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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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What's the difference between animal lysosomes and vacuoles in plants/fungi that carry out enzymatic hydrolysis?

I am aware that some plants and fungi have vacuoles that carry out hydrolysis using enzymes and in general act very similar to animal lysosomes. So what is the difference between the two? Why aren't ...
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How much shorter is the short arm of a chromosome? And why?

I keep reading that the p arm is shorter than the q arm. But I cannot find an explanation of how much shorter nor an explanation for the difference.
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Is there a good resource for detailed molecular/atomic information about plant cells?

Can anyone point me to a good source for understanding the molecular/atomic details for the structure of a plant cell? I’m thinking of the classic kind of plant cell diagram: https://goo.gl/images/...
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30 views

Why sometimes we can see the core inside the vacuole?

Why is it that we can sometimes see the core inside the vacuole? I tried to understand it and i have some answers but I’m not sure and i want you to answer me Thanks
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What physiological processes give rise to a linear cell survival curve?

If we plot the number of surviving cells in a structure over time (assuming no replacement), the shape of that curve should imply something about the underlying process responsible for cell death. For ...
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What change would you expect in phospholipid orientation of the membrane if the enviornment were mostly heptane?

The external and internal environment of the cell is basically water, thus phospholipids organize themselves the way they do (bilayer). If the environment were to magically become mostly heptane, how ...
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How exactly do microfillaments change the cell membrane's shape?

I understand that they are concentrated under cell membrane and can contract, but the details aren't very clear. How do they attach to membrane, and in what direction do they pull? Do they draw two ...
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19 views

How cells determine how many enzymes are needed for digestion

How do pancreatic cells, epithelial cells of the stomach and intestinal epithelium cells determine the right amount of enzymes for digesting carbohydrates, proteins, fats? How does the pancreas ...
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10 views

Typical thickness of a human cheek epithelial cell

I am using a quantitative phase imaging microscopy to take phase images on a human cheek cell: All units are in micros. The shown height $h$ is obtained via converting the measured optical path ...
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25 views

Confusion on SAT Subject Test Question

About Question 20, Do cells form 3 poles?
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15 views

How cnidocytes work?

I have googled for the structure of cnidocyte but images of google is unclear or complex .so please draw a simple understandable structure of cnidocyte .I know that cnidocyte works by osmosis but I ...
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2answers
47 views

There are small parts between Genes in an Operon that does not encode for any amino acids. What is the purpose of these parts?

What is the purpose of these parts in the translation process ? Picture to demonstrate below :
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Can cells push?

Can a cell produce a compressive force - a force that might look like a push/hop. Since actin filaments are generally massively long relative to their radius, and since actin polymerization is an ...
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33 views

Is it possible to create a biological radio? [closed]

If someone had taken the genome for a basic single or multi-celled organism, and had the understanding of genetic code to write his own program, is it possible on a fundamental level to create the ...
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39 views

How do molecular biologists determine biochemical pathways?

I'm new to this community, so hopefully this is the right place to ask this question. I know my question is really general, but in all of my biology courses we are merely taught the chemical pathways ...
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Which part of the Centrosome actually forms and organizes the microtubules?

I read from my textbook that centrosomes have the function of organizing and originating Microtubules and that they are made up of a pair of perpendicularly placed centrioles. Then I came across the ...
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2answers
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DNA replication and Protein synthesis

Is DNA replication required for Protein Synthesis or can proteins be synthesized without DNA being replicated?
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Immortal DNA Hypothesis

Confused by the immortal DNA hypothesis. My instructor states that it arises from the notion that stem cells divide asymmetrically, and so I thought that the original DNA template strands were always ...
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39 views

Do chromosomes line up as pairs in mitosis or meiosis?

Here is a question from the book SAT II Success Biology E/M (where the SAT is the exam taken by the American high school students): Homologous chromosomes line up in pairs in (A) metaphase of ...
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18 views

What is the “central vesicle” in centrioles?

Stubblefield and Brinkley describe a central vesicle in centrioles. What is it, exactly? References Stubblefield, E., Brinkley, B.R. (1967). Architecture and function of the mammalian centriole.
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28 views

What is (roughly) the net charge of the DNA in an average human cell?

I was wondering about what general range for the net charge of DNA in human cells is in Coulombs. I imagine that kind of thing would be hard to measure but could be approximately calculated/estimated....
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93 views

Can mitochondria become cancerous?

Given that mitochondria have their own DNA and can replicate independently, can they ever become cancerous? For example, could a mutation in their DNA cause them to rapidly replicate, ultimately ...
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1answer
50 views

What's the decomposition rate of a mammal at -20 Celsius? [closed]

Is there any where to predict it without thawing? In terms of measuring it. What if the body was immersed in sugar prior to freezing?
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23 views

What makes Citrate or Citric Acid an acid? [migrated]

As far as I know, an acid is something that gives off a proton or hydrogen ion $H^{+}$. But when I look at Citric Acid, There are three $COO^{-}$, which I think is a carboxyl group, that lacks $H^{+...
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1answer
59 views

Can oral baking soda effect tumor cells in mice

Could anyone explain me please, how exactly (according to research article in Cell journal) adding the baking soda in drinking water can influence the acidity of tumor cells? What about homeostasis ...
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1answer
38 views

Tight Junctions in Cell Types

I took a quiz today on cell structure basics, which included cell junction types. I disagree with the "correct answer" according to the teacher. Here is the question: ...
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Long-term Vs Short-term hematopoietic stem cells

What is the conceptual difference between Long-term Hematopoietic stem cells (LT-HSCs) and Short-term (ST-HSCs)? Over the web I got into different definitions...does someone know the more accepted one?...
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14 views

Is lignin an indicator for cell tension and resilience?

Concerning the properties of biosynthesized wood, a class of organic polymers is named lignin; Most often found occurring in cell walls. I would like to know whether its presence or abundance ...
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29 views

How do the bacteria producing bacteriocins protect themselves from it?

Whenever there is Col plasmid in a bacteria it will produce bacteriocins which will kill other bacteria around it. Why will the bacteriocin not kill the bacteria which has produced it? How does the ...
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Why is voltage across a battery analogous to the equilibrium potential of an ion in a neuron?

Why is voltage across a battery analogous to the equilibrium potential of an ion? Trying to get an intuition as to why this might be the case
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1answer
462 views

Why are the cells the smallest unit of life? [closed]

Please Tell me why the cells are called the smallest unit of life. According to me I know that they are called so because they are smallest entity which is alive that is they show the properties of ...
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38 views

Is there a limit on how big a free living unicellular mono-nuclear organism can be?

When I looked for the largest protozoan I've found the name Syringammina fragilissima. According to wikipedia " .. Syringammina fragilissima, is among the largest known coenocytes, reaching up to 20 ...
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19 views

How hypoxia causes increase in intracellular $Ca^{2+}$?

Ischemia can cause depletion of ATP inside cell which can affect the efflux of $Ca^{2+}$ via energy dependent calcium pumps. This may (How?) cause increase in $Ca^{2+}$ ions intracellularly (Effect of ...
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1answer
42 views

How long does each of the stages in meiosis take?

For each stages of meiosis (i.e. Interphase, Prophase I, ...), I wanted to know the time between each stages either in percentages or minutes. However, while I could find the cell cycle for mitosis ...
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22 views

Why functional enzymes get denatured in coagulative necrosis?

In coagulative necrosis the architecture of dead tissues is preserved for at least some days. This is possibly due to denaturation of functional enzymes which causes cell lysis and therefore ...
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Low energy in phosphate bonds in ADP molecule

I know that a phosphate bond breaks in an ATP molecule to release a lot of energy which results in an ADP molecule. Why does the phosphate bond in ADP molecule not break to release an equal amount of ...
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What Does Transcription Factor E25 Activate When a Cell is Transitioning from G1 to S

Cyclin D/ CDK4 phosphorylates Rb allowing for the activation of transcription factor E25 during the G1 phase of the cell cycle. Supposedly, this transcription factor then activates as set of genes ...
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1answer
49 views

Reversal form of endosymbiotic theory?

Cell's organelles give us evidence that they might have been independent organisms on their own. Are there any single-cell microorganisms known to have gone so to say this way back as well, i.e. ...
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51 views

Why are there no multicellular prokaryotes [closed]

Why don't complex multicellular prokaryotes exits and also what made eukaryotes to become multicellular ?
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1answer
51 views

Can the face bones be “compressed” or forced together? What would happen? [closed]

Say someone doesn't like that their maxilla bone is too long because the height of the maxilla affects the placement, position and angle of the mandible relatively. If one were to apply mechanical ...
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2answers
41 views

What is the chance a given gene will end up in a given gamete?

Let us say a somatic cell had a desired gene. This somatic cell was replicated during interphase so that it had two of the desired gene. It then underwent meiosis. My question then is, what is the ...
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22 views

Can I do a test for Hayflick limit in my body?

Are there any tests available for the public which can tell me where am I on a Hayflick limit? If Hayflick limit is 50 for example, the results I would like to have is this skin cells: 20 out of 50 ...
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1answer
35 views

Is every neurotransmitter receptor an ion channel?

This is a rudimentary question--perhaps the answer is well known to biologists, but is every neurotransmitter receptor also an ion channel? For example, NMDAR is a glutamate receptor and cation ...
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Can a viable embryo develop from the fusion of two egg cells?

For a zygote to form, two haploid gametes undergo meiosis and fuse during fertilisation. Since two egg cells (or even two sperm cells) are both haploid, is it theoretically possible for them to make ...
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1answer
34 views

Sample suggestions for phase contrast microscopy

I am a non-bio student working on an academic paper recently and would like to have some sample preparation for phase contrast microscope. For it to work, I imagine the sample to be: Transparent; ...
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1answer
61 views

Is there a specific suffix for “with in a cell”? i.e. in a similar manner to how -aemia refers to within the blood

Words like hyperglycemia, hyponatremia, refer to the relative level of that component in the blood, not in the cell, is there a specific suffix for within the cell? I would like one word as an ...
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1answer
55 views

Which vaccines are damaged by freezing? [closed]

I have noticed that many of the freeze-sensitive vaccines are antigen only vaccines, for example Hib, pneumococcus, and tetanus vaccines. Why are these vaccines damaged by freezing? Are inactivated or ...
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1answer
24 views

How does LDL leave the circulatory system and enter the interstitial fluid to deliver cholesterol to cells?

I have read that small molecules like oxygen and carbon dioxide diffuse through the capillaries, but larger structures can't fit through. This answer indicates that some proteins go through via ...
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2answers
62 views

Why a cell contains all DNA when it only needs a few genes?

Is that what they called junk? Why does a simple cell have the DNA code for everything else when it just needs a few codes to function? Wouldn't that be a wasteful?
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What waste products do cells secrete in culture, and at what rate?

I am designing microfluidic chips for mammalian cell culture. One aspect I am interested in modeling is the rate at which I must renew media to ensure that: Cells receive enough nutrients Cytotoxic ...