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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Why do fingers/finger tips swell during winters?

Why do fingers/finger tips swell during winters (of temperature 5-15 degree celsius)? During winters mine and many others's fingers swell. is it due to blood circulation or what?
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Why do flagella form a bundle only when they rotate counterclockwise during chemotaxis?

During Chemotaxis in bacteria with flagella, the flagellar rotation dictates how the cell moves. If the flagella rotate counterclockwise, then they form a bundle at one end of the cell (---O) and ...
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Are there human cells, apart from red blood cells and platelets, without a nucleus?

I know that blood platelets and erythrocytes do not have a nucleus. Are there more cells in the human body without a nucleus, such as pancreas, cartilage, or lung cells?
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Are stem cell lines also kept worldwide like HeLa cells?

There are HeLa cells, which were taken from sick cancer patient and now is growing worldwide in different laboratories for experiments. HeLa cells can be kept because they are immortal and so they are ...
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45 views

Do non-enzyme catalysed reaction pathways exist?

Can their be a kind of chemical reaction pathway in a cell, that is catalyzed or regulated but NOT necessarily by enzymes? I could not find anything on Google. I have almost no background in biology, ...
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37 views

One targeted mutation that cause cell death?

Is there possibility to make one targeted DNA mutation in the cell, that will cause its death? My question: What gene (one) we need to target to cause cell death? (Human cells, searching for ...
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27 views

What is 'refractile' cell morphology?

I can't find a definition for 'refractile' (not 'refractory', and not explicitly in an optical context). As in: A tumour cell phenotype features increased proliferation, anchorage- and growth ...
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Question about cytoskeleton coordination

I am trying to study for a biology and I am having some confusion over the following topic. Can anyone help explain/ shed some light on the concepts of Rho family GTPases. Is it true that we have Rho ...
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37 views

Why use creatine phosphate?

We use creatine phosphate as an energy storage to resupply ADP with a phosphate group as our muscle cells only contain about 2-5 mM ATP. But why doesn't the muscle cells just keep 20-30 mM ATP instead ...
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26 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
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What kind of experiments could you do to see which end of a microtubule is most dynamic?

I'm stuck between two ideas. Not sure which one of them would be best. Do a FRAP on the middle of a MT. If it grows from the + end, that section will remain dark. If it grows from the - end, ...
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How does the placement of it's motor domain affect the directionality of a motor protein?

I'm going over some of my notes, and I have written down that motor proteins with + cytoskeletal directionality have a reversed schematic representation relative to - directed motor proteins. Then I ...
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92 views

Why does a “cascade” of events happen during signal transduction?

I've been watching some videos on signal transduction and it says that because there are enzymes being activated by the signal, then there is a "cascade" which happens afterwards...I don't understand ...
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73 views

Difficulties understanding a pathway [closed]

I am not a biologist and I would love to understand what is going on with this pathway. I went to the description but it's still complicated, and I couldn't follow. Can someone please help me with it? ...
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1answer
51 views

How is excretion of metabolic wastes from a cell related to its size?

As with anything that is taking place within a cell, the metabolic waste too must be proportional to the size of the cell. In particular the surface area to volume ratio. But how is the waste ...
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1answer
34 views

What are iPSC cells, and what are their applications? [closed]

I also searched it on internet, and just basically know it's related to the Stem Cells, but there are too many resources, can anyone help me find out more about them, like their applications? They ...
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60 views

Are nucleic acids found in cell membranes?

I've found various results online and I was recently marked in on an important test as wrong when I made the assumption they were not found in the cell membrane. Does anyone know what the correct ...
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1answer
48 views

Membrane potential in gram negative bacteria

Does the membrane potential usually quoted for gram negative bacteria (e.g. E. coli) refer to the potential across both membranes? - If yes, then does the potential fall more over the inner or outer ...
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3answers
63 views

Can bioluminescence be used for cancer or tumor detection? [closed]

What diagnostic applications, if any, are there in using bioluminescence to detect cancer or tumors (in vivo)?
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54 views

What percentage of a cell's volume is occupied by protein?

I was looking at one of David Goodsell's illustrations of a cell: And it seems to suggest a very crowded picture of the intracellular environment. Just how crowded are cytoplasms? What percentage ...
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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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24 views

Why can't some organisms match miRNA perfectly to the target mRNA like in plants? [closed]

What causes other organisms to be impaired in making perfect matches like plants do and is there a way to increase matching?
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2answers
62 views

Why do mitochondria fuse together?

Contrary to all of the textbook images of mitochondria that I have seen over the years, I had just learned that the mitochondria within a cell form a dynamic branching network along microtubule ...
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1answer
74 views

What happens to the precursor protein's signal sequence after it is cleaved?

Where does this signal sequence "go" after it has been cleaved by signal peptidase and what is its next function?
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Why do restriction-modification systems work?

Some RM systems (restriction-modification systems) are plasmid-borne and are transferred through bacterial conjugation. As you all know, there are two genes in an RM system, the gene that codes for ...
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What is NK-cell compartments?

with respect to the paper: Adaptive reconfiguration of the human NK-cell compartment in response to cytomegalovirus: A different perspective of the host-pathogen interaction What is meant by ...
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2answers
83 views

Name two reasons why it is impossible to determine a gene's nucleotide sequence from the amino acid sequence of the polypeptide

I can only think of one reason, which is because different codons can specify the same amino acids. However I am having trouble thinking of another reason.
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281 views

What is our skin made up of?

Again, it is a basic question. What is our skin made up of? is it made up of many cells arranged in a systematic way or is it just like any layer say of a book?? what is the difference? where is the ...
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2answers
57 views

The Ancient Kingdom of Monera

Why exactly were bacteria and archaea kingdoms separated from the now unused kingdom of Monera? Aren't they the same? They are both prokaryotes, so what is the difference?
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What is the basic structure of the nuclear lamina

What gives the nucleus its shape is a mesh of intermediate filaments called the nuclear lamina. It forms an interface between the chromosomes and the inside of the nuclear envelope. If these ...
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1answer
39 views

Detailed mechanism of the cause of diabetes mellitus type 1?

I have read in some texts that diabetes mellitus type 1 is caused by degeneration of beta cells due to our body's own immune reaction.Is it true? Can you explain further how are such types of immune ...
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1answer
25 views

How did multicellular life evolve? [duplicate]

I can imagine several specialized unicellular beings collaborating. But how does life get from that point to a unique pluricelular being that reproduces into another pluricelular being?
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2answers
185 views

Can cell exist without Ribosomes? [closed]

Last night I came across a question that goes as follows:- Cells cannot exist without a) cell wall b) cell membrane c) mitochondria d) ribosomes I am getting confused with option B and option D ...
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80 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 ...
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153 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 ...
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1answer
83 views

What is the present tense verb form of apoptosis?

For example, if I want to say something along the lines of "this signaling pathway causes a cell to go through the process of apoptosis", but I want to shorten the phrase "go through the process of ...
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1answer
50 views

Expression/Mechanism of ROR1 in healthy tissue

ROR1 is currently under investigation as a therapeutic target for cancer (1). A number of studies show different cancers may have their metastatic potential reduced, or become apoptotic through ...
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1answer
37 views

What is Trypsin? [closed]

I am currently helping a PhD student in his research lab. We have been using Trypsin for the past couple of weeks but I am unsure of its purpose. I was wondering how Trypsin functioned and what it was ...
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1answer
113 views

What allows Valonia ventricosa cells to get so big?

Valonia ventricosa are single celled algae that range between one and few centimeters. In rare cases they can reach sizes exceeding 5cm. Weirdly, a lot of the literature covering these organisms ...
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1answer
66 views

What are senescent cells doing in our bodies? [closed]

I'm reading a paper that mentioned the elimination of senescent cells delays aging. I'd like to receive more information about it. The Baker study published in Nature demonstrates that targeted ...
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65 views

What advantage does an enzyme serve over catalysis by the addition of heat energy?

I understand that an enzyme lowers the activation energy, allowing the reaction to run faster, however I am not sure, how it may be favorable during the addition of heat energy. Wouldn't that lower ...
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1answer
38 views

How can I isolate live Wolbachia endosymbionts from Drosophila [closed]

I am interested to culture Wolbachia bacteria in cell line.
6
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1answer
43 views

What is a positive epitope fragment

What is a positive epitope fragment? I found one paper on the subject: COBEpro: a novel system for predicting continuous B-cell epitopes by Michael J. Sweredoski and Pierre Baldi
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48 views

How long can a human neuron cell live outside the body in a controlled environment?

Have there any experiments been to keep neurons alive (stationary) without preserving methods such as freezing? If yes, for how long?
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1answer
113 views

Which of the two mitochondorial membranes relate to bacteria according to the endosymbiotic theory?

I seached for endosymbiotic theory in Wiki and I found this about endosymbiotic theory: Symbiogenesis, or endosymbiotic theory, is an evolutionary theory which explains the origin of eukaryotic ...
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1answer
90 views

Trying to differentiate between the three muscle tissues with small pictures

For an assignment I have to differentiate the three types of muscle tissues in these three pictures . I'm having difficulty seeing the striations and branches etc. because the pictures are so small. ...
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1answer
21 views

Why does a tumour's genome change depending on the environment?

According to the book "Primer of The Molecular Biology of Cancer" by Vincent, Theodore and Ateven, the tumour cell is changed depending on its environment. performed genome-wide analysis on three ...
4
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1answer
25 views

Can methylation of a promoter induce gene expression in some rare cases?

Can methylation of a promoter induce gene expression in some rare cases? I've read somewhere that methylation of an intron can induce gene expression (eg. Igf2). How is that even possible? Thank ...
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2answers
417 views

What are the differences between cancer and tumour?

What are the differences between cancer and tumour? I mean is it in the DNA or shape or something else... And how can a benign tumour turn into a malignant tumour? The body has a lot of tumours all ...
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1answer
195 views

Is this a grass cell?

I found this picture online claiming it was a grass cell. Clearly it is a cross section image but I was hoping you could tell me if this is actually grass, or something else if anything. Thanks!