what is a cell? Are cells alive?
351610
yes it is alive and is the structural and functional unit of all living organisms and sometimes called the "building blocks of life"
694879
Cell culture is the process by which either prokaryotic or eukaryotic cells are grown under controlled conditions. In practice the term "cell culture" has come to refer to the culturing of cells derived from multicellular eukaryotes, especially animal cells. The historical development and methods of cell culture are closely interrelated to those of tissue culture and organ culture.\n\nAnimal cell culture became a routine laboratory technique in the 1950s,[1] but the concept of maintaining live cell lines separated from their original tissue source was discovered in the 19th century.[2]\n\nYou could get more information from the link below...
773822
A stem cell is a cell that hasn't been differentiated yet.  Meaning it is not yet a skin, brain, liver, heart, muscle, etc. cell.  They are mostly found in embryos because they obviously are still developing so there is a large amount of stem cells there.  Adults also have stem cells in our bone marrow because that is the site of blood cell synthesis (we are constantly making new blood cells).  \nStem cell research is important in finding out how to differentiate cells into what we want.  This would be nice for making new organs for transplants or even new skin for grafts.  I'm not sure if we can use the stem cells from adults or not, but as far as i know, in the US we are not allowed to use new stem cells for research, only the ones we already have. \nIn my opinion, since there are abortions already being performed (no matter what your opinion of it, it's being done) , instead of just wasting the embryo/fetus, we should at least put it to good use and use it for research to help others.
770961
Usually, textbooks define living things as anything that has a list of characteristics.  For example, they reproduce, they metabolize, they grow, they respond to their environment....\n\nTHere isn't a single thing that you can use to define "living".
99964
So lets learn cell structure. We are made of cells. Cells form tissues and tissues form organs and organs form systems and systems make the organism so we are made from cells (Microbes.). Or if you want to be very specific and start from everything before atoms then We are made up of Gluon cells inside atoms.The structure of a cell is a cytoplasm or liquid bag in the center. Cell tissue inside most of it and and a nucleus inside the cytoplasm. I hope sincerely that this answers your question.
528998
Yes.  The term'subcellular" would just mean it is comprised of peices smaller than a cell.\n\nThe term 'components' is simply a word for parts used for assembly.  \n\nMost of these parts are an integral part of the cell, meaning if you get rid of them you lose the cell.
1046768
this is a good question. what decides a cell living or nonliving is its metabolic activity. ..now you got me thinking... \n\nBut  to clear some confusion, they don't have nucleus, and that's why they can't reproduce by themselves.\n\nK...finally got some info from a very good friend, a hematologist. Here is what he says...\n\n"The question you asked is a very very deep one indeed.  In fact, we can have a very lively debate about it.  It is a very philosophical question, in that it's equivalent to asking, "Is virus a living organism?"  If we define life, as you say, by metabolic activities, then yes, red blood cell is a living cell.  Red blood cell uses the metabolic pathway of glycosis to generate energy.  It also has a variety of proteins and enzymes responsible for signal transduction.\n \nHowever, a red blood cell is a terminally differentiated cell and more than that it lacks the genetic material, the means and the mechanism to replicate.  Given that one of the primary goal of life is to have "offsprings" either through asexual replication or sexual duplication, red blood cell lacks that ability.  However, the progenitor of red blood cell (hematopoietic stem cells) does have the ability to replicate and differentiate."
312511
Mitosis is the process of cell division.  Our cells are constantly dying off.  Mitosis allows living organisms to continue to survive by replacing the dying cells.
798450
Mitochondria is said to be a living organelle because it has its own DNA and it can reproduce separately from the cell it self (just like chloroplast). Mitochondria is a living cell inside another living cell. It has its own DNA (which is different from the cell's DNA) and has 2 layers of membrane: the outer layer has the same composition as the cell membrane but the inner layer has a different composition, unique to the mitochondria. There are evidence that at one point, mitochondria (as well as chloroplast) was a free living cell. That is why both mitochondria and chloroplast are called living organelles.\n\nPlatelets are said to be non living because they are not real cells, they are cell particles. They don't have nucleus and don't metabolize anything. They are more like free chemicals in blood.
41904
I know of two kinds of cells that are not regenerated: Brain cells (neurons) and if you are female, eggs cells in the ovary.  The ones you are born with are still with you.
379154
Living cells such as eukaryotes have many organelles such as: a nucleus, Mitochondria, Rough and smooth endoplasmic reticulum (rough has ribosomes on the surface of it), Golgi body, Lysosomes, cytoplasm, ribosomes and so on\nOther types of cells include prokaryotes, these don't have a nucleus or any other membrane bound organelles... they also have other organelles of which I can't really be bothered listing at the moment. hehe
741756
In the most general sense, cellular life falls into one of 2 categories: prokaryotic cells and eukaryotic cells.  Prokaryotic cells are relatively small (1-10 um) and lack a nucleus and other major organelles as found in eukaryotic cells.  Prokaryotic cells are reminiscent of the earliest forms of life that appeared perhaps as much as 4.0 billion years ago.  The forms of life found today known as bacteria are the only living things made of prokaryotic cells.  Most bacteria are unicellular and very tiny, but some form small filaments or clusters of cells known as cyanophytes (aka blue-green algae). Eukaryotic cells are on average much larger and internally more complex than prokaryotic cells; we will investigate them is greater detail in this lab later.
1024553
erythrocytes not a cell at all, although it's derived from true cells. erythrocytes is the mature stage of development of a cell line in which the nucleus (present in earlier forms) has been lost.meanwhile  leukocytes, are true cells with nuclei and organelles.
1134366
Good question. Again what is life?
80083
Let's get semantical on you.\n\nWhat is biology?... the study of life, right?\n\nWhat is life? Or maybe better way of phrasing that question is: What is alive?\n\nAnything that meets all the following criteria:\n\nAble to obtain and use energy. \nAble to reproduce.\nAble to respond and adapt to their environment. \n\nSo when we study biology we study things that can do these different things and, more specifically, we study how living things do these different things. Basically, we're trying to understand how living things live.\n\nNow, back to you question concerning chemistry...\n\nHow do you suppose living things are able to do all the things on the list above? You guessed it: CHEMISTRY.\n\nAll the processes above are carried out by chemical reactions that take place between different molecules. Most of these reactions include tiny sub-microscopic machines called proteins. All these proteins are doing is carrying out very specific chemical reactions.\n\nSo when you boil it all down, biology is nothing more than the study of chemical processes that take place in living systems. In fact, it's these chemical processes that allow for life to begin with.
951836
All cells have cell membranes.  They both have DNA and a lot of other stuff common to all life forms.  The main difference is that animal cells don't have cell walls but plant cells do.  If I were God, I would make animal bone cells have cell walls.  That would be cool.
54241
Life is a multi-faceted concept. Life may refer to the ongoing process of which living things are a part, the period between the conception (or a point at which the entity can be considered to be an individualized being) and death of an organism, the condition of an entity that has been born (or reached the point in its existence at which it can be established to be alive) and has yet to die, and that which makes a living thing alive.