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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Can our body cells have problems with let through too big clusters of watermolecules?

As a commercial product there is Kangen water introduced which is a water ionizer (also known as a alkaline ionizer). One of the reasons it should be healthy is that in contrary of tapwater, where the ...
2
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2answers
50 views

Diffusion coefficient of cells in blood?

What's the diffusion coefficient of white cells in blood? Is it well defined, or are cells too large and few as to be treated as particles in this context? P.S. I have tried to look this up, but what ...
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2answers
4k views

Are mature erythrocytes prokaryotic?

Mature mammalian erythrocytes have all the characteristics of a eukaryotic cell except that they don't have a nucleus, they don't have any cell organelles. Does this mean that erythrocytes are ...
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22 views

How does plant life obey the constraint that the change in Gibbs free energy in a reaction must be negative?

My understanding is that if a reaction takes place, either entropy of the system must rise, or energy must be released from the system as heat, or both. (Citation: paraphrasing from The Vital Question,...
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16 views

Choose the intruder [on hold]

A. Antibody B. Antibiotics C. Micro-tubule D. Cholesterol I couldn't find a link between any of these 3 components to actually find an intruder.
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23 views

When frozen rain moves up and down within an anvil cloud, _____ is formed [closed]

When frozen rain moves up and down within an anvil cloud, _____ is formed. A. hail B. snow C. thunder D. lightning
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25 views

Are the three different cones really distinguishable?

Our retina has three different cones (S,M and L) for the colors blue (S), green (M) and red (L). But the sensitivity of these cones do overlap each other. For example, the S is sensitive for 400-500nm ...
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1answer
56 views

Maintenance of Diploid chromosome number at mitosis

I'm just not understanding this: A regular human cell is diploid - because it has 46 chromosomes, in 23 pairs. So that means that when the cell undergoes mitosis, it will still have the full ...
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7 views

Obout oxygen presence in krebs cycle [duplicate]

Q- If oxygen is not utilized in the cycle then why it is present in the Krebs Cycle?
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14 views

What are extracellular matrix pathways?

I was reading a research paper dealing with acute myeloid leukemia and the term "extracellular matrix pathway" came up. What does it mean? I found literature on extracellular matrix, but I'm not sure ...
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29 views

Where does transamination and deamination take place?

The only information I know is about deamination,it occurs in the liver and kidney. But in which part of the cell does deamination occur? To which tissues is transsamination specific to and in which ...
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1answer
56 views

Does the formation of water inside the mitochondrial matrix help contribute to the proton gradient during the electron transport chain?

Does the synthesis of water in the final step of the electron transport chain significantly increase the electrochemical gradient across the matrix? I understand that pumping protons out of the matrix ...
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2answers
192 views

Do chromosomes uncoil in interphase II?

During interphase II, there is no S phase in which DNA replicates. However, in this stage, do the chromosomes remain wound? Or have they unwound into chromatin form, and recondense during prophase II?
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3answers
68 views

Doubt in a multiple choice question involving cell organelles

Find the odd one out and state the category of the rest. Chloroplast Mitochondria Nucleus Grana Now my answers are : 1st possibility : grana Category : presence of DNA in ...
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0answers
17 views

Do Tumor-Infiltrating T Cells Experience Any Prolonged Effects Due To Hypoxia After They Return To Normoxia?

Adoptive cell transfer (ACT) therapy using tumor-inflitrating lymphocytes (TIL) is at the cutting edge of immuno-oncology treatments involving metastatic melanoma and other indications (1). The idea ...
3
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2answers
72 views

Why does azithromycin not affect human mitochondria?

Drugs like tetracyclines, macrolides and aminoglycosides bind to prokaryotic ribosomes. It is interesting that our body too having mitochondria, which have prokaryotic ribosomes, there is little(?) ...
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0answers
440 views

Why do some white blood cells have lobed nuclei?

Several types of white blood cells (eg Neutrophils) have lobed nuclei. Is this for a functional reason? I have seen people refer to structural differences in the lobes as indicative of problems, but ...
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1answer
27 views

What is the difference of function between palisade and spongy layers of leaf? [closed]

I was just wondering what is the difference between palisade and spongy layers of leaf?
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1answer
46 views

Why must DNA be packed into chromosomes during mitotic phase?

Why does DNA have to be packed into chromosomes? Why can't DNA just divide itself evenly?
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4answers
7k 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?
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0answers
30 views

How does DNA organise a cell's physical position within a body?

How do cells "know" where they are supposed to be in relation to other cells, in forming the physical shape of the body? If you have ever tried to organise or choreograph the physical positions of a ...
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1answer
375 views

Why should phospholipid non-polar tails be “protected” in the membrane bilayer?

lipids are arranged within the membrane with polar head towards the outer side and non polar tails towards inner side, this ensures that the non polar tail is protected from aqueous environment. My ...
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1answer
319 views

Is reproduction intrinsically part of life? [closed]

If all of the characteristics of life are required for something to be defined as living, how can we account people or other life that can not reproduce?
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11 views

Does alcohol affect water potential across a tonoplast? If so, would it cause it to explode or implode?

This was a question I saw in a biology exam I recently sat. I know it affects the r-groups of the transport proteins, causing them to change shape and become leaky, but does it also affect water ...
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2answers
160 views

Blebbistatin effect on vesicles

Blebbistatin is a drug that specifically inhibits the assembly of myosin in the cytoskeleton. What effect would you expect blebbistatin to have on intracellular vesicles? ...
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1answer
85 views

What is the mass of an E.coli cell?

I'm trying to get into Biology, reading introductory texts. A discussion on E.Coli estimates the mass of the cell from $$density =1g/mL=1g/cm^3$$ and $$volume=1µm^3$$ From this I get $$ mass=density × ...
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1answer
29 views

Does common X-like picture represent one doubled chromosome or two homologous chromosomes?

What is on common X-like picture of chromosome? Here is the image from Wikipedia: Are (for example) lower petals homologous to each other? If yes, then why (1) ...
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2answers
31 views

How does the peptidoglycan layer of a bacterial cell wall help prevent osmotic lysis? [duplicate]

I recently read that penicillin works by damaging the peptidoglycan layers of a bacterial cell wall causing osmotic lysis, which is when the bacteria cell bursts due to osmotic pressure. I just ...
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1answer
54 views

How do cells age and die if they are dividing into new cells?

If cells in our body keep on dividing into new cells how do they ever grow old? The only cells to grow old would be defunct cells or those who won't divide into new cells like nerve cells. What am I ...
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1answer
22 views

Using exogenous genes to reduce the set of essential amino acids?

Various organisms have sets of essential amino acids that they cannot synthesize themselves, but rather that they must obtain from food. Humans have 9 of these amino acids. However, obviously certain ...
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1answer
29 views

How do normal cell division chance into a tumor forming cell division? [closed]

Or its better to say what happens at molecular level that tumors are formed? I tried normal google search and google books but couldn't find any appropriate explanation. I am trying to understand why ...
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1answer
50 views

Photosynthesis and its subtopics [closed]

Which of the following statements about photosynthesis is true? a. Photosynthesis is an energy consuming process b. The light-dependent reactions produce the energy-rich compounds that are used up ...
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2answers
84 views

Is cell wall and cytoplasm an organelle?

So cell wall is an organelle? Whereas, it is not a membrane-closed organelle? Cytoplasm is an organelle? Whereas, it is not a membrane-closed organelle?
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1answer
92 views

Which are the last cells of the human body to die?

When somebody dies, which are the last surviving cells of his/her body? Those of hair, nails, or some other obscure but resilient cells? Shedding light on why and how they are so vital might boost ...
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1answer
28 views

Can a protein kinase phosphorylate both a threonine and tyrosine residue?

I know that some kinases can phosporylate both serine and threonine residues because of their structural similarities, but can such a kinase phosphorylate a tyrosine residue as well? If not, then why?...
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136 views

Have people in Africa already started evolving resistance to AIDS?

Are people living in areas where AIDS is rampant (for e.g. Africa), less likely to die from it than they once were because some of the people without genes/mutations that give them resistance already ...
2
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1answer
146 views

Attaching suspension cells to coverslip during mycoplasma contamination detection

I am planing to screen my cell cultures for mycoplasma contamination using the Hoechst 33258 DNA staining method. This method is suitable for adherent cultures. Is this method suitable for ...
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1answer
37 views

What kind of detergent should I use in cell culture laboratory for cleaning purposes?

I work on establish a cell culture laboratory in the company where I work. All equipment are new and I want to clean lab before I start to work with cells. Is there any special detergent for cleaning ...
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3answers
77 views

Cell cycle selection

Is it possible to select from colonies only cells which are at a certain stage in the cell cycle? E.g. if I was trying to analyse expression of a number of genes during different stages of the cell ...
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0answers
33 views

Barcode exchange between neighbouring cells

I am currently interested in equipping animal cells in a tissue with individual barcodes. These barcodes should get amplified in the cells (not to a cell degrading extent, of course), and also ...
3
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1answer
87 views

How does a protein reach its substrate within the cell?

After a protein has been synthesized and its the final tertiary/quartenary adopted, how does it reach its substrate within the cell and what causes it to interact with it? The transcription factors ...
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2answers
101 views

How do T-cells determine which cells they've already inspected?

From what I understand, T-cells are constantly traveling in the body, inspecting cells by looking for antigens. If they're self antigens, then the T-cell doesn't attack, whereas if they're non-self, ...
2
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1answer
67 views

Cell biology books

I'd like to know, what is the best list of books for non-biologist to understand, how signalling between organels is organized inside of eukaryotic cells. I really want to get how cell as separate ...
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2answers
838 views

What determines the fate of a cell with respect to differentiation?

I have been reading about Townes and Holtfreter's work in 1955, in which cells are dissociated from a blastocyst in an alkaline solution then mixed together and spontaneously reaggregates based on ...
34
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1answer
659 views

How does a cell sense its size?

Cells come in all sorts of sizes. How do they regulate their cell size to the point where similar cell types have a fairly mono-disperse size distribution? Reasked from http://www.quora.com/How-Does-...
2
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2answers
59 views

Cellular specific mass (in grams-dry-weight per pico liter)?

What is the cellular specific mass, in units of pgDW (pico-gram dry-weight) per pL (pico liter)? I suspect there is some variability between cell types, but this variability must be limited. Perhaps ...
4
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1answer
689 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 ...
4
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0answers
41 views

Does depolymerisation take place at the minus end of microtubule?

Wikipedia says that Dynamic instability refers to the coexistence of assembly and disassembly at the 'ends' of a microtubule. but Karp's Cell Biology, 7th edition says Dynamic instability ...
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1answer
33 views

What information do bipolar cells encode?

Short version: I don't see what information on-centre bipolar cells are actually capturing. Longer: Actually, the question could be extended to on-centre retinal cells as well, but I'll focus on ...
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1answer
64 views

Do bacteria grow on pure dry glucose?

I've accidentally touched pure glucose with my bare hands (fingers to be specific), which was intended for cell-culture. I'm worried that bacteria from my skin may start to grow on the glucose and ...