEM) over Scanning Electron Microscope (SEM) and vice versa? Thanks!
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Location of ABO and Rh antigens

I read somewhere that in addition to red blood cells (RBCs), ABO antigens can be found in the other body tissues of the human. But Rh antigens located just on RBCs, in the other words, Rh polypeptides ...
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Can Programmable Cell Death (PCD) be engineered in a bacterium like E. coli?

I am reading a paper which says : Messages not received after a certain time can be considered lost, as bacteria carrying them will suicide. I even read some paper which says about PCD like this, but ...
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Determining pH damage to cells by eye

For an upcoming research project, I intend to apply different solutions to cultures of cells. How would I determine if the cells are incurring damage from the solutions due to the pH of the solutions ...
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1answer
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What is the difference between Integrin to Cadherin?

My question is probably very basic but i couldnt get it in lecture and not from looking in the net. What is the difference between Integrin to Cadherin. By difference I am looking for say: ...
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Can metabolically inactive cells still replicate? pertaining to mitochondria specifically

If some drug acts on mitochondrial enzymes (probably dehydrogenases) and inhibits their activity; could cell still replicate or undergo mitosis via some other means? Is Cell proliferation possible ...
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Preparation of DNA ladder

how to prepare working stocks of 100 bp and 1 kb DNA ladder supplied by promega? the pack that we purchased contains a 6X loading dye. thanks!
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Significance of Nissl bodies

What is the significance of Nissl bodies? How are Nissl bodies different from any other RER seen in any other cell of the body?
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What is(are) the mechanism(s) that stop cells from fusing in vivo?

I just learned about the phenomenon of 'cell fusion' in which two diploid somatic cells can combine into some aneuploid cell in vitro and proceed to proliferate in culture. Apparently this can even ...
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1answer
267 views

Is “Virus” a part of Acaryote?

I am just a beginner of BIOLOGY as a Grade 7 student! But the information which I got from my textbook and Internet has got me confused as MY TEXTBOOK SAID:- Viruses are part of "Akaryote" And '...
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25 views

Does vesicles fragmantation (fusion) during endocytosis require energy?

In the process of endocytosis, does the stage of fragmanting of the vesicle membrane to the cell membrane requires energy? I know that the disconection of the Vsnare and t-snare from the membrane ...
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1answer
52 views

How is each region of the DNA replicated only once?

In "Molecular Biology of THE CELL" 3rd Edition, 1994, by Alberts, Et al. (Yes I know there is a newer edition) the question is posed on page 362 How is each region of the DNA replicated only once? ...
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1answer
78 views

Why can a zygote develop into all different types of cell, whereas a differentiated cell cannot? [closed]

A cell formed by the fertilization between two gametes has all the DNA and can lead the development of a human person (or other animals in other species). But other cells in a human person has also ...
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1answer
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Why can only small molecules pass through the phospholipid bilayer of the cell membrane?

TO put simply: I am just wondering what mechanism or substance only enables small molecules to pass through the cell membrane. Is it cholesterol? My textbooks are not very clear.
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Glycoprotein binding with water to stabilise cell surface membrane

I am reading a book about the fluid mosaic model of the plasma membrane and it reads the following: Glycoproteins present on the outside of the plasma membrane can bind with water via hydrogen ...
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1answer
46 views

How can you design a drug to modify apoptosis to treat a disease such as cancer? [closed]

How can you design a drug to modify apoptosis to treat a disease such as cancer? Im in highschool so can someone please explain in simple terms. Thankyou.
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Hi, im trying make a work about Hayflick limit, and I have a question about the DNA replication. [duplicate]

What I do not understand is why in almost the whole literature it is written that the telomere shortening will only be on the lagging chain, although the leading chain at the beginning with the end ...
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2answers
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What repairs faster when injured: white matter or grey matter?

This was the exact wording of a test question given by my biology teacher and she said that white matter would repair faster, because there is a myelin sheath to protect the cells. Do you agree with ...
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93 views

Is this sentence about RER correct on Wikipedia?

While studying about Endoplasmic Reticulum on Wikipedia, I came across this sentence A ribosome only binds to the RER once a specific protein-nucleic acid complex forms in the cytosol. This special ...
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1answer
120 views

We know archea and eukarya are more closely related but endosymbiotic theory says eukarya have evolved from prokaryotes, justify the statements?

I am confused if eukaryotes have evolved from prokaryotes then how are they more closely related to archea?
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How were genes located before the development of bioinformatics?

I would like to know the detailed procedure of how scientists in earlier time were able to locate genes like how we were able to locate Huntington gene in 1983?
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1answer
103 views

Do all transmembrane proteins contain channels or tunnels?

In my book, there is written something like this. The integral proteins pass into the lipid bilayer to different depths and establish hydrophobic bonds with lipid molecules. Some of the integral ...
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Transport in cell

Don’t the substances transported by the carrier protein against the concentration gradient diffuse through channel protein to again maintain the same concentration across the cell membrane? I mean , ...
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How does the Lgr5 receptor contribute to maintaining stemness in the intestine?

I don't understand the connection between Lgr5 receptor and Wnt between Paneth cells and stem cells. And how does this link to the EphB-EprinB inhibition between transit amplifying cells and ...
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1answer
332 views

Why are prokaryotic promoter sequences written 5' to 3', when transcription proceeds from 3' to 5'?

It seems that the promoter regions are written from the 5' to 3' direction. My lecture notes, for example, give the -35 and -10 promoter regions sequences like so: Wikipedia seems to agree, on their ...
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1answer
50 views

Is their goli in plant cell?

We know that plant cells have dictyosomes instead of golgi but in my book it was written that plant cells have golgi apparatus?
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What is the purpose of Prostaglandin F2-alpha and the Prostaglandin F receptor in the melatonin cell signaling pathway?

I've been doing a lot of research recently on the melatonin cell signaling pathway for an extra credit project at school. I've included an image in this post, which is a diagram of the MT1 pathway. It ...
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1answer
175 views

Why don't cells of aquatic animals burst?

We know that if we keep plant cells in water, they don't burst because of a cell wall. But the cells of aquatic animals lack cell walls but they still survive. Why?
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190 views

Can cells show negative growth?

I know that growth is an irreversible increase in mass or overall size of a cell, organ or whole organism. I also found that growth occurs due to the net result of anabolism and catabolism. My teacher ...